Thalia democratica (Forskal, 1775)

Franco, P., Dahms, H. - U., Lo, W. - T. & Hwang, J. - S., 2017, Pelagic tunicates in the China Seas, Journal of Natural History 51 (15 - 16), pp. 917-936 : 930

Thalia democratica

Morphology

Length of the aggregated zooids of this salp is 1.8–18.2 mm. Lengths of solitary zooids are 2.3–11.7 mm. Aggregate form is characterised by an anterior end of the body which is rounded and by a posterior end which is somewhat fusiform. Testis is never echinate, and is pentagonal. Nucleus with a posterior projection. Testis pentagonal posteriorly. Number of muscle fibres in MI–MV is15–17. Atrial opening not central, with a posterior lateral protuberance on one side only. Solitary forms with a smooth test and simple atrial palps. Lateral projections are small, medio-ventral ones are small and of unequal length and anterior projections are smallest. All test projections are echinate. MI to MIV are continuous dorsally and ventrally; MV is interrupted ventrally. MII –MIV and MV–MVI converge mid-dorsally over a short distance. Stomach extends partly into the middle posterior projection (authors’ personal observations; ( Marine Species Identification Portal 2017); Godeaux et al. 1998).

Biogeography

Cosmopolitan, eurythermic species from warmer waters; roughly occurring between ca. 60°N and 40°S. Also present in the Mediterranean Sea. Epipelagic, living in the upper 100 m; does not perform diurnal vertical migration (WoRMS Editorial Board 2017).