Meeting Abstract

P3.80  Sunday, Jan. 6  Gonad morphology and reproductive modes in fishes of the Tribe Starksiini (Teleostei, Blenniiformes) FISHELSON, L; BALDWIN, C; HASTINGS, P*; Tel Aviv University; Smithsonian Institution; Scripps Institution of Oceanography phastings@ucsd.edu

The Starksiini is one of only two lineages of reef-dwelling blennies thought to exhibit internal fertilization. We studied the gonad morphology of 17 of the 30 species using standard histological methods. The testes are of the lobular type and have a small testicular gland. Isodiametric sperm (aquasperm) with a globular head or anisodiametric sperm (introsperm) with an elongate head, or both, were observed in various species. Ovaries are bilobed and exhibit either synchronous or asynchronous egg production. We found evidence of both internal and external fertilization and three modes of reproduction within the group. External fertilization and ovuliparity is suggested for the Starksia atlantica and S. lepicoelia species complexes by the presence in males of a short genital papilla that is free from the first anal-fin spine and by the absence of sperm within ovaries. Internal fertilization and zygoparity is indicated for most species by the presence of a long intromittent papilla in males that is adhered to the first anal-fin spine, “nests” of sperm within ovaries, absence of embryos within the ovarian lamellae and usually thick egg envelopes bearing dense covers of adhesive filaments. Internal fertilization and embryoparity is indicated for Starksia fulva and Xenomedea rhodopyga by an adhered intromittent papilla, anisodiametric sperm, delicate egg envelopes without adhesive filaments and developing embryos within ovarian follicles. Starksiins differ from internally fertilizing clinid blennies in retaining the testicular gland typical of labrisomids and in lacking sperm packaging typical of clinids and other internally fertilizing teleosts.