Spiriferida

Spiriferida
Temporal range: Late Ordovician–Triassic
Mucrospirifer mucronatus
Scientific classification Edit this classification
Kingdom: Animalia
Phylum: Brachiopoda
Class: Rhynchonellata
Order: Spiriferida
Waagen, 1883
Subgroups

See text.

Spiriferida is an extinct order of brachiopods, known from the Ordovician to the Triassic.

Description

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The order Spiriferida belongs to the subphylum Rhynchonelliformea, approximately corresponding to the former subphylum Articulata (articulate brachiopods) characterised by calcareous shell with teeth and sockets, and to the class Rhynchonellata defined on the basis of the shell microstructure.[1]

Spirifer striatus, a Carboniferous spiriferide: the top image shows the dorsal view of an articulated shell; the bottom image shows the ventral valve (the dorsal one has been removed) allowing to notice the spiralium (laterally oriented cones forming the skeleton of the lophophore)

The spiriferides are characterised by a spiralium (skeleton of the lophophore) that is oriented laterally or postero-laterally, the absence of a jugum (an element of the skeleton linking two spiralian cones), and an impunctate shell.[2] The two latter characters allow the distinction between the orders Spiriferida and Spiriferinida (the latter having a punctate shell and a jugum).[2] These two orders were merged in older brachiopod systems, which explains information about Jurassic spiriferides being found in older sources.[3][4] The feature that gives both the spiriferides and the spiriferinides their name ("spiral-bearers") is the internal support for the lophophore; this brachidium (more precisely, a spiralium), which is sometimes preserved in fossils, is a thin ribbon of calcite that is coiled tightly within the shell forming a cone.[5]

Externally, the spiriferides are known for their costate shells with a long hinge-line, which is often the widest part of the shell. In some genera (e.g. Mucrospirifer) it is greatly elongated, giving them a wing-like appearance. They often have a deep fold down the center of the shell. However, some spiriferides have quite different shell shapes.[5]

Stratigraphic range

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Spiriferides first appear in the Late Ordovician with the appearance of Eospirifer radiatus. They increased in diversity throughout the Silurian and underwent a dramatic evolutionary radiation during the Devonian period, reaching peak development in variety and numbers. Spiriferida survived the great Permian extinction (albeit at much less diversity), finally becoming extinct during the Triassic.[6][5]

A Devonian spiriferide brachiopod from Ohio which served as a host substrate for a colony of hederellids.

Taxonomy

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Order Spiriferida

References

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  1. ^ Williams, Alwyn; Carlson, Sandra J.; Brunton, C. Howard C.; Holmer, Lars E.; Popov, Leonid (January 1997). "A supra-ordinal classification of the Brachiopoda". Philosophical Transactions of the Royal Society of London. Series B: Biological Sciences. 351 (1344): 1171–1193. doi:10.1098/rstb.1996.0101.
  2. ^ a b Carter, J.L. & Johnson, J.G. (2006) Spiriferinida, [In:] Roger L. Kaesler (ed.), Treatise on Invertebrate Paleontology, Part H, Brachiopoda, Revised. Volume 5: Rhynchonelliformea (part), Boulder, Colorado–Lawrence, Kansas: Geological Society of America and University of Kansas Press, pp. 1877–1937.
  3. ^ Moore, Raymond C., ed. (1965). Treatise on invertebrate paleontology : pt. H Brachiopoda. Internet Archive. Boulder, CO : Geological Society of America ; Lawrence, KS : University of Kansas. ISBN 978-0-8137-3008-0.
  4. ^ Barnes BD, Sclafani JA, Zaffos A (April 2021). "Dead clades walking are a pervasive macroevolutionary pattern". Proceedings of the National Academy of Sciences of the United States of America. 118 (15). doi:10.1073/pnas.2019208118. PMC 8053996. PMID 33827921. S2CID 233184869.
  5. ^ a b c Carter, J.L., Johnson, J.G., Gourvennec, R. & Hou Hong-fei (2006) Spiriferida, [In:] Roger L. Kaesler (ed.), Treatise on Invertebrate Paleontology, Part H, Brachiopoda, Revised. Volume 5: Rhynchonelliformea (part), Boulder, Colorado–Lawrence, Kansas: Geological Society of America and University of Kansas Press, pp. 1689–1876.
  6. ^ Zhan, RenBin, JiSuo Jin, Yan Liang, and LingKai Meng. "Evolution and paleogeography of Eospirifer (Spiriferida, Brachiopoda) in Late Ordovician and Silurian." Science China Earth Sciences 55, no. 9 (2012): 1427–1444.