Diabloroter bolti, 2019

DIABLOROTER BOLTI MANN & MADDIN , SP. NOV.

urn:lsid:zoobank.org:act:5D9564C0-626D-455C-A6DE-3ED53A9423E4

Holotype: ACFGM V-1634 ( Fig. 1), a near-complete cranial and postcranial skeleton, preserved only in dorsal aspect, most of the autopodial elements are covered by matrix and are not visible. Additionally, two latex peels and a plaster cast of the specimen in dorsal aspect exist at the FMNH, under the single number of FMNH PR 847 About FMNH ( Figs 2, 3).

Etymology: The generic name derives from the Spanish diablo, devil, referring to the hellishly red latex peels from which the taxon was initially identified, and rota, a wheel, from English rotavator, a digger, referring to the fossorial habits of recumbirostrans. The specific epithet honours Dr John Bolt, who contributed much to the study of early microsaurs and, in particular, his curation of Mazon Creek tetrapod fossils prompted this and several future studies.

Horizon and locality: Sunspot Mine of Ayrshire Collieries Corp. (later Amax Coal Co.), 2 miles north of Astoria , Fulton County , Illinois, Francis Creek shale, Carbondale Formation, Mazon Creek , Middle Pennsylvanian (307–309 Mya), Carboniferous ( Chenoweth, 2015). Collected by Mr L. A. Lasco .

Diagnosis: A brachystelechid recumbirostran diagnosed by the following combination of autapomorphies: long maxilla; cranial vault that is ornamented with radiating grooves; circular pits on the prefrontal; snout narrow and blunt. Diabloroter differs from Batropetes in a lesser length expansion of the mid dorsal ribs and a less robust pectoral girdle. It differs from Quasicaecilia in the skull that is not as round and the nasals do not contribute significantly to the recumbent snout. Also differs from Quasicaecilia in the lateral cheek being more extensive, similar to the condition found in Batropetes and Carrolla .

Comments: Two characters not included in the above diagnosis deserve mention. First, the presence of 17 presacral vertebrae is also present in one species of Batropetes palatinus Gleinke, 2015 , to which is likely an independent acquisition of this trait in the species Batropetes palatinus and is not present in other members of the genus. Thus, this feature may be independently derived in Diabloroter . Second, re-analysis of the holotype specimen of Carrolla craddocki ( Mann et al., 2019b) confirms the presence of triscuspate teeth, revealing less dental diversity than previously recognized among brachystelechids; the presence of a simple non-cuspate dentition in Diabloroter is, therefore, as far as known, a unique feature among brachystelechids.