The description of Pseudometeorina eratosthenica sp. nov. from the eastern Mediterranean Eratosthenes Seamount was the release for a detailed phylogenetic comparison of a group of derived representatives of the family Idyanthidae Lang, 1944, namely Aspinothorax Moura & Martínez Arbizu, 2003, Meteorina George, 2004, Pseudometeorina George & Wiest, 2015, and Styracothorax Huys, 1993. The named genera share the derived presence of a 2-segmented P1 exopod as well as the transverse elongation of the bases of the swimming legs P1–P4, being these five deviations unique for Idyanthidae and therefore hypothesized here as synapomorphic for the above-named taxa. Consequently, they are pooled in the newly established Aspinothoracinae Moura & Martínez Arbizu, 2003 subfam. nov. The new species described from Eratosthenes Seamount doubtlessly belongs to Pseudometeorina, sharing with P. mystica George & Wiest, 2015, a set of 24 synapomorphies. Otherwise, P. eratosthenica sp. nov. provides nine autapomorphies that justify its establishment as distinct species. A detailed phylogenetic analysis, based on 131 morphological characters, is presented. Moreover, a key to the species of Aspinothoracinae subfam. nov. is provided. |
