Journal article
A DYROSAURID CROCODYLIFORM BRAINCASE FROM MALI
Journal of paleontology, Vol.76(6), pp.1060-1071
11/2002
DOI: 10.1666/0022-3360(2002)076<1060:ADCBFM>2.0.CO;2
Abstract
A well-preserved crocodyliform specimen from the Maastrichtian or Paleocene of Mali preserves the braincase and posterior dermatocranium. It is referred to Dyrosauridae on the basis of several derived features (a prominent anterior process of the postorbital, discrete occipital processes on the exoccipitals, significant quadratojugal contribution to jaw joint) and tentatively referred to Rhabdognathus on the basis of supratemporal fenestra shape. The lacrymal and prefrontal are relatively short compared with those published for other dyrosaurids. The palatines border the internal choanae anteriorly, and the choanae are divided by a midline septum derived from the pterygoids. The prefrontal pillars are mediolaterally broad and contact the palate ventrally. One stapes is preserved in place. The basicranial pneumatic system is very unusual, in that the anterior and posterior branches of the median eustachian canal are both separate at the palatal surface, and the pterygoids form part of the border for the anterior branch. The lateral eustachian openings lie within fossae on the lateral surface of the braincase and face laterally, with a descending process of the exoccipital nearly intersecting the opening. The braincase and surrounding dermal bones are elongate anteroposteriorly, and the postorbital's posterior ramus extends along the posterodorsal margin of the infratemporal fenestra. The quadrate ramus projects ventrally. These observations clarify character optimizations in previous phylogenetic analyses of Crocodyliformes.
Details
- Title: Subtitle
- A DYROSAURID CROCODYLIFORM BRAINCASE FROM MALI
- Creators
- CHRISTOPHER A Brochu - University of IowaMAMADOU L Bouaré - École Normale Supérieure - PSLFAMORY Sissoko - Institut des Sciences Humaines, Bamako, MaliERIC M Roberts - University of UtahMAUREEN A O'LEARY - Stony Brook University
- Resource Type
- Journal article
- Publication Details
- Journal of paleontology, Vol.76(6), pp.1060-1071
- DOI
- 10.1666/0022-3360(2002)076<1060:ADCBFM>2.0.CO;2
- ISSN
- 0022-3360
- eISSN
- 1937-2337
- Number of pages
- 12
- Language
- English
- Date published
- 11/2002
- Academic Unit
- Earth and Environmental Sciences; University College Courses
- Record Identifier
- 9984229299602771
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