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  • 1
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    Sexual reproduction in four Caribbean commercial sponges. I. Reproductive cycles and spermatogenesis (1991)
    Taylor & Francis
    In:  Invertebrate Reproduction & Development, 19 (1). pp. 1-11.
    Details
    Publication Date: 2017-02-01
    Description: Sexual reproductive cycles of a Florida, U.S.A., population of four Caribbean commercial sponge species, Hippospongia lachne, Spongia barbara, S. cheiris and S. graminea, were determined by analysis of tissue samples collected over a three-year period. Spermatogenesis in these species was studied using light and transmission electron microscopy. The production of male gametes occurs in cysts within the endosomal tissue of mature specimens. Reproductive elements within an individual cyst develop synchronously while development between cysts is asynchronous. All available evidence suggests that these species are dioecious. Spermatogonia differentiate directly from choanocytes in situ. All cells of the chamber lose their collars and flagella and undergo mitosis to produce primary spermatocytes, each possessing a single flagellum. The ratio of nucleus to cell diameter in these cells is almost double that of choanocytes. Circumstantial evidence suggests that primary spermatocytes undergo meiosis to produce four spermatids, but confirmational chromatid linkage figures are still lacking. The mature spermatozoa lack both intermediate segments and acrosomes. Male gametes displayed a bright yellow-white autofluorescence when excited with blue light (460–485 nm).
    Type: Article , PeerReviewed
    Format: text
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  • 2
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    Sexual reproduction in four Caribbean commercial sponges. III. Larval behaviour, settlement and metamorphosis (1991)
    Taylor & Francis
    In:  Invertebrate Reproduction & Development, 19 (1). pp. 25-35.
    Details
    Publication Date: 2017-02-01
    Description: Larval behaviour, settlement, and metamorphosis were investigated in four Caribbean commercial sponges, Hippospongia lachne, Spongia barbara, S. cheiris and S. graminea, using light and transmission electron microscopy. The parenchymella larvae of these viviparous and gonochoristic species have an average size of 350 μm by 420 μm when released. Symbiotic bacteria occur intercellularly in both larvae and post-larvae. Laboratory behavioural studies demonstrate that free-swimming larvae display directional swimming with constant lateral rotation and negative phototaxis. Larval settlement occurs 26–56 hours after release from the parent and involves the formation of a basal lamella between the post-larva and substrate. There is no evidence of larval substrate selection by type or orientation. The canal system begins to form six days after settlement and oscules are apparent eleven days post-settlement. Available evidence suggests that larval ciliated epithelial cells are terminally differentiated and do not appear to contribute to formation of post larva or adult in this group of Porifera.
    Type: Article , PeerReviewed
    Format: text
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  • 3
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    Natural gamete release and oviparity in Caribbean Demospongiae (1976)
    Acad. Press
    In:  In: Aspects of sponge biology. , ed. by Harrison, F. W. and Cowden, R. R. Acad. Press, New York, pp. 99-112. ISBN 0-12-327950-X
    Details
    Publication Date: 2020-10-28
    Description: Reports of natural gamete release by Caribbean sponges are reviewed to determine if such events are correlated to physical cycles. Release of spermatozoa is not seasonally limited, but it is diurnally concentrated in the afternoon, 1400 to 1700 hours local time. Oviparity is reported in four species among the genera Hemectyon and Agelas (Demospongiae). Two of these species release gametes annually at specific seasons and stages of the lunar phase. These release events may prove to be precisely predictable over extensive geographic ranges. Review of biochemical and embryological evidence suggests that Agelas be transferred from the order Poecilosclerida to the Axinellida.
    Type: Book chapter , NonPeerReviewed
    Format: text
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