Osteology and phylogenetic position of the diminutive ‘ microsaur’ Odonterpeton triangulare from the Pennsylvanian of Linton, Ohio, and major features of recumbirostran phylogeny Author Mann, Arjan Author Pardo, Jason D Author Sues, Hans-Dieter text Zoological Journal of the Linnean Society 2023 2023-03-01 197 3 641 655 https://academic.oup.com/zoolinnean/article/197/3/641/6646571 journal article 10.1093/zoolinnean/zlac043 94ce56c4-b3c8-489b-aff0-accff1349430 0024-4082 7690904 ODONTERPETON TRIANGULARE MOODIE, 1909 Holotype : USNM PAL 4465 + 4467 , part and counterpart cannel coal blocks containing the anterior portion of a skeleton exposed in dorsal view ( USNM PAL 4465 ) and ventral view ( USNM PAL 4467 ) ( Figs 1 , 2 ). Type locality and horizon: Abandoned coal mine operated originally by the Ohio Diamond Coal Company at Linton, Saline Township, Jefferson County, OH, USA (for details, see Hook & Baird, 1986 ). Local cannel coal is immediately below the Upper Freeport coal of the Allegheny Group. This horizon is dated as Middle Pennsylvanian (Moscovian). ReƲised diagnosis: Diminutive recumbirostran with the following distinctive combination of characters: 19 maxillary tooth positions; posterior maxillary teeth enlarged; lateral surface of maxilla bearing series of pits; undulating midline sutures between frontals and parietals; nasals small; short forelimbs; and autopodium with three digits and phalangeal count of 2-4-3. Shares the field of palatal teeth with pantylids and gymnarthrids. Shares with Joermungandr Mann et al ., 2021 and brachystelechids large parietals. Shares with Joermungandr and at least Diabloroter Mann & Maddin, 2019 among brachystelechids the anterior position of the pineal foramen. Shares with Joermungandr oval, ornamented dermal scales, a short snout and the presence of a single splenial. Differs from Joermungandr in the absence of an anteriorly restricted tooth row, the greater number of teeth in the upper and lower dental arcade, the presence of a tabular, proportionally shorter nasals and the presence of a well-ossified forelimb and pectoral girdle.