Scotiophryne sp.

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 : 83

cf. Scotiophryne sp.

( Text-fig. 3l, m )

M a t e r i a l a n d o c c u r r e n c e s: Maxilla from

Judith River Formation, Montana, USA (Appendix 2).

D e s c r i p t i o n: The sole example, AMNH FARB 33045, is an incomplete left maxilla about 6.3 mm in preserved length ( Text-fig. 3l, m ). It preserves the suborbital region and the adjacent pre- and postorbital regions. Anteriorly the specimen is broken through the base of the processus frontalis and posteriorly it is broken just behind the level of the processus pterygoideus. The preserved portion of the pars facialis is moderately deep. Its incomplete pre-and postorbital portions are moderately high, and enclose between them a moderately concave margo orbitalis that is lingually thickened. A well-developed facet for contact with the squamosal extends anteriorly along the dorsolingual surface of the preserved portion of the processus zygomatico-maxillaris, onto the adjacent (i.e., posterior) portion of the suborbital region. Although it is sheared off, judging by its broken base the processus pterygoideus would have been well developed. The lamina horizontalis is relatively deep and lingually narrow, with its lingual surface vertical and shallowly convex lingually. The posteriorly incomplete tooth row extends posteriorward at least as far as the level of the processus pterygoideus. No teeth are intact, but smooth rims on the better preserved bases suggest the teeth were pedicellate. The labial surface of the pars facialis is ornamented. Across the preserved portion of the postorbital region and about the posterior three-quarters of the suborbital region, labial ornament consists of small, moderately spaced tubercles. More anteriorly, those tubercles give way to low, irregular ridges enclosing shallow pits. The ventral portion of the ornamented surface is dominated by short, irregular ridges oriented horizontally along the posterior portion and shallowly inclined dorsally along the anterior portion.

R e m a r k s: In terms of its general structure and size, the above-described maxilla from Clambank Hollow is most similar to Judithian and Lancian maxillae of Scotiophryne pustulosa (Estes 1969: fig. 2c–f; Gardner 2008: fig. 13.1L–M; Roček et al. 2010: fig. 16Aj–l and Bd; here: Text-fig. 3a–d ) and Judithian maxillae described below for our unnamed genus and species I ( Text-fig. 6a–h ). It differs from both in being slightly deeper through the suborbital region and in that its labial ornament is somewhat intermediate, being predominantly formed by tubercles but also with some ridges. Even in the region where the Scotiophryne -like ornament is best developed on AMNH FARB 33045, those bony tubercles are more broadly separated, rather than being more closely packed as in examples from the Judithian of Utah ( Roček et al. 2010: fig. 16Aj–l; here: Text-fig. 3a, b ) and especially in geologically younger maxillae from the Lance and Hell Creek formations (Estes 1969: fig. 2d, e; Gardner 2008: fig. 13.1L, N). To highlight the distinctiveness of this unusual maxilla from the Judith River Formation and in recognition of its Scotiophryne -like ornament, we identify this specimen as cf. Scotiophryne sp.

Figures

Text-fig. 3. Skull bones of Scotiophryne pustulosa ESTES, 1969 and cf. Scotiophryne sp. from the middle – late Campanian (Judithian) of Utah and Montana, USA. All images are photographs and most depict specimens lightly dusted with ammonium chloride to enhance details and texture. Images at different magnifications; see corresponding scale bars. a–k – Scotiophryne pustulosa ESTES, 1969, all from Kaiparowits Formation, OMNH locality V9, Utah: a, b – incomplete right maxilla, OMNH 67093, in labial (a) and lingual (b) views; c–e – incomplete right maxilla, OMNH 67105, entire specimen in labial (c) and lingual (d) views and close up (e) of partially obscured, in situ replacement tooth crown (arrow) in lingual view; f, g – dorsal part of left squamosal, OMNH 67107, in lateral (f) and medial (g) views; h, i – anterior part of left frontoparietal, OMNH 67109, in dorsal (h) and ventral (i) views; j, k – median part of left frontoparietal, OMNH 67110, in dorsal (j) and ventral (k) views. l, m – cf. Scotiophryne sp., incomplete left maxilla, AMNH FARB 33045, in labial (l) and lingual (m) views, from Judith River Formation, Clambank Hollow, Montana.

Text-fig. 6. Skull bones and tentatively associated ilium of Anura unnamed genus and species I from the middle – late Campanian (Judithian) of Alberta, Canada and Montana, USA. Except where noted otherwise, images are photographs and depict specimens lightly dusted with ammonium chloride to enhance details and texture. Images at different magnifications; see corresponding scale bars. a – incomplete left maxilla, UALVP 40177, in labial view, from either Dinosaur Park Formation or Oldman Formation, UALVP locality DM-19, Alberta. b – incomplete left maxilla, UALVP 40179, in labial view, from Dinosaur Park Formation, Railway Grade locality, west of Dinosaur Provincial Park, Alberta. c – incomplete left maxilla, UALVP 40178, in lingual view, from either Dinosaur Park Formation or Oldman Formation, UALVP locality DM-19, Alberta. d–f – incomplete right maxilla, TMP 2008.004.0016, entire specimen in labial (d) and lingual (e) views and close up (f) of two intact teeth in anterolingual view (all three images are scanning electron micrographs), from Dinosaur Park Formation, TMP locality L0086, Dinosaur Provincial Park,Alberta. g, h – incomplete left maxilla, AMNH FARB 8460, in labial (g) and lingual (h) views, from Judith River Formation, Clambank Hollow, Montana. i, j, – dorsal part of right squamosal, UALVP 40181, in lateral (i) and medial (j) views, from Dinosaur Park Formation, Irvine locality, Alberta. k – incomplete left nasal, UALVP 40810, in dorsal view, from Dinosaur Park Formation, Irvine locality, Alberta. l, m – anteriorly incomplete left frontoparietal, UALVP 40182, in dorsal (l) and ventral (m) views, from Dinosaur Park Formation, Irvine locality, Alberta. n – anterior end of right frontoparietal, UALVP 40183, in ventral view, from Dinosaur Park Formation, Irvine locality, Alberta. o, p – incomplete left ilium, UALVP 40184, in lateral (o) and medial (p) views, from Dinosaur Park Formation, Irvine locality, Alberta.