Molecular reassessment of the phylogeny of Coelogynoporidae (Platyhelminthes, Proseriata), with the description of two new genera and three new species from Cuba and the Pacific coast of Panama

Abstract

An integrative analysis of the intra-family phylogenetic relationships of Coelogynoporidae Karling, 1966 (Proseriata Meixner, 1938) was performed using morphological traits and concatenated 18S and 28S rDNA subunits data. The molecular data set included sequences of 31 specimens of Coelogynoporidae and, as outgroups, two of Calviriidae Martens & Curini-Galletti, 1993, two of Otomesostomidae Midelburg, 1908, and two of Monocelididae Hofsten, 1907, 11 of which were newly sequenced for this research. The genus Vannuccia Marcus, 1948 was recovered as paraphyletic, with the species resolving in two distinct clades. These clades are morphologically diagnosable due to the presence or absence of accessory stylets within the male copulatory bulb. The species without accessory stylets cluster in a more basal position within the family than those with accessory stylets. Those with accessory stylets, including the type species V. martae Marcus, 1948 and the newly described V. pacifica sp. nov. and V. santiaguera sp. nov., form a monophyletic sister clade to Prosogynopora riseri Laumer & Curini-Galletti, 2014. Therefore, we restrict the genus Vannuccia to species with accessory stylets, and erect a new genus, Anoplovannuccia gen. nov., for those without such stylets, including the new species A. berovidesi sp. nov. The new species are distinguished from their congeners by the specific morphology of the sclerotised structures of the male copulatory bulb. The two known species of Invenusta Sopott-Ehlers, 1976 do not make up a monophyletic grouping in the tree, and the shared morphological features between them are thus mainly based on the absence of characters that may have been lost independently. Consequently, we transfer I. paracnida (Karling, 1966) Sopott-Ehlers, 1976 to the new genus Pseudoinvenusta gen. nov., now P. paracnida comb. nov. The findings from our study provide a foundation for addressing questions about the phylogenetic placement of various coelogynoporid species, such as the enigmatic position of P. riseri.