''Ecolsonia'' is an extinct
genus
Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...
of
trematopid
Trematopidae is a family of dissorophoid temnospondyls spanning the late Carboniferous to the early Permian. Together with Dissorophidae, the family forms Olsoniformes, a clade comprising the medium-large terrestrial dissorophoids. Trematopids ar ...
temnospondyl
Temnospondyli (from Greek language, Greek τέμνειν, ''temnein'' 'to cut' and σπόνδυλος, ''spondylos'' 'vertebra') or temnospondyls is a diverse ancient order (biology), order of small to giant tetrapods—often considered Labyrinth ...
. Its phylogenetic position within
Olsoniformes
Olsoniformes is an extinct clade of dissorophoid temnospondyls, including 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 ...
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 (Urban Zakapa album), ''01'' (Urban Zakapa album), 2011
* ''01011 ...
Cutler Formation
The Cutler Formation or Cutler Group is a stratigraphic unit 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.
Desc ...
of
New Mexico
New Mexico is a state in the Southwestern United States, Southwestern region of the United States. It is one of the Mountain States of the southern Rocky Mountains, sharing the Four Corners region with Utah, Colorado, and Arizona. It also ...
.
The specimen was originally reposited at the now defunct
University of California, Los Angeles
The University of California, Los Angeles (UCLA) is a public university, public Land-grant university, land-grant research university in Los Angeles, California, United States. Its academic roots were established in 1881 as a normal school the ...
Vertebrate Paleontology collections. The genus name is for the American paleontologist
Everett C. Olson
Everett Claire Olson (November 6, 1910 – November 27, 1993) was an American zoologist, paleontologist, and geologist noted for his seminal research of origin and evolution of vertebrate animals.
Through his research studying terrestrial verte ...
, 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 (Pittsburgh), Oakland neighborhood of Pittsburgh, Pennsylvania. It was founded by List of people from the Pittsburgh metropolitan area, Pit ...
.
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
Dissorophidae
Prehistoric amphibian genera