SOME ANATOMICAL AND BEHAVIORAL-ASPECTS OF REPRODUCTION IN MEMBERS OF AN UNUSUAL TELEOST FAMILY - THE PHALLOSTETHIDAE

Male phallostethids have complex asymmetrical modifications of the pel vic girdle and associated structures, illustrated here for Neostethus bicornis and N. lankesteri. This is associated with modifications of t he reproductive system in these and another species (Phenacostethus sm ithi): the atherinomorph-type testis leads into a duct system which is specialized for the secretion of a protein-rich seminal fluid. The sp ermatozoa are packaged as spermatophores in Neostethus spp., whereas a ny such organization is but transitory in P. smithi. Females produce r elatively small numbers of large, filamented oocytes; large numbers of spermatozoa are present in the ovarian lumen, especially in neostethi ds. Mating behaviour of the two Neostethus spp. is described briefly o n the basis of a small number of video recordings, and reconstructed w ith anaesthetized specimens: the male grasps the female, presumably us ing modified pelvic elements (the ctenactinia), this culminating in a bolus of spermatophores in a proteinaceous secretion being deposited i n the vicinity of the female's oviducal opening. The sperm must someho w then migrate into the oviduct to fertilize the eggs prior to their b eing laid.