Acropora ID mini-class

[EricHugo]

For anyone interested in participating, I am going to host a mini-class where you can get hands on experience in identifying Acropora. You will learn firsthand what it takes to try and assign a species name to this diverse genus.

I will not be able to provide holotypes of your corals, but we should be able to at least progress pretty far without it.

Requirements: A representative branch from an Acropora colony you have kept. Ideally, you might want to pick one from a colony that is currently alive in your tank...and even better, one that was sold with a species name attached. I will need you to snip off a branch and put it in household bleach for a day until you have a nice bare skeleton. At that point, you might want to use some food coloring or iodine or something to lightly stain it to provide contrast, or you can leave it white.

You will also need some sort of magnification device. A magnifying glass, hand lens, loupe, dissecting scope, etc.

I will provide all the references you'll need.

Optional: your own references.

Time frame: We will begin in one week on Sunday, May 9, 2004. I suspect it will take about a week or two given the time between posts and normal internet-type board responses as well as your own abilities. There will be no class time...It will work just like a normal board thread with questions and responses. If you plan on participating, please have your selected Acropora branch ready by next week.

There are no other requirements. It can be a frag, whole colony, wild, captive grown, any size, whatever. You will understand soon enough why I don't care anything more about the coral you choose ;-)

[EricHugo]

In fact, if you want to, you can even use a live branch or colony. If you do, your class time will be relatively short, but you'll still get the point.

[piercho]

Eric,

I'm looking forward to it. I only keep a couple, but I have one I'd like to try and identify.

I'm a little lost how we will verify our attempts at identification. I have a digital camera of decent quality, but my skills at fine detailed macro shots, especially where it's difficult to get contrast (white skeleton), are lacking.

I'm not sure what the word "Holotype" means, even with a definition:
Holotype A single specimen designated as the name-bearing type of a species when it was established. In simple terms, the original specimen of a species. Usually abbreviated to 'type'.

[EricHugo]

Holotype = known specimen filed with museums, etc.

How will you verify? Well, you can send it to me. I know I won't be able to do it from a photo, but the photos will help us with providing examples ofsome specific features.

[davejnz]

Would a branch with an axial corallite be preffered for the branch to be studied? BTW,could you refer me to any sources where i could obtain a jewelers loupe or other magnifiying devices mentioned above?Looking forward to the class:cool:

[EricHugo]

art supply store should have them - camera store, hobby store, office supply store, even WalMart type stores maybe. Magnifying glass would be fine, I think....sort of ;-)

You will need a representative branch, and yes, axials are important. In other words, pick one that is typical of the colony, if from a colony.

[piercho]

could you refer me to any sources where i could obtain a jewelers loupe Try Harbor Freight tools. I picked up a good 10X-20X loupe from them for less than $10 a year ago. The directions were in Russian ;) .

[EricHugo]

Or American Science and Surplus

[Boomer]

Eric

:thumbsup:

I got some members from another board to take the ride also :D

[G-money]

Originally posted by EricHugo
...but you'll still get the point.

I'm sensing a very "grounding" lesson in the future...
I'd love to participate, but I think I already know the results (not to be presumptuous). :)

Eric, are you trying to halve the number of new threads in your forum? ;)

[JB NY]

Something tells me I'll have to practice my amazing abilities at jumping to conclusions ;)

[EricHugo]

Graham: Yes and No. I mean, if you have never really sat down and tried to do it, it's really quite an experience. It's like a jigsaw puzzle and fun and challenging and time consuming and enlightening. At least, that's how I find it to be.

[ddenham]

This sounds exciting, will it be conducted here at RC?

[Xmodius]

I think it will turn out to be an exercise resulting in a profound feeling of humility...(edit).....almost...futility.

[EricHugo]

Right here, on this thread. Starting tomorrow. I'll make my first post in the morning.

[EricHugo]

OK, you guys ready?

For the most part, I will be using the following reference:

Wallace, Carden C. 1999. Staghorn Corals: A revision of the genus Acropora, CSIRO publishing, Queensville, Australia. 421 pp.

I may also use:

Veron, J.E.N.. 2000. Corals of the World. Volume 1. AIMS, Townsville. pp. 176-443.

Veron, J.E.N., and C.C. Wallace. 1984. Scleractinia of Eastern Australia Vol 6, Part 5: Acroporidae. AIMS, Townsville. 485 pp.

Wallace, CC., and J Wolstenholme. 1998. Revision of the coral genus Acropora (Scleractinia: Astrocoeniina: Acroporidae) in Indonesia. Zool J Linnean Soc 123: 199-384.

Wallace, C, and M. Aw. 2000. Acropora staghorn corals: A "getting to know you" and identification Guide, Indian Ocean: Southeast Asia: Pacific Ocean. OceanNEnvironment Ltd, Australia. 128 pp.

and any other specific articles or texts on Acropora that I have, as necessary.

Background:

Species boundaries in corals were highlighted in JEN Veron's book, Corals in Space and Time. Hybridization, plasticity of growth form, and other factors makes the taxonomy of corals quite difficult in many cases. Acropora is the largest extant genus of hermatypic coral, comprised of 2 species in the Caribbean (and a third that is a hybrid - A. prolifera), and about 160-175 species in and around the greater Tropical Pacific and Indian Oceans. Acropora is also one of the most widespread.

There is considerable question as to the utility of using a Linnaean or Lamarckian categorization scheme in Acropora. That is, using morphology, growth form, and physical characteristics, along with variability, to assign species designations. Use of molecular techniques may show in the relatively near future that efforts to identify species using such classical systematics are too often wrong.

But, that is what we have at present, and that is the focus of this class.

[EricHugo]

The genus Acropora can be broken up into two subgroups - Acropora and Isopora. The latter lack perisistent axial corallites. Examples of these would be the elkhorn coral, A. palmata in the Caribbean, and the cat's paw coral, A. cuneata and A. palifera in the Indo-Pacific. One might make the argument that in A. palmata, there is a lack of persistent radial corallites, too! To me, they all look like axials. Acropora, incidentally, is characterized by the appearance of this special terminal polyp that is housed in a generally elongated corallite called the axial corallite.

Other thigns to know: any "species" of Acropora can vary in its skeletal morphology - by geographic location, environmental conditions, age, size, season, mechanical impacts, hybridization, etc. Therefore, the single colony you have chosen might or might not be indicative or typical of the species. This will become clear as we begin to look at your specimens.

So, before going much further, let's look at some basic terminology. I am going to list a lot of terms we have to be familiar with before going further.

Growth form of the colony:
Acropora develops as a consequence of the extension of axial corallites, budding of radial corallites, development of new axial corallites, and subsequent branching. Colony growth form varies from a little to a lot, and various growth forms may occur within a colony, within a species, and between species.

digitate - colonies have short, non-dividing, non-anastomosing branches (like fingers of a hand)
hispidose - colonies have numerous short side branchlets projecting outwards from the mainbranch
corymbose - colonies consist of horizontal anastomosing branches and short upright branchlets
tabulate or plate-like - colonies are flat, either with one cental stalk (leg) or attached to the substrate at one side
arborescent - tree-like branches
caespitose - colonies are bushy and branches interlock (anastomose) similarly in three dimensions
massive - colonies are solid and similar in all dimensions

other colony growth forms than could be used:
cushion-like - colonies consist of fine branches that grow into the shape of a cusion
encrusting - colonies encrust the substrate, sometimes with short branchlets projeting upwards
prostrate - colonies sprawl across the substrate
staghorn - colonies composed mainly of large antler-like upright branches
thickets - colonies consist of closely compacted upright branches
columnar - colonies form columns

Any given specimen may have more than one colony growth form, and may not fit specifically into any one of these categories. In the case of aquarium corals, generally the colonies are very small and the growth form that might develop in a larger and more mature colony is not yet apparent. With fragments, such as by propagation efforts, this is certainly the case.

So, step 1 in this class is to try and assign a growth form to your specimen, if it can be done. If it has multiple characters, list them all.

Skeletal features

axial corallite - the central corallite that determines the axis or growth on an Acropora. It often lies at the end of a branch, though axials and incipient axials may also form along the sides of branches, or on the surface of plates and encrustations. We will cover the axial corallite in depth in the next few days.

radial corallite - peripheral corallites that like arranged around the axials, often on the sides of branches or between axials on plates and encrustations. Sometimes, they look very much like axials. We will cover the radial corallites in depth in the next few days.

coenosteum - the skeletal matrix that lies between the corallites but not part of the axial or radial corallites. Often, the boundary is indistinct.

Step 2 in this class is to examine your colony or branch and determine where the axials are, where the radials are, and where the coenosteum is. Also, if using a branch, see if you can determine if there are axials corallites that are incipient. Axials along branches may be in the process of forming from radials.

Tomorrow, we will examine axial corallites. Then, we will examine radial corallites. Then coenosteal features. Then we will try and use those keys to break down our specimen into subgroups. Then we will use a systematics key to try and determine the species.

In the next post, I will put some photos of the Acropora I am using. I will basically be doing this along with all of you as this is a specimen which I have not identified to species yet, so I am as clueless as to what it might be as you guys are with yours.

Next, if you will, please let me know a bit about your choice, why you chose it, background of the coral, assumed identity, etc.

Also, please ask questions about anything as we go along. Please post photos if you want for confirmation or discussion of your particular specimen, too.

[EricHugo]

I would call my colony digitate and clump-like

I would also say this colony is probably about 3-4 years old.

Sorry about the pet hair, but this is what happens when you have dogs and cats around ;-)

[EricHugo]

These is the gross appearance of a branch from the colony with some features identified.

[JB NY]

Here is the coral I will be using.

Picture when first acquired.
http://www.cnidarianreef.com/images/animals/DSCN3117.jpg

After 9 months.
http://www.cnidarianreef.com/images/animals/DSCN4178.jpg

Hispidose growth form?

Picture of the branch I will be using that has been cut and left in bleach.

Overall branch.
http://www.cnidarianreef.com/images/misc/acro01_DSCN4318.JPG

Close up of main branch showing axial corallites and radial corallites as well as coenosteum. (I'll try to edit it tonight to point to the features.)

http://www.cnidarianreef.com/images/misc/acro01_DSCN4314.JPG

[piercho]

Here is one I would like to identify. A whole colony was brought to a PSAS meeting and this image is of my fragment of that colony. It has encrusted on rock at the very back of the tank and cannot be readily removed to be photographed so the image here is poor. The fragment was mounted on it's side and instead of starting new growth from it's upper side coralites(what I expected), the existing axial coralites are bending up as they grow.

As I recall, there was a lot of anastomosing branches on the colony, especially in the lower, older, regions. The tips of the entire colony rose up to an even level like a tabletop, but this may be because they had reached the top of the water in the tank, I don't know. A form description that best applies - I would say - is corymbose. The anastomosing branches were generally in the lower, horizontal region and they terminate in short, upright branchlets. My fragment picured here is just an upright branchlet (mounted on it's side).

An image of a skeletal tip follows this post. I apologize for attaching photos rather than links, but the RC upload to gallery function is currently broken.

*edit* The upload image fuction also appears to be broken to attach images directly to a post. Hmmm.... I'll have to post back with links. Sorry.

[EricHugo]

JB - looks like you have a fairly regular corallite distribution...should be a good choice (in contrast to mine!)

I would call yours caespitose to corymbose. Hispidose corals have fine branches off the main branch. A classic example would be something like A. echinata.

howard - looking forward to seeing your photo.

I will post the axial information in a while.

[piercho]

I uploaded the photos to Reef Frontiers. Hopefully you'all can access them.
A fragment of the colony (http://www.reeffrontiers.com/photos_members/showphoto.php?photo=689&password=&sort=1&cat=500&page=1)
A skeletized tip of the fragment (http://www.reeffrontiers.com/photos_members/showphoto.php?photo=690&password=&sort=1&size=medium&cat=500&page=1)

[JB NY]

Originally posted by EricHugo
JB - looks like you have a fairly regular corallite distribution...should be a good choice (in contrast to mine!)


I tried to pick something that the distinctions would be easier to notice.

Originally posted by EricHugo
I would call yours caespitose to corymbose. Hispidose corals have fine branches off the main branch. A classic example would be something like A. echinata.

Caespitose I was thinking about as well, but your description stated that the branches interlock. I don't see any of the branches fused together.

Actually I find this first part, IDing the type of growth form, for some reason very difficult for me.

Like why would you think that the coral I chose has a corymbose growth form. Wouldn't that kind of growth be similar to a classic table such as A. cytherea and A. hyacinthus?

[EricHugo]

JB it is hard, you're right. Its a subjective distinction in many cases, with overlap and variation made all the more difficult by the size of the colony. I would have said something very different from the first photo to the second, but as the colony developes, you see different characters. So, here is an image from Wallace 1999 that shows "idealized" growth forms. Would that it was this easy.

So, here is where familiarity with variation comes in. The definition is a "loose" one. Degrees of connectivity... well, look at the fusion of a common base brought by extreme anastomoses. But, tables like A. hyacinthus or A. cytheria are not corymbose. A. millepora is corymbose. But, when young, A. hyacinthus and A. cytheria might look corymbose, and others in the hyacinthus group even have corymbose characters as well-developed colonies.

Mine is actually a cross between caespitose, caespito-corymbose, and digitate. I have a feeling the digitate nature might become less if the colony were larger.

Your case exemplifies the change over relatively small time frames and sizes how deceptive ID of a small colony growth form can be. I have received numerous small colonies over the years that were sold as "tables" but really weren't.

Fortunately, this is just one step in the "narrowing down" process, and it is either helps, or it doesn't. For most available in stores, it is probably mostly unhelpful. For those that have grown quite a bit in tanks, maybe a bit more helpful, depending on how determinate the growth form for that species is across environmental gradients.

[EricHugo]

idealized growth forms

from Wallace, CC. 1999. Staghorn Corals of the World. CSIRO, Queensland, p. 52.

[EricHugo]

ok piercho - looks good.

So, other corals besides Acropora may have dimorphic polyps/corallites, but the characteristic is pronounced in Acropora. The axial corallites make up the axis of a branch, and the branch can sort of be considered as one long formation of the axial, with the solid part of the branch being the outer wall of the axial, with radial corallites budded off from below the growing axial. Sometimes, as in my photo, it can be difficult to tell which are really axials. Same is true for some hispidose colonies. Also, if growth slows or ceases, axial length by be reduced or even halted. Sometimes, the axial is very long and tubular...sometimes it is short and berry-like.

Contributions of branch thickness may be formed mainly from axials, radials, or both. But the wall of the axial corallites is formed from synapticular rings of varying numbers. If you look down directly into the axial corallite, you will see the septa. In some cases, they are very immersed deep in the corallite, while in others they are more apparent. There will be either six or twelve septa, arranged in one or two cycles. By cycles, I mean that there may be primary septa that are typically larger, thicker, and reach farther towards the center of the corallite. Secondary series are usually smaller, thinner, and do not extend as far towards the center. If you look at enough axials, you might find variation, with sometimes only 4 or 5 of the 6 secondary septa showing any development at all, so that it appears at first look as though there is not a full set. In other cases, primary and secondary are almost indistinguishable. In still others, there are only primary septa. You may also find that one set of primary septa are larger than the rest of them. These are called the directive septa.

I will take some photos later of different axials, including my specimen. These characters of your axial corallites should be written down. Also important is to take measurements. You will need to known the outer diameter of the axial corallite (outer wall to outer wall) and the inner diameter (from inner wall to inner wall - basically across the void into which the septa penetrate). You should use a millimeter scale or calipers to determine these measurements. You should also take a measurement of several axials and take the mean of them. There can be considerable variation in them across a colony. Alternately, you could measure the smallest fully developed axial and the largest, and this would be the range of diameters.

All of this information will be used in determining the species. You may see already how impossible it is to determine this information in a living coral where tissue covers these minute skeletal characteristics.

[JB NY]

Thanks for that image from Wallace, pictures are worth a thousand words. OK I see why A. millepora, not A. hyacinthus, would be considered corymbose. I've seen that kind of anastomoses on some of my larger A. millepora colonies.

Looking at that table, my coral most resembles a caespitose-corymbose growth form, letter H on the picture.

[EricHugo]

I would agree with you.

So, I did not take my camera to lab today, so I am trying to get a good photo by hand of my Acropora. I am also having to use a ruler, which you may have already discovered is not an easy thing to do.

So, Until tomorrow when I use the scope, my coral has two cycles of septa, no clear directive septa, and the secondary series is highly irregular and imperfect. In many axials, I only see one or two secondary septa, and they do not show any real consistency as to how far towards the center they go. The primary septa extend about 50-60% of the radius. The outer corallite diameter is about 1.8-2.0mm and the inner diameter appears to be about 0.5-0.75mm, although this is at best an estimate using a ruler. Here is what it looks like.

[piercho]

Yokes, dude, this is almost comical with a 20X loupe. You made me go chop off a new 3-axial piece to get this done.

# Septa: 12
# Cycles: 2
Notes on septa: the secondary septa are inconsistently apparent on some axial coralites. Rarely you can count all 12 septa, sometimes just >6 & <12. My primary septa don't extend nearly as far out into the center as the ones you show do, and are not always distinct from the secondaries.
Outer diameter: ~2.4 mm, until I can get a better scale. We are talking about all the way across the end of the tip here, right?
Inner diameter: 0.8 mm, estimated. Roughly 1/3 of the outer diameter, by eye.

Here was something I found interesting: the new bit I chose to chop off had a anastomized (use?) branch joining it. I expected to have to clip it twice to free it. When I made the first clip, it popped right off the branch growing into it - which had a blunt cylindrical end covered with flesh. The clipped fragment has a 1/4" deep socket where the anastomized branch grew into it which was bare (no apparent flesh) and slick. I suppose this would allow these pieces to flex on some axis - rather than break - if mechanically stressed.

[EricHugo]

here is my image with the diameters shown

good job, piercho.

[EricHugo]

You guys still with me or am I just typing for nothing? If so, let me know, because I have lots of other things I could be doing....

here are some more images of axials and the corals they came from.

[EricHugo]

juvenile table and its axial

[EricHugo]

axial

[EricHugo]

hispidose and its axial

[EricHugo]

arborescent hispidose and axial

[EricHugo]

axial 1

[EricHugo]

axial 2

[EricHugo]

caespito-corymbose? and axial

[EricHugo]

axial

[EricHugo]

unsure how to describe this one and axial

[JB NY]

I'm with you. I had a few late nights at work so I still don't have a way of measuring the diameters of the axial corallites. I hope to have that tomorrow.

[EricHugo]

and finally, the better shot of the Acropora axial I am working on.

[EricHugo]

Also, the jevile table closup seems to have been lost..so here it is.

[saltyseaman]

I'm with you!! Sounds like fun!! I would really like to see what these corals coming in from Bali labeled as "Echinata" truly are, or see what the ever so popular "California Acropora Tortuosa" truly is.

But ... I'm not quite sure if I wanna chop off and kill a potential trade yet. I think I wanna wait it out and see what some of the results are before I pull out the sodium hypochlorite.

How do you feel about extreme tardiness :D

[EricHugo]

thanks JB...I'll keep going, and trust others are reading since the photos are getting plenty of downloads and the thread quite a few views.

Notice how many of the new photos I posted do not have two cycles of primary septa. Also a pain was trying to get the corals under the scope without snapping branches..which I had to do for a couple. I'm destroying my coral collection for you guys!

Some of these also have good photos of radials, which I will post information about tomorrow. This will be a longer lesson as there are lots of types of radials.

[TDEVIL]

Originally posted by EricHugo
You guys still with me or am I just typing for nothing? If so, let me know, because I have lots of other things I could be doing....

here are some more images of axials and the corals they came from.

im with you, just trying to keep from crying as i take a wack at one of my corals :), will try Wed or Thursday, but i am here and learning

Jay

PS, thanks for doing this
@ Boomer, thanks for bringing this to my attention

[EricHugo]

caespitose close-up also got lost in my two browser working at a time uploads.

[EricHugo]

LOL...I hear ya...It's worth a branch, though.

[Gary Majchrzak]

Originally posted by EricHugo
You guys still with me or am I just typing for nothing? If so, let me know, because I have lots of other things I could be doing....

Eric, RC frowns on people just posting "tagging along".
Great class. Thanks for taking the time to do this.;)

[Julio]

This is a gret thread already with out the class even starting.

[EricHugo]

ok...so tomorrow we do radials..and then its time to get out the books and see what we have.

[firefish15]

Hi Eric,
I took your Coral Biology class over at Reefs.org last year. I didn't have my tank set up at that time so could not do any of the labs. This is a great opportunity for me. The coral I'm trying to identify is a " Fancy Acropora" I bought at as a lfs. It was mostly brown at the time but changed into a real beauty after a few weeks. It's a small colony about 3" x 4" so I'm not sure of the growth form. It looks similar to yours which you describe as digitate and clump-like.

[firefish15]

After 3 months.

[firefish15]

branch.

[firefish15]

Here's a view from the top showing axial and radial corallites.

[firefish15]

Closup of axial corralite. 6 primary and 6 secondary septa. I don't have the measurements yet. I'll try tomorrow.

[piercho]

Firefish those are excellent photographs of the coralites. Can I ask for a simple description of how you are getting them?

[MiddletonMark]

How did you get those pictures? They're great.

Time to get on board.

Purple-Tip Acro, acquired by frag, not given species name [though likely what's often called A. nana]. If I had a photo of the mother colony [many years old] it probably would help a lot. :rolleyes:

Anyway, photo of mother colony below:
http://webpages.charter.net/markfelten/acroID_purpletip_colony.jpg
http://webpages.charter.net/markfelten/acroID_purpletip_branch.jpg

With a small piece, it's hard to tell growth form ... but I'm thinking it looks like Wallace's `H' ... caespitose-corymbose.

Bleached frag is here [hopefully I don't need to frag again to get something more, but oh well, it'll just grow]:
http://webpages.charter.net/markfelten/acroID_purpletip_specimen.jpg
Need to pick up batteries for my calipers tonight, jump on the corallites with even more added information to swim through :)

[EricHugo]

Nice to see some more vicitims here.

So, as mentioned radial corallites typically form as buds from the axials and lie between and around them. By comparison with axials, radials are quite variable. Wallace notes that the terminology for them stems from Dana in 1846 and makes significant use of anatomical terms. The wall of the radials can be complete and tubular, or they can be incomplete, as though an incipient tube-like corallite was chopped off. In contrast to axials with their normally round openings, radials can have round, oval oblique or have an extra bit of skeleton lost at the outer and upper edge (dimidiate) or an extra bit added to the outer and upper edge. The latter case produces nose-like or nariform radial corallites. Additionally, the angle of the radials against the corallum or axial wall can vary from perpendicular (sticking straight out) to totally appressed. The shape of the corallites is also variable as will be seen in the idealized drawing below. As if this isn't enough, numerous variations may occur along a branch and within a colony. Gradations are common along a branch in many species. Radial corallites can also be dimorphic, with more that one type/size occurring on a colony. Finally, one must again consider the septa in each type of radial corallites, the same as with the axials.

It is probably helpful to look at many colonies to become more familiar with all the different sizes, shapes, types, and variations.

Whew. Now, let me post the image of radial corallites from Wallace, Carden C. (1999) Staghorn Corals of the World, CSIRO, Queensville. p. 55.

[EricHugo]

Here is a list of terms:

tubular : tube-like
cochleariform : ear-like
nariform : nostril- or nose-like
labellate : lip-like (can be flaring or straight)
conical : the distal end tapers from a wider base
rounded tubular : berry- or keg-like
appressed : angled so that the inner edge lies against the corallum
sub-immersed : barely sticking out from the corallum with little ridges of wall showing
immersed : totally flat against the corallum
oblique : the opening appears as though a tube was cut at an angle
round: the opening is rounded when viewed from the end
oval : the opening is oval when viewed from the end
dimidiate : the wall forming the opening is incompletely developed

So, in a nutshell:

1. determine how many basic types of radial corallites exist on your colony
2. assess the angle - see if any gaps exist completely around the corallite, or if part of the corallite touches and remains connected with the rest of the corallum (appressed)
3. determine the opening shape
4. detemine the corallite shape
5. Measure the average corallite length, outer and inner diameter
6. Assess the septa as with the axials (how many, in how many cycles, and the degree as an approximate percentage of the radius with which they project into the opening).

Fortunately, we really don't have to address the variations along the septa as is required for many other corals. That makes is so much easier, doesn't it?

[davejnz]

Just got my branch and will be geting some photos tonight of mother colony so i'll be with ya soon

[JB NY]

Here is the best closeup of the axial corallite I could get.
http://www.cnidarianreef.com/images/misc/DSCN4322.jpg

I count primary six septa. No secondary.

Trying to add it little more that I can observe.

Septal lenght is mostly equal
Cycles of septal: One cycle
Septal height: not exsert
septal dentition: forms comb rows (not 100% on this as it's hard to see)
Paliform structures: absent

Hopefully I'll get a caliper today.

[EricHugo]

So, for my coral, I have a big mess.

I seem to have two primary types of radials

One set is mostly immersed with some sub-immersed towards the branch ends, with round openings ( I'll measure and assess septa under the scope later)

The other set is pretty much everything but the kitchen sink....I'll point this out in the figures attached.

[EricHugo]

and again

[EricHugo]

and the last

[EricHugo]

now...knowing this, and having come this far (though we have a ways to go yet), go back and look at an Acropora in your tank and try to evaluate it. ;)

Tomorrow we will do the coenosteum, and then we are finished with the morphology.

[JB NY]

http://www.cnidarianreef.com/images/misc/acro01_DSCN4314.JPG

1 One type of radial corallite
2 Radial corallites are 'appressed'.
3. radial corallite opening is dimidiate.
4. radial corallite shape is nariform.
5 & 6 I'm having poor luck finding a caliper to measure such small amounts (mm).

[ReefDiver]

WOW! I have been following this thread but do not happen to have an Acroporid available for ID at this time. Talk about a putting a puzzle together? Very interesting, to say the least. I wonder, after all is said and done, what the accuracy of this endeavor is? It obviously would vary depending on the person doing the examination procedure, would it not? So, if we took a colony of the same species and had three different examiners go through this and each come up with an ID, what would be the interexaminer error? Eric, what about a species that exhibits different growth forms and is found on different parts of the reef? If one were to take samples of these different growth forms and perform this evaluation would it be expected that they would key out as the same species? Or, would the variations in growth form lead to different results? Considering that one must use all of this sequencing to perform an ID, how really accurate is the process? I guess if a coral taxonimist is doing the ID, then his/her results should be fairly accurate and reproducible by another examiner. Not trying to be difficult here just had some questions related to this very interesting topic.

Thanks for putting this together and giving us your time. As usual, you have outdone yourself! ;)

[MiddletonMark]

Steve, if you'd be interested in a branch to look at ... I could probably get you one ... somewhat of a small one [1.5" or a little more], but that's all my coral has right now [as my purple-tip shudders in fear ;)]
If you want to join the befuddled masses ... watching from the peanut gallery might be more fun.

-- And great questions. I think part of this exercise is to make very clear that the `observer' is an important part of the ID, never mind that we may not have `representative' specimens in our tanks.

[davejnz]

heres a pic of the branch i have

[davejnz]

and here's the colony from the LFS that it was broken off of.It was sold as a blue-tipped Acro.I would say its closest to E arborescent according to Wallace
I'll be taking measurements and septa counts later this evening and will post back

[JB NY]

Eric, on your branch you labeled a few corallites on your branch as "not appressed, tubular". I would assume that when a new axial corallite forms it takes this look before it becomes more distinct as an axial corallite. How do you differentiate between a radial corallite and a newly formed axial corallite?

[piercho]

To repeat the history of mine, it was a fragmented from a larger colony 3 months ago. When it was placed in my aquarium, it was oriented on its side. Instead of starting new growth from the upper side (like I've seen A. youngei do) the original axial tips continued to grow, but bend upward as they grow.

When I look at a branch with 3 axials, the radial coralites are fairly consistent, within zones. I am calling these the zones of my piece:
Axial, upwards.
Axial, lower.
(below the) Branch, upwards.
Branch, lower.

Axial, upwards: radials are appressed tubular, becoming more submersed as you go from the axial tip toward the branch. Septa are similar to axials described earlier.

Axial, lower: radials are appressed tubular, but more submersed than the axial, upwards radials. Occasional tubular with round opening on lower side. I think these are probably incipient axials. The septa seem more distinct in the tubular with round opening corallites.

Branch, upwards: Very submersed appresed tubulars. Denser (more numerous per unit area) than the branch, lower radials. Corallites appear smaller than the radials on the axials.

Branch, lower: Nearly emmersed radials. These coralites appear to be the smallest. Septa are very indistinct.

Measurements are not possible with the calibers I have. Maybe it's time to break out for a new instrument...

[EricHugo]

Nicely done guys:

Steve: Charlie Veron gives a talk where he describes the speciation problem in corals using a eucalyptus example...the eucalypt he knows from Townsville changes as you go towards Melbourne, and by timeyou get there, if he saw the tree without seeing the variations along the path, he would not know it as the same eucalypt. Same thing here. You will expect great variation across a range, and that is why when ID'ing these corals you need to be familiar with the variations, some of which are available by personally knowing/collecting/ID'ing them, some of the variations shown in photos like in Wallace and the early Veron Scleractinia of E. Australia. Tank conditions change it, too. And yes, bias by the person working the samples. And yes, maybe the morphological characters are too deceptive.

But, all of that is part of the excercise. We are seeing how to do it, even if only theoretically or technically, and then if we do arrive at a species designation, this variation will be part of the lesson, even as in mine...within the same colony. So, long and short is that everyone is learning how to identify to species, seeing how it is not possible to see a living coral, a fragment, or a photo and say this is A. blahblahensis for the vast majority of cases. And, doing this really does bond you more to what you are keeping in the tank, knowing what it is, therefore knowing more about where it comes from, what conditions are ideal, etc. Plus, its just sort of fun.

JB - that is exactly right, and also what I suspect is happening in my coral...it is a developmental thing. But, given the numbers of variations and the gradient between types, what is "average" or "characteristic" of this colony? I don't know yet. I suspect as we get to the key part, I will have more choices to ponder than some of you.

For you guys having difficulty measuring...do your best. If you find there are parts of the identification you cannot accomplish, then you know the limitations you have and is valuable information in and of itself. You may be able to get to species without the measurements, or it might be critical in distinguishing between two or more. Time will tell.

So tomorrow, its the coenosteal features. Then time to hit the books.

[EricHugo]

By the way....I'm sure many of you have read descriptions of Acroporid features before and sort of skimmed over them. Now, in a matter of days, you guys are basically able to do the same.

You would describe your colony of Acropora as, say, ceaspito-corymbose with axials having one cycle of equal-sized immersed septa, primary septa extending 75% of the radius, radial corallites appressed nariform to dimidiate, without radial dimorphism. Now that's a real description, not like "blue table with a cream base"

way to go!!

[firefish15]

Originally posted by piercho
Firefish those are excellent photographs of the coralites. Can I ask for a simple description of how you are getting them?
Howard,
The pictures were taken with a Nikon cooplix 990 attached to a Leica GZ6 zoom microscope.
Paul

[davejnz]

looks like i'm gonna have to sit this one out,I tried with a 6x magnifying lens and with my poor eyesight it has been unsuccesful.thanks eric,this thread has been quite informative

[Julio]

How much do corals change in captivity to be calssified as a new species if much at all?

Great detail pics!!

[firefish15]

Axial corallite of my coral is approximately 2.5mm outside diameter and 0.8 inside diameter. These are rough estimates using a ruler. Here's a picture of the corallite next to the ruler.

[firefish15]

Originally posted by EricHugo
I would call my colony digitate and clump-like


Eric,
Your picture shows small branches at the top of some of the branches. Is this still considered to be digitate?
Paul

[EricHugo]

Later I amended that because it is small yet, and the clump-like part takes into account the branching, and I also said it might become more caespitose or corymbose over time. But, also, as mentioned, the definitions and sketches are idealized, and a number (in fact whole groups) of clump-like Acropora that stay smallish and have some branching at the ends are described as digitate. They don't all look like the classic A. humilis/gemmifera/monticulosa etc.

also, great job on the axial of yours.

[EricHugo]

Coenosteum is a term used to describe the skeletal material between polyps on corals. In Acropora, the coenosteum consists of the skeletal material formed by layering of synapticular material around the axial and radial corallites. Becuase it has different polyps types creating different corallite types, the coenosteum may be very different around and between corallites. However, this is not always the case, and it can be quite uniform.

There are relatively few terms used here, although a great degree of variation. The costae on coral skeletons are defined as the radial elements outside the corallite wall. A good example can be seen on an average Favia, where these radial skeletal elements are nearly continuous as the move over the wall of a corallite, forming the septa as they converge towards the center of the corallite.

In Acropora, similar radial elements can appear as parallel or nearly parallel raised bands of skeleton. The top edges of the bands can be smooth, or they can have jagged edges that appear like regular "teeth." These "teeth", or dentititons, are also called spinnules. Spinnules means "small spines." Spinnules have various degrees of development, and can be simply little points or shark-like teeth, or can be globular, highly ornately branched, forked, , labellate, lobed, etc. The spinnules tend to be quite regular, although again variation can exist. Finally, the coenosteum can be rather homogenous, forming a net-like appearance whereby it is termed reticulate. There can be a simple or elaborate reticulate structure. There are some excellent photos of examples in Wallace (1999) on p. 57 for those of you who have this book. Many of the photos posted here also have some nice views of coenosteum. The coenosteum very well might be among the most distinct characters on a species, and when coupled with the other characters already assessed, provides a pretty strong morphological description of the coral. Because of the variation in coenosteum, it is hard to describe in words, and often this is a place where comparison to photos becomes useful. It is also the least easily observed in living corals, being mostly to completely obscured by living tissue. It also becomes dificult sometimes where the base of the radial coenosteum joins the axial coenosteum, and this continuous structure sometimes becoomes a gradient of forms if the two have very distinct coenosteal morphologies. In other cases, it can be nearly continuous with very little distinction between the two. This seems to be more common with a simple costate or reticulate coenosteum.

Photos coming soon.

[ReefDiver]

Eric:

This is a little off topic but I was wondering how the directional growth patterns of the skeletal structure is laid down? If the polyp lays down the Ca matrix via the calicoblastic epithelium, then how is the girth or thickness of the main branches & corallites produced? I also notice in the cross sections of the corallites that between the inner and outer walls, there are many reticular "holes" (for lack of a better term} seen. Therefore, I would assume that the skeletal structure is far from solid. Do these "holes" serve as any connection for transport of nutrients, etc... or am I way off course here? Are these holes filled with tissue? Just trying to get a handle on the structural aspects. Thanks! :D

[piercho]

This may relate to what Steve just asked:

The cross-section of my branch where it was clipped from the colony had hollow-ish "channels" in it. There was one central channel surrounded by 5 smaller channels. The 5 smaller channels were arranged around the central channel in a relatively symmetric pattern.

Are these characteristics that are useful for specie identification? Or are they common to the genus?

[piercho]

I tried with a 6x magnifying lens and with my poor eyesight it has been unsuccesful It is pretty comical with my 20X eye loupe and makeshift light-box. I don't know how you would get by without at least 20X magnification. I think I need what we use to call a "dissection" microscope with at least 25X magnification, a tray adjustable in 3 axis, and multi-directional illumination with intensity control. And a camera adapter so I can share what I'm talking about. And my calipers - which are pretty d*mn good for shop use - are still too clumsy for measuring anything except the outer diameter on the axials. And even then my accuracy is limited to 1/64". A digital caliper that can measure to 10ths of mm and the appropriate tips is what I need. This is interesting stuff but I don't know if I'm willing to invest in the tooling to do it properly.

[Meisen]

Eric,
Awesome thread! Just what all us acro-heads need to humble us even more lol. Is it OK to jump in to class a few days late? I just caught this thread today. I am going to bring a dead piece into my office tomorrow where I have a dissecting scope to work with. I will try to get up to speed with the morphology using what you guys have laid down already. Can I ask you to backtrack slightly if (when) I get all lost and confused?

[EricHugo]

Meisen
Is it OK to jump in to class a few days late?

Of course

Can I ask you to backtrack slightly if (when) I get all lost and confused?

definitely

piercho

It is pretty comical with my 20X eye loupe and makeshift light-box. I don't know how you would get by without at least 20X magnification.

LOL - indeed

I think I need what we use to call a "dissection" microscope with at least 25X magnification, a tray adjustable in 3 axis, and multi-directional illumination with intensity control. And a camera adapter so I can share what I'm talking about.

That's about right...because once you get it under the scope, its hard to get the right position of the corallites without clamping or propping.

And my calipers - which are pretty d*mn good for shop use - are still too clumsy for measuring anything except the outer diameter on the axials. And even then my accuracy is limited to 1/64". A digital caliper that can measure to 10ths of mm and the appropriate tips is what I need.

Hence the handiness of the scale bar in a scope lens.

This is interesting stuff but I don't know if I'm willing to invest in the tooling to do it properly.

You don;t have to...just do the best you can.


piercho

This may relate to what Steve just asked:

The cross-section of my branch where it was clipped from the colony had hollow-ish "channels" in it. There was one central channel surrounded by 5 smaller channels. The 5 smaller channels were arranged around the central channel in a relatively symmetric pattern.

Are these characteristics that are useful for specie identification? Or are they common to the genus?

The degree of interconnection is a hallmark of very porous skeletons and the polyps of corals like Acropora. It is not, to my knowledge, used in systematics.


ReefDiver Eric:

This is a little off topic but I was wondering how the directional growth patterns of the skeletal structure is laid down? If the polyp lays down the Ca matrix via the calicoblastic epithelium, then how is the girth or thickness of the main branches & corallites produced? I also notice in the cross sections of the corallites that between the inner and outer walls, there are many reticular "holes" (for lack of a better term} seen. Therefore, I would assume that the skeletal structure is far from solid. Do these "holes" serve as any connection for transport of nutrients, etc... or am I way off course here? Are these holes filled with tissue? Just trying to get a handle on the structural aspects. Thanks!

The holes are largely filled with tissue...Acropora is a reticulate network of interconnected polyps to a certain depth in the skeleton. Deeper than that, you get infilling, probably via precipitation and microbes rather than coral calcification - or possibly indirectly from calcification. There is a great schematic of the polyp network in Acropora in the Wallace book, as well.

[justgettinstarted]

i am going to have to try and get in on this when i get off work tonight.... I have an acro that i would be curious to try and ID

Eric, does it matter if it has been dead for maybe a month or so but still in the tank? The frag RTN'd

thanks

Garrett

[EricHugo]

Garrett:

It depends how much the skeleton has been encrusted...most will probably be algae and easily removed with the bleach. If there is a lot of erosion or coralline or calcareous stuff on it, it willbe variably useful - from partly to not at all.

[davejnz]

Well I'll try to continue,My colony is arborescent
measurement of axial: outer 3.8mm,inner1.6mm
axial appears to have 6 primary septa that are immersed and extend to center of corallite(columella?)
radial corallites are appressed,labellate,and dimidiate
will get radial measurements later.

[davejnz]

pic of branch with calpers used to obtain measurements

[EricHugo]

OK, sounds like everyone has moved along well.

Hopefully by now you have all seen what your coenosteum looks like

Now, both Carden Wallace and Charlie Veron have grouped Acroporid species into larger subcategories. Veron lists 38 categories, Wallace has 20. I rather prefer the way Wallace lists them since they are arranged phylogenetically, while Veron separates them morphologically. It may seem easier to deal with the latter, but the descriptives of the categories require almost as much work to translate as would the species itself, and many of the terms seem a bit vague. For example, Wallace would have A. horrida in the A. horrida group, consisting of 8 species related to A. horrida. In general, the members have a lot in common, but in some cases may be quite different in appearance. Not that this really matters, given the variability we have learned about, right? In contrast, Charlie puts them in the "species with middle sized branches and irregular radial corallites" group that has four unrelated or related species in it.

I will list them all for you guys in case you do not have these references. It will be helpful for you to be able to move your coral into one of these categories.

Wallace's grops:

A. rudis group - 4 species
A. humilis group - 8 species
A. nasuta group - 7 species
A. divaricata group - 5 species
A. lovelli group - 3 species
A. verweyi group - 1 species
A. cervicornis group - 3 species
A. muricata group - 5 species ( Wallace refers to A. formosa as A. muricata - Veron disagrees, and says no basis or need exists for changing a distinct and well-recognized taxon. I agree.)
A. robusta group - 8 species
A. togianensis group - 1 species
A. selago group - 8 species
A. aspera group - 7 species
A. florida group - 2 species
A. hyacinthus group - 7 species
A. latistella group - 4 species
A. horrida group - 8 species
A. plumosa group - 1 species
A. elegans group - 7 species
A. loripes group - 12 species
A. echinata group - 8 species

then there is the Isopora subgenus, consisting of 4 species (according to Wallace).

Let's do some easy intial work using the process of elimination.

Now, you might note the discrepancy in numbers of species. It is helpful here to note especially the ones with a lot or few species. Without going any further, I would look at the list and think about reproduction and dispersal. If a coral has many relatives, it has probably had ample time to diverge, and is probably a widespread group. By contrast, those with few related members are probably more recent or have significant barriers to dispersal - either being relatively new species or really old ones on their way to the genetic glue factory. In fact, if we look at the A. togianensis group, which consists of A. togianensis, I would thinkthe name means that it is found in and around the Togian Island group of Northeast Sulawesi, Indonesia. In fact, this is the case, and it is restricted to that area. The Togian Islands are a protected area, and are also very hard to reach. It is unlikely any corals collected for the aquarium trade came from here, and so one can immediately almost cross this species and group off the list.

It is notable that using a name is not a good thing to use in making assumptions. Often, a name may indicate a place of first discovery, but the species with all its variations was later found to be very widespread. This brings up another very important aspect in identifying your Acropora corals. The range. Unless you have good reason to believe, or know, that a coral was collected elsewhere, there are relatively few areas of coral collection for the aquarium trade. Veron and Wallace both give the known ranges for the species. Thus, one can immediately eliminate the A. cervicornis group which consists of Caribbean/Tropical western Atlantic species. One can, as one looks at the invidual groups, rule out species that are only known from Australian waters, the Hawaiian islands, the eastern Pacific, the east African coast, and, likely, the Red Sea. Now, if the range goes into that wide Indian Ocean, Indo-Pacific, Central Pacific region, then it must stay in the list of possibiltiies. Mind you, this does not rule out a lot, since the vast majority of Acroporids will be found in areas where it is possible they were collected for the aquarium trade. However, geographical range is a quick a dirty way to eliminate species that yours cannot possiby be with very little work.

Another quick and dirty technique is abundance data. When we begin using our characters, it may be helpful to see whether a species is common or rare. In general, odds are that your coral is probably not some rare coral, simply by virtue of the odds of collection. The same is true with habitat information. A rare Acroporid known only from deep current swept reef slopes or in mangrove areas is not likely to be your coral species, because collectors are unlikely to collect there, or to find it if they were. This is not a definite method of elimination, but it should be helpful.

Words of advice as we proceed, just general bits of trivia regarding preconceived notions if they haven't already been dispelled. Do not trust what the name of the coral was when you purchased it. Do not trust names you have previously associated with your specimen. As with my favorite example, everyone calls whorling or plating Montipora M. capricornis, even though this growth form is very common in Montipora and many many species exist other than M. capricornis....trust me when I say idenitfication of Montipora is hard. Similiary, the hobby tends to call any Acropora with scale-like radial corallites A. millepora, and although the radials are distinct and a good beginning, A, millepora belongs in the A. aspera group which has 7 similar species. Also, there are several others in other groups altogether that are very distinct as adult colonies, but very similar as small colonies or fragments, that have similar looking corallites. Also, do not believe if someone has told you your coral is rare. So, if you have a "rare deepwater Bali Acropora," do not begin by looking for deepwater uncommon corals where Bali is within their range. Just, throw out any preconceived notions, in general, and go from where we are now.

Tomorrow, I will list the characters for each group. Then, we will get a list of groups from each of you and begin moving in on the species.

When we are finished, I will also take you through an example using the Coral ID CD, which is a very user friendly coral identification method produced by AIMS.

I will also take you through a systematics key that is more traditional.

[firefish15]

My acropora has four types of radial corallites.
1. tubular nariform opening.
2. nariform elongate opening.
3. appressed tubular
4. immersed.
Size is quite variable. The largest being eliptical 2mm x 2.5mm outside diameter, 1 mm x 0.7 mm inside diam. The smallest circular 1 mm outside diam, 0.5 inside diam.
Eric, do these corallites change as they age? for example do appressed tubular change to nariform elongate opening then tubular nariform opening?
here's a picture of types 1 and 2.

[firefish15]

The septae are also varaible, all have2 cycles, The most nuimerous being 6 primary and 6 secondary. The least nulerous 2 primary, 4 barely visible secondary.
appressed tubular and immersed corallites.

[firefish15]

The costae around the axial and radial corallites are similar with shark-like teeth.

[firefish15]

The coenosteum seems to be a simple reticulate structure.

[EricHugo]

A. rudis group - A. rudis, A. variolosa, A. austera, A. hemprichii
growth form - large, thick-branched, simple, robust with simple, irregular branching
radial corallites - rounded tubular, evenly sized, thick sometimes swollen walls, relatively small calices
axial corallites - large, numerous synapticular rings, contribute a lot to branch thickness
coenosteum - elaborate spinules throughout
habitat - subtidal
range - Indian Ocean and Red Sea, except A. austera
notes - A. austera is the only species likely in the trade

A. humilis group - A. humilis, A. globiceps, A. gemmifera, A. monticulosa, A. samoensis, A. digitifera, A. multiacuta, A. retusa
growth form - corymbose or digitate, sturdy, conical or terete branches
Radial corallites - short, thick tubular, nariform to dimidiate openings, dense,evenly sized or two sizes, often touching
axial corallite, large and dominant, dense reticulum, contribute a lot to branch thickness
coenosteum - reticulate or reticulo-costate, with laterally flattened, blunt, or flaky irregular spinules
habitat - most restricted to shallow, intertidal, strong water flow, usually very common on reef flats
range - wider Indo-Pacific

A. nasuta group - A. nasuta, A. cerealis, A. valida, A arabensis, A. secale, A. lutkeni, A. kimbeensis
growth form - all are corymbose
radial corallites - nariform or tubular-nariform, evenly sized or in two sizes, contribute a lot to branch thickness
coenosteum - reticulate with simple spinules, sometimes spinules in rows or joined to form costae
habitat - subtidal, shallow, common
range - Indo-Pacific

A. divaricata group - A. divaricata, A. solitaryensis, A. kosurini, A. hoesksemai, A. clathrata
growth form - always determinate, central or side attachment, mostly very similar, often symmetrical
radial corallites - nariform, thick walls, round, oblique, or dimidiate openings, contribute a lot to branch thickness, multiple types and sizes common within colony, spaced out, often even
coenosteum - reticulate with forked or simple spinules, very dense to costate depending on habitat
habitat - often occur across wide depth range
notes: A. clathrata, A. divaricata and A. solitaryensis are commonly named in aquarist circles, and represent species thought to be fairly distinct in growth form...THEY ARE NOT! They can form plates, tables, or thinly branched caespitose to arborescent colonies with the distinction being the attachment point. Small colonies will be indistinct in growth form.

A. lovelli group - A. lovelli, A. bushyensis, A. glauca
growth form - varies
radial corallites - appressed rounded tubular, evenly sized
coenosteum - reticulate with simple spinules, spinules sometimes in rows, or costate
habitat - broad, but restricted - shallow coastal fringing reefs
range - wide, but restricted
notes: kind of an oddball, catch-all group in terms of appearances.

[EricHugo]

see if you can eliminate your species based on these five groups. I'll do another five tonight. whew.

[EricHugo]

A. verweyi group - A. verweyi
growth form - digitate or caespito-corymbose, branches 5-10mm in diameter, up to 100mmm long. Low clumps or patches, often flat topped. Whitish cream to cream brown, occasionally with orangishaxial corallites
radials - evenly distributed, equal sizes and shapes, appressed tubular with large flaring round openings, two sets of septa (primary 3/4R, secondary to 1/3R)
axials - outer diameter 2.8-3.5mm, inner 0.8-1.1 mm, two cycles (primary to 3/4R, secondary to 1/3R), a tertiary set of septa may be present
coenosteum - uniform reticulate with subcostate simple or leterally flatttened spinules
habitat - fills in spaces between other Acropora, exclusively shallow water species.
range - wider Indo-Pacific/Indian Ocean

A. muricata group - A. muricata (A. formosa), A. grandis, A. acuminata, A. valenciennesi, A. pharaonsis
growth form - open arborescent or arborescent tables with thick sturdy branches
radials - tubular, various openings, evenly spaced, variable in size, contribute equally with axials to branch thickness
axials - can become thickened and contribute to heavier sturdier branches
coenosteum - uniform reticulate with simple spinules, somewhat variable
habitat - fairly broad.
range - depends on species

A. robusta group - A. robusta, A. abrotanoides, A. palmerae, A. intermedia, A. polystoma, A. downingi, A. listeri, A. sukarnoi
growth form - variable - subarborescent, corymbose to digitate, simple sturdy branches
radials - dimorphic; long tubular with dimidiate openings and sub-immersed
axials - contribute most to branch thickness
Coenosteum - retiuclate between radials, costate on radials
habitat - shallow high-water movement environments, except A. intermedia (wider range of habitats)
range - variable, depends on species

A. togianensis group - A. togianensis
- looks like a Montipora with unusual corallites and coenosteum

A. selago group - A. selago, A. tenuis, A. eurystoma, A. striata, A. donei, A. yongei, A. loisetteae, A. dendrum
growth form - variable - corymbose, corymbose table, arborescent, hispidose, etc.
radials - cochleariform with flaring lip, evenly sized
Coenosteum - retiuclate with simple spinnules b/t radials, costate on radials
habitat - variable, but usually protected from strong water flow.

A. aspera group - A. aspera, A. pulchra, A. millepora, A. spathulata, A. spicifera, A. papillare, A. roseni
growth form - corymbose or arborescent
radials - labellate, upper edge absent, lower edge flaring lip
coenosteum - open, simple, with few simple spinules b/t radials, costate on radials
habitat - shallow water on reef flats, lagoons or shallow slopes
notes - degree of lip development is what separates species in this group. They also interbreed often, though some breeding barriers exist. Genetic differences small, hybridization common. i.e. - hard to tell apart!!

More later.

[EricHugo]

Acropora florida group - A. florida, A. sarmentosa
growth form - modified robust hispidose, with even small branches around heavy main branch
radials - evenly sized, appressed tubular, thick labelate lower wall and round openings, radials contribute equally with axials to branch thickness.
cornosteum - reticulate without much spinule development at all between radials, costate or reticulo-costate on radials.
habitat - varies
range - Indo-Pacific, but not Central Pacific

Acropora hyacinthus group - A. hyacinthus, A. tanegashimensis, A. anthocercis, A. cytherea, A. microclados, A. paniculata, A. indonesia
growth form - tables or plates, central or side attachment, thickened stalk; juveniles are digitate before the mature table or plate forms (elaborate horizontal branching/anastomoses with short thin vertical projections)
radials - even sized, labellate, uppper wall absent, lower wall lip is rectangular
coenosteum - reticulate with simple spinules between radials, costate on radials
habitat - most reef zones but often shallow
range - depends on species

Acropora latistella group - A. latistella, A. subulata, A. nana, A. aculeus.
growth form - corymbose, slender branches, varies with depth, can form plates or tables
radials - evenly sized, appressed tubular, round openings, contribute equally with axials to branch diameter, spacing varies with depth
coenosteum - uniform reticulate with well-spaced simple spinules between radials, reticulate to reticulo-costate on radials.
habitat - broad depth range

Acropora horrida group - A. horrida, A. vaughani, A. tortuosa, A. abrolhosensis, A. microphthalma, A. kirstyae, A. derawanensis, A. halmaherae
growth form - highly variable, even within a colony, indeterminate
radials - evenly sized, simple tubular, round openings
coneosteum - simple to elaborate spinules, coenosteum sometimes partly fused, reticulate to costate between and on radials
habitat - variable, usually protected and lower water flow
range - variable

Acropora plumosa group - A. plumosa
growth form - irregular, flat-topped arborescent tables to twisted arborescent, branches 3-15mm diameter up to 50mm long; horizontal branchlets 3-4 mm diameter, sometimes anastomosing, the loose, open tables can form multiple tiers, cream to yellow-brown, yellow-grey, brown color
axials - 1.2-2.1mm OD, 0.6-1.2 ID, primary septa to 2/3 radius, secondary cycle absent or barely developed
radials - even, not touching; tubular; round, oval or dimidiate openings, primary septa to 1/4 radius; secondary cycle absent or barely developed
coenosteum - reticulate to reticulo-costate on radials with laterally flattened spinules, reticulate between radials with laterally flattened spinules between, sometimes in rows
habitat - deep slopes and walls below 40 feet
range - Indonesia and Papua only

4 groups to go...

[EricHugo]

Acropora elegans group - A. elegans, A. pichoni, A. tenella, A. walindii, A cardenae, A. torihalimeda, A. russelli
growth form - mostly horizontal branching with sparse flattened
branches
radials - evenly sized, tubular or appressed tubular; most species reticulate withs ome forming rows or being nearly costate with elebaorate spinules.
coenosteum - moderate to dense with eleaborate spinules
habitat - deeper calm water, mainly below 60 feet
range - localized to Indonesia or Australia, depending on species.

Acropora loripes group - A. loripes, A. squarrosa, A. chesterfieldensis, A. willisae, A. lokani, A. granulosa, A. speciosa, A. suharsonoi, A. caroliniana, A. desalwii, A. jacquelineae, A. simplex
growth form - various, depending on secondary branching of hispidose or corymbose colonies with a whitish glow
radials - evenly sized, rounded appressed tubular; some branches may lack radial develpment; mostly reticulate but some species develop costate aspects
axials - prominet and major contributor to branches
coenosteum - densely arranged eleborate spinules
habitat, frequently deep or shaded reef slopes
range - varies according to species, but most localized to Indonesia

Acropora echinata group - A. echinata, A. batunai, A. subglabra, A. carduus, A. awi, A. elseyi, A. longicyathus, A. turaki
growth form - well developed hispidose colones; evenly arranged secondary branchlets around primary branches
radials - sparse; evenly sized, "pocket-like" appressed tubular
axials - prominent; major contributor to colony development. Colonies have many axials and few radials and axials may be mistakenly be considered radials.
coenosteum - uniform; costate, or rows of simple to slightly elaborate spinules
habitat - protected areas (lagoons, deep slopes, sheltered bays); often form large fields with species intermixed
range - varies with species, some narrow, some wide, but centered around Indonesia.

Isopora subgenus - A. palifera, A. cuneata, A. crateriformis, A. brueggemanni (A. palmata in Caribbean)
growth form - thick, often wedge-shaped branches (except A. brueggemanni which is arborescent)
radials - absent, except in A. brueggemanni
axials - multiple
coenosteum - dense, meandorid arrangement, elaborate spinules on and between axials - most elaborate spinules in Acropora genus
habitat - variable
range - variable

So, now, the trick is to assign your coral to a group.

Can you do it? If so, please list which group, and we will go down to species level for each example.

[piercho]

I still need help finding the correct terms to describe the coenosteum on my piece. Would it be possible to get images showing what the terms descibe? That is a lot of typing you have been doing so I hate to ask for more...

[JB NY]

Here is what I've got.

Growth Form
caespitose-corymbose

axials
Septa: six primary. No secondary.
Septal lenght: mostly equal
Cycles of septal: One cycle
Septal height: not exsert
septal dentition: forms comb rows (not 100% on this as it's hard to see)
Paliform structures: absent

Radials
One type of radial corallite
Radial corallites are 'appressed'.
Radial corallite opening is dimidiate.
Radial corallite shape is nariform.


Coenosteum
Coenosteum between radials is costate or broken costate.
Top edges of the costae contain spinnules that are shark-like.

Grouping
Acropora latistella

Based of the above I picked the Acropora latistella group. I came down to that and the Acropora echinata group. But in echinata the radials were different and the also the radials are similar to the axials, which is not the case on my branch.

click for larger image
http://www.cnidarianreef.com/images/misc/acro01_DSCN4305_sm.JPG (http://www.cnidarianreef.com/images/misc/acro01_DSCN4305.JPG) http://www.cnidarianreef.com/images/misc/acro01_DSCN4314_sm.JPG (http://www.cnidarianreef.com/images/misc/acro01_DSCN4314.JPG)

http://www.cnidarianreef.com/images/misc/acro01_DSCN4315_sm.JPG (http://www.cnidarianreef.com/images/misc/acro01_DSCN4315.JPG) http://www.cnidarianreef.com/images/misc/DSCN4322_sm.jpg (http://www.cnidarianreef.com/images/misc/DSCN4322.jpg)

[EricHugo]

ok..here is the coenosteum image (Wallace 1999 as reviously referenced)

[EricHugo]

Joe:

I think the latistella group is a good option for yours. Do your radials have one or two cycles of septa? You might want to look at a number of them to se if there is any development - also, how far in do they protrude (both axial and radial septa) - try to be as accurate as possible on this, because these four species are very hard to distinguish - Wallace mentions that latistella and aculeus may sometimes only be distinguished in the lab...and IMO, the others are darn close, too.

[firefish15]

Originally posted by EricHugo
how far in do they protrude (both axial and radial septa)
Do you measure this at the top of the corallite? The septa on my coral protrudes further the deeper into the corrallite you go.
Paul

[Mantis]

I have a coral that I believe is one from the latistella group as well. My rough ID has always been aculeus. My question is are there any corals in that group whose axials are oval or flattened instead of round. As this coral continues to grow it appears to be getting more pronounced. It seems like this would be a distinguishing characteristic, any thoughts

http://home.earthlink.net/~divers2/sitebuildercontent/sitebuilderpictures/aculeus.jpg

Here is another pic

http://reefcentral.com/gallery/showphoto.php?photo=10658&papass=&sort=1&thecat=500

[EricHugo]

Paul: good question. Some septa are arched, and many corallites are not tubular and so, for example, in a nariform with straight septa, you basically have a cone and the septa would naturally project further at the bottom than towards the open end. I really don't even know how to answer the question "officially" but I would I would probabbly judge it from near the opening unless there is a strong arc, in which case I would estimate from the high point of the arc.

Mantis, I cannot see the characters of this coral. That has rather been the point of this excercise is that without analysis of the morphological features, once cannot in the majority of cases know what species of Acropora it is. As for the group, I have thus far listed the characteristics of the groups...have only listed species characters for two...toganensis and plumosa. If you cannot identify the characters, I cannot even tell you which group unless it is distinct.

It's like soft corals...certain things have to be known for many soft corals before even assigning a genus...species is not possible in soft corals without much greater effort than we have gone to so far in this Acropora example.

The answer to your question: what do you mean the axials are oval or flattened instead of round? Oval and round are characters of the opening. What is flattened? What are the radial and coenosteum characters? I see that the openings on some are oval shaped, but in this case, since I cannot see much of anything in the photo except basic growth from which is a common type, and also highly variable and basically unhelpful, I would have to go through several hundred species, many many books and look at all the conceivable or known variations to even guess what this might be. It would take weeks to do this, and the character might still be a result of the tank environmental conditions. No offense, but I'm not going to do this!

[JB NY]

I only have a 8x mag to look at the radials and it's not strong enough to notice any septa. I ordered a 20x loop that should be here today. But if I don't have time to look tonight I will not get a chance until Sunday, due to a quick trip I need to take Friday and Saturday. I'll also try and get some measurements, as close as I can.

I bought the Wallace book and it arrived the other day. Last night I spent some time with it and I think this coral also fits into the Nasuta group. After looking at it for some time I think that this group might be a better fit than the latistella group I had chosen previously.

[EricHugo]

No worries...take your time. Now that you have the book, we can really rock on yours! It shows the variations and features much better than Veron's Corals of the World (which might be a good thing or a bad thng, depending on your view or effort!). It has less variations than he and Wallace's earlier book (Scleractinia of E. Australia), but many of those corals may not be quite correctly ID'ed according to both him and her.

I think many aquarists avoid this book because of the limited color photos of living corals, but if you love Acropora, it is a must-have. It's sort of like those who are really into the lighting apparatus of their tanks (bulbs, ballasts, reflectors,etc. who spend thousands of dollars on this aspect, but will not spend $100 or so for a device to measure the light levels and yet also spend fifty dollars to measure ammonia and nitrite....Weird.

So, I think your choices in the nasuta group are pretty limited, but certainly possible...and you'll really have to consider those radials well on a species-by species level.
Look carefully at the photos of radials earlier in the book - those are quite helpful to keep referring to.

[firefish15]

Originally posted by JB NY
I bought the Wallace book and it arrived the other day.
JB,
Where did you get the book? I could only find the CD version of the book online at Amazon. I orderded this but estimated delivery is end of june.
Paul

[JB NY]

Eric, your right about it being a great resource. At first I was surprised that almost all the photos are in black and white. After spending some time looking through it, I realized for what they are explaining B/W works better than color photos. It's goes into much greater depth than the Veron books did on Acropora.

So true on the light meter as well. :)


Paul, I ordered if from the publisher CSIRO, in Austrialia.

http://www.publish.csiro.au/pid/2187.htm

Took about 7 business days to receive. I'm on the east coat of the US. I bought both the CD and book. I found the Coral ID CD an excellent resource so I was hoping this would be the same. This CD seems to be the second half of the book. Not bad, but the Coral ID CD is so good I was hoping for a little more out of this one.

[Mantis]

Now I know how my students feel when they are unprepared for class.

No problem, I totally understand. I am having trouble getting a nice photo of my dead frag. I'll have to borrow a better digital camera. I was just curious if those flattened axial openings were a dead giveaway, common to many acro's, or possibly caused by environmental factors.

I should have known it couldn't be that easy.

[cabrerad]

I am sorry to jump in late, but I will try my best to catch up. The acropora sp. I have chosen was provided to me as several small frags glued to a small rock in various orientations. I have bleached a frag containing two branches and what appears to be two distinct axial corallites and at least one incipient axial corallite.


http://reefcentral.com/gallery/data/500/39105Acro_fragbluewhole.jpg

http://reefcentral.com/gallery/data/500/39105acrobleached.jpg


Here is what I could glean:

Growth form: Caespitose-Corymbose (a bit of a guess given this is a frag)

Axial structure:

Outer diameter: Mean: 2.6mm (range 2-3 mm). I did notice the axials are not perfectly round and one diameter is longer than the one perpendicular to it.

Inner diameter: Mean: 0.9mm (range 0.8-1 mm)

Septa: 12 (6 primary and 6 secondary, 2 cycles?): What I am calling primary septa are the longer ones and they extend about a third of the inner diameter. What I am calling secondary septa are about half the length of the primaries. The picture is blue corrected for contrast. It was the best I could do with a scope made to look at cells. I need to find a dissecting scope I can use to take pictures.

http://reefcentral.com/gallery/data/500/39105acroblue_axial-med.jpg


Radial structure:

Types of radials: Almost all the corallites appear tubular (but almost nariform at the very tip near the opening) There are a few appressed tubular and sub immersed radials.

Radials are appressed: roughly a 45 degree angle for most.

Opening shape: Oblique

Measurements:
Length: 3.5-5 mm ( the corallite I think is incipient is longer, 7 mm)
Outer Diameter: 1mm X 2mm
Inner diameter: the septa are oblique and run almost the entire length of the opening (0.8mm X 1.8mm). The measurements are consistent among corallites, with the shorter length radials having slightly smaller openings.


Septa: My pictures of the radials are horrible, I‘ll try to get some better ones. Many have no distinct septa that I can see and some appear to have 5-6 septa. Below is an example where I could not make anything out.

http://reefcentral.com/gallery/data/500/39105Radialacroblue.jpg


I am reasonably sure my measurements and estimates are kinda close to reality:). I would like to obtain better pictures, but my equipment is rather limiting with coral identification (great for cells though). i will try to get a better picture of the bleached coral though.

David

[firefish15]

Originally posted by JB NY


Paul, I ordered if from the publisher CSIRO, in Austrialia.


Thanks JB, I cancelled my Amazon order and ordered the book and CD from CSIRO.
Paul

[cabrerad]

Ok,

Last few bits to catch myself up:


Coenosteum (I found this one difficult)..some of the areas around the radials appear reticulate. Close to the radials and at the base of the coral, the coenosteum appears costate with spinnules.


Based on the information I have, I think my best fit is the A. robusta group.

Below are some preliminary pics with a dissecting scope I was able to find in a dark corner at work and "un-mothball". The micrometer on the slides is calibrated so that 100 units=50mm (so 1mm is 20 units).

Picture of axial and radials

http://reefcentral.com/gallery/data/500/39105acroclose-_slide.jpg


And, side view of radials:

http://reefcentral.com/gallery/data/500/39105acrocoenost.jpg

I am going to try to clean up the microscope and get some more illumination when I get time.

David

[EricHugo]

be with you all shortly..have to get to lab.

[Mantis]

Well I got creative and took my branch to a camera store and asked them if I could play around with a nice camera. Here's the result:

http://home.earthlink.net/~divers2/sitebuildercontent/sitebuilderpictures/acro1.jpg

http://home.earthlink.net/~divers2/sitebuildercontent/sitebuilderpictures/acro2.jpg

http://home.earthlink.net/~divers2/sitebuildercontent/sitebuilderpictures/acro3.jpg

Growth form:
caespitose-corymbose

Axials:
Not sure how to describe, they are squished

Radials:
Seems like one type
Nariform rounded opening
Appressed

Coenosteum:
Uniform reticulate

My best estimate would be:
Latistella group

[Mantis]

I need to go ask the science department for some kind of magnification device so I can examine the septa.

[cabrerad]

two more pictures, same scale:

Axial and radials:

http://reefcentral.com/gallery/data/500/39105acroclosepub.jpg


Coenosteum and radials (10 units = 1 mm, entire micrometer is 10 mm):

http://reefcentral.com/gallery/data/500/39105coenostpub.jpg

David

[EricHugo]

Mantis: no worries! No, it really sin;t that easy..wish it was!

David: The ground color of the coral is hard to judge...normal or somewhat bleached?

The growth form for this piece would be a total gues...probably confounding to even attempt that trait.

The axials are as you describe, and it appears to have a good set of directive septa, too.

On your radials, good assessment, but it appears some are dimidiate, too...are they or am I just not seeing them correctly. I would say your coenosteum is not really costate, but tending towards it - probably from the spinules lining up in rows, but it doen't appear they have formed solid ridges, have they?

Mantis:

nice work. So, it doesn;t look to me like round openings on your radials althoughs some are...try to take note of all types, and then decide which are the majority, too. Are some dimidiate? Also, agree on the nariform - mostly appressed. Any smaller ones in there between the primary radials? Those are unusual axials. Can you see the septa at all in them?

[EricHugo]

So, does everyone think they know their group? Should we move to species?

[davejnz]

sorry Eric,its hard for me to get accurate septa counts on radials and axials with my poor lens.coenosteum does appear reticulate and costate near the radials.It is hard to pick a group as not many are arborescent but if i had to guess it would be A.aspera.
I'm trying to borrow a better magnifying device so bear with me

[cabrerad]

Eric,


Sorry for the late reply, internet at home was down for the weekend.

To answer your questions: The coral is light blue on the top 2/3 and is brown at the base. No bleaching is apparent.

After looking at the coral again I would agree some of the radials are mildly dimidiate. As for the coenosteum, you are correct, the spinules are lined up, but do not form plates on the radials.

I am not sure if the lack of costate structure on the radials knocks the A. robusta complex/group id out, but I have now added A. divaricata and A. nasuta to the mix. I have Veron's Corals of the World, but am hesitant to use it to narrow down further and possibly be led astray by some coral looking like mine.

So that's where I am.

David

[JB NY]

Originally posted by EricHugo
So, I think your choices in the nasuta group are pretty limited, but certainly possible...and you'll really have to consider those radials well on a species-by species level.
Look carefully at the photos of radials earlier in the book - those are quite helpful to keep referring to.

OK, I got my 20X loop and looked my branch a bit more.

Same extra info

Radials
Nariform with elongate openings (picture I on p 56)
No septa in radials, Larger radials that look as if they will form axials, have 4 radials.

Coenosteum
Costate with spinule development. Closest to picture E on p 57

As to the grouping, if you think that latistella group is more appropriate, I'll stick with that. It was just that, after looking at the groups again, I wasn't sure if the best grouping was latistella or nasuta.

[piercho]

So, does everyone think they know their group? Should we move to species? I'm sorry to be lagging behind but was hoping to get hooked up with a better tool to examine the coenosteum details. That didn't pan out so I'll just have to make best guesses. I should be down to a group by tomorrow.

[firefish15]

Originally posted by EricHugo
So, does everyone think they know their group? Should we move to species?
I was waiting for delivery of Wallace's book but I'll give it a shot.

Axials - 2.5mm outside diameter and 0.8 inside diameter.
Septa.
2 cycles. 6 primary extending to 75% of radius, 6 secondary.

Radials - variable in size from 2mm x 2.5mm to 1 mm x 0.7 mm outside diameter.
Four types of radial corallite
1. tubular nariform opening.
2. nariform elongate opening.
3. appressed tubular
4. immersed.
Septa. also variable but all have 2 cycles. the majority having 6 primary and 6 secondary. Some having 2 primary, 4 barely visible secondary.


Coenosteum
Coenosteum around radials is costate. Between radials it is reticulate.
The costae around the axial and radial corallites are similar with shark-like teeth.


Grouping
Acropora humilis group. Even though you describe the axial corallite as being "large and dominant", there is one species in this group with small axials (globiceps).

I took some closeup pictures of the coenosteum, this one of the coenosteum between the corallites.

[firefish15]

This is a closeup of the coenosteum around the corallites.

[Mantis]

Mantis:

nice work. So, it doesn;t look to me like round openings on your radials although some are...try to take note of all types, and then decide which are the majority, too. Are some dimidiate? Also, agree on the nariform - mostly appressed. Any smaller ones in there between the primary radials? Those are unusual axials. Can you see the septa at all in them?

As far as radial openings are concerned, I would say 50/50 oval to round. If I had to make a choice I would say the majority is round.

No dimidiate radials, though I may have chipped a couple handling the piece, man made dimidiate.

No small radials between primaries, but there are some sub-imersed, round radials on the undersides of the branches.

No visible septa in axials under 30 power microscope.

Does the high number of oval radial opening disqualify my coral from the Latistella group?

I've looked at all of the corals in that group on the Whelk coral search web page and think all of those corals look similar to mine but none are exact. I know there is much greater variability that source simply can't handle.
Brad

[piercho]

Heck, I don't know. If I work by process of elimination, I seem to eliminate them all. So... latistella??
3-branch skeletal fragment (http://reefcentral.com/gallery/showphoto.php?photo=37759)
Front quarter shot of branches (http://reefcentral.com/gallery/showphoto.php?photo=37760)
Radial detail (http://reefcentral.com/gallery/showphoto.php?photo=37761)
[list=1]
Growth form: corymbose. Branches rising from fused base with anastomose branches between bases. Branches of 'mature' colony mine came from rising to uniform level like a tabletop.
Axials: very distinct and contribute the majority of branch width. Septa: 12. Cycles: 2. Primary series are distinct but with inconsistent protrusion. Each of the secondary series cannot be made out in each corallite. Septa do not protrude very far into corallite.
Radials: distinct from axials and tend to be consistent within zones. Septa: 12. Cycles: 2. The majority are appressed tubular much like fig 33 category C, a few are rounded tubular and are judged to be incipient axials.
Corralites in the fused area below the branches are sub-immerssed or immersed.
Coenosteum: This is where I get confused. I would call the entire branch, including radials costae, costate with simple spinnules. This doesn't fit with any of the group descriptions that otherwise match my piece. Below the branches, reticulate. Help with this would be appreciated.
[/list=1]

[EricHugo]

OK guys, major apologies for my absence on this thread. I will be with you all first thing in the morning now that I appear completely caught up on the board and with my email.

[EricHugo]

All right.

So, we are now to a species level, hopefully. If any of you have any questions about your respective corals and you want me to take a look and confirm or deny your analysis, please show the photos.

I have uploaded three documents to my website which I will need you to print. You will probably want to print multiple copies so you can write on them as you go.

This is the systematics key for Acropora. It does not work like other keys, and I actually like it better than most types. But, there are a lot of characters, and I know you guys will have questions about some of the categories. If you are not sure on your specimen, or it appears to have more than one character trait in a category, its ok.

What you will do is work through each category, and then put a black dot over every species in the list that does not have that character. Then, move to the next category and do the same. Eventually, you will have a list of one to several (or maybe many) species with the characters you have described.

If you are comfortable with your grouping designation based on the characters, you can get a big leg up by eliminating all species that do not appear in that group (I listed them earlier in this thread). If you are unsure, or have eliminated all but a few groups, it will still behelpful to eliminate down to the potential species of that group.

Once you are finished, let me know. Then, we can look at comparative photos for that group and do a final reanalysis by comparison to see if you can get the species from your sample.

The pages are at www.bchs.uh.edu/~coralreef

Click on graduate student research / my page "here"/research/aquarium related work/Acropora ID class

Have fun!!

[piercho]

Ugh..frames. For others trying to find these downloads, follow this path once you get to the "The Lab Of G.M. Wellington" page linked by Eric, above:

->Graduate Student Research
->Eric Hugo Borneman; visit his page
here
->Research
->Aquarium Related Works
And you will be on a page with links with these titles:
Wallace characters p. 1.
Wallace characters p. 2
Wallace characters p. 3

[piercho]

Well, I need some clarification with some character numbers.
2. Branching orders: “Tertiary or later orders present.” Don’t know what this means.
7 & 8. The coenostenum on mine has spinnules in rows, there is a low ridge along the row (“broken costate”, right?). The spinnules are tooth-like and separate. I would call them costate with simple spinnules. Would this character be “costate” or “open spinnules”?
11. Radial corallite inner wall: What is “developed”?
17. Branch thickness: My branch taper is conical. Would this be the average thickness, or at the base, or other?

TIA

[EricHugo]

OK

A single branch or the main branch is primary branching. A second set (major limbs) that comes off the main branch is secondary branching. Tertiary has branches off the second branch, etc.

Probably costate. Open spinnules are where the coenosteum is very open and proous and the spinnules just sort of seem to come up from the reticulate network.

A developed inner wall means its solid and flush, like a wall. If you look at others, the inner wall is rather concave and the septa just sort of appear from inside. Kind of hard to describe. Picture a coffee mug for a developed inner wall.

On tapering branches, I don't know. I would tend to take a middle branch reading. I might write to Carden and ask her that question...its a good one.

[piercho]

I went through the list and identified character states that I felt were strong eliminators. Then I went through the list and identifed the characters states I felt were strong identifiers. I was left with these specie:
acuminata (rare)
hyacinthus
anthocercis
cytherea
microclados
paniculata
indonesia
subulata
acuminata is far outside the grouping so I discarded it. The strongest distinguishing characteristic of those left was whether the radial coralite shape was nariform or dimidiate. Although I felt they were appressed tubular, nariform seemed the closest, so I picked that. That left microclados (http://whelk.aims.gov.au/coralsearch/html/001-100/Species%20pages/45.htm) and indonesia (http://whelk.aims.gov.au/coralsearch/html/601-700/Species%20pages/626.htm)
My branch pics are just a couple of posts back.

[EricHugo]

Hi Howard:

Um, I'm not sure you are on the right track here. The radials are spaced quite far apart, and that whole group is quite similar. Nicely done on the grouping, though. I think there is some character, though, that you have misinterpreted that put you into this group. This group tends to have more labellate and flaring radials that are more crowded. Ordinarily, you would expect some variability, but I'm really not seeing the similarity with your photos. Take another look if you want and see what you might have missed.

[piercho]

I'm not sure you are on the right track here. Agreed.The radials are spaced quite far apart, and that whole group is quite similar. I thought the character state was radials not touching, but I couldn't make it fit with the way I was going, so I rationalized I must be looking at them wrong. Same thing are the radial shape.Take another look if you want I did and came up with different grouping. Where I ended up, the coralites and branchlets seem better described, but the growth form seems wrong. I'll go through each character and maybe somebody can steer me in a better direction. TIA
I'll color some character states as follows:
picked state that is strong identifier
(state that is an eliminator)


branch formation: around single axial around more than one axial
branching orders: tertiary not present
colony outline: determinant
Predominant outline: corymbose (cuneiform, encrusting, elkhorn, plate, free-living aborescent)
Branch diameter: axial dominated (radial dominated)
Coenosteum: same on and between different coralites
Radial coralite coenosteum: broken costate
Between radials coenosteum: broken costate
Spinule shape:
Radial corallite sizes: one size or graded
Radial corallite inner wall:
Radial corallite: apressed tubular (dimidiate, conical, immersed)
Radial corallite openings: oval to rounded (chocleaform, dimidiate)
Axial/radial ratio: (many) (few)
Axial coralite outer diameter: small (2.5 mm) (big)
Radial coralites: small (very large, large)
Branch thickness: thin (super thick, thick)
Branch taper: tetrete (wedge)
Max branch length: (super short)
Radial crowding: don't touch (crowded)
Axial corallite syn rings: 2
Skeletal porosity: porous
Radial cor syn rings: 2
[/list=1]
That leaves me with these guys, mostly by elimination:
[list]
acuminata (http://whelk.aims.gov.au/coralsearch/html/001-100/Species%20pages/7.htm) - no
horrida (http://whelk.aims.gov.au/coralsearch/html/001-100/Species%20pages/34.htm) - no
vaughani (http://whelk.aims.gov.au/coralsearch/html/001-100/Species%20pages/78.htm) - not really
kirstyae (http://whelk.aims.gov.au/coralsearch/html/001-100/Species%20pages/38.htm) - sort of except growth form
derawanensis (http://whelk.aims.gov.au/coralsearch/html/601-700/Species%20pages/623.htm) - no
halmeaherac

Some notes on selected character states:
4. outline: I had to leave arborescent in to avoid eliminating everything. In my first attempt at this I eliminated that state.
5. branch diameter: I eliminate radial-dominated types, which eliminates a whole group of corymbose candidates starting with latistella. This is where I thought that my coral would be found. Maybe this is where I'm screwing up.
12 & 13. radials: I eliminate dimidiate candidates. I don't see notches in my radial cups, but maybe I don't understand this state.
18. taper: visually, conical. Measuring at below the first radials and above the last, tetrete.
19. max branch length: I added super-short as an eliminator. This knocks out my earlier picks of indionesia and microlados.

[JB NY]

I'm not sure I understand what the corallite synapticular rings are.

[EricHugo]

Hi Howard:

Some I cannot determine from your photos, some may not be able to be dtermined, and some are all yours to determine. Did you post a photo of the whole colonY.. I must be missing it, if so.

So, here'show I would answer based on what i can see from your corals (you should be able to do much better with it than me)

1. around single axial around more than one axial
2. can't tell (need to see whole colony)
3. can't tell (need to see whole colony)
4. can't tell (need to see whole colony)
5. axial dominated
6. can't tell from photo but appear to be different
7. can't tell
8. appears to be broken costate
9. can't tell
10. one size or graded
11. appears to be developed?
12. I'd probably call them nariform, but varied
13. oval to rounded
14. many
15. all yours
16. small to medium
17. all yours
18. terete
19. need to see whole colony, and may not be possible to determine unless mature
20. don't touch
21. can't tell
22. porous
23. can't tell

JB:

Look at the diagram on p. 54. That one has three synapticular rings. Synapticulae are the plates and rods and layers between the walls and rings can form from them...and sometimes they don't. So, you can see in that photo that there are three layers outside the axial wall, and all three form rings.

[piercho]

Thanks for taking the time, Eric. A few more questions:
[list=1]
Is character 5, Branch diameter axial or radial dominated, a good character to go by? Or could an axial-dominated branch in the tank be 50/50 in other circumstances?
Is character 20, radial crowding, a good character to go by? Does "radials don't touch" mean that non-axials absolutely never touch?
Is branch thickness a good indicator? Could a tank branch be much smaller than a wild branch?
[/list=1]
For my piece, judging the branch to be axial dominated and that the radials don't touch eliminates almost the entire list. You'd think this would be a good thing, but those specie that remain have poor correlation with the rest of the character states of the piece, especially branch thickness.

This is the last time I intend to bug you on this thread. I've got no special affection for Acroporas, and my interested:having to think hard character state is starting to be a fractional number. Anyway, I now have a vague notion about what such a thing as "coenosteum" is, which I think has it's own worth, even if I can't tell my Acropora from a ham sandwich.

[JB NY]

After a crazy amount of time looking at my branch, the Wallace book and this thread, here is what I've come up with.

Here is another picture of my coral from the first page.

When I first bought the coral
http://www.cnidarianreef.com/images/animals/DSCN3117.jpg

Now
http://www.cnidarianreef.com/images/animals/DSCN4178.jpg

Growth Form
caespitose-corymbose

axials
Septa: six primary. No secondary.
Septal lenght: mostly equal
Cycles of septal: One cycle
Septal height: not exsert
septal dentition: forms comb rows (not 100% on this as it's hard to see)
Paliform structures: absent

Radials
One type of radial corallite
Radial corallites are 'appressed'.
Radial corallite opening is dimidiate.
Radial corallite shape is nariform.
Nariform with elongate (looks oval shape) openings (picture I on p 56)
No septa in radials, Larger radials that look as if they will form axials, have 4 radials.

Coenosteum
Coenosteum between radials is costate or broken costate.
Top edges of the costae contain spinnules that are shark-like.
Costate with spinule development. Closest to picture E on p 57

Grouping
Acropora latistella also thought maybe nasuta.

[JB NY]

1.branch formation: 0
2.branching orders: 1
3.colony outline: 0
4.Predominant outline: 5
5.Branch diameter: 0
6.Coenosteum: 0
7.Radial coralite coenosteum: 0
8.Between radials coenosteum: 0
9.Spinule shape: 6
10.Radial corallite sizes: 0
11.Radial corallite inner wall: 1 ?
12.Radial corallite shape: 0
13.Radial corallite openings: 1
14.Axial/radial ratio: 1
15.Axial coralite outer diameter: 2
16.Radial coralites: 3
17.Branch thickness: 2
18.Branch taper: 1
19.Max branch length: 2
20.Radial crowding: 0
21.Axial corallite syn rings: 0
22.Skeletal porosity: 0
23.Radial cor syn rings: 0

<b>click for larger image</b>
<a href="http://www.cnidarianreef.com/images/misc/acro01_DSCN4305.JPG" target="_blank"><img src="http://www.cnidarianreef.com/images/misc/acro01_DSCN4305_sm.JPG" border="0" alt=""></a> <a href="http://www.cnidarianreef.com/images/misc/acro01_DSCN4314.JPG" target="_blank"><img src="http://www.cnidarianreef.com/images/misc/acro01_DSCN4314_sm.JPG" border="0" alt=""></a>

<a href="http://www.cnidarianreef.com/images/misc/acro01_DSCN4315.JPG" target="_blank"><img src="http://www.cnidarianreef.com/images/misc/acro01_DSCN4315_sm.JPG" border="0" alt=""></a> <a href="http://www.cnidarianreef.com/images/misc/DSCN4322.jpg" target="_blank"><img src="http://www.cnidarianreef.com/images/misc/DSCN4322_sm.jpg" border="0" alt=""></a>

Narrowing it down to the corals in the latistella and nasuta groups

species/score

latistella/13
subulata/10
nana/10
aculeus/12

nasuta/8
cerealis/10
valida/10
secale/7
lutkeni/7
kimbeensis/10

So based on score I am closest to latistella but looking at the Wallace skeletal pictures, I feel it looks to be closest to cerealis.

[JB NY]

Hi Eric,

Now that your back, do you have time to start this thread up again?

[greenbean36191]

Kind of off topic, but is there any way to do something like this with montis, or is there too much variation within a species to be able to ID them by the skeleton? I just thought it might be interesting to see how many people's "caps" are really caps.

[NuclearReefs]

wow,, i got some catching up to do,LOL Great thread eric .just not one to start at 1am reading...:)

[NuclearReefs]

wow,, i got some catching up to do,LOL Great thread eric .just not one to start at 1am reading...:)

[bskiba]

Bump...........

[cabrerad]

I thought I would finish to species to catch up (after a long break) in case this starts up again:

First, after re-evaluating, I concluded my group was nasuta:

Some of the species characteristics were identical for all the species in the group and some I could not ID in my acro with any degree of certainty (the synapticicular rings). Lucky for me these rings were identical in all the species except for one which I was able to eliminate due to other characters. I'll use JB NY's abbreviations for consistency (hope you don't mind)

1.branch formation: 0
2.branching orders: 1
3.colony outline: All species identical (mine is frag so can't tell)
4.Predominant outline: All species identical (mine is frag so can't tell)
5.Branch diameter: 1
6.Coenosteum: 0
7.Radial corallite coenosteum: 1
8.Between radials coenosteum: 1
9.Spinule shape: 5,6
10.Radial corallite sizes: 0
11.Radial corallite inner wall: 0
12.Radial corallite shape: 0, 4
13.Radial corallite openings: 0
14.Axial/radial ratio: 1
15.Axial corallite outer diameter: 2
16.Radial corallites: 2
17.Branch thickness: 1
18.Branch taper: 2
19.Max branch length: all identical (mine is frag)
20.Radial crowding: 1
21.Axial corallite syn rings: can't tell
22.Skeletal porosity: 1
23.Radial corallite syn rings: can't tell


So counts are (number of matching characters out of 18:

A. nasuta: 14
A. cerealis: 16
A. valida: 15
A. arabensis: eliminated due to geography
A. secale: 13
A. lutkeni: 12
A. kimbeensis: 13



So A.cerealis wins by score and a closer look at the two species. One major difference between A. valida and A. cerealis was that the latter has rather uniform reticulate structure adjacent to the radials and between the radials. In addition, the skeletal characteristics more closely match that in Corals of the World. My sample does not exhibit any of the tubular radials with unique bulge and round opening seen in A. valida. The description that the radials begin appressed and flare out more as they reach the axial corallite also matches my coral. One character that matches A. valida is branch thickness, but my thickness at 10 mm is near the intersection of the characters for the two species. As a result, I am fairly confident mine is A. cerealis.

David

[EricHugo]

good job, David. I have had a lot of requests to pick this back up. If there is a demand, we can do it all again and get some more practice. Maybe you guys can help me on some corals I am currently working on as new species or rage extensions from a recent trip to Easter Islands...at least one Letastrea and at least one Psammacora....its been fun, and we are now working on writing up a revision of the scleractinia of Easter Island.

[cabrerad]

Thanks Eric,


I am in for doing it again whether it is Acropora or another genus. Sorry for the late reply, I am moving into a new house and got a puppy..talk about busy. But that should be over with after this week anyways.

David

[EricHugo]

Let's try an easier one....I'll post a date when I have some time to devote to it....maybe a faviid or something with bigger polyps.

[Anthony Calfo]

Do monotypic corals count? :p

[EricHugo]

rotflmao. absolutely. In fact, that might be the best to start with. Although, I see single polyps of Lobophyllia being sold as Cynarina or Scolymia, and Scolymia is often confused with the monotypic Cynarina. But...maybe Nemenzophyllia? ehhehehehe

[greenbean36191]

Fungiids maybe?

[shane 1111]

how about Acanthastrea

[JB NY]

Are you going to drop that $200 a polyp acan in bleach? :lol:

[shane 1111]

one polyp yes. and the most i have spent is $50 per polyp.

[EricHugo]

I think, seriously, that we should do Acanthastrea. I think the timing is perfect right now...and also for Blastomussa. They are large, have disitnct features, and will be so opportune insofar as people actually paying such sums for corals that are almost assuredly misidentified.

Want to make a go of it? I have a potential donor, and have one bleached colony in my collection of Acanthastrea, and several Blastomussa.

[cabrerad]

I am in as long as I can find a donor. Don't have either Genus myself.

David

[EricHugo]

OK - how about any faviid or mussid? Lots of choices but good characters to use and larger polyps to see the characters.

[piercho]

I would participate. A branching hammer would be the easiest larger polyped coral, for me. I have a couple of bigger Favias that I could break off some to bleach, as well.

[cabrerad]

Sounds good to me

[EricHugo]

All right - show of hands for participants and the coral they choose.

Go ahead and break off a section of the coral with at least a few representative polcyps/corallites, and place in bleach till you get a nice clean skeleton. Remove excess tissue with strong water flow...like an outdoor hose or the sprayer on your sink...or a water pik if you have one.

Let me know when you are ready. For Euphllids, live polyps are also important, so photos and notes prior to the bleaching are important.

[cabrerad]

I am in. I am going to use two different Caulastrea. I have always wondered if they are furcata or something else.

David

[piercho]

I just moved my household Saturday and don't know where the camera is so pictures may be lagging. I will try two or three, the Favia is large and attached to a large piece of rock so maybe not that one. Initial identifications:

Euphyllia paraancora
Favia sp.
Unknown, looks Favites-like.

Common fellas, don't be a baby, get a hammer and chisel and join in.

[goblinsharkman]

Aww... did this thread die again? I was just running to get a skeleton to identify.... Are you starting class again for this new semester? :)

[EricHugo]

Yeah...I will.

I'll start one over this weekend.

Remind me.

[goblinsharkman]

Forgot to remind you on the phone. Oh well, hopefully youll remember :) I have a little skeleton that I have a species name for, but I want to see if it really is that species!

[EricHugo]

shoot - see what happens? Ok, I'll take some photos tonight and post them.

[EricHugo]

No, I didn't forget. My camera died. A new one is on the way - hang tight.

[mike89t]

Just starting to research Acros and this is a very cool thread! Mind blowing stuff.

:bum: