PELOBATIDAE

Sahni, Ashok, 1972, The vertebrate Fauna of the Judith River formation, Montana, Bulletin of the American Museum of Natural History 147 (6), pp. 319-416 : 348

FAMILY PELOBATIDAE

Figure 7J, K

Two ilia, AMNH 8452 and 8453, are tentatively referred to the Pelobatidae (fig. 7J, K). The identification is uncertain as the specimens are broken and consist only of the acetabular region. AMNH 8452 and 8453 are easily distinguished from other anuran ilia in the collection by the shape of the acetabulum and the relatively greater elongation of the posterior ischial process. In size AMNH 8452 most closely resembles UCMP 49524, a left pelobatid ilium, tentatively identified by Estes (1964, p. 59). The acetabulum of AMNH 8452 is more triangular than semicircular, with a raised and pointed dorsal apex. The posterior part of the acetabulum is at the same level as the ischial process, although anteriorly it develops a prominent rim near the pubic process. This process is broken in both specimens but was probably developed to the same extent as in UCMP 49524 from the Lance Formation. The medial view shows no features of diagnostic value except for an ornamentation consisting of parallel striations along the contact with the ischium and the pubis.

Figures

FIG. 7. A. AMNH 8446, ventral view of left discoglossid (A) humerus. B. Dorsal view. Both x 5. C. AMNH 8449, ventral view of left discoglossid (B) humerus. D. Dorsal view. Both x 5. E. AMNH 8450, ventral view of left discoglossid (C) humerus. F. Dorsal view. Both x 5. G. AMNH 8456, lateral view of distal portion of right discoglossid ilium, x 5. H. AMNH 8457, lateral view of distal portion of left discoglossid ilium, x 5. I. AMNH 8459, lateral view of distal portion of left discoglossid ilium, x 5. J. AMNH 8452, lateral view of distal portion of left pelobatid ilium, x 5. K. AMNH 8453, lateral view of distal portion of pelobatid ilium, x 5. L. AMNH 8460, external view of left discoglossid (C) maxilla. M. Internal view. Both x 5. N. AMNH 8462, external view of right discoglossid (B) maxilla. 0. Internal view. Both x 5. P. AMNH 8461, external view of left discoglossid (A) maxilla. Q. Internal view. Both x 5. R. AMNH 10100, occlusal view of?Paralbula sp. S. Basal view. Both x 10. T. AMNH 10101, occlusal view of?Paralbula sp. U. Basal view. Both x 1.0.