Isastrea
{{Short description|Extinct genus of corals}}
{{Automatic taxobox
| fossil_range = {{fossil range|Jurassic|Cretaceous|ref={{#tag:ref|Sources variously indicate Jurassic, Middle–Late Cretaceous, and Jurassic–Cretaceous.|group=note}}}}
| image = Isastrea richardsoni.jpg
| image_caption = I. richardsoni showing calyces at various levels of magnification
File:Fossil Isastrea sp from Middle Jurassic, Tabas, Iran.jpg
| taxon = Isastrea
| authority = Milne-Edwards & Haime, 1851{{cite web | url=https://paleobiodb.org/classic/checkTaxonInfo?taxon_no=54179 | title=Isastrea | work=The Paleobiology Database | access-date=March 8, 2012}}
}}
Isastrea is an extinct genus of corals that lived during the Jurassic and Cretaceous periods.{{cite book | title=Fossil Invertebrates | publisher=Harvard University Press | author=Taylor, Paul D. | year=2005 | isbn=0674025741 | chapter-url=https://books.google.com/books?id=7kPwZ2LeSAoC&pg=PA31 | chapter=Living in Colonies | page=31 | edition=reprint, illustrated |author2=Lewis, David N. | chapter-format=Google eBook}} Its fossils have been found in Europe, Africa, North America, Asia and South America.
Description
Isastrea belonged to a group known as the hexacorals, so named for the shape of each individual polyp skeleton (corallite). Each corallite was between {{convert|3|mm|in}} and {{convert|15|mm|in}} in diameter. In addition, 30–80 septa (walls dividing body cavities) were present in each animal. Its walls were "weak, discontinuous or absent". In some species, adjacent septa would fuse. Dissepiments ("small blistery plates" serving the purpose of internal support) were plentiful in the animal. Columella (central "rod- or plate-like" structures) were present as well, but were not very strong.{{cite book | editor-first=Joanna | editor-last=Potts | title=Firefly Guide to Fossils | publisher=Firefly Books | year=2003 | edition=first | location=Buffalo, New York | pages=[https://archive.org/details/guidetofossilsfi00fire/page/62 62–63, 71] | isbn=1552978125 | url-access=registration | url=https://archive.org/details/guidetofossilsfi00fire/page/62 }} The genus is believed to have lived in colonies (each of which could have been {{convert|39|in|m}} long) and formed coral reefs. The colonies were "massive", "encrusting, platey, dome-shaped or sometimes ramose". It was a hermatypic coral, which require "warm, clear, shallow water" and live in symbiotic relationships with algae. It is also likely that zooxanthellae (a kind of protozoa) lived on the coral. It has been theorized that Isastrea could endure lower temperatures than most other hermatypic corals because it occurs farther north than them.{{cite book | title=Prehistoric Life: The Definitive Visual History of Life on Earth | publisher=Dorling Kindersley | last=Palmer | first=Douglas | year=2009 | edition=first American | location=New York | page=236 | isbn=9780756655730|display-authors=etal}}
File:Fossil_Isastrea_coral_from_Middle_Jurassic,_Tabas,_Iran_01.jpg
Species and fossil sites
At least 49 species of Isastrea have been described. Milne-Edwards and Haime originally described the following species of Isastrea:
{{columns-list|colwidth=30em|
- I. oblonga from the Portland stone{{sfn|Milne-Edwards & Haime|1850–1854|p=74}}
- I. explanata and I. greenoughi from the coral rag{{sfn|Milne-Edwards & Haime|1850–1854|pp=94, 96}}
- I. conybearii, I. limitata, I. explanulata, and I. serialis from the Great Oolite{{sfn|Milne-Edwards & Haime|1850–1854|pp=113–16}}
- I. richardsoni, I. tenuistriata, and I. lonsdalii from the Inferior Oolite{{sfn|Milne-Edwards & Haime|1850–1854|pp=138–9}}
}}
References
= Notes =
{{Reflist|group=note}}
= Inline citations =
{{Reflist|2}}
= General references =
{{refbegin}}
- {{cite book|title=A Monograph of the British Fossil Corals|last1=Milne-Edwards|first1=H.|last2=Haime|first2=Jules|location=London|year=1850–1854|publisher=Palæontographical Society|url=https://books.google.com/books?id=8v3pjSkVcC8C|ref={{SfnRef|Milne-Edwards & Haime|1850–1854|format=Google eBook}}}}
{{refend}}
{{Taxonbar|from=Q6079002}}
Category:Prehistoric Hexacorallia genera
Category:Mesozoic invertebrates
Category:Jurassic animals of Europe
Category:Cretaceous animals of Africa
Category:Mesozoic animals of Asia
Category:Mesozoic animals of North America
Category:Mesozoic animals of South America
Category:Fossil taxa described in 1851