Ostéologie et relations de Catervariolus (Teleostei, "Pholidophoriformes") du Jurassique moyen de Kisangani (Formation de Stanleyville) en République Démocratique du Congo
Taverne, L. (2011). Ostéologie et relations de Catervariolus (Teleostei, "Pholidophoriformes") du Jurassique moyen de Kisangani (Formation de Stanleyville) en République Démocratique du Congo. Bull. Kon. Belg. Inst. Natuurwet. Aardwet. = Bull. - Inst. r. sci. nat. Belg., Sci. Terre 81: 175-212
In: Bulletin van het Koninklijk Belgisch Instituut voor Natuurwetenschappen. Aardwetenschappen = Bulletin de l'Institut Royal des Sciences Naturelles de Belgique. Sciences de la Terre. KBIN: Brussel. ISSN 0374-6291, meer
The osteology of Catervariolus, a small fish from the Middle Jurassic of Kisangani (Stanleyville Formation) in the Democratic Republic of Congo, is studied in detail on the basis of more than 600 specimens. It is shown that the genus is monospecific and that Catervariolus passaui is a junior synonym of Catervariolus hornemani. Catervariolus is less evolved than the “classical” teleosts. Indeed, its ural vertebra 1 is still divided into two distinct centra. It still has an opisthotic, a surangular, a prearticular, coronoids, a Meckelian bone, six epurals and nine hypurals. Its scales are lepisosteid and not cycloid. The inclusion of Catervariolus in the order “Pholidophoriformes” is justified by some specialized characters of its skeleton. It possesses an impair vomer, an ossified supraoccipital, a quadrate with a quadratic process, a toothed dermobasihyal and a foramen for the efferent pseudobranchial artery pierced in the parasphenoid. Long epineurals are fused with the neural arches. Indeed, these apomorphies separate the “Pholidophoriformes” from the Pachycormiformes, their plesiomorphic sister-order. The toothed laterodermethmoids of Catervariolus form the middle of the upper jaw and reject laterally the premaxillae. The African fossil fish does not yet have an hypoethmoid associated with the vomer, neither a subtemporal fossa nor a bony prootico-intercalar bridge. It has three supraorbitals, three large postorbitals, a unique small supramaxilla and three toothed coronoids on the lower jaw. The toothed part of its dentary is elongated and not descending ventrally. The leptolepid notch of the oral border of the dentary is feebly developed or even absent. The combination of these characters shows that Catervariolus is the most primitive of all hitherto described “Pholidophoriformes”.
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