UNUSUAL REPRODUCTIVE FEATURES IN THE FRESHWATER CRAB ZILCHIOPSIS COLLASTINENSIS (PRETZMANN, 1968) (BRACHYURA, PORTUNOIDEA, TRICHODACTYLIDAE).

LÓPEZ GRECO, L.S.1,2, OLALLA, N., TROPEA, C.1

Coquimbo, Chile

Congreso; Mid-Year Meeting of the Crustacean Society; 2007

The Crustacean Society

UNUSUAL REPRODUCTIVE FEATURES IN THE FRESHWATER CRAB ZILCHIOPSIS COLLASTINENSIS (PRETZMANN, 1968) (BRACHYURA, PORTUNOIDEA, TRICHODACTYLIDAE).   López Greco, L.S.1,2, Olalla, N., Tropea, C.1   1Dept. of Biodiversity and Experimental Biology, FCEyN, University of Buenos Aires, Cdad. Univ. C1428EHA, Buenos Aires, Argentina, 2CONICET, Argentina. Email: laura@bg.fcen.uba.ar   Trichodactylidae are the only freshwater crabs distributed in Argentina with 15 described species. Due to the scarce information available about their reproductive biology, the functional anatomy of the reproductive system in Z. collastinensis was studied. Females and males adult crabs were dissected and their reproductive systems were processed for histological analysis. At least three uncommon reproductive features were observed. Unlike all described crabs that have an H-shaped ovary, the ovary of Z. collastinensis has an inverted “U” shape presenting only the posterior ovarian lobes. A short oviduct connects these lobes with the seminal receptacles (SR).The histological analysis of the SR sheath shows that the ectodermic component is greater than the mesodermic one, so according to the histological structure and to the relative position of the mesodermic epithelium, the SR of Z. collastinensis correspond to the dorsal type like in other Portunoidea. The ectodermic epithelium of SR has an unusual pattern of folding that could be involved in the expansion of the SR when the female is inseminated. Another unusual feature was seen in males related to the formation of spermatophores. Free spermatozoa can be detected at the vas deferens, while most of the spermatophores has two, three and up to five spermatozoa. The reduction in the number of spermatozoa/spermatophore as well as including the presence of free spermatozoa in the vas deferens could be two characters related to freshwater habitat since the same fact is observed in the South American Parastacidae and in Aeglidae. In Z. collastinensis this reduction is accompanied by a great quantity of a “jelly-like” matrix produced at the proximal vas deferens and an intense PAS+ component secreted at the middle and distal vas deferens. Financial Support: ANPCYT (PICT 2004, project 953), UBACYT (2004-2007 X 143) POSTER PRESENTATION