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Live specimens of the genus Aegla, unique crab-like decapod crustaceans endemic to freshwaters of temperate South America, were returned to aquaria at Florida State University. External morphology was described with light and scanning electron microscopy. Morphology of aeglids closely resembles that of members of the marine family Galatheidae, which are presently grouped with aeglids in the superfamily Galatheoidea Samouelle. Certain characters of Aegla are not seen in the Galatheidae or in any other family of the Galatheoidea. These characters include a complex system of dorsal carapace sutures, trichobranchiate gills, absence of male pleopods, direct development, and a tendency to be left handed (i.e., have the left cheliped larger than the right). The occurrence of some of these characters in other superfamilies of the Anomura, specifically the Paguroidea sensu largo, would seem reason to question the currently accepted phylogenetic placement of the aeglids within the Galatheoidea. / Behavior of aeglids is similar to that known for other families of the Anomura. Grooming behavior involves primarily the third maxilliped and chelate fifth pereiopod. Setal types on aeglid appendages are essentially identical to those of other anomurans. Grooming behavior and general morphology of grooming appendages in aeglids resemble those of their marine relatives in the Anomura rather than those of other freshwater decapods. This observation suggests that grooming behavior may serve as an indicator of phyletic affinity. Comparison of aeglid grooming with studies of grooming in the Paguroidea should be made with caution; apparent similarities must be tempered by the realization that few such studies exist in other anomuran superfamilies. / Phenetic and phylogenetic (cladistic) analyses were performed on 20 taxa that are now or have previously been included in the Anomura. Fifty-four morphological and ecological characters were scored for all families and selected characters illustrated for representatives of 11 families. The dendrobranchiate genus Penaeus was used as an outgroup for the cladistic analyses. Results of both phenetic and cladistic analyses depict aeglids as members of the superfamily Galatheoidea, in accordance with classifications of earlier workers. A suggested hypothesis for anomuran phylogeny separates thalassinoids from Anomura sensu stricto, places aeglids with other galatheoids, and removes lithodids and Lomis from the paguroid line. Thus, the suggested phylogeny deviates only slightly from traditional classificatory schemes. / Source: Dissertation Abstracts International, Volume: 47-06, Section: B, page: 2342. / Thesis (Ph.D.)--The Florida State University, 1986.
ContributorsMARTIN, JOEL WILLIAM., Florida State University
Source SetsFlorida State University
Detected LanguageEnglish
Format262 p.
RightsOn campus use only.
RelationDissertation Abstracts International

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