Benthosuchus

Benthosuchus Temporal range: Early Triassic
Skull of Benthosuchus sushkini
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Order:	†Temnospondyli
Suborder:	†Stereospondyli
Family:	†Benthosuchidae Efremov, 1937
Genus:	†Benthosuchus Efremov, 1937
Species
†B. sushkini (Efremov, 1929 [originally Benthosaurus sushkini]) (type) †B. korobkovi Ivachnenko, 1972 †B. bashkiricus Otschev, 1972 †B. gusevae Novikov, 2012

Life restoration of Benthosuchus sushkini

Skull

Benthosuchus is an extinct genus of temnospondyl amphibian from the Early Triassic of Russia. The genus was named in 1937, and the type species, Benthosuchus sushkini, was named in 1940. Benthosuchus has traditionally been considered a member of the temnospondyl superfamily Trematosauroidea, and the family Benthosuchidae was established in 1940 to include Benthosuchus and the related trematosauroid Thoosuchus. Some recent phylogenetic studies have removed Benthosuchus from Trematosauroidea entirely, placing it as a closer relative of Mastodonsauroidea, another group of Triassic temnospondyls. Other studies retain Benthosuchus within Trematosauroidea, but since Benthosuchus and Thoosuchus have successively basal positions on these trees they form a paraphyletic grouping, not a valid clade.^[1] In either case, Benthosuchidae is a monotypic family containing only Benthosuchus.

Description

Benthosuchus skull is about 0.75 m long (it is comparatively short in young individuals but lengthens with age), and the overall body length is about 2.5 m. It existed in widely overflowing rivers of the East Russian Depression.^[2]

Phylogeny

Benthosuchus is traditionally considered a close relative of a group of temnospondyls called capitosaurids. In particular, it bears a close resemblance to the capitosaurid Wetlugasaurus. Many of the early large-scale phylogenetic analyses of temnospondyls place Benthosuchus within a clade called Capitosauria. However, more recent analyses such as that of Fortuny et al. (2011) recover Benthosuchus within another clade called Trematosauria. Occasionally it is grouped near the trematosaurid family Trematosauridae as a basal member of the group Trematosauroidea.^[3] Fortuny et al. found that Benthosuchus positioned outside Trematosauroidea as a more basal trematosaurian. Below is a cladogram from Fortuny et al. (2011) showing the phylogenetic placement of Benthosuchus:^[4]

Stereospondyli

Lydekkerina huxleyi Rhinesuchidae Rhineceps nyasaensis Uranocentrodon senekalensis Capitosauria Wetlugasaurus angustifrons Odenwaldia heidelbergensis Vladlenosaurus alexeyevi Edingerella madagascariensis Watsonisuchus spp. Xenotosuchus africanus Cherninia denwai Paracyclotosaurus crookshanki Stanocephalosaurus pronus Stanocephalosaurus birdi Procyclotosaurus stantonensis Eocyclotosaurus spp. Quasicyclotosaurus campi Parotosuchus orenburgensis Calmasuchus acri Cyclotosaurus robustus Tatrasuchus wildi Eryosuchus garjainovi Mastodonsaurus giganteus Trematosauria Benthosuchus sushkini Trematosauroidea Thoosuchus yakovlevi Angusaurus spp. Trematosaurus brauni

References

1. Damiani, R.J.; Yates, A.M. (2003). "The Triassic amphibian Thoosuchus yakovlevi and the relationships of the Trematosauroidea (Temnospondyli: Stereospondyli)" (PDF). Records of the Australian Museum 55: 331–342. doi:10.3853/j.0067-1975.55.2003.1388.
2. http://encyclopedia2.thefreedictionary.com/Benthosuchus
3. Shishkin, M.A.; Sulej, T. (2009). "Early Triassic temnospondyls of the Czatkowice 1 tetrapod assemblage" (PDF). Palaeontologica Polonica 65: 31–77.
4. Fortuny, J.; Galobart, À.; Santisteban, C. D. (2011). "A New Capitosaur from the Middle Triassic of Spain and the Relationships within the Capitosauria". Acta Palaeontologica Polonica 56 (3): 553. doi:10.4202/app.2010.0025.