Symbiotic copepod associated with a planktonic invertebrate
O copépode S. angusta vive na cavidade do corpo do tunicado planctônico Thalia democratica, se alimientando dos tecidos do hospedeiro, o que pode causar sua morte.
Floating colonial hydrozoan - detail of dactylozooids
Porpita is a colonial hydrozoan which lives floating on the sea surface. The polyps are arranged concentrically on the lower surface of a hard, chitinous central disk. There is a large central polyp (gastrozooid) around of which are arranged numerous gastro-gonozoids, polyps responsible for food intake and production of jellyfish. The dactilozooids are the polyps responsible for capturing food and defense, being located more externally.
The Echiura, or spoon worms, have a pear shaped, non-segmented body and a large and non-retractile proboscis. In the anterior ventral region there is a pair of setae or hooks. They live in burrows in sand, mud, corals and coral crevices. Some species are found inside the tests of dead sand dollars and between the shells of dead bivalves. There is strong evidence that echiurans are in fact modified annelids.
Anfioxo - detalhe da região anterior, destacando os cirros - estruturas que se dispõem ao redor da boca e impedem a entrada de particulas muito grandes
The subphylum Cephalochordata (called vernacularly as lancelets) is represented by a small (up to 6 cm long) animals characterized to have the notochord as an axial organ throughout the whole body length. The lancelet body plan is similar to that of fishes and other vertebrates: dorsally-situated neural tube, and ventrally-situated alimentary system sandwiched laterally with myotomes (or myomeres), arranged as a series of segmented muscle blocks on each side. They are exclusively marine, inhabiting intertidal to subtidal sandy bottoms in boreal to tropical waters around the world. Recently, however, the true deep-sea species was firstly described. The adults have at benthic life within the superficial layer of bottom sediment, and are filter-feeders. Adults can also swim, but only rarely and sporadically.