Bopyrids of the Thalassinidean Transition First Phylogenetic Data and Evolutionary Implications


Meeting Abstract

S2.1  Sunday, Jan. 4  Bopyrids of the Thalassinidean Transition: First Phylogenetic Data and Evolutionary Implications BOYKO, Christopher B; American Museum of Natural History cboyko@amnh.org

In 1986, John Markham proposed the term thalassinidean transition for those bopyrid isopod taxa that appeared to link the subfamilies Pseudioninae, Ioninae and Phyllodurinae and which occurred on thalassinoid hosts. Thalassinoids are an important host group for bopyrids with 56 species of bopyrid parasites (37 Pseudioninae, 17 Ioninae, 1 Phyllodurinae, and 1 Entophilinae) known from this group, behind only Anomura and Caridea in terms of percentage of host species infested by bopyrids. Markham proposed a non-cladistic pattern of evolution from the putatively primitive Pseudioninae (including the likely para- or polyphyletic type genus) through the Ioninae (both branchial parasites) to the advanced Phyllodurinae and the Athelginae (both abdominal parasites, with the Athelginae found only on paguroids).It is possible that these transitional forms may represent stem groups. Recently, several studies have called into question the monophyly of the Thalassinidea, providing an opportunity to examine the monophyly and relationships within the bopyrid subfamilies found on thalassinoids and to compare their patterns of evolution with those of their hosts. Six species of bopyrids parasitizing both upogebiid and callianassid hosts were studied from both a morphological and molecular perspective and the concept of the thalassinidean transition is analyzed in light of these results.

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