| Abstract: | A new genus and species of hybodontoid elasmobranchs,Gansuselache tungshengi, is described on the basis of an articulated skeleton from the Fangshankou Formation （Late Permian） of the Mazongshan Mountain of Gansu Province, northwestern China. All dermal skeletons including dorsal fin-spines, cephalic spines, dermal denticles and one tooth are well preserved in their natural position. It is a shark of about 490 mm total length with a fusiform body. The braincase has large, downturned articulation, long palatoquadrate and large triangular postorbital processes and otic capsules, no postorbital Meckel＇s cartilage. It bears two dorsal fins and two pairs of heteromorphic cephalic spines. The tooth is of low-crowned, muhicuspid type; the elongate tooth crown has stout crown shoulder and well-developed, rounded labial peg; the cusp and cusplets are moderately tumid, and have a few strong and curved folds; the tooth root is higher on the labial face than the lingual face. The dermal denticle is placoid scale-like, with its crown surface ornamented with some parallel ridges. Gansuselache, the first articulated hybodontiform from Asia, also represents the first complete hybodontiform from the Permian. |
