. A diapsid reptile from the Pennsylvanian of Kansas. Reptiles, Fossil -- Kansas; Paleontology -- Pennsylvanian; Paleontology -- Kansas. 12 SPECIAL PUBLICATION MUSEUM OF NATURAL HISTORY NO. 7. Fic. 7.—PetTolacosaums kansensis Lane. Braincase of adult individual, KUVP 9951, X 2. Braincase ex- posed in ventral (A) and dorsal views (B), with the lateral, occipital and ventral elements compressed into a single plane. See Fig. 2 for key to abbreviations. the alveolar shelf. In KUVP 9952, the entire left maxilla is exposed. Thirty teeth are in place, with room for five others. Laterally the teeth ar
. A diapsid reptile from the Pennsylvanian of Kansas. Reptiles, Fossil -- Kansas; Paleontology -- Pennsylvanian; Paleontology -- Kansas. 12 SPECIAL PUBLICATION MUSEUM OF NATURAL HISTORY NO. 7. Fic. 7.—PetTolacosaums kansensis Lane. Braincase of adult individual, KUVP 9951, X 2. Braincase ex- posed in ventral (A) and dorsal views (B), with the lateral, occipital and ventral elements compressed into a single plane. See Fig. 2 for key to abbreviations. the alveolar shelf. In KUVP 9952, the entire left maxilla is exposed. Thirty teeth are in place, with room for five others. Laterally the teeth arc covered by a thin sheet of bone that extends up to one-third of the length of the teeth below the alveolar shelf. The me- dial surface of the alveolar shelf is smooth in the region where it forms the lateral border of the internal naris and the lateral border of the suborbital fenestra. Between these two openings, directly beneath the anterior mar- gin of the orbit, the alveolar shelf bears a small striated process, that is exposed in both KUVP 9952 (Fig. 8b) and KUVP 33602 (Fig. 9a). This process which occupies only 17 per cent of the length of this bone, is sutured to the palatine. It is significant that, as in all "eosuchians," the maxilla in Petrolacosaiirus is attached directly to the palate only through this jirocess. Posterior to this contact with the palatine, the maxilla forms the lateral border of the suborbital fe- nestra. The maxilla is not attached to the ectoptcrygoid. In primitive captorhinomorphs and pelycosaurs, on the other hand, the max- illa is sutured behind the internal naris (more than 50 per cent of the total length of the bone) to both the palatine and the ectoptcry- goid. There is no buttressing on the medial sur- face of the maxilla, above the caniniform teeth. This area is somewhat strengthened, however, by the ventral margin of the lacri- mal which fits into a long longitudinal groove along the dorsal margin of the maxilla. The cross-s
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Keywords: ., bookcentury1900, bookcollectionbi, booksubjectpaleontologykansas
