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1 August 2006 ULTRASTRUCTURE OF SPERMATOGENESIS IN THE WHITE CLAM CHIONE CALIFORNIENSIS (BRODERIP, 1835) (MOLLUSCA: PELECYPODA)
ESPERANZA ORTIZ-ORDOÑEZ, ESTHER URÍA GALICIA, ANGELICA SILVA-OLIVARES, VICTOR TSUTSUMI, MINEKO SHIBAYAMA
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Abstract

Although studies of this species have focused on its reproductive cycle, there is no literature available on the ultra-structure of its germ cells. This study consequently aims to describe the latter cells as well as the shape of the acrosome, a character that may be of help in the taxonomic allocation of species of this family or other bivalve families. Results indicate spermatogonia have a central, spherical nucleus as well as scattered heterochromatin granules throughout the nucleoplasm. Rough endoplasmic reticulum is scarce, but the cytoplasm is rich in mitochondria and disperse glycogen granules. In primary spermatocytes, heterochromatin is more highly condensed and there is a reduction in the amount of cytoplasm and number of mitochondria as compared with spermatogonia. In secondary spermatocytes, heterochromatin is present in peripheral areas of the nucleus, forming occasional projections towards its center. In spermatids chromatin is fully condensed, taking up the entire nucleus. Mitochondria increase in size and migrate to the basal pole, giving rise, along with the centriole, to the spermatozoon neck. In spermatozoa, the nucleus is ovoid, the acrosome is round and the centriole is surrounded by four mitochondria, unlike other bivalves, like Anadara tuberculosa, in which the nucleus is reported to be round, the acrosome is pyramidal and there are five mitochondria.

ESPERANZA ORTIZ-ORDOÑEZ, ESTHER URÍA GALICIA, ANGELICA SILVA-OLIVARES, VICTOR TSUTSUMI, and MINEKO SHIBAYAMA "ULTRASTRUCTURE OF SPERMATOGENESIS IN THE WHITE CLAM CHIONE CALIFORNIENSIS (BRODERIP, 1835) (MOLLUSCA: PELECYPODA)," Journal of Shellfish Research 25(2), 399-401, (1 August 2006). https://doi.org/10.2983/0730-8000(2006)25[399:UOSITW]2.0.CO;2
Published: 1 August 2006
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