# Derwentiinae

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Extinct subfamily of amphibians

Derwentiinae Temporal range: Permian - Triassic Deltasaurus kimberleyensis Scientific classification Kingdom: Animalia Phylum: Chordata Clade: Tetrapoda Order: †Temnospondyli Suborder: †Stereospondyli Family: †Rhytidosteidae Subfamily: †Derwentiinae Dias-da-Silva and Marsicano, 2011 Subgroups See text

**Derwentiinae** is a [subfamily](/source/Subfamily_(biology)) of [rhytidosteid](/source/Rhytidosteid) [temnospondyls](/source/Temnospondyl) from the [Permian](/source/Permian) and [Triassic](/source/Triassic) periods of [Australia](/source/Australia) and [India](/source/India). It includes the genera *[Arcadia](/source/Arcadia_(genus))*, *[Deltasaurus](/source/Deltasaurus)*, *[Derwentia](/source/Derwentia_(amphibian))*, *[Indobrachyops](/source/Indobrachyops)*, and *[Rewana](/source/Rewana)*. Derwentiinae was named in a 2011 study that analyzed the [phylogenetic](/source/Phylogenetic) relationships of rhytidosteids. It was a replacement name for the family Derwentiidae, which was named in 2000.

## Description

Like many other Permian and Triassic temnospondyls, derwentiines are known primarily from their skulls, which are triangular or rounded when viewed from above. Derwentiines are diagnosed as a [clade](/source/Clade) (evolutionary grouping) by several shared characteristics or [synapomorphies](/source/Synapomorphies): a [palate](/source/Palate) with a nearly straight back margin, a [parasphenoid](/source/Parasphenoid) bone at the back of the palate that is covered in small bumps, an [ectopterygoid](/source/Ectopterygoid) bone on the palate that forms part of the border of a large hole called the [subtemporal fossa](https://en.wikipedia.org/w/index.php?title=Subtemporal_fossa&action=edit&redlink=1), and a [postorbital bone](/source/Postorbital_bone) behind the eye that is rounded or squarish. Although derwentiines are considered the most [derived](/source/Synapomorphy) rhytidosteids, the last characteristic is shared with the most primitive rhytidosteids and non-rhytidosteid temnospondyls, suggesting an evolutionary reversal. The small bumps covering the parasphenoid are an unambiguous synapomorphy because the characteristic is only in derwentiines, while all other synapomorphies are ambiguous because they are also present in some other temnospondyls such as *[Chomatobatrachus](/source/Chomatobatrachus)* and *[Lapillopsis](/source/Lapillopsis)*.[1]

## Classification

Derwentiidae was named in 2000 as a family of Australian temnospondyls in the suborder [Stereospondyli](/source/Stereospondyli). The subfamily Derwentiinae was named in 2011 as a replacement for Derwentiidae because all of these Australian temnospondyls were found to be members of the family Rhytidosteidae. The 2011 analysis also placed *Indobrachyops* from India in Derwentiinae as the first non-Australian member of the group. Below is a [cladogram](/source/Cladogram) from the analysis, showing the phylogenetic relationships of derwentiines and other stereospondyls:[1]

Stereospondyli Benthosuchus Watsonisuchus Uruyiella Peltobatrachus Rhineceps Australerpeton Rhytidosteus Lapillopsis Lydekkerina Trematosauria Trematosaurus Luzocephalus Chomatobatrachus Brachyopoidea Bothriceps Xenobrachyops Keratobrachyops Rhytidosteidae Nanolania Trucheosaurus Boreopelta Peltostega Pneumatostega Sangaia Mahavisaurus Derwentiinae Deltasaurus Arcadia Rewana Acerastia Derwentia Indobrachyops

## References

1. ^ [***a***](#cite_ref-DSM11_1-0) [***b***](#cite_ref-DSM11_1-1) Dias-da-Silva, S.; Marsicano, C. (2011). "Phylogenetic reappraisal of Rhytidosteidae (Stereospondyli: Trematosauria), temnospondyl amphibians from the Permian and Triassic". *Journal of Systematic Palaeontology*. **9** (2): 305–325. [doi](/source/Doi_(identifier)):[10.1080/14772019.2010.492664](https://doi.org/10.1080%2F14772019.2010.492664). [hdl](/source/Hdl_(identifier)):[11336/68471](https://hdl.handle.net/11336%2F68471).

v t e Stereospondyli Kingdom: Animalia Phylum: Chordata Clade: Tetrapodomorpha Order: Temnospondyli Tetrapodomorpha see Tetrapodomorpha Temnospondyli see Temnospondyli Stereospondyli see below↓ Stereospondyli Stereospondyli Arachana Capulomala Peltobatrachus Lapillopsidae Lapillopsis Manubrantlia Rhigerpeton Rotaurisaurus Rhinesuchidae Australerpeton? Broomistega Laccosaurus Parapytanga? Rastosuchus Rhineceps Rhinesuchoides Rhinesuchus Uranocentrodon Lydekkerinidae Chomatobatrachus Cryobatrachus Deltacephalus Eolydekkerina Indobenthosuchus Luzocephalus? Lydekkerina Capitosauria Antarctosuchus Bukobaja Calmasuchus Capitosaurus Cherninia Cyclotosaurus Edingerella Eocyclotosaurus Eryosuchus Heptasaurus Huangfuchuansuchus Jammerbergia Kestrosaurus Kupferzellia Mastodonsaurus Meyerosuchus Odenwaldia Paracyclotosaurus Parotosuchus Quasicyclotosaurus Procyclotosaurus Promastodonsaurus Rhadalognathus Samarabatrachus Sassenisaurus Sclerothorax Selenocara Stanocephalosaurus Stenotosaurus Subcyclotosaurus Tatrasuchus Vladlenosaurus Volgasaurus Volgasuchus Warrenisuchus Watsonisuchus Wellesaurus Wetlugasaurus Xenotosuchus Yuanansuchus Trematosauria see below↓ Trematosauria Trematosauria Almasaurus Bothriceps Callistomordax Chinlestegophis Keratobrachyops Laidleria Latiscopus Qantas Rileymillerus Syrtosuchus Uruyiella Benthosuchidae Benthosuchus Kwatisuchus Trematosauridae Angusaurus Aphaneramma Cosgriffius Erythrobatrachus Gonioglyptus Hyperokynodon Icanosaurus Indolyrocephalus Inflectosaurus Lyrocephaliscus Microposaurus Panchetosaurus Platystega Prothoosuchus Stoschiosaurus Tertrema Tertremoides Thoosuchus Tirraturhinus Trematolestes Trematosuchoides Trematosaurus Trematosuchus Trematotegmen Wantzosaurus Metoposauridae Anaschisma Apachesaurus Arganasaurus Buettnererpeton Dutuitosaurus Metoposaurus Panthasaurus Rhytidosteidae Boreopelta Mahavisaurus Nanolania Peltostega Pneumatostega Rhytidosteus Sangaia Trucheosaurus Derwentiinae Arcadia Acerastia Deltasaurus Derwentia Indobrachyops Rewana Chigutisauridae Arenaerpeton Chigutisaurus Compsocerops Koolasuchus Pelorocephalus Siderops Brachyopidae Banksiops Bathignathus Batrachosaurus Batrachosuchoides Batrachosuchus Blinasaurus Brachyops Gobiops Hadrokkosaurus Notobrachyops Platycepsion Sinobrachyops Vanastega Vigilius Xenobrachyops Plagiosauridae Gerrothorax Megalophthalma Plagiobatrachus Plagiorophus Plagiosaurus Plagioscutum Plagiosternum Plagiosuchus See also: Trematosauroidea Metoposauroidea Rhytidosteoidea Brachyopomorpha Brachyopoidea Plagiosauroidea Category

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Adapted from the Wikipedia article [Derwentiinae](https://en.wikipedia.org/wiki/Derwentiinae) by Wikipedia contributors ([contributor history](https://en.wikipedia.org/wiki/Derwentiinae?action=history)). Available under [Creative Commons Attribution-ShareAlike 4.0 International](https://creativecommons.org/licenses/by-sa/4.0/). Changes may have been made.