Larval development in <Emphasis Type="Italic">Guancha arnesenae</Emphasis> (Porifera,Calcispongiae, Calcinea) |
| |
Authors: | Alexander V Ereskovsky Philippe Willenz |
| |
Institution: | (1) Centre d’Océanologie de Marseille, Station marine d’Endoume, Aix-Marseille Université, CNRS UMR 6540-DIMAR, rue de la Batterie des Lions, 13007 Marseille, France;(2) Department of Embryology, Faculty of Biology and Soils, Saint-Petersburg State University, Universitetskaja nab. 7/9, St. Petersburg, 199034, Russia;(3) Department of Invertebrates, Royal Belgian Institute of Natural Sciences, 29 rue Vautier, 1000 Brussels, Belgium |
| |
Abstract: | Larval development and follicle structure of a representative of the Calcinea (Calcispongiae) Guancha
arnesenae from the White Sea have been studied for the first time at the ultrastructural level. The follicle in G.
arnesenae has an unusual structure: it consists of trapezoid cells rich in phagosomes and a surrounding dense collagen layer. Follicular
cells differentiate from choanocytes. Cleavage results in formation of a hollow, equal, non-polarized coeloblastula. Larval
morphogenesis occurs by means of direct hollow blastula formation without any individual cell or cell layer movements. The
coeloblastula (calciblastula) larva of G.
arnesenae is completely ciliated. The larva also contains rare non-ciliated cells: vacuolar cells, bottle-shaped cells and free cells
in a central cavity. The basal ciliary apparatus of larval cells includes the basal body, an accessory centriole oriented
perpendicularly to it, the basal foot, and two cross-striated rootlets. A bundle of microtubules emerges from the side of
the basal body, opposite to the basal foot, running parallel to the outer surface. All bundles of cells are parallel to each
other and oriented towards the posterior larval pole, forming a transverse cytoskeletal system. Specialized intercellular
junctions in the apical regions of all ciliated cells are revealed for the first time in a Calcispongiae larva. The central
larval cavity contains symbiotic bacteria, which are included inside the embryo at the blastula stage. |
| |
Keywords: | Calcinea Embryonic development Larva Coeloblastula Phylogeny |
本文献已被 SpringerLink 等数据库收录! |
|