Describer

Sereno and Brusatte 2008

Time

Cretaceous Early Aptian Albian

Classification

Saurischia Theropoda Abelisauridae

Diet

Carnivore

Fossilsite

“Gadoufaoua” on the western edge of the Ténéré Desert, coordinates N 1626’, E 97’, Echkar Formation, Niger

Info

Genus - Typespecies - Skull

Represented by a single individual preserving the maxilla, pelvic girdle, vertebrae and ribs. Several features, including a maxilla textured externally by impressed vascular grooves and a narrow antorbital fossa, clearly place Kryptops palaios within Abelisauridae as its oldest known member.

Ethymology

From Greek krypto, covered; ops, face; in reference to the pitted surface and impressed vessel tracks on the maxilla, which is indicative of a firmly attached, possibly keratinous, integument or covering. From Greek palaios, old; in reference to its Early Cretaceous age.

Holotype

MNNGAD1, partial skeleton including a left maxilla (MNNGAD1−1), several partial vertebrae and ribs (MNNGAD1−3 to GAD1−8), and an articulated pelvic girdle and sacrum (MNN GAD1−2).

Diagnosis

Abelisaurid theropod characterized by the following two autapomorphies: a deep secondary wall in the anteroventral corner of the antorbital fossa that completely obscures the antorbital fossa and that has a scalloped and fluted dorsal margin and external texture on the maxilla, which is composed of short linear grooves. It differs most obviously from other abelisaurids and nearly all other theropods in the marked development of a secondary wall on the maxilla that completely obscures the antorbital fenestra in lateral view.

In addition, the derived abelisaurid articular trough for the nasal on the maxilla is narrower and less developed in K. palaios than in other abelisaurids, a primitive condition. Finally, the texturing of the external surface of the maxilla is composed of shorter grooves than typical of similar ornamentation on other abelisaurids. The sacrum and ilium are also more primitive than in Majungasaurus and Carnotaurus (Bonaparte et al. 1990; Carrano 2007); the sacrum is composed of only five vertebrae, and the ilium has a relatively deeper preacetabular process. (Sereno and Brusatte 2008).