Synoicum molle ( Herdman, 1886 )

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 molle ( Herdman, 1886)

References: Polyclinum molle Herdman 1886: 194 , pl. XXV, figs. 7–9.

Synoycum molle Van Name 1945: 84 , fig. 20; Maggioni et al. 2016: 181 –185, figs. 2–4.

Material examined: seven colonies; net; -37.9783 lat. -55.1983 long. (station 3); 308 m; 16 August 2012 ( Fig. 6 ).

Colonies are ovoid. They show various sizes, ranging from 2.5 to 9.1 cm in diameter. The tunic is grayish. When alive, zooids are white. When fixed in formalin, they turn pale yellow. The atrial languet is thin and long, and can be simple or bifid. There are 13 rows of stigmata. Each half row contains ten rectangular stigmata. The stomach wall is smooth and shows two alternate shapes: circular, almost spherical or dome-shaped with a straight base. The anus is bilobed and finishes at the eighth row of stigmata.

Remarks. Until this date, only one colony (the type specimen) had been collected 1097 m deep ( Herdman 1886) few kilometres away from the present study area. Van Name (1945) acknowledged the inadequacy of the original description for a proper species identification. The present material allowed to perform the first exhaustive and complete morphological description of S. molle (see Maggioni et al. 2016).

Figures

FIGURE 6. Synoicum molle (Herdman, 1886): zooid.