Redescription of ‘Diplomystus’ solignaci Gaudant & Gaudant, 1971 from the Cretaceous of Tunisia, and a new hypothesis of double-armored herring relationships

The Late Cretaceous double-armoured herring Diplomystus solignaci, represented by a single specimen collected from a limestones outcrop near El Hamma, in the region of Gabès of central Tunisia (North Africa), is redescribed in detail herein. This taxon exhibits a unique combination of features that clearly support its alignment with the ellimmichthyiform family Paraclupeidae, whereas a new phylogenetic analysis, performed on the largest, most comprehensive, and updated dataset of clupeomorph characters so far established, nests this taxon within the genus Paraclupea, together with the Early Cretaceous P. chetungensis and P. seilacheri. A new combination, Paraclupea solignaci, is therefore proposed. This species is identified by a combination of specific traits that clearly justify the taxonomic separation from the other congenerics. The presence of a Late Cretaceous species of Paraclupea in the Tethyan realm extends the biogeographic and temporal range of this widely distributed genus, providing additional information for our understanding of the evolutionary and biogeographic history of Paraclupea.