''Ecolsonia'' 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 trematopid

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 ...

. Its phylogenetic position within

Olsoniformes Olsoniformes is a clade of dissorophoid temnospondyls. It includes the families Dissorophidae and Trematopidae. Most members of the clade were highly adapted to a terrestrial lifestyle. The clade was named in 2008 and is defined as the least inc ...

has been historically debated, but it is presently considered to be a trematopid.

History of study

The holotype of ''Ecolsonia'' is a partial skull that was collected in 1963 from the VanderHoof quarry in 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 ...

Cutler Formation The Cutler Formation or Cutler Group is a rock unit that is exposed across the U.S. states of Arizona, northwest New Mexico, southeast Utah and southwest Colorado. It was laid down in the Early Permian during the Wolfcampian epoch. Descript ...

New Mexico ) , population_demonym = New Mexican ( es, Neomexicano, Neomejicano, Nuevo Mexicano) , seat = Santa Fe , LargestCity = Albuquerque , LargestMetro = Tiguex , OfficialLang = None , Languages = English, Spanish ( New Mexican), Navajo, Ker ...

. The specimen was originally reposited at the now defunct

University of California, Los Angeles The University of California, Los Angeles (UCLA) is a public land-grant research university in Los Angeles, California. UCLA's academic roots were established in 1881 as a teachers college then known as the southern branch of the California St ...

Vertebrate Paleontology collections. The genus name is for the American paleontologist Everett C. Olson, and the species name is for the geologic provenance. A number of more complete specimens from the Morfin quarry in the Cutler Formation were discovered in 1983 and described by Berman et al. (1985), including a complete skull and large amounts of postcranial material. These specimens are currently reposited at the

Carnegie Museum of Natural History The Carnegie Museum of Natural History (abbreviated as CMNH) is a natural history museum in the Oakland neighborhood of Pittsburgh, Pennsylvania. It was founded by Pittsburgh-based industrialist Andrew Carnegie in 1896. Housing some 22 millio ...

Anatomy

Schoch & Milner (2014) listed seven features in the diagnosis of ''Ecolsonia'': (1) tabular and squamosal frame otic fenestra; (2) prefrontal and postfrontal separated (shared with most other trematopids); (3) preorbital region of equal length to posterior skull table; (4) vomer with a posteromedial process meeting the pterygoid (shared with other trematopids); (5) a supratemporal that is twice as long as it is wide; (6) triangular patch of denticles on the parasphenoid (shared with other trematopids); and (7) basipterygoid region unsutured (shared with some other trematopids). Trematopid synapomorphies include the posterior process of the vomer, the denticles on the parasphenoid, and the supinator process of the humerus. A large number of small scales were also found with some specimens of ''Ecolsonia'' that probably covered the entire body, a feature similar to that seen in the trematopid ''

Anconastes ''Anconastes'' is an extinct genus of dissorophoid temnospondyl within the family Trematopidae. It is known from two specimens from the Late Carboniferous Cutler Formation of north-central New Mexico in the southwestern United States. The genus n ...

''; these are distinct from the osteoderms of dissorophids that are only associated with the vertebral column.

Relationships

''Ecolsonia'' was originally classified as a trematopid by Vaughn (1969). At this time, only one other currently recognized trematopid was known (''Acheloma'' and its junior synonym ''Trematops''), in comparison to 13 known dissorophids, but Vaughn noted that the proportions of the skull, the sutural patterns, and the elongate naris were all features similar to those of ''Acheloma''. Berman et al. (1985) classified ''Ecolsonia'' as a dissorophid in part because features considered to be diagnostic of trematopids were also found in other taxa interpreted as dissorophids, '' Actiobates peabodyi'' (now a trematopid) and ''Longiscitula houghae'' (now a junior synonym of the dissorophid '' Dissorophus multicinctus''). In general, these authors considered many of the features that now link ''Ecolsonia'' to trematopids to be convergences acquired independently in dissorophids, a hypothesis that is no longer widely accepted or supported by phylogenetic analyses.

References

{{Taxonbar, from=Q5333307 Dissorophids Prehistoric amphibian genera