Osteology and relationships of Luxembourgichthys (“Pholidophorus”) friedeni gen. nov. (Teleostei, “Pholidophoriformes”) from the Lower Jurassic of Belgium and the Grand Duchy of Luxembourg

1. IntroductionThe lower Toarcian strata of southeast Belgium and the Grand Duchy of Luxembourg, known as the Grandcourt Marls or the Grandcourt Formation, yield a rich and diverse ichthyofauna, comprising the saurichthyid Acidorhynchus Stensio, 1925, the amiiform Caturus Agassiz, 1834, the semionotid Lepidotes Agassiz, 1832, the dapediids Dapedium Leach, 1822 and Tetragonolepis Bronn, 1830, the pachycormids Sauropsis Agassiz, 1832, Pachycormus Agassiz, 1833, Saurostomus Agassiz, 1833, Euthynotus Wagner 1860 and Haasichthys Delsate, 1999, the pholidophorid Pholidophorus Agassiz, 1832 (represented by two species) and the primitive cycloid teleost Leptolepis Agassiz, 1832 (Delsate, 1999a, b).Delsate (1999c) described the new species Pholidophorus friedeni on the basis of specimens found in different Toarcian localities of the Grand Duchy of Luxembourg. He stated that this taxon was also recorded in Germany and attributed this new species to the genus Pholidophorus, although without giving any reason for his choice. Moreover, he expressed some doubts about this generic attribution. Fragmentary samples of the same species, collected in the lower Toarcian strata of Athus (southeast Belgium), are housed in the collection of the Royal Belgian Institute of Natural Sciences (Brussels), but were not studied until now. The aim of this paper is to study the osteology of “Pholidophorus” friedeni in a more detailed way than had been previously done, to discuss its generic attribution and t