Phylogenetic evidence for a new Acanthocephalan family?

Phylogenetic evidence for a new Acanthocephalan family?

In my previous paper on acanthocephalans we proposed a new family (the Pyriproboscidae) based on phylogenetic evidence. In a follow up article, Lesley and I argue for the recognition of a new genus and another new family, Spinulacorpus and the Spinulacorpidae, respectively.

Huston, D.C. and Smales, L.R. 2020. Proposal of Spinulacorpus biforme (Smales, 2014) n. g., n. comb. and the Spinulacorpidae n. fam. to resolve paraphyly of the acanthocephalan family Rhadinorhynchidae Lühe, 1912. Systematic Parasitology. https://doi.org/10.1007/s11230-020-09923-7

One of the things we observed in our previous project was the species Rhadinorhynchus biformis Smales, 2014, resolved basal to the families Rhadinorhynchidae + Transvenidae, resulting in a paraphyletic Rhadinorhynchidae. In the original description, Smales (2014) noted that the trunk spine pattern in R. biformis was unlike any other species described in the genus. So it seemed like we had phylogenetic and potentially morphological evidence that R. biformis didn’t truly belong in the Rhadinorhynchidae (so long as we continue to consider the Transvenidae as distinct from the Rhadinorhynchidae). We didn’t have enough specimens at the time of our first paper to get into this particular problem, but later we examined additional specimens and did some far more intensive phylogenetic analyses. Overall, we found sufficient evidence to consider R. biformis as distinct from the Rhadinorhynchidae, and thus proposed our new genus and family.

Our aim with this paper was to help bring the Rhadinorhynchidae towards a modern classification scheme based on integrated molecular and morphological data. We think we’ve done this, but I suspect that there is much left to do. The Acanthocephala as a whole just keeps throwing up surprises and morphology and molecules seem to clash in the Acanthocephala much more than the other groups I have worked on.