Stygivenator cristatus (Marsh, 1892) Olshevsky, G., 1995

Olshevsky, G., 1995, The origin and evolution of the Tyrannosaurids, Part 1, Dino-Frontline 9, pp. 92-119 : 92-119

? Stygivenator cristatus (Marsh, 1892) n. comb.,

formerly Aublysodon cristatus Marsh, 1892 (= Deinodon cristatus ), See text for details.

Discussion: Since Stygivenator is so strikingly different from other tyrannosaurids, it is first necessary to justify its inclusion in Tyrannosauridae . Naturally, Stygivenator differs strongly enough from the “orthodox” tyrannosaurids that at least subfamilial separation is warranted. But the smooth, constricted nasals; low, pointed maxillae; long frontals; unsenrated D-sectioned premaxillary tooth; relatively slender dentaxy; and lateral buttress above the surangular foramen are a combination of characters present in Stygivenator that are diagnostic of the tyrannosaurid parasubfamily Shanshanosaurinae (= Aublysodontidae [nomen dubium] of authors). The surangular buttress and morphology of the articulation point of the dentary in particular are quite similar to that of Shanshanosaurus huoyanshanensls , Stygivenator is thus best viewed as a highly derived, late-occurring member of that taxon.

Most of the diagnostic characters may be found in the description of this genus (as the “Jordan theropod” and as Aublysodon ) by Molnar (1978) and Molnar & Carpenter (1989). The specimen was personally examined by the author on a visit to the University of California at Berkeley Museum of Paleontology in the early 1980s, when the specimen was on loan to that institution.