Actinula release in Ectopleura crocea (Cnidaria, Hydrozoa, Tubulariidae) скачать в хорошем качестве

Actinula release in Ectopleura crocea (Cnidaria, Hydrozoa, Tubulariidae)

Hydrozoan Life Cycle Ectopleura crocea (Cnidaria, Hydrozoa, Hydroidolina, Anthoathecata, Aplanulata, Tubulariidae) is a common marine hydroid in the Atlantic ocean, usually abundant on artificial substrates. They form dense tufs with hundreds of individuals, which hydrocaulli are up to 10-12 cm long. The species doesn't have a medusa in its life cycle, and gametes are produced within structures called gonophores, which stay fixed to the polyp body. Individuals are either male or female. Spermatozoa are released into the water from male gonophores, fertilizing the eggs that remain within female gonophores. Embryos develop inside female gonophores into actinula larvae, the dispersive stage of the species. A mature female polyp releases hundreds of actinulae. As you may see in the video, the actinula larva struggles to get free from the gonophore. It pushes several times using its tentacles; it succeeds in liberating one tentacle at a time, until it finally got out through the aperture of the gonophore. It took about 2 hours for the actinula shown in the video (time-lapse) to get free, but this period may vary a lot. The actinula settles by its aboral end and elongates to form a juvenile polyp. It may settle on the perisarc of adults, as is seen in the video. Newly released actinulae have aboral tentacles and rudiments of oral tentacles. References: Imazu, M.A., Ale, E., Genzano, G.N. & Marques, A. C. 2014. A comparative study of populations of Ectopleura crocea and Ectopleura ralphi (Cnidaria, Hydrozoa, Tubulariidae) from the Southwestern Atlantic Ocean. Zootaxa 3753 (5): 421–439. More images of hydroids and marine beings at http://cifonauta.cebimar.usp.br/ Support CNPq - Conselho Nacional de Desenvolvimento Científico e Tecnológico, Edital MCT/CNPq nº 42/2007 - Difusão e Popularização da C&T (processo nº 551951/2008-7). Centro de Biologia Marinha, Universidade de São Paulo http://cebimar.usp.br/index.php/pt/   / cebimarusp