Capitosauria

Capitosauria Temporal range: Triassic
Mastodonsaurus
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Order:	†Temnospondyli
Clade:	†Stereospondylomorpha
Suborder:	†Stereospondyli
Clade:	†Capitosauria Schoch and Milner, 2000
Clades
†Mastodonsauroidea

Capitosauria is an extinct group of large temnospondyl amphibians with simplified stereospondyl vertebrae. Mainly living as piscivores in lakes and rivers, the Capitosauria and its sister taxon Trematosauria were the only major labyrinthodonts that existed during the Mesozoic in ecological niches broadly similar to those of modern crocodiles, and some grew to very large sizes. At 6 meter in length, the Mid-Triassic Mastodonsaurus giganteus is not only thought to have been the largest capitosaur, but possibly also the largest amphibian to have lived.^[1] The capitosaurs enjoyed a brief period of success in the early Triassic, but with the rise of crocodiles in the middle Triassic they went into decline, and the capitosaur lineage is not known beyond the Late Triassic.^[1]

Capitosauria was first named by Schoch and Milner (2000) and further described by Yates and Warren (2000), who assigned Lydekkerina and Mastodonsauroidea to it.^[2][3] It was described by Damiani (2001) under the name Mastodonsauroidea.^[4] In their phylogenetic analysis of temnospondyls, Ruta et al. (2007) placed Lydekkerina and its relatives within the clade Rhytidostea, while placing only mastodonsauroid taxa within Capitosauria.^[5]

Phylogeny

Below is a cladogram from Fortuny et al. (2011) showing the phylogenetic relationships of capitosaurs:^[6]

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. "Capitosauria". Palaeos. Retrieved 18 June 2014.
2. Schoch, R. R.; Milner, A. R. (2000). "Stereospondyli". In P. Wellnhofer (ed.). Handbuch der Paläoherpetologie 3B. Munich: Verlag Dr. Friedrich Pfeil. p. 203.
3. Yates, A. M.; Warren, A. A. (2000). "The phylogeny of the "higher" temnospondyls (Vertebrata: Choanata) and its implications for the monophyly and origins of Stereospondyli". Zoological Journal of the Linnean Society 128: 77–121. doi:10.1111/j.1096-3642.2000.tb00650.x.
4. Damiani, R. J. (2001). "A systematic revision and phylogenetic analysis of Triassic mastodonsauroids (Temnospondyli: Stereospondyli)". Zoological Journal of the Linnean Society 133 (4): 379–482. doi:10.1111/j.1096-3642.2001.tb00635.x.
5. Ruta, M.; Pisani, D.; Lloyd, G. T.; Benton, M. J. (2007). "A supertree of Temnospondyli: cladogenetic patterns in the most species-rich group of early tetrapods". Proceedings of the Royal Society B 274 (1629): 3087–3095. doi:10.1098/rspb.2007.1250. PMC 2293949. PMID 17925278.
6. 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.

External links

• Capitosauria in the Paleobiology Database
• Cladogram of Mastodonsauroidea (=Capitosauria) at Mikko's Phylogeny Archive