Comparative ultrastructural studies on scleractinian spermatozoa (Cnidaria, Anthozoa)

Steiner, Sascha C. C.

doi:10.1007/bf00403090

Cited by 37 publications

(27 citation statements)

References 20 publications

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“…This is the so-called "Spitzenkorper" or anterior process. The anterior process has been found in the sperm of gonochoric scleractinians (Schmidt and Zissler 1979;Harrison 1985;Steiner 1991Steiner , 1993Steiner and Cortés 1996) where, in Steiner's (1991) opinion, it serves a possible acrosomal function. This is the first time that the anterior process is described in the sperm of a hermaphroditic scleractinian.…”

Section: Spermatogenesismentioning

confidence: 99%

“…During spermiogenesis, this membrane-bound lamella shifts forwards reaching the spermatid anterior pole where it disappears. Among Anthozoa, a single sheet-like membrane-bound lamella has been observed in mature sperm of some scleractinians (Harrison 1985;Steiner 1991Steiner , 1993Steiner and Cortés 1996). According to Steiner (1993), this sheet-like lamella structurally resembles the Golgi-derived membrane-bound vesicles that vary in size, number and location and are usually found in many anthozoan sperm.…”

Section: Spermatogenesismentioning

confidence: 99%

“…Among Anthozoa, a single sheet-like membrane-bound lamella has been observed in mature sperm of some scleractinians (Harrison 1985;Steiner 1991Steiner , 1993Steiner and Cortés 1996). According to Steiner (1993), this sheet-like lamella structurally resembles the Golgi-derived membrane-bound vesicles that vary in size, number and location and are usually found in many anthozoan sperm. The exact function of these vesicles has not been ascertained, but they are interpreted as being proacrosomal vesicles by Hinsch (l974), Miller (1983) and Steiner (1993).…”

Section: Spermatogenesismentioning

confidence: 99%

“…According to Steiner (1993), this sheet-like lamella structurally resembles the Golgi-derived membrane-bound vesicles that vary in size, number and location and are usually found in many anthozoan sperm. The exact function of these vesicles has not been ascertained, but they are interpreted as being proacrosomal vesicles by Hinsch (l974), Miller (1983) and Steiner (1993).…”

Section: Spermatogenesismentioning

confidence: 99%

“…Clark and Dewel (1974), Lyke and Robson (1975) and Schmidt and Zissler (1979) carried out most of the available observations on spermiogenesis in Anthozoa. Recently, much attention has been given to the ultrastructural features of mature sperm in Scleractinia (Harrison 1988;Steiner 1991Steiner , 1993Steiner and Cortés 1996). However, no ultrastructural data exist on spermatogenesis in this taxon of Anthozoa except for a study by Schmidt and Zissler (1979) on Cladocora caespitosa (Linné, 1767).…”

Section: A Introductionmentioning

confidence: 99%

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Ultrastructural observations of the spermatogenesis of the hermaphroditic solitary coral Balanophyllia europaea (Anthozoa, Scleractinia)

2000

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Spermatogenesis ultrastructure was studied in a simultaneous hermaphrodite population of the solitary coral Balanophyllia europaea. In this species, spermatogenesis takes place in spermatocysts located within gametogenetic mesenteries surrounded by a bilayered boundary. Spermatogonia and spermatocytes are large flagellate cells, densely packed at the outermost edges of the spermatocyst. Spermatids and sperm are loosely distributed near the centre of the spermatocyst. The cytoplasm of spermatogonia and primary spermatocytes often contains short lengths of free axonemes, probably derived from the reabsorption of a primitive flagellum. Maturing spermatids either contain long intracytoplasmic axonemes, that may be stages of the tail synthesis, or have a flagellum. The morphological features of the sperm of this hermaphroditic scleractinian, very similar to those observed in the sperm of gonochoric taxa, support the hypothesis that the hermaphroditism of this population is an adaptive condition.

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Section: Spermatogenesismentioning

confidence: 99%

Section: Spermatogenesismentioning

confidence: 99%

Section: Spermatogenesismentioning

confidence: 99%

Section: Spermatogenesismentioning

confidence: 99%

Section: A Introductionmentioning

confidence: 99%

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Ultrastructural observations of the spermatogenesis of the hermaphroditic solitary coral Balanophyllia europaea (Anthozoa, Scleractinia)

2000

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Mating in the box jellyfish Copula sivickisi—Novel function of cnidocytes

Garm

Lebouvier

Tolunay

2015

Journal of Morphology

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Within cubozoans, a few species have developed a sexual reproduction system including mating and internal fertilization. One species, Copula sivickisi, is found in a large area of the indo pacific. They have separate sexes and when mature males and females meet they entangle their tentacles and the males transfer a sperm package, a spermatozeugmata, which is ingested by the female fertilizing her eggs internally. After 2-3 days, the females lay an embryo strand that sticks to the substrate and after another 2-3 days, the fully developed larvae leave the strand. We have examined the ultrastructure of the gonads and spermatozeugmata to look for structural adaptations to this specialized way of reproduction and understand how the fertilization takes place. Surprisingly, we discovered that the male gonads were heavily packed with cnidocytes of the isorhiza type and that they are transferred to the spermatozeugmata. The spermatozeugmata does not dissolve in the female gastrovascular cavity but is attached to the female gonad probably using the isorhizas. Here, the sperm cells are partly digested and the nuclei are released. The actual fertilization seems to happen through phagocytosis of the released nuclei by the epithelial cells. The female gonads are likewise packed with cnidocytes but of the eurytele type. They do not mature inside the female and putatively serve to protect the developing larvae once the embryo strand is laid. This specialized way of fertilization is to our knowledge novel and so is this first account of cnidocytes being directly involved in cnidarian reproduction.

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