Sperm tail differentiation in the nudibranch mollusc <i>Hypselodoris tricolor</i> (gastropoda, opisthobranchia)

Medina, Antonio; Moreno, F. Javier; Garcı́a-Herdugo, G.

doi:10.1002/mrd.1120200212

Cited by 10 publications

(4 citation statements)

References 21 publications

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“…The terminology applied for the description of sperm ultrastructure follows Thompson (1973), Medina et al (1988) and Healy & Willan (1991). The spermatozoa are subdivided into the head, the midpiece and the tail.…”

Section: Resultsmentioning

confidence: 99%

“…The 'wavelength' of the keel is almost 1 mm ( Figure 3A) in the apical region. The cross and longitudinal sections show a shallow (about 0.3 mm) basal invagination of the nucleus (implantation fossa sensu Medina et al, 1988) ( Figures 1D, 3E & 4D). Spermatids in the late stage of spermiogenesis have already a well developed nucleus with highly condensed chromatin, but still show a row of microtubules (microtubular manchette sensu Medina et al, 1986) surrounding the nucleus (and the midpiece) helically ( Figures 2B & 4B,C,E,F) that disappears at the end of spermiogenesis (Figure 3).…”

Section: Acrosomal Complex and Nucleusmentioning

confidence: 99%

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Sperm ultrastructure of Microhedyle remanei, an interstitial acochlidian gastropod with dermal fertilization

et al. 2007

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The ultrastructure of sperm of an acochlidian opisthobranch is described for the first time in detail, in the tiny, gonochoristic Microhedyle remanei (Microhedylidae) from Bermuda. Transmission electron microscopy (TEM) shows the spermatozoa of M. remanei sharing many plesiomorphic features with opisthobranch gastropods, such as having an apical spiral nucleus with a basal invagination filled with a bell-shaped centriolar derivative; there is a single glycogen helix embedded into matrix and paracrystalline material. Sperm of M. remanei are characterized by possessing a strongly helically coiled nucleus with up to five keels terminating into one very prominent and intertwined keel. The sperm midpiece shows the glycogen helix which is very densely arranged. This clearly differs from Hedylopsis ballantinei, a member of the related acochlidian family Hedylopsidae, where three glycogen helices with different lengths and a probably much shorter nucleus are present. This variation among acochlidian sperm may be phylogenetically relevant and may be related to special acochlidian reproductive features such as sperm transfer via hypodermic injection or dermal fertilization via spermatophores.

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Section: Resultsmentioning

confidence: 99%

Section: Acrosomal Complex and Nucleusmentioning

confidence: 99%

Sperm ultrastructure of Microhedyle remanei, an interstitial acochlidian gastropod with dermal fertilization

et al. 2007

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“…The following summary and supporting micrographs ( Fig. 4A-L Medina et al 1985Medina et al ,1986Medina et al ,1988Healy l982,1988bHealy l982, ,1990aHealy l982, , 1991Healy & Jamieson 1991).…”

Section: Spermiogenic Featuresmentioning

confidence: 85%

Comparative sperm ultrastructure and spermiogenesis in basal heterobranch gastropods (Valvatoidea, Architectonicoidea, Rissoelloidea, Omalogyroidea, Pyramidelloidea) (Mollusca)

Healy

1993

Zoologica Scripta

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Hcaly, J. M. 1993. Comparative sperm ultrastructure and spermiogenesis in basal hctcrobranch gastropods (Valvatoidca, Architectonicoidca, Rissoclloidca. Omalogyroidca, Pyramidelloidea) (Molluscs).-Zool. Scr. 22: 263-276. Three distinct groups of basal hctcrobranch gastropods (= ' AlIogastropodaiHetcrostropha') can be distinguished on the basis of sperm and spcrmiogenic features: ( I ) Valvatoidea; (2) Architcctonicoidea; (3) Rissoelloidea + Omalogyroidca + Pyramidclloidea. Spcrm of pentaganglionate hcterobranchs (Opisthobranchia sensu slriclo + Pulmonata) conform in all respects to thc pattern shown by group (3). Hetcrobranchia are united, and differentiated from other gastropods, by a shared suite of sperm and spcrmiogenic features (rounded acrosomal vesicle, nucleus usually helical, highly modified mitochondrial derivative, spermatid acrosomc associated with a dense nuclear plaque, formation of thc mitochondrial derivative through fusion of numerous small mitochondria along the length of the axonemc). Spcrm autapomorphies of thc Architectonicoidea and the Valvatoidea suggest that these two superfamilics arc distinct but terminal offshoots from ancestral hctcrobranchs.

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“…There have been a number of transmission electron microscopical (TEM) studies dealing with sperm or spermiogenesis of non-Discodorididae nudibranchs (Thompson, 1966(Thompson, , 1973Schmekel, 1971;Holman, 1972;Eckelbarger and Eyster, 1981;Eckelbarger, 1982;Medina et al, 1985Medina et al, , 1986Medina et al, , 1988Healy and Willan, 1991). Healy and Willan (1991) examined sperm ultrastructure of 27 nudibranchs representing the two suborders and four superfamilies of the Nudibranchia (Doridoidea, Dendrono-toidea, Arminoidea, Aeolidoidea).…”

mentioning

confidence: 98%

Sperm ultrastructure in the nudibranch genus Halgerda with reference to other discodorididae and to chromodorididae (mollusca: Opisthobranchia)

Fahey

Healy

2003

Journal of Morphology

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Comparative sperm ultrastructure within the molluscan nudibranch genus Halgerda (Discodorididae) was examined for the first time using transmission electron microscopy (TEM), based on 17 of the 35 known species. In addition, observations on two other discodorids are made to facilitate outgroup comparison with Halgerda, including one species of Discodoris (D. boholiensis) and Asteronotus cespitosus (currently accepted as the closest sister taxon to Halgerda). Comparison was also made with some genera of the Chromodorididae in view of sperm similarities. Spermatozoa of all species examined were of the complex, helical, elongate ( approximately 300-400 micro m) type characteristic of most heterobranch gastropods. These cells exhibit the following discrete regions (in anteroposterior sequence) : an acrosomal complex (composed of a rounded, membrane-bound vesicle and a column-like pedestal); a solid, helical nucleus; an elongate, helical midpiece (composed of an axoneme and associated nine coarse fibers, an enveloping mitochondrial derivative of matrix, and paracrystalline materials and glycogen helix); an annular complex; and a short glycogen piece. Of these regions, the midpiece is by far the longest, occupying over 90% of the total sperm length. Comparison with other members of the radula-bearing cryptobranch dorids reveals several sperm similarities to other genera in the clade, particularly those of other Discodorididae and also with the Chromodorididae. Comparison with previously studied genera reveals noteworthy sperm differences within the Discodorididae. The most notable differences are the internal structure of the acrosomal pedestal (long and homogeneous in Halgerda, Discodoris; short and homogeneous in Asteronotus; long and finely striated in Rostanga; oblong with angular electron-lucent striations in Jorunna) and the internal structure of the glycogen piece. The pronounced helical keels of most Halgerda and Discodoris nuclei contrast with the weakly helical nucleus of Asteronotus. Sperm features alone do not provide a means of defining the genus Halgerda or the family Discodorididae nor do they support the monophyletic status of the caryophyllidia-bearing dorids. Important sperm characters such as the acrosome, nucleus, and midpiece can often still be determined from specimens that have been initially fixed in formalin, then stored in ethanol for extended periods of time (i.e., museum material). Of all sperm features, the mitochondrial derivative of the midpiece is the most resistant to long-term fixation : the survival of acrosomal, nuclear, and axonemal components is variable, presumably a factor of prefixation autolysis, varied primary fixation times and temperatures, formalin quality, and duration of alcohol storage.

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Sperm tail differentiation in the nudibranch mollusc Hypselodoris tricolor (gastropoda, opisthobranchia)

Cited by 10 publications

References 21 publications

Sperm ultrastructure of Microhedyle remanei, an interstitial acochlidian gastropod with dermal fertilization

Sperm ultrastructure of Microhedyle remanei, an interstitial acochlidian gastropod with dermal fertilization

Comparative sperm ultrastructure and spermiogenesis in basal heterobranch gastropods (Valvatoidea, Architectonicoidea, Rissoelloidea, Omalogyroidea, Pyramidelloidea) (Mollusca)

Sperm ultrastructure in the nudibranch genus Halgerda with reference to other discodorididae and to chromodorididae (mollusca: Opisthobranchia)

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