Rugosa
Rugosa Temporal range:
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Solitary rugose coral Grewingkia canadensis in three views; Ordovician, Indiana | |
Scientific classification | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Cnidaria |
Class: | Hexacorallia |
Subclass: | †Rugosa Milne Edwards & Haime 1850[1] |
Suborders | |
The rugosa, also called the tetracorallia or horn coral, are an extinct order of solitary and colonial corals that were abundant in Middle Ordovician to Late Permian seas.[3]
Solitary rugosans (e.g.,
Rugose corals have a skeleton made of
Morphology
Rugose corals always show tabulae, horizontal plates that divide the corallite skeleton. The corallites are usually large relative to different types of coral. Rugose corals will sometimes have dissepiments, which are curved plates connected to septa and tabulae. The symmetry can be distinguished by the orientation of septa in a transverse section of the coral. Rugose corals always display bilateral symmetry whereas tabulate and scleractinian corals show radial symmetry. Initially there are only 4 major septa; later minor septa are added in the 4 resulting spaces. The complex arrangement of septa is diagnostic of rugose corals. Rugose corals will also always have a columella, an axial rod which supports the septa running up the center of the corallite. It is present in rugose corals because they were mainly solitary and so required the extra support. Tabulate corals have no columella because they were always colonial and relied on the support of neighboring corallites.[6]
References
- ^ "Rugosa". WoRMS. World Register of Marine Species. 2015.
- ^ "order Stauriida Verrill 1865 (horn coral)". Fossilworks. Retrieved 17 December 2021.
- ^ "Rugosa". www.encyclopedia.com. A Dictionary of Earth Sciences. Retrieved 20 February 2017.
- PMID 24587277.
- . Retrieved 2015-06-18.
- ISBN 9780521270281.