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Ultrastructure of spermiogenesis, spermatozoa and the tegument in Atriaster sp. (Platyhelminthes, Monogenea, Polyopisthocotylea, Microcotylidae)
Author(s) -
JUSTINE JEANLOU
Publication year - 1992
Publication title -
zoologica scripta
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.204
H-Index - 64
eISSN - 1463-6409
pISSN - 0300-3256
DOI - 10.1111/j.1463-6409.1992.tb00326.x
Subject(s) - viral tegument , biology , spermiogenesis , spermatid , ultrastructure , monogenea , cytoplasm , autapomorphy , anatomy , spermatozoon , zoology , fish <actinopterygii> , microbiology and biotechnology , botany , sperm , gill , fishery , virology , biochemistry , gene , phylogenetic tree
Atriaster (Atriaster) sp., a gill parasite in the fish Diplodus cervinus caught near Dakar, Senegal, was studied by transmission electron microscopy. Spermiogenesis is similar to the general scheme in the Cercomeridae and particularly the polyopisthocotylean monogeneans, but shows two remarkable characteristics: (a) the zone of differentiation for each spermatid is separated from the common spermatid cytoplasmic mass by a region without longitudinal microtubules but with many mitochondria, herein termed the pre‐zone of differentiation; (b) transverse sections of nuclei in late spermatids are polygonal with concave sides. These two characteristics are provisionally interpreted as autapomorphies, since observations in other species are lacking. The outer layer of the tegument is similar to that of other polyopisthocotylean monogeneans, and has microvilli and three kinds of cytoplasmic inclusions: granules with fibrous contents, granules with homogeneous contents, and elongate electron‐dense bodies.