Ctenochasma? porocristatum Sos 2179 (Buisonjé 1981, Late Jurassic, ~150mya, ~26 cm skull length), was originally considered a species of Ctenochasma due to its many teeth. However, those teeth were not elongated and laterally oriented, as in Ctenochasma. They were short, sharp and interlocking. The bump on top of the skull was considered a crest of sorts, but ctenochasmatids have a narrow comb-like crest (when present). Actually the "bump" is the missing premaxilla, broken off and displaced during taphonomy. The “vertical striae in the flanks of the crest, placed at regular intervals of .12mm,” according to Buisonjé (1981) are actually the anterior teeth. Only the skull is known. SoS 2179 was derived from a sister to Sos 2428 (no. 57 in the Wellnhofer catalog.)
Larger than and distinct from SoS 2428, the skull of SoS 2179 was much longer with a skull length:height ratio estimated at 14:1. The antorbital fenestra was less than one quarter of the rostral length. The teeth were more slender, more numerous (200+ per ramus) and shorter. Many maxillary teeth angled anteriorly to match the slightly posterior orientation of the dentary teeth. The anterior two premaxillary teeth were procumbent. Maxillary teeth extended posteriorly below orbit.
Considering its close relationship to the flightless pterosaur, SoS 2428, together with its greater size and greater relative skull length, SoS 2179 was likely also flightless.
See the pterosaur family tree here. |