New callipurbeckiid genus (Ginglymodi: Semionotiformes) from the Tithonian (Late Jurassic) of Canjuers, France

摘要

Ginglymodian fishes are abundant and diverse in Upper Jurassic limestones of Germany, but rarer in coeval sequences in France. Only a single ginglymodian is so far known from the Tithonian at Canjuers. Our study of this excellently preserved specimen revealed that it represents a new taxon aEuro Occitanichthys canjuersensis gen. et sp. nov., which is retrieved in a cladistic analysis as a member of the semionotiform family aEuro Callipurbeckiidae. Additionally, two specimens among fishes from the Middle Purbeck Beds at Swanage referred to aEuro Callipurbeckia minor were found to represent the new callipurbeckiid taxon. The new taxon inhabited the epicontinental seas that covered most of Europe connecting the Tethys with the North Atlantic during Jurassic and Cretaceous, and its minimum biochron ranges from the Early Tithonian to the Early Cretaceous. After incorporation of the new and recently described taxa and the re-evaluation and addition of morphological characters, our cladistic analysis recovered a somewhat different pattern of relationships compared with previous phylogenetic hypotheses for Ginglymodi. Mainly, in the new topology, a monophyletic aEuro Lepidotidae includes the Jurassic genera aEuro Lepidotes and aEuro Scheenstia, and the Tithonian-Berriasian aEuro Camerichthys from Spain, which has been classified in aEuro Semionotiformes. Among semionotiforms, our results retrieved the family aEuro Macrosemiidae as the sister group of aEuro Semionotidae occupying a more distal position within the clade aEuro Semionotiformes than previously thought.