A new Lepisosteidae (Actinopterygii, Ginglymodi) from the Cretaceous of the Kem Kem Beds, southern Morocco

Abstract

Abstract Lepisosteids or gars constitute a very special neopterygian group, with seven living species in two genera: Lepisosteus and Atractosteus. They live in freshwaters from the eastern part of North America and Central America. A new lepisosteid, Oniichthys falipoui gen. nov., sp. nov., is described on the basis of two well preserved specimens. Although the type locality is unknown, information provided by the fossil collector, the type of preservation of the specimen, and the nature of the attached matrix indicate, with confidence, that it comes from the Kem Kem beds of southern Morocco (fig. 1). The Kem Kem beds are rich fossiliferous horizons, exposed along the face of an escarpment extending from the north of Erfoud town to the Kem Kem area. The age of these outcrops is still debatable being considered as ?Albian in age [Forey and Grande, 1998] or regarded as Cenomanian, due to their elasmobranch assemblage [Sereno et al., 1996]. Oniichthys falipoui shows several derived characters of gars such as an elongated ethmoid region, an upper jaw formed by a chain of tooth-bearing bones, a joint between the quadrate and the lower jaw lying far forward, in front of the orbit and a large splint-like quadratojugal overlying the horizontal branch of the preopercle. O. falipoui shares with the primitive gar, Obaichthys decoratus, from the ?Albian Santana Formation of Brazil, the presence of toothed maxillaries, although in the Moroccan taxon, the maxillaries are anteriorly fused with infraorbitals. This structure confirms that, at least, some of the "infraorbital chain" bones bear maxillary teeth, fused to them during ontogeny. Discussion of characters leads to regard O. falipoui as more derived than Obaichthys, and to place it as the sister-group of Lepisosteus-Atractosteus.