Meeting Abstract
33.3 Friday, Jan. 4 Re-examination of Hexapanopeus, Acantholobulus, and related genera of the Panopeidae (Crustacea: Decapoda: Brachyura) by morphological and molecular methods. THOMA, B.P.*; SCHUBART, C,D,; FELDER, D.L.; University of Louisiana – Lafayette; Universit�t Regensburg, Germany; University of Louisiana – Lafayette brent.thoma@louisiana.edu
Historically, placement of some brachyuran taxa within families has been based on characters now known to be phylogenetically uninformative, and in some cases this served to obscure actual relationships. This has for example occurred among xanthoid crabs, especially for taxa formerly assigned to the Goneplacidae sensu lato. To some extent these problems have been addressed in recent years by accepting that traditional characters reflect ecophenotypic plasticity of carapacial morphology and convergence in general habitus. Family and generic assignment has alternatively been based on characters of the male gonopod and related structures. We re-examine these morphologically-based assignments by molecular methods in the course of studying the xanthoid genera Acantholobulus, Hexapanopeus, and Glyptoplax, all now assigned to the Panopeidae. Phylogenetic relationships are inferred from sequences of three mitochondrial loci (12S rDNA, 16S rDNA, and CO1) and a single nuclear locus (18S rDNA). In addition to clarifying composition of the genus Hexapanopeus sensu stricto, we establish its relationships to several other panopeid genera. Preliminary phylogenetic analyses show strong congruence between relationships based upon gonopod morphology and molecular data. Analyses support restricted application of the name Hexapanopeus, while alternative generic assignments are justified for most species presently assigned to the genus. Additionally, the membership of Glyptoplax is known to warrant re-examination, with evidence that its present membership is highly paraphyletic. Pending needed revisions, several undescribed Atlantic panopeids can be unambiguously assigned to monophyletic genera (supported under NSF/AToL EF-0531603).
