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| Rugose coral. Image credit: paleo.cortland.edu |
This post will look at three types of corals; rugose, tabulate and scleractinian.
First of all, there is the geological context of these corals, in partcular what age the sediments will be that you find them in. Rugose corals are found in Ordovician to Permian sediments, being wiped out at the Permian extinction. Tabulate corals also have the same range, so this would not be useful if you were trying to differentiate the two using geology. However, scleractinian corals have a younger range, from the Triassic to recent times. giving a feature to differentiate this coral from the other two.
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| Tabulate coral. Image credit: fossillady.wordpress.com |
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| Scleractinian coral. Image credit: hoopermuseum.earthsci.carleton.ca |
Scleractinian and Rugose corals both also have well developed septa, so this cannot be used to tell the difference. But again, tabulate corals have weak or absent septa. The tabulae can be used to identify Scleractinians easily as they are usually absent in these corals. They are well developed in tabulate and most rugose possess tabulae.
Symmetry is useful for differentiating Rugose corals from tabulate and scleractinians. The symmetry in rugose is bilateral, meaning that two identical halves can be created, humans are bilaterally symmetrical. However, tabulates and scleractinians have radial symmetry.
Scleractinian skeletons are made from aragonite which is unstable in fossilisation, whereas the tabulate and rugose corals have calcite skeletons.
Summary:
Rugose: Ordovician to Permian. Well developed septa. Bilaterally symmetrical. Colonial and solitary. Most possess tabulae. Calcite skeleton.
Tabulate: Ordovician to Permian. Weak or absent septa. Radial symmetry. Always colonial. Well developed tabulae. Calcite skeleton.
Scleractinian: Triassic to Recent. Well developed septa. Radial symmetry. Colonial and solitary. Absent tabulae. Aragonite skeleton.
Did you find this helpful? Let me know what you think in the comments.
18 comments:
Helpful. In identification and age difference.
Thank you, I'm glad you found it helpful!
Great
So would UNPAIRED septa, as in tube anemones and black corals, be rugose or just an odd kind of scleractinian coral? I may be out of my league, no pun intended, but trying to understand differences between black corals and tube anemones. So cool that this site exists, thank you!
Although the anemones and corals are both anthozoans, anemones are of the order Actiniaria thus separate form the order Scleractinia. I'm very glad you found and enjoyed this page! Thank you
Its helpful to me,between the three of them. Thank you so much. I think I should visit this page often. 👍👍
Love This Page. In college and this really helps.
Very helpful
This helped SO much! I was doing a project on Lophophyllidium Proliferum (of Rugose), and this helped a lot.
Very helpful.... Thank you
Very helpful
Thanks very much
How common is this to dine in your backyard?
*find
Very helpful
Yes, this was helpful. I presume the calcitic nature of both Rugosa and Tabularia makes it diffucult to conside them as ancestral to Scleratinia?
Very cool stuff 👍👍👍👍👌👌👌👌
-I found one a couple of days ago . I have no clue what to do with it .
-its covered in this like super brown sand on it it comes off but it'll stain my brush like if it was a brown eyeshadow
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