Direct Development of Golf Ball Sponges, Genus Craniella (Demospongiae, Tetractinellida) From the Northeast Atlantic Ocean.

ABSTRACT: Among the eight types of development in sponges, the least common and least studied is direct, non-larval development during viviparity. To supplement our knowledge of this rare type of demosponge development, we present here a description of the embryonic development of four species of the genus Craniella (Demospongiae, order Tetractinellida) from the deep-sea in the Northeast Atlantic. Craniella development is asynchronous within one sponge. Mature oocytes are polylecithal and isolecithal. Embryonic development occurs in a dense double-layer follicle: layers of flattened cells and a thick layer of collagen. The cleavage is total, unequal, and asynchronous. It is characterized by collagen layers penetrating inside the embryo and surrounding blastomeres. As a result of cleavage, an oval-sh

SUBMITTER: Cardenas P 

PROVIDER: S-EPMC12509478 | biostudies-literature | 2025 Oct

REPOSITORIES: biostudies-literature