Possible sexual dimorphism in Pankowskichthys libanicus (Neopterygii, Pycnodontiformes) from the Cenomanian of Lebanon.

Abstract

Sexual dimorphism is a commonly observed phenomenon in the natural world today but it is far more difficult to determine how common it was in extinct taxa. Here, we describe a new specimen of Pankowskichthys libanicus (Pycnodontiformes, Gladiopycnodontidae) from Haqel, Lebanon (MNHN HAK 1950), which has distinct morphological differences from the holotype of this taxon (IRSNB P9278) which occurs in Hjoula, Lebanon but has also been found at Haqel. Since most of the cranial and pectoral girdle morphologies as well as other postcranial characters are similar to that seen in IRSNB P9278, the distinctive characters seen in MNHN HAK 1950 are unlikely to define a second species but rather represent sexual dimorphic traits.