Trematopidae
Trematopidae Temporal range:
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Skeleton of Acheloma cumminsi in the Field Museum of Natural History. | |
Scientific classification | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Chordata |
Order: | †Temnospondyli |
Clade: | †Olsoniformes |
Family: | †Trematopidae Williston, 1910 |
Genera | |
Acheloma |
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 are known from numerous localities in North America, primarily in New Mexico, Oklahoma, and Texas, and from the Bromacker quarry in Germany.
History of study
The clade Trematopidae was first proposed by American paleontologist S.W. Williston in 1910, although it was named as "Trematopsidae" following the historical (but inaccurate) derivation from the genus "Trematops" (now synonymized with Acheloma).[1] British paleontologist D.M.S. Watson proposed a related clade in 1919, Achelomidae, for Acheloma, based on perceived differences separating the taxa;[2] this is now considered a junior synonym of Trematopidae following guidelines of historical precedent.
19th century history
In 1882, American paleontologist
20th century history
In the first half of the 20th century, American paleontologist S.W. Williston named a new genus from the early Permian of Texas, Trematops.[6] At the time, most workers regarded it as only distantly related to Cope's Acheloma.[7] Two additional species of Trematops were named in short order, Trematops thomasi from Oklahoma, named by American paleontologist Maurice Mehl,[8] and Trematops willistoni from Texas, named by American paleontologist E.C. Olson in 1941.[9] Both are now regarded as junior synonyms of Acheloma cumminsi. Olson also named two species of Acheloma, A. whitei and A. pricei; both are now regarded as belonging to Phonerpeton.[10] In the same paper that he named these taxa, Olson also provided the first review of the Trematopidae, synthesizing all of the known material and providing updated taxonomic frameworks.
The second half of the 20th century saw an increase in trematopid research. In 1956, Olson named a new genus and species of trematopid from the Vale Formation of Texas, Trematopsis seltini;
21st century history
The 21st century has seen a renewed flurry of research into trematopids. In 2010, a team led by Berman described a new taxon from the late Carboniferous of Pennsylvania,
Anatomy
Trematopids have typically been identified by the presence of a noticeably enlarged naris that is often sub-divided in Permian forms such as Acheloma. They are also among the largest of the dissorophoids, with some specimens of Acheloma exceeding 18 cm in skull length and thus being rivaled only by middle Permian dissorophids such as Anakamacops. Schoch & Milner (2014) diagnosed trematopids by the following features: (1) greatly expanded naris replacing much of the lacrimal; (2) medially situated narial flange meeting antorbital bar; (3) otic notch with a ventral margin sloping at less than 45-degrees in large individuals; (4) a medial inflection of the rim of the adductor fossa; (5) a pterygoid-vomer contact; (6) a triangular patch of denticles on the basal plate of the parasphenoid; and (7) a humerus with a supinator process.[21] Milner (2018) further refined this based on his restudy of Mordex, including only characters 1, 3, and 5 from Schoch & Milner (2014), noting that some typical trematopid features are either not known or are not present in the primitive Mattauschia and Mordex.[5]
The function of the naris remains largely unresolved. Olson (1941) suggested that the anterior half served the typical function of smell detection and that the posterior half housed some kind of gland.[9] Bolt (1974) conjectured that the well-developed nasal flange was probably for distribution of stresses throughout the skull and might be a hallmark of terrestrial dissorophoids.[18] He then suggested that there might be a gland related to salt excretion (the "glandula nasalis externa") that would produce the enlargement of the naris. Dilkes (1993) did not discount this hypothesis, but suggested alternatives, namely that the nasal flange and the expanded naris may have been for another physiological function, such as improving respiratory efficiency and water retention, an important attribute for a terrestrial amphibian to have.[24] However, all of these hypotheses remain speculative in the absence of much complexity of the hard tissues surrounding the naris and given the relatively vague paleoecological information available for trematopids (e.g., diet).
Relationships
The placement of trematopids within Dissorophoidea has long been accepted, as has their close relationship to dissorophids, although Olsoniformes was not formalized until 2007.[32] Ecolsonia and Mordex have been more uncertainly placed in their history of study,[13][5] but both are now accepted as unequivocal trematopids. The two most recent phylogenetic analyses of Trematopidae are those by Berman et al. (2011) and Polley & Reisz (2011):
Topology of Berman et al. (2011):[27]
Topology of Polley & Reisz (2011):[28]
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Gallery
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late Carboniferous of New Mexico
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Fedexia striegeli, of the late Carboniferous of Pennsylvania
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early Permian of North America
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Phonerpeton pricei, of the early Permian of Texas
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Rotaryus gothae, of the early Permian of Germany
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Tambachia trogallas, of the early Permian of Germany
References
- S2CID 224836685.
- ISSN 0962-8436.
- JSTOR 982692.
- ^ Fritsch, Antonin (1881). "Fauna der Gaskohle und der Kalksteine der Permformations Bohmens". Self-published. 1 (3).
- ^ S2CID 133895158.
- ISSN 0022-1376.
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- ^ S2CID 129647184.
- ^ ISSN 0272-4634.
- )
- .
- ^ a b Berman, David S.; Reisz, Robert R.; Eberth, David A. (1985). "Ecolsonia cutlerensis, an early Permian dissorophid amphibian from the Cutler Formation of north-central New Mexico". New Mexico Bureau of Mines and Minerals Research Circular. 191: 1–31.
- )
- OCLC 1068422466.)
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has generic name (help)CS1 maint: multiple names: authors list (link - ^ Milner, Andrew R. (1985). "On the identity of the amphibian Hesperoherpeton garnettense from the Upper Pennsylvanian of Kansas". Palaeontology. 28 (4): 767–776.
- .
- ^ OCLC 914664.
- JSTOR 1305010.
- ISSN 0008-4077.
- ^ OCLC 580976.
- S2CID 203119272.
- ISSN 0272-4634.
- ^ a b Dilkes, David W. (1993). "Biology and evolution of the nasal region in trematopid amphibians". Palaeontology. 36 (4): 839–853.
- ^ Sumida, Stuart S.; Berman, David S.; Martens, Thomas (1998). "A new trematopid amphibian from the Lower Permian of central Germany". Palaeontology. 41 (4): 605–629.
- S2CID 85974488.
- ^ S2CID 84780478.
- ^ ISSN 0024-4082.
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- S2CID 55943106.