Dissertation/Thesis Abstract

Phylogenetic Analysis of North American Representatives of the Brachyuran Genus Palicus, With Focus on Gonopod Morphology and Mitochondrial Gene Sequences
by Pecnik, Simon James, M.S., University of Louisiana at Lafayette, 2016, 61; 10163333
Abstract (Summary)

The brachyuran superfamily Palicoidea Števčić, 2005, commonly referred to as stilt-crabs, currently includes the families Crossotonotidae Moosa and Seréne, 1981 and Palicidae Bouvier, 1898, consisting of two and nine genera, respectively. Both genus and species level relationships remain largely enigmatic and are based primarily upon highly variable morphological characters. Molecular phylogenetic analyses, based on COI and 16S mitochondrial gene sequences, are used to clarify relationships among primarily western Atlantic species and to independently validate diagnostic morphological characters. The resultant molecular phylogenetic tree resolves three major clades: one grouping Palicus affinis, Palicus alternatus, and Palicus bahamensis; a second grouping Palicus faxoni and Palicus obesus; and the third grouping Crossotonotus sp., Pseudopalicus sp., Palicus cristatipes, and Palicus sica. Putative specimens of P. floridanus were positioned as sister species to other groups. Molecular phylogenetic evidence infers intrageneric evolutionary history of Palicus Philippi, 1838, concordant with relationships suggested by gonopod morphology of congeners. Gonopod morphology was found to be highly conserved within species, moderately conserved among species sharing a common clade, and divergent among species in different well-separated clades. Conversely, many morphological characters that have historically been applied to describe and identify palicids were found to be highly variable within species, inconsistently variable among species, and in some cases relatively conserved across divergent clades. On the basis of present molecular phylogenetic analyses, separation of the families Crossotonotidae and Palicidae may be supported only if further revisions to membership of the family Palicidae were to be undertaken. These revisions are deferred pending more robust genetic analyses.

Indexing (document details)
Advisor: Felder, Darryl L.
Commitee: France, Scott C., Klerks, Paul L.
School: University of Louisiana at Lafayette
Department: Biology
School Location: United States -- Louisiana
Source: MAI 56/01M(E), Masters Abstracts International
Subjects: Biology, Systematic
Keywords: Gonopods, Gulf of mexico, Palicidae, Palicoidea, Palicus, SEM
Publication Number: 10163333
ISBN: 9781369180251
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