|Genital apparatus and ultrastructure of the spermatozoa in Alvinella pompejana (Annelida: Polychaeta)|
Jouin-Toulmond, C.; Zal, F.; Hourdez, S. (1997). Genital apparatus and ultrastructure of the spermatozoa in Alvinella pompejana (Annelida: Polychaeta), in: Biologie des sources hydrothermales profondes = Biology of deep-sea hydrothermal vents: Journées d'échanges du Programme DORSALES = DORSALES Workshop Roscoff 6-8 octobre 1997. Cahiers de Biologie Marine, 38(2): pp. 128-129
In: (1997). Biologie des sources hydrothermales profondes = Biology of deep-sea hydrothermal vents: Journées d'échanges du Programme DORSALES = DORSALES Workshop Roscoff 6-8 octobre 1997. Cahiers de Biologie Marine, 38(2)[s.n.][s.l.]. 111-149 pp., more
In: Cahiers de Biologie Marine. Station Biologique de Roscoff: Paris. ISSN 0007-9723, more
|Authors|| || Top |
- Jouin-Toulmond, C.
- Zal, F.
- Hourdez, S.
Alvinella pompejana is a gonochoric species which, like Paralvinella grasslei, exhibits a sexual dimorphism. The males have a pair of well developed peribuccal tentacles which are lacking in the females. As in P. grasslei there is, in both sexes, only one pair of gonoducts, which terminal parts go forward and lead into two symmetrical pockets (spermathecae in females and seminal vesicles in males), joining and opening out into a unique genital pore located medio-dorsally at the base of the gills. Clusters of spermatozoa were found at the female pore opening, in a small "mucus" deposit, and the spennathecae were filled with well preserved spermatozoa. In the coelomic fluid of the males, clusters of spermatocytes and of spermatids are present, among free spermatozoa, coelomocytes and erythrocytes. The spermatozoa of A. pompejana are small cells with a conical shape, a short flagellum and no middle piece. They contain a round nucleus, located towards the top of the cone, and in which the chromatin is not condensed. A few mitochondria with a dense matrix are present around the nucleus. The basal part of the conical spermatozoa is a rather flat vesicular surface, about 4 microm in diameter. Membrane bound vesicles, with an electron-dense layer surrounding an electron lucent core are regularly arranged side by side along the flat vesicular surface. Approximately in the middle of this surface, a short flagellum arises from a distal centriole (basal body) and the axoneme has the normal 9x2 + 2 pattern. The abundant and well preserved spermatozoa from the spermathecae are very similar in structure to those observed in the coelomic fluid of the males. In A. pompejana, as in Paralvinella grasslei, clusters of spermatozoa are tranferred to the female spermathecae, probably during a pseudocopulation process and in both species the sperms belong to the introsperm type.