Rhabdosaurus Bergounioux, 1956

Hill, Robert V., Mccartney, Jacob A., Roberts, Eric, Bouaré, Mohamed, Sissoko, Famory & O'leary, Maureen A., 2008, Dyrosaurid (Crocodyliformes: Mesoeucrocodylia) Fossils from the Upper Cretaceous and Paleogene of Mali: Implications for Phylogeny and Survivorship across the K / T Boundary, American Museum Novitates 3631 (1), pp. 1-20 : 6

(5 Rhabdosaurus Bergounioux, 1956 )

TYPE SPECIES: Rhabdognathus rarus Swinton, 1930 ; nomen dubium ( Jouve, 2007).

INCLUDED SPECIES: R. aslerensis Jouve, 2007 ; R. keiniensis Jouve, 2007 .

AGE AND DISTRIBUTION: Maastrichtian- Paleocene, Tilemsi Valley, Mali.

DIAGNOSIS: As in Jouve (2007); dyrosaurid with caudal wall of supratemporal fenestra largely visible in dorsal view; interfenestral bar narrow and unornamented; occipital tuberosities long, well-developed and widely spaced; suture between parietal and supraoccipital gently sinuous ventrally (not W-shaped). See Jouve (2007) for other diagnostic characters of this genus.

DISCUSSION: Swinton (1930) described Rhabdognathus rarus based on a few fragmentary, tubular segments of lower jaw from the Paleocene of Nigeria. Additional mandibular material was referred to this genus by Halstead and Middleton (1976) and Buffetaut (1980). Buffetaut (1980) also described the first cranial remains referred to Rhabdognathus , but did not include any characters of the skull in his emended diagnosis. Because Rhabdognathus could be recognized only on the basis of mandibular characters, subsequent referrals of cranial material to the genus were necessarily tentative (e.g., Langston, 1995; Brochu et al., 2002). Jouve (2007) recently revised the genus, examining all known material and recognizing two species of Rhabdognathus : R. aslerensis and R. keiniensis . He declared Rhabdognathus rarus a nomen dubium, but retained it as the type species of the genus. Rhabdognathus compressus ( Buffetaut, 1980) was transferred to the genus Congosaurus on the basis of alveolar morphology.

Jouve (2007) referred to another species as ‘‘ Rhabdosaurus acutidentatus ’’ and attributed it to Bergounioux (1956), acknowledging that it was later transferred to Rhabdognathus by Buffetaut (1978b). In fact, Bergounioux (1956) named Rhabdosaurus acutirostris (not acutidentatus ), which Buffetaut (1978b) transferred to Rhabdognathus acutirostris . The holotype and only known specimen of this species has been lost ( Buffetaut, 1978b; and see Jouve, 2007), but because it consists of mandibular material, according to Jouve (2007) it can only be referred to Rhabdognathus sp. The two currently recognized species of Rhabdognathus ( R. aslerensis and R. keiniensis ) differ from one another primarily in characters of the occipital region ( Jouve, 2007).