Premium
Comparative spermatogenesis, spermatocytogenesis, and spermatozeugmata formation in males of viviparous species of clinid fishes (Teleostei: Clinidae, Blennioidei)
Author(s) -
Fishelson Lev,
Gon Ofer,
Holdengreber Vered,
Delarea Yakob
Publication year - 2007
Publication title -
the anatomical record: advances in integrative anatomy and evolutionary biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.678
H-Index - 62
eISSN - 1932-8494
pISSN - 1932-8486
DOI - 10.1002/ar.20412
Subject(s) - biology , sperm , spermatogenesis , germinal epithelium , anatomy , sertoli cell , spermiogenesis , teleostei , flagellum , zoology , botany , fishery , fish <actinopterygii> , endocrinology , biochemistry , gene
Spermatogenesis and spermatocytogenesis in 16 species of viviparous clinid fishes (Clinidae, Blennioidei) from various localities were followed for the first time by means of light and electron microscopy. The testes of the studied species are of the lobular type, with germinal stem cells situated at the apical ends of the lobules and a vas efferens along the internal margin. Maturation of the spermatides takes place in spermatocysts formed by Sertoli cells around the B‐spermatogonia. The gradual condensation and relocation of the chromosomes along the nuclei membranes are highly prominent in this process, which can be divided into several stages. Anisodiametric and slightly flattened sperm heads are eventually formed, 0.4–0.5 μm in diameter and 7.5 ± 1 μm long, bearing 80 ± 15 μm long flagella. The sperms are packed into spermatozeugmata within the spermatocysts, enveloped and penetrated by the mucotic material of the Sertoli cells. With division of the germ cells and maturation of the spermatids, the spermatocyst dimensions increase, attaining 40 ± 8 μm in diameter in the smaller species of Heteroclinus , and up to 90 ± 10 μm in the larger males of Clinus superciliosus and C. cottoides . Accordingly, the volume of the maturing spermatocysts attains ca. 1,300 ± 100 μm 3 in the smaller species, and ca. 6,500 ± 300 μm 3 in the larger ones. As sperm head volume is ca. 2.24 μm 3 , the number of sperm in the smallest mature spermatocysts reaches ca. 440 and in the largest over 2,900. Upon release from the cysts, the spermatozeugmata are transported along the sperm ducts to the posterior ampullae where they are stored in the epididymis. During copulation, the sperms are transported from there to the female via the intromittent organ. The sperm formation parameters and their structure and numbers are discussed. Anat Rec Part A, 2007. © 2007 Wiley‐Liss, Inc.