A new approach to the systematics of Laeviprosopon (Brachyura: Homolidae), with remarks on molting process of the early brachyurans

Abstract

Our understanding of the molting process in the Jurassic brachyurans is very scarce because useful material is rare. New specimens from Poland and Germany, in addition to previously known specimens, let us further investigate the molting process. Specimens of Laeviprosopon laeve reveal characters not known before. On the dorsal carapace, molting lines are confirmed in three species of Laeviprosopon: the type species L. laeve, L. laculatum and L. fraasi. This brought questions about the systematic position of Laeviprosopon, which we here reassign to Homolidae within Homoloidea. Furthermore, two specimens ascribed previously to L. sublaeve are transferred to L. fraasi, and one specimen ascribed previously to Navarrahomola hispanica is transferred to Laeviprosopon hispanicum. Three new species of Laeviprosopon (L. joecollinsi n. sp. and L. lanceatum n. sp. from the Oxfordian of Poland, and L. ewakrzeminskae n. sp. from the Tithonian of Austria) are erected. Finally, we deliberate on Laeviprosopon as a possible phyletic link between homolodromioids and homoloids in the light of new data on the evolution of molting line.