PROCEEDINGS OF THE BIOLOGICAL SOCIETY OF WASHINGTON 115(1):1 18-128. 2002. Spermatozoal morphology of the freshwater anomuran Aegla longirostri Bond-Buckup & Buckup, 1994 (Crustacea: Decapoda: Aeglidae) from South America Christopher C. Tudge and David M. Scheltinga (CCT) Biology Department, American University, 4400 Massachusetts Ave. NW, Washington, D.C. 20016-8007, U.S.A., e-mail:
[email protected] & Department of Systematic Biology, National Museum of Natural History, Smithsonian Institution, Washington, D.C. 20560-0163, U.S.A., e-mail:
[email protected]; (DMS) Department of Zoology and Entomology, University of Queensland, Brisbane 4072, Australia, e-mail:
[email protected] Abstract. — Unique sperm morphology is described for Aegla longirostri Bond-Buckup & Buckup, 1994, a representative of the freshwater anomuran family Aeglidae from South America. Comparisons of the spermatozoal ultra-structure of this species with that described for other anomurans indicate that A. longirostri has a distinct suite of spermatozoal characters. Within the Ano-mura, the aeglids share more spermatozoal characters with the superfamily Lomoidea, represented by the monotypic Australian endemic genus, Lomis, than to any previously described representative from the Galatheoidea, Hip-poidea, or Paguroidea. A more basal ancestry, with an independent evolution-ary lineage, within the Anomura is postulated for the Aeglidae. A superficial resemblance of the spermatozoal ultrastructure of A. longirostri to that de-scribed for a palinurid lobster, Jasus, and a thalassinidean mud shrimp, Neaxius, is also noted. The endemic South American freshwater anomuran crab family Aeglidae Dana, 1852, currently consists of the genus Aegla Leach, 1820, with more than 60 species, and the two fossil genera Haumuriaegla Feldmann, 1984 and Protaegla Feldmann et al., 1998. The taxonomy and systematics of the genus Aegla has been adequately sum-marized by Martin & Abele (1988). The family Aeglidae is one of 14 anomuran families, and is currently placed in the su-perfamily Galatheoidea, with the families Chirostylidae, Galatheidae, and Porcellani-dae (Bowman & Abele 1982, Martin & Da-vis 2001). Following the classification suggested by McLaughlin (1983b) and Martin & Davis (2001), but acknowledging the existence of alternative classifications with an additional superfamily Coenobitoidea (Bowman & Abele 1982, Forest 1987), we concur that the Anomura consists of only four super-families, the Lomoidea, Hippoidea, Pagu-roidea, and the Galatheoidea. The relation-ships of the Aeglidae to other anomuran families continues to be equivocal. Milne-Edwards & Bouvier (1894) concluded that the aeglids were derived from marine her-mit crabs, and placed them on a direct lin-eage to the galatheids (Galatheidae). Later workers (Martin 1985, 1989; Martin & Abele 1988) linked the aeglids with the her-mit crabs (Paguroidea) rather than with the galatheids, but a sister-group relationship with the Galatheoidea has also been sug-gested (Martin & Abele 1986). The simi-larity of aeglids, in gross external morphol-ogy, to the marine galatheids and chirostyl-ids is the source of much of this confusion and resulting speculation. Representatives of the Aeglidae were absent from a recent phylogenetic analysis of anomuran relation-
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