Hensonbatrachus kermiti GARDNER et BRINKMAN, 2015

Gardner, James D., Redman, Cory M. & Cifelli, Richard L., 2016, The Hopping Dead: Late Cretaceous Frogs From The Middle - Late Campanian (Judithian) Of Western North America, Fossil Imprint 72 (1 - 2), pp. 78-107 : 84-85

Hensonbatrachus kermiti GARDNER et BRINKMAN, 2015

( Text-fig. 4 )

M a t e r i a l a n d o c c u r r e n c e s: Maxillae (including holotype), squamosals, nasal, frontoparietals, humerus, and ilia from Dinosaur Park and Oldman formations, Alberta, Canada; maxillae from Judith River Formation , Montana, USA (Appendix 2) .

D e s c r i p t i o n: The detailed description of skull bones (maxillae, squamosals, nasal, and frontoparietals), ilia, and humerus provided by Gardner and Brinkman (2015) in the recent type description for Hensonbatrachus kermiti does not need to be repeated. Instead, here we simply figure examples of those elements ( Text-fig. 4a–d, i–j ). During the course of our review, two previously unreported maxillae ( Text-fig. 4e–h ) were identified from the Judith River Formation , Montana. Both specimens are moderately large and robust, are from the left side, and are broken dorsally, anteriorly, and posteriorly. Each preserves the region bearing the processus pterygoideus, specifically the more posterior part of the suborbital region, the adjacent part of the postorbital region, and a posterior portion of the tooth row. The more nearly complete specimen, AMNH FARB 33042 ( Text-fig. 4e, f ) preserves enough of the processus zygomatico-maxillaris and suborbital region to demonstrate that those portions of the maxilla were at least moderately high. In lingual view, both specimens bear a small, weakly-developed, scoop-shaped processus pterygoideus arising at the posterior end of a ledge-like lamina horizontalis; the latter is moderately deep and lingually wide, and has a flattened lingual face that faces slightly ventrally. In both specimens, the labial surface of the bone above the level of the crista dentalis is ornamented with moderately deep and irregularlyshaped pits and short grooves that are bordered by moderately tall, thick, and vermiform ridges .

R e m a r k s: As described by Gardner and Brinkman (2015) Hensonbatrachus kermiti is a distinctive anuran characterized by a unique combination of features, including its pattern of cranial ornament, form and contacts of its maxilla and squamosal, pattern of its frontoparietal incrassations, and iliac features. Compared to other known Late Cretaceous frogs from North America, Hensonbatrachus was relatively large, with an estimated snout – vent length of 75–115 mm. Based on its body size, robustly built bones, and ornamented skull bones, Hensonbatrachus was interpreted as a generalized, ground dwelling anuran.

All specimens included in the type description for Hensonbatrachus kermiti came from localities in the lower and middle parts of the Dinosaur Park Formation and the upper part of the underlying Oldman Formation, both in southeastern Alberta ( Gardner and Brinkman 2015; here: Appendix 2). The first examples were collected in the mid-1960s. The somewhat Eopelobates -like ornament on the maxilla, squamosal, and skull roof bones may have been the basis for “ Eopelobates n. sp. ” and “ Eopelobates ” having been recorded in preliminary faunal lists for the region (e.g., Fox 1976a and Currie 1986, respectively). One of us ( Gardner 2000) informally recognized and briefly described the species now known as H. kermiti in his PhD dissertation as “Genus and Species Unnamed B”.

The two maxillae described here are from the paracontemporaneous Judith River Formation, farther to the south at Clambank Hollow in central Montana. These newly recognized specimens are the first record for the species outside of Alberta. Although both specimens are fragmentary, they can be reliably assigned to H. kermiti on the basis of their moderately large size and robust build, presence of teeth, structure of the lamina horizontalis and the processus pterygoideus, and pattern of labial ornament. Although we did not find examples of other skull or postcranial bones of H. kermiti among the small collection of anuran fossils made by Ashok Sahni from Clambank Hollow in the mid-1960s, we predict such specimens might remain to be identified in more recent collections from other localities in the type area of the Judith River Formation (e.g., see Blob et al. 2001, Rogers and Brady 2010).

Figures

Text-fig. 4. Skull and postcranial bones of Hensonbatrachus kermiti GARDNER et BRINKMAN, 2015 from the middle – late Campanian (Judithian) of Alberta, Canada and Montana, USA. All images are photographs and depict specimens lightly dusted with ammonium chloride to enhance details and texture. Images at same magnifications; see scale bar. a, b – nearly complete right maxilla (holotype), UALVP 40167, in labial (a) and lingual (b) views, from Dinosaur Park Formation, Irvine locality, Alberta. c, d – incomplete right maxilla, UALVP 40202, in labial (c) and lingual (d) views, from Dinosaur Park Formation, Irvine locality, Alberta. e, f – incomplete left maxilla, AMNH FARB 33042, in labial (e) and lingual (f) views, from Judith River Formation, Clambank Hollow locality, Montana. g, h – incomplete left maxilla, AMNH FARB 33043, in labial (g) and lingual (h) views, from Judith River Formation, Clambank Hollow locality, Montana. i – nearly complete left squamosal, UALVP 40171, in lateral view, from Dinosaur Park Formation, Irvine locality, Alberta. j – nearly complete left nasal, UALVP 40170, in dorsal view, from Dinosaur Park Formation, Irvine locality, Alberta. k, l– anterior part of right frontoparietal, UALVP 40173, in dorsal (k) and ventral (l) views, from Dinosaur Park Formation, Irvine locality, Alberta. m, n – median part of right frontoparietal, TMP 1986.023.0032, in dorsal (m) and ventral (n) views. o, p – left ilium, TMP 1974.010.0088, in lateral (o) and medial (p) views, from Dinosaur Park Formation, TMP locality L0086, Dinosaur Provincial Park, Alberta. q – distal end of left humerus, UALVP 40176, in ventral view, from Dinosaur Park Formation, Irvine locality, Alberta.