Didemnidae

• Main Authors: Monniot, Françoise, Dettai, Agnès, Eleaume, Marc, Cruaud, Corinne, Ameziane, Nadia
• Format: Other/Unknown Material
• Language: unknown
• Published: 2011
• Subjects: Biodiversity; Taxonomy; Animalia; Chordata; Ascidiacea; Enterogona; Didemnidae; Antarctic; Terre Adélie; Terre-Adélie; Antarc*
• Online Access: https://zenodo.org/record/6187330; https://doi.org/10.5281/zenodo.6187330

Didemnidae Didemnum biglans (Sluiter, 1906) (Figure 2) Sluiter, 1906: 29 pl. 2 figs 27, 28. Millar 1960: 57 fig. 11. Kott 1969: 75 and synonymy. Monniot & Monniot 1983: 42 fig. 7 DE, pl. 3 H, I and synonymy. Vasseur 1974: 617 figs. 4, 5, pl. 2 fig 1 Stations (events when several trawling operations per station): 2-5 - 8-9 - 13 A- 21-40 - 54 A- 65 (322). The colonies settle in thin crusts on all kinds of substrates: rocks, pebbles or other invertebrates. The abundance of spicules varies in different parts of a same colony. The wide common cloacal cavity encircles pillars of tunic containing the zooids. The larvae are embedded in the basal layer of the colonies, close to the substrate; they are often missing in the damaged colonies of the CEAMARC cruise. The main characters of the species are a small atrial languet, well expanded lateral thoracic organs, no fixative appendage. The testis, with one or two closely pressed vesicles, is circled with 4 to 5 turns of the sperm duct. The larvae 1.6 to 1.8mm long have 3 parallel adhesive papillae and 6 pairs of lateral vesicles (Fig. 2 A). The stellate spicules (40 µm) have numerous short rays (Fig. 2 B), and many of them are poorly calcified. Two highly divergent (20.77 %) COI sequences were obtained for specimens A 2 DID.C 597 a (BOLD: ASCAN 001- 10) and A 2 DID.C 598 a (BOLD: ASCAN 002- 10). No close hit in BOLD (best: 82 %). Further data would be needed to be able to conclude on the wide molecular divergence observed for this species, as the colonies were damaged. This species is common in Terre Adélie between 200 and 800 m deep and was previously recorded in the peri- Antarctic area down to 1000 m. Polysyncraton trivolutum (Millar, 1960) (Figure 3) Didemnum trivolutum Millar, 1960: 58. Polysyncraton trivolutum: Monniot & Monniot 1983: 43 fig. 8 A–H, pl. 4 A–D and synonymy. Tatian et al 2005: 209. Stations (events when several trawling operations per station): 2-3 - 8-10 - 21-27 (45)- 27 (46)- 79. The colonies are arranged in thick cushions (Fig. 3 B) with a ...