| one publication added to basket [258559] | Gametogenesis, embryogenesis, and larval features of the oviparous sponge Petrosia ficiformis (Haplosclerida, Demospongiae)
Maldonado, M.; Riesgo, A. (2009). Gametogenesis, embryogenesis, and larval features of the oviparous sponge Petrosia ficiformis (Haplosclerida, Demospongiae). Mar. Biol. (Berl.) 156(10): 2181-2197. http://dx.doi.org/10.1007/s00227-009-1248-4
In: Marine Biology: International Journal on Life in Oceans and Coastal Waters. Springer: Heidelberg; Berlin. ISSN 0025-3162; e-ISSN 1432-1793, more
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| Abstract |
This study describes the reproductive cycle of Petrosia ficiformis and documents for the first time embryogenesis in an oviparous haplosclerid demosponge. Gonochoric adults, occurring in 2:1 female/male ratios, spawned in late autumn, after a 7-month long oogenesis and a 2.5-week-long spermatogenesis. Following a remarkable migration, the oocytes were released as 250 µm eggs bearing attached polar bodies and a thin mucous cover. Round-headed spermatozoa with three large mitochondria, and many proacrosomal vesicles fertilized the eggs externally. A fertilization membrane appeared around the zygotes. Nearly equal and total cleavage led to a stereoblastula that subsequently became an entirely ciliated larva. The larva alternated spherical and multilobate body shape and consisted of undifferentiated cells. It had poor abilities to swim and glide, probably experiencing passive dispersal and unselective attachment. Settlers developed choanocyte chambers after 1.5 months. Symbiotic microbes were absent from gametes and larvae, being necessarily acquired from the ambient at each sponge generation. |
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