Capitosauria is an extinct group of large
temnospondyl
Temnospondyli (from Greek τέμνειν, ''temnein'' 'to cut' and σπόνδυλος, ''spondylos'' 'vertebra') is a diverse order of small to giant tetrapods—often considered primitive amphibians—that flourished worldwide during the Carb ...
amphibians with simplified
stereospondyl
The Stereospondyli are a group of extinct temnospondyl amphibians that existed primarily during the Mesozoic period. They are known from all seven continents and were common components of many Triassic ecosystems, likely filling a similar ecologi ...
vertebrae. Mainly living as
piscivores in lakes and rivers, the Capitosauria and its
sister taxon
In phylogenetics, a sister group or sister taxon, also called an adelphotaxon, comprises the closest relative(s) of another given unit in an evolutionary tree.
Definition
The expression is most easily illustrated by a cladogram:
Taxon A and ...
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 t ...
were the only major
labyrinthodonts that existed during the
Mesozoic in ecological niches broadly similar to those of modern
crocodile
Crocodiles (family Crocodylidae) or true crocodiles are large semiaquatic reptiles that live throughout the tropics in Africa, Asia, the Americas and Australia. The term crocodile is sometimes used even more loosely to include all extant mem ...
s, and some grew to very large sizes. At 6 meters 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.
The latest known remains are from the
Rhaetian of Germany and are referred to ''
Cyclotosaurus
''Cyclotosaurus'' is an extinct genus of temnospondyl within the family Mastodonsauridae. It was of great size for an amphibian, had an elongated skull up to .
Etymology
The name means "round eared lizard" in Ancient Greek, derived from round ...
''.
Capitosauria was first named by Schoch and Milner (2000) and further described by Yates and Warren (2000), who assigned ''
Lydekkerina
''Lydekkerina'' is an extinct genus of stereospondyl temnospondyl. It is the type genus of the family Lydekkerinidae. Fossils have been collected from Early Triassic deposits in South Africa and Australia. The type species is '' L. huxleyi'', ...
'' and
Mastodonsauroidea to it.
It was described by Damiani (2001) under the name Mastodonsauroidea.
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.
Phylogeny
Below is a
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 ...
from Fortuny ''et al.'' (2011) showing the
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 ...
relationships of capitosaurs:
References
External links
Capitosauriain the
Paleobiology Database
The Paleobiology Database is an online resource for information on the distribution and classification of fossil animals, plants, and microorganisms.
History
The Paleobiology Database (PBDB) originated in the NCEAS-funded Phanerozoic Marine Pal ...
Triassic temnospondyls
Triassic first appearances
Triassic extinctions
Capitosaurs
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