''Zatrachys'' 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 ...

of large and flat-headed zatracheidid

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 01 or '01 may refer to: * The year 2001, or any year ending with 01 * The month of January * 1 (number) Music * '01 (Richard Müller album), 01'' (Richard Müller album), 2001 * 01 (Son of Dave album), ''01'' (Son of Dave album), 2000 * 01 (Urban ...

of North America.

History of study

''Zatrachys'' was named by American paleontologist

Edward Drinker Cope Edward Drinker Cope (July 28, 1840 – April 12, 1897) was an American zoologist, paleontologist, comparative anatomist, herpetologist, and ichthyologist. Born to a wealthy Quaker family, Cope distinguished himself as a child prodigy interested ...

in 1878 for the type species, ''Z. serratus'', based on a partial skull from the early Permian of Texas. Additional material has been reported from the early Permian of New Mexico and Oklahoma. Urban et al. (2007) reported material attributed to ''Z. serratus'' from the late Carboniferous and the early Permian of West Virginia. This is the only record of ''Zatrachys'' in the Carboniferous. ''Zatrachys microphthalmus'' is now placed within '' Dasyceps''.

Anatomy

Like all zatracheidids, ''Zatrachys'' is easily recognized by the presence of a large opening in the snout, the internarial fontanelle or fenestra. Of the three genera of zatracheidids, that of ''Zatrachys'' is the largest, extending as far back as to fully divide the nasals and to partially divide the frontals, a unique feature (

autapomorphy In phylogenetics, an autapomorphy is a distinctive feature, known as a derived trait, that is unique to a given taxon. That is, it is found only in one taxon, but not found in any others or outgroup taxa, not even those most closely related to t ...

). Other features that distinguish this genus are the presence of prominent spiky projections from the posterior skull (maxilla and quadratojugal), bosses and ridges on the lower jaw, a supratemporal that borders the otic notch, long and slender tabular horns and short postparietal horns, contact between the palatine and the vomer to fully enclose the choana on the palate, and a U-shaped skull profile intermediate to that of '' Acanthostomatops'' (broad and parabolic) and ''Dasyceps'' (elongate). Although there are numerous reports of postcranial material attributed to ''Zatrachys'', all of this was referred to species that are now reassigned to other temnospondyl taxa (e.g., "''Zatrachys crucifer''") or material of other taxa that was mistakenly attributed to cranial material of ''Z. serratus'' due to close proximity during preservation (e.g., ''

Platyhystrix ''Platyhystrix'' (from el, πλατύς , 'flat' and el, ῠ̔́στρῐξ , 'porcupine') was a temnospondyl amphibian with a distinctive sail along its back, similar to the unrelated synapsids, ''Dimetrodon'' and ''Edaphosaurus''. It lived du ...

''). This often led to hypothesized close relationships with ''Platyhystrix'' in particular.

References

{{Taxonbar, from=Q3267944 Cisuralian temnospondyls of North America Permian geology of Texas Taxa named by Edward Drinker Cope Fossil taxa described in 1878 Prehistoric amphibian genera