Spermatozoon ultrastructure and its systematic implications in fishes

Abstract

We have studied approximately 280 species spread over more than 100 families. New data on 80 species are reported. The spermatozoon of Chondrichthyes is characterized by two synapomorphies in the midpiece and the flagellum. Within the Chondrichthyes the subclass Holocephali is characterized by two spermatic apomorphies that distinguish it from the Elasmobranchii. The Osteichthyes, on the other hand, show great spermatic diversity. In each of the most primitive among them, the Actinistia, Dipnoi, Cladistia, Chondrostei, and Ginglymodi, the spermatic model is different, constituting many autapomorphies. The neopterygians possess a common character that distinguishes them from the other fishes: the lack of an acrosome. We propose a structure for the ancestral model of the spermatozoon of Neopterygii that resembles the gamete of aquatic invertebrates employing external fertilization. This simplified gamete exhibits several derived forms in teleosteans. It is mainly in the primitive Teleostei that these evolved forms are of taxonomic interest, as we demonstrate in the Mormyroidea and the Elopomorpha. In the evolved Teleostei we define a spermatozoon of the "perciform type." The distribution of this gametic type within the Perciformes may provide useful data for use with this ill-defined group whose phylogenetic interrelations are so little known.

Biflagellate spermatozoon structure of the hermaphrodite fish Satanoperca jurupari (Heckel, 1840) (Teleostei, Cichlidae) from the Amazon River

“…Although they belong to the primitive type they show some unusual features. To date all the fish spermatozoa examined show some structural homogeneity which supports the idea that the ultrastructural features of spermatozoon can be useful for taxonomic and phylogenetic studies (Baccetti et al, 1984;Mattei, 1991;Mattei & Mattei, 1984;Gwo et al, 1993Gwo et al, , 1996.…”

“…Although spermazoan structure has been reported from about 300 fish species spread over more than 100 families (Mattei, 1991;Jamieson, 1991), S. jurupari is the first member of the family Cichlidae from Brazil to be examined. Examination of other cichlids will be necessary to determine whether the primitive features of S. jurupari spermatozoa are common to this family (Mattei, 1991).…”

“…On the other hand, the presence of the two lateral cytoplasmic extensions (or ribbons) in opposite insertion on each flagellum has been described in few teleost species (Billard, 1970) as well as in other fish groups (Mattei, 1970;Matos & Azevedo, 1989). Despite a well and detailed date on spermatogenesis, the majority of teleost spermatozoa remains unexamined lacking data to allow the establishment of phylogenetic relationships amongst the teleost fishes (Mattei, 1991;Gwo et al, 1993).…”

Relationships of Lower Euteleostean Fishes

“…Patterson and Johnson (1995) noted a possible salmoniform character in Jamieson's (1991) records of a single annular mitochondrion in the sperm of alepocephaloids, salmonids, and Galaxias. Mattel (1991) also commented on sperm ultrastructure in alepocephaloids and salmonids, citing three characters that seem to relate the two groups, though an annular mitochondrion does not occur in all sampled alepocephaloids or salmonids.…”

The Ultrastructure of the Spermatozoon of Dromidiopsis-Edwardsi Rathbun, 1919 (Crustacea, Brachyura, Dromiidae) - Confirmation of a Dromiid Sperm Type

“…1991) and, with the erection of a higher taxon, the Trepaxonemata, on sperm ultrastructure (Ehlers 1985); Nematoda (Baccetti et al 1973); Polychaeta (Jamieson and Rouse 1989); Oligochaeta (Jamieson 1981(Jamieson , 1983Jamieson et al 1987); Clitellata (Ferraguti 1983); Mollusca (Healy, many papers, e.g. 1988); insects and other Hexapoda (references in Jamieson 1987); Myriapoda (Baccetti 1978); Crustacea (Pochon-Masson et al 1970;Jamieson 1991a); Chelicerata (Alberti 1990); Urochordata (Holland 1989); Echinodermata, protochordates and fish, including the erection of a new Order, the Esociformes (Jamieson 1991b); fish (Mattei 1991); Amphibia (Pugin-Rios 1980;Jamieson et al 1992;Lee and Jamieson 1992); Reptilia (Furieri 1970); Aves (Phillips and Asa 1986;Baccetti et al 1991); Marsupialia (Harding et al 1986;Temple-Smith 1987); Eutheria (Roldan et al 1991;Rouse and Robson 1986); and many phyla (Franztn, 1970;Afzelius 1979;Wirth 1991).…”