Synoicum, Phipps, 1774

Maggioni, Tamara, Taverna, Anabela, Reyna, Paola B., Alurralde, Gastón, Rimondino, Clara & Tatián, Marcos, 2018, Deep-sea ascidians (Chordata, Tunicata) from the SW Atlantic: species richness with descriptions of two new species, Zootaxa 4526 (1), pp. 1-28 : 13

Synoicum sp.

Material examined: one colony; net; -37.9966 lat. -55.2079 long. (station 4); 319 m; 17 August 2012 ( Figure 7 ).

The colony is almost spherical. It measures two cm in diameter and 1.8 cm in height ( Fig. 7 ). Zooids present a short post-abdomen. The oral aperture has six lobes. The atrial aperture is small and simple, and it is located at the upper quarter of the thorax. The atrial languet is simple and short. There is no constriction connecting the abdomen and the post-abdomen. There are eight rows of stigmata. The stomach is rounded and its walls are smooth. The gut loop is simple.

Numerous underdeveloped tailless larvae were found in the atrial cavities of some zooids. There was evidence of strobilation, a characteristic asexual type of reproduction in most Polyclinidae members.

Remarks. Due to the poor state of conservation and stage of sexual maturation of the zooids, the colony was characterized up to genus level. No reliable indicators of species status could be distinguished. The absence of a constriction between the thorax and abdomen, in combination with the presence of a rounded and smooth-walled stomach and a simple gut-loop, enabled us to classify the present specimen as Synoicum .

Figures

FIGURE 7. Synoicum sp.