Genus: Elginerpeton

Classification: Tetrapoda - Elginerpetontidae

Etymology: Generic name after the town of Elgin and Greek herpeton, crawling.

Synonyms:

Type species: Elginerpeton pancheni

Other Species:

Diagnosis: The genus can be recognized as a stem-group tetrapod by the possession of a fang pair and tooth row on the parasymphysial plate; a pair of conspicuous foramina lateral and mesial to the posterior part of this plate; absence of exposed Meckelian bone dorsal to the prearticular; and irregular, radiating ornament on the premaxilla and infradentaries. None of these derived characters are found in non-tetrapod sarcopterygians1,6, but they occur with minor variations in all known Devonian tetrapods. Most are secondarily lost in the crown group. Elginerpeton differs from all other known Devonian tetrapods in having rounded ventral infradentary margins and an accessory tooth row on the dentary. Elginerpeton and Obruchevichthys share several synapomorphies, which are defining characters of the Elginerpetontidae.

Species: Elginerpeton pancheni

Etymology: Specific name in honour of Alec L. Panchen, in recognition of his important contributions to the study of early tetrapods.

Synonyms: Polyplocodus Pander; Miles 1968.
Tetrapod-like mandibular fragments'; Ahlberg 1991.
Scat Craig tetrapod'; Ahlberg, Luksevics and Lebedev 1994.

Holotype: RMS G 1967.17.1, an incomplete left lower jaw ramus. Holotype housed at the National Museums of Scotland, Edinburgh.

Referred Specimens: referred material, which includes upper and lower jaw elements.

Time: Upper Frasnian, Upper Devonian. The site yields psammosteids, a vertebrate group that dies out at the Frasnian-Famennian boundary16. The age is ~368 Myr.

Horizon: Scat Craig Beds,

Location: Scat Craig is a streamside exposure on the Longmorn Burn near Fogwatt village south of Elgin, Morayshire, Scotland.

Total length:

Mass:

Diagnosis: As for genus.

Comments: The first 'tetrapod-like' bones from the Scottish Upper Devonian site of Scat Craig (Scat Craig beds, Upper Frasnian) were figured and discussed in 1991. Additional specimens have since been discovered that permit a formal description, and the background knowledge of Devonian tetrapod anatomy has greatly improved. These discoveries emphasize the uniqueness and phylogenetic importance of the Scat Craig material. Elginerpeton pancheni gen. et sp. nov., described here on the basis of cranial remains from Scat Craig, is, together with the fragmentary genus Obruchevichthys from the Upper Frasnian of Latvia and Russia, the oldest known stem tetrapod. Elginerpeton and Obruchevichthys form a clade that is the sister group of all other Tetrapoda. This contrasts with the later Devonian stem tetrapods, which all seem to represent separate plesions. Elginerpeton also has a unique, derived head morphology; it shows that the earliest phase of tetrapod evolution was accompanied by previously unrecognized morphological and phylogenetic diversification.

Remark. The group is traditionally defined by the possession of limbs9 12. However, there are also derived cranial tetrapod characters1,6. Elginerpeton is assigned to the Tetrapoda on cranial characters, but associated tetrapod limb elements probably also belong to the genus.

Illustrations:

References:

© Tetrapoda Database Roman Ulansky roman.ulansky@gmail.com or adios85@mail.ru