# Arachana

> Mediated Wiki article. Canonical URL: https://mediated.wiki/source/Arachana
> Markdown URL: https://mediated.wiki/source/Arachana.md
> Source: https://en.wikipedia.org/wiki/Arachana
> Source revision: 1341690344
> License: Creative Commons Attribution-ShareAlike 4.0 International (https://creativecommons.org/licenses/by-sa/4.0/)

Extinct genus of amphibians

Arachana Temporal range: Late Permian or Early Triassic Scientific classification Kingdom: Animalia Phylum: Chordata Clade: Tetrapoda Order: †Temnospondyli Suborder: †Stereospondyli Genus: †Arachana Piñeiro et al., 2012 Type species †A. nigra Piñeiro et al., 2012

***Arachana*** is an [extinct](/source/Extinct) [genus](/source/Genus) of [rhinesuchid](/source/Rhinesuchid)-like [temnospondyl](/source/Temnospondyl) known from the [Late Permian](/source/Late_Permian) to [Early Triassic](/source/Early_Triassic) [Buena Vista Formation](/source/Buena_Vista_Formation) of northeastern [Uruguay](/source/Uruguay). *Arachana* was first named by Graciela Piñeiro, Alejandro Ramos and Claudia Marsicano in [2012](/source/2012_in_paleontology) and the [type species](/source/Type_species) is *A. nigra*. It shares characteristics with both rhinesuchids and [lydekkerinids](/source/Lydekkerinid), making it a transitional form between basal and more advanced [stereospondyls](/source/Stereospondyl).[1]

## Description

*Arachana* is known from the [holotype](/source/Holotype) FC-DPV 1369, a three-dimensionally preserved nearly complete [skull](/source/Skull) that has not been distorted. It was collected in the Colonia Orozco locality from the [Buena Vista Formation](/source/Buena_Vista_Formation) of the [Norte Basin](https://en.wikipedia.org/w/index.php?title=Parn%C3%A1_Basin&action=edit&redlink=1). The formation spans the boundary between the [Permian](/source/Permian) and the [Triassic](/source/Triassic), and it is uncertain whether FC-DPV 1369 was found in rocks above or below the boundary.[1]

*Arachana* shares several characters with [rhinesuchids](/source/Rhinesuchid). For example, it has a large head with [orbits](/source/Orbit_(anatomy)) or eye sockets placed slightly behind the mid-length of the skull. The surface of the skull is deeply pitted and the margins of the cheek regions are smooth and convex. The [basioccipital](/source/Basioccipital) bone at the back of the skull is small. On the [palate](/source/Palate), the [pterygoid bone](/source/Pterygoid_bone) is connected to the [vomer](/source/Vomer) by a projection called the palatal ramus. The ramus separates the interpterygoid vacuities, two large holes in the palate. In many temnospondyls, the [palatine](/source/Palatine_bone) and [ectopterygoid bones](https://en.wikipedia.org/w/index.php?title=Ectopterygoid_bone&action=edit&redlink=1) also touch the vacuities, but in *Arachana* and rhinesuchids, the palatine ramus excludes these bones from the vacuity margins.[1]

*Arachana* also has characteristics of a more [derived](/source/Synapomorphy) group of stereospondyls called [lydekkerinids](/source/Lydekkerinid). In both *Arachana* and lydekkerinids, the [otic notch](/source/Otic_notch) in the back of the skull is shallow and is not touched by the [supratemporal bone](/source/Supratemporal_bone) as is otherwise the case in temnospondyls. Sensory [sulci](/source/Sulci), grooves in the skull that held a [lateral line](/source/Lateral_line) system in life, run across the [lacrimal bone](/source/Lacrimal_bone) but are not angled sharply as in other temnospondyls. On the palates of both *Arachana* and lydekkerinids, rows of palatine teeth are relatively small and the main body of the pterygoid bone is covered in small projections. None of these features are present in rhinesuchids, suggesting that *Arachana* was a [transitional form](/source/Transitional_form) between basal stereospondyls like rhinesuchids and more advanced forms like lydekkerinids.[1]

The transitional features of *Arachana* place it as part of an entire transitional fauna that existed around the Permo-Triassic boundary. While it is uncertain whether *Arachana* lived before or after the [Permian-Triassic extinction event](/source/Permian-Triassic_extinction_event), its transitional position shows that some temnospondyls were diversifying rather than diminishing across the boundary.[1]

## Phylogeny

Below is a [cladogram](/source/Cladogram) from the analysis of Piñeiro *et al.* (2012):[1]

Stereospondyli Peltobatrachus Rhinesuchidae Arachana Watsonisuchus Benthosuchus Lydekkerina Arcadia Sangaia Uruyiella Laidleria Keratobrachyops Bothriceps Pneumatostega Plagiosauridae

## References

1. ^ [***a***](#cite_ref-Arachana_1-0) [***b***](#cite_ref-Arachana_1-1) [***c***](#cite_ref-Arachana_1-2) [***d***](#cite_ref-Arachana_1-3) [***e***](#cite_ref-Arachana_1-4) [***f***](#cite_ref-Arachana_1-5) [Piñeiro, Graciela](/source/Graciela_Pi%C3%B1eiro); Ramos, Alejandro & Marsicano, Claudia (2012). "A rhinesuchid-like temnospondyl from the Permo-Triassic of Uruguay". *[Comptes Rendus Palevol](/source/Comptes_Rendus_Palevol)*. **11** (1): 65–78. [doi](/source/Doi_(identifier)):[10.1016/j.crpv.2011.07.007](https://doi.org/10.1016%2Fj.crpv.2011.07.007).

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

Taxon identifiers Arachana Wikidata: Q21445996 Wikispecies: Arachana GBIF: 9489492 IRMNG: 1479875 Open Tree of Life: 7665764 Paleobiology Database: 367351

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