ABSTRACT
The family Pinnotheridae de Haan, 1833 is a highly adapted group of largely symbiotic species distributed among 49-56 genera, some of debatable status. Many species remain to be described, a task complicated by the confused state of systematics in the group. Despite a massive taxonomic literature base, illustrations of morphology are of limited scope and quality, hampering morphologically based phylogenetic comparisons. Striking post-planktonic changes in ontogeny, related to unique life histories, can occur among subadults, and different stages of the same species have occasionally been named independently. Polyphyly of the Pinnotheridae has been previously suggested in our own preliminary analyses that combined findings from adult and larval morphology with molecular genetic data. While some issues of polyphyly center at the generic level, questions also remain as to how family and subfamily ranks should be applied to reflect monophyletic clades. The present molecular analysis was based on combined sequence data for the partial mitochondrial large subunit 16S rRNA gene, the tRNA-Leu gene, and the partial mitochondrial gene for NADH1, primarily to examine generic assignments. The results of mitochondrial gene analyses are relatively unambiguous, with strong support values for transfer of Xenophthalminae and Asthenognathinae out of Pinnotheroidea. The family Pinnotheridae is partitioned between two primary clades representing the subfamilies Pinnothereliinae and Pinnotherinae, and smaller clades may justify one or more additional subfamilies. Members of several genera within these subfamilies require taxonomic revision. Analyses based upon the 18S nuclear gene, while supporting morphologically and mitochondrial gene-based definition of the Pinnothereliinae, did not clarify relationships between most other pinnotherid genera and were thus not incorporated into our analysis.
