<p> 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 <i>Palicus affinis, Palicus alternatus,</i> and <i> Palicus bahamensis;</i> a second grouping <i>Palicus faxoni</i> and <i>Palicus obesus;</i> and the third grouping <i>Crossotonotus </i> sp., <i>Pseudopalicus</i> sp., <i>Palicus cristatipes, </i> and <i>Palicus sica.</i> Putative specimens of <i> P. floridanus</i> were positioned as sister species to other groups. Molecular phylogenetic evidence infers intrageneric evolutionary history of <i> Palicus</i> 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.</p>
| Identifer | oai:union.ndltd.org:PROQUEST/oai:pqdtoai.proquest.com:10163333 |
| Date | 01 December 2016 |
| Creators | Pecnik, Simon James |
| Publisher | University of Louisiana at Lafayette |
| Source Sets | ProQuest.com |
| Language | English |
| Detected Language | English |
| Type | thesis |
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