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3 Classification
Brachiopod Taxonomy
Extant taxa in green, extinct taxa in grey
after Williams, Carlson, and Brunton, 2000
|
| Subphyla | Classes | Orders | Extinct
|
|---|
| Linguiliformea | Lingulata
| Linguilida | no
|
| Siphonotretida | Ordovician
|
| Acrotretida | Devonian
|
| Paterinata | Paterinida | Ordovician
|
| Craniformea | Craniforma
| Craniida | no
|
| Craniopsida | Carboniferous
|
| Trimerellida | Silurian
|
| Rhychonelliformea
| Chileata
| Chileida | Cambrian
|
| Dictyonellidina | Permian
|
| Obolellata | Obolellida | Cambrian
|
| Kutorginata | Kutorginida | Cambrian
|
| Strophomenata
| Orthotetidina | Permian
|
| Triplesiidina | Silurian
|
| Billingselloidea | Ordovician
|
| Clitambonitidina | Ordovician
|
| Strophomenida | Carboniferous
|
| Productida | Permian
|
| Rhynchonellata
| Protorthida | Cambrian
|
| Orthida | Carboniferous
|
| Pentamerida | Devonian
|
| Rhynchonellida | no
|
| Atrypida | Devonian
|
| Spiriferida | Jurassic
|
| Thecideida | no
|
| Athyridida | Cretaceous
|
| Terebratulida | no
|
In older classification schemes, phylum Brachiopoda was divided into two classes: Articulata and Inarticulata. Since most orders of brachiopods have been extinct since the end of the Paleozoic Era, classifications have always relied extensively on the morphology (that is, the shape) of fossils. In the last 40 years further analysis of the fossil record and of living brachiopods, including genetic study, has lead to changes in taxonomy. The taxonomy is still unstable, however, so different authors have made different groupings. In the their 2000 article as part of the Treatise on Invertebrate Paleontology, Alwyn Williams, Sandra J. Carlson, and C. Howard C. Brunton present current ideas on brachiopod classification; their grouping is followed here. They subdivide Brachiopoda into three subphyla, eight classes, and 26 orders. These categories are believed to be approximately phylogenetic. Brachiopod diversity declined significantly at the end of the Paleozoic. Only five orders in three classes include forms which survive today. Compare this to the mid- Silurian Period, when 16 orders of brachiopods coexisted.
4 External links
5 Reference
- Williams, A., Carlson, S.J., and Brunton, C.H.C. (2000). "Brachiopod classification" in v. 2 of Williams, A. et al. Brachiopoda (revised), part H of Treatise on Invertebrate Paleontology (Kaesler, R.L., ed.). Boulder, Colorado: Geological Society of America and Lawrence, Kansas: The University of Kansas (BooksEnthsiast.com)
Fossils
