''Plemmyradytes'' is an

extinct Extinction is the termination of a kind of organism or of a group of kinds (taxon), usually a species. The moment of extinction is generally considered to be the death of the last individual of the species, although the capacity to breed and ...

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 ...

of dissorophoid

temnospondyl Temnospondyli (from Greek language, Greek τέμνειν, ''temnein'' 'to cut' and σπόνδυλος, ''spondylos'' 'vertebra') is a diverse order (biology), order of small to giant tetrapods—often considered Labyrinthodontia, primitive amphi ...

from the early

Permian The Permian ( ) is a geologic period and stratigraphic system which spans 47 million years from the end of the Carboniferous Period million years ago (Mya), to the beginning of the Triassic Period 251.9 Mya. It is the last period of the Paleoz ...

(early Asselian stage). It is an

amphibamiform Amphibamiformes is an unranked clade with Dissorophoidea created by Schoch (2018). It encompasses all of the taxa traditionally considered to be "Amphibamidae, amphibamids" (subsequently restricted to ''Doleserpeton, Doleserpeton annectens'' and ...

from the Eskridge Formation exposures of Nebraska. 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 ''Plemmyradytes shintoni''. The genus name derives from the Greek ''plemmyris'' ('tide' or 'wave') and ''dytes'' ('diver'), while the specific name honors John Shinton, a fossil preparator at the

Denver Museum of Natural History The Denver Museum of Nature & Science is a municipal natural history and science museum in Denver, Colorado. It is a resource for informal science education in the Rocky Mountain region. A variety of exhibitions, programs, and activities help mus ...

where all known specimens of this taxon are reposited following collection in the late 20th century.

Anatomy

Huttenlocker et al. (2007) differentiated ''Plemmyradytes'' from other amphibamiforms by: (1) the reduced lateral exposure of the palatine (LEP); (2) a long and narrow supratemporal without a ventral flange; (3) a posteriorly extensive squamosal, long and slightly recurved teeth that decrease in size posteriorly; (4) a shallow dentary with a trough below the tooth row; and (5) smaller teeth on the dentary relative to the maxilla.

Phylogeny

The phylogenetic relationships of ''Plemmyradytes'' are variably recovered by different authors. Huttenlocker et al. (2007) found ''P. shintoni'' to be the sister taxon of the micropholid ''

Micropholis stowi ''Micropholis'' (Greek mikros = small and pholis = scale) is an extinct genus of dissorophoid temnospondyl. Fossils have been found from the ''Lystrosaurus'' Assemblage Zone of the Karoo Basin in South Africa and are dated to the Induan ...

.'' Similar results were obtained by Bourget & Anderson (2011) when the character coding was left unchanged. Conversely, updated character coding resulted in ''P. shintoni'' being recovered as the sister taxon to ''

Eoscopus ''Eoscopus'' is an extinct genus of dissorophoidean euskelian temnospondyl in the family Micropholidae. It is known from Hamilton Quarry, a Late Carboniferous lagerstätte near Hamilton, Kansas. Members of Micropholidae were historically include ...

.'' Similarly, Fröbisch & Reisz (2008) recovered ''P. shintoni'' as being closer to amphibamids proper (''

Doleserpeton ''Doleserpeton'' is an extinct, monospecific genus of dissorophoidean temnospondyl within the family Amphibamidae that lived during the Upper Permian, 285 million years ago. ''Doleserpeton'' is represented by a single species, ''Doleserpeton anne ...

'' + '' Amphibamus'') between the Carboniferous amphibamiforms ''Eoscopus'' from Kansas and ''

Platyrhinops ''Platyrhinops'' is an extinct genus amphibamid temnospondyl from the Late Carboniferous (late Westphalian stage) of Ohio and the Czech Republic. It is known from many partial skeletons from the Linton site in Saline Township, Ohio and at leas ...

'' from Ohio. Subsequent analysis with increased taxon sampling using the same matrix by Maddin et al. (2013) recovered the same results. Cladogram after Huttenlocker et al. (2007): Cladogram after Fröbisch and Reisz (2008):

References

{{Taxonbar, from=Q7204517 Amphibamids Dissorophids Cisuralian temnospondyls of North America Permian geology of Nebraska Fossil taxa described in 2007 Prehistoric amphibian genera