Gladius-bearing coleoids from the Upper Cretaceous Lebanese Lagersatten: diversity, morphology, and phylogenetic implications

Gladius-bearing coleoids are rare in the fossil record. For the Cretaceous period, these cephalopods are mainly recorded in a few Lagersatten in Lebanon (Haqel, Hajoula, En Nammoura, and Sahel Aalma). Here, we study 16 specimens of gladius-bearing coleoids from these Upper Cretaceous Lebanese Lagersatten to investigate their taxonomic diversity. Besides two species that were already reported (Dorateuthis syriaca and Glyphiteuthis libanotica), one new species is identified in the Cenomanian site of Hajoula: Rachiteuthis acutali n. sp., as well as another form of Glyphiteuthis from En Nammoura. Several studied specimens exhibit well-preserved soft-part characters. Among them, we document for the first time two transverse rows of sessile suckers in D. syriaca and we confirm the absence of tentacles, as well as the presence of a crop in this species. This strongly supports the phylogenetic proximity of D. syriaca with modern vampyropods rather than with modern decabrachians. In turn, the similarity in gladius morphology between this taxon and modern squids is regarded as convergent.