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The flagellar apparatus of spermatozoa in fish. Ultrastructure and evolution
Author(s) -
MATTEI Xavier
Publication year - 1988
Publication title -
biology of the cell
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.543
H-Index - 85
eISSN - 1768-322X
pISSN - 0248-4900
DOI - 10.1016/0248-4900(88)90054-8
Subject(s) - spermatozoon , flagellum , biology , axoneme , human fertilization , gamete , anatomy , ultrastructure , fish <actinopterygii> , sperm , acrosome , evolutionary biology , microbiology and biotechnology , botany , semen , genetics , fishery , gene
Chondrichthyes posses an evolved type of spermatozoa. Their flagellar apparatus is characterized by the presence of flagellar roots which form the axis of the midpiece, and the existence of one or two lateral elements associated with the axoneme, Osteichthyes, mainly teleosteans, show a great diversity of spermatic forms. The primitive spermatozoon with a 9+2 pattern flagellum is common. The primitive spermatozoon has evolved along different lines. The spermatic diversity which results from this is mainly evident in the structure of the flagellar apparatus. In the animal kingdom the primitive spermatozoon with a 9+2 pattern flagellum, present in primitive metazoa, is retained in phyla where external fertilization is maintained. The main evolutionary tendencies – elongation, aflagellarity or biflagellarity – are generally connected with the acquisition of internal fertilization. These evolutionary tendencies are found in teleosteans. It is not Possible to link aflagellarity or biflagellarity of the gamete in certain fishes to this method of fertilization. Only the elongation of the spermatozoon is connnected, in certain cases, with interanl fertilization, but this cannot be taken as general.