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Ultrastructure of Thunnus thynnus and Euthynnus allettevatus spermatozoa
Author(s) -
Abascal F. J.,
Medina A.,
Megina C.,
Calzada A.
Publication year - 2002
Publication title -
journal of fish biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.672
H-Index - 115
eISSN - 1095-8649
pISSN - 0022-1112
DOI - 10.1111/j.1095-8649.2002.tb02394.x
Subject(s) - axoneme , biology , spermatozoon , flagellum , ultrastructure , anatomy , acrosome , thunnus , scombridae , tuna , sperm , zoology , fishery , fish <actinopterygii> , semen , paleontology , botany , bacteria
The spermatozoa of Thunnus thynnus and Euthynnus alletteratus consist of an acrosome‐less head (comprising the ovoid nucleus and the short midpiece) and a long flagellar tail that contains the conventional 9 + 2 axoneme and lacks lateral fins. The centrioles are arranged at approximately right angles and lie outside of a shallow nuclear groove. The flagellum inserts laterally on the nucleus, therefore the spermatozoon is asymmetrical. The midpiece contains a few mitochondria which are separated from the axoneme by the cytoplasmic canal; they are spherical in T. thynnus and elongate, somewhat irregular in E. alletteratus . Although the main ultrastructural characteristics of the spermatozoa appear to indicate a great homogeneity in the sperm morphology within the family Scombridae, small species‐specific divergences may be of use in systematics.