''Vladlenosaurus'' is an extinct

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In the hierarchy of biological classification, genus com ...

capitosaur 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 t ...

from

Russia Russia (, , ), or the Russian Federation, is a List of transcontinental countries, transcontinental country spanning Eastern Europe and North Asia, Northern Asia. It is the List of countries and dependencies by area, largest country in the ...

. It lived during the late Vetlugian (

Early Triassic The Early Triassic is the first of three epochs of the Triassic Period of the geologic timescale. It spans the time between Ma and Ma (million years ago). Rocks from this epoch are collectively known as the Lower Triassic Series, which is a un ...

). Based on the type of deposits it was found in, ''Vladlenosaurus'' probably inhabited

lacustrine A lake is an area filled with water, localized in a basin, surrounded by land, and distinct from any river or other outlet that serves to feed or drain the lake. Lakes lie on land and are not part of the ocean, although, like the much larger ...

, or lake, habitats. The

type species In zoological nomenclature, a type species (''species typica'') is the species name with which the name of a genus or subgenus is considered to be permanently taxonomically associated, i.e., the species that contains the biological type specimen ...

is ''V. alexeyevi'', named in 2000.

Description

Unlike the flatter, more rounded snouts of other capitosaurs, ''Vladlenosaurus'' had a wedge-shaped snout. This characteristic is also seen in

trematosauria Trematosauria is one of two major groups of temnospondyl amphibians that survived the Permian-Triassic extinction event, the other (according to Yates and Warren 2000) being the Capitosauria. The trematosaurs were a diverse and important group th ...

ns, although it was independently acquired in both cases as a result of

convergent evolution Convergent evolution is the independent evolution of similar features in species of different periods or epochs in time. Convergent evolution creates analogous structures that have similar form or function but were not present in the last com ...

Classification

''Vladlenosaurus'' is similar in appearance to the benthosuchids, a group of trematosauroid temnospondyls, but is more closely related to mastodonsauroids. Among capitosaurs, it shares many features with the basal form ''

Wetlugasaurus ''Wetlugasaurus'' (meaning "Vetluga River lizard") is an extinct genus of Temnospondyli, temnospondyl amphibian from the Early Triassic (Olenekian) Charkabozh Formation, Charkabozh, Kzylsaiskaya Formation, Kzylsaiskaya, Petropavlovka Formation, ...

'', also from the Early Triassic of Russia. ''Vladlenosaurus alexeyevi'' was even considered to be a species of ''Wetlugasaurus'' in a 2006 study. In a 2011

phylogenetic In biology, phylogenetics (; from Greek φυλή/ φῦλον [] "tribe, clan, race", and wikt:γενετικός, γενετικός [] "origin, source, birth") is the study of the evolutionary history and relationships among or within groups o ...

analysis, the first to incorporate ''Vladlenosaurus'', the genus was found to be most closely related to '' Odenwaldia''. It and ''Odenwaldia'' formed a basal clade of capitosaurs more derived than ''Wetlugasaurus'', the most basal capitosaur. Below is a modified

cladogram A cladogram (from Greek ''clados'' "branch" and ''gramma'' "character") is a diagram used in cladistics to show relations among organisms. A cladogram is not, however, an evolutionary tree because it does not show how ancestors are related to d ...

from Fortuny ''et al'' (in press) showing the relationship of ''Vladlenosaurus'' to other stereospondyls:

References

Triassic temnospondyls Triassic temnospondyls of Asia Triassic temnospondyls of Europe Prehistoric amphibian genera {{temnospondyli-stub