Eudistoma viride Tokioka, 1955

Monniot, Françoise, 2009, Some ascidians from Indonesian marine lakes (Raja Ampat Islands, West Papua), Zootaxa 2106, pp. 13-40 : 28

Eudistoma viride Tokioka, 1955

( Figure 11 C,D)

Eudistoma viride Tokioka, 1955: 49 pl;4 figs 1–5; 1967:122. Millar: 1975: 220 fig.12; Monniot F. & Monniot C. 2001: 247 fig. 36 and synonymy; Monniot F. & Monniot C. 2008: 843 .

Material. Indonesia. West Papua, Gam Island, Danau A Gam marine lake, on mangrove root, 00°26.518’S – 130°41.134’E, 0.5m, 23/XI/2007, coll. L.J. Bell and L.E. Martin, DAG 0 43 ( MNHN A3 EUD 344). West Papua, Mansuar Island, Danau Mansuar, marine lake, 01°35.315’S – 130°35.830’E, 0.5m, 19/XI/ 2007, coll. L.J. Bell and L.E. Martin, DMM 0 3 ( MNHN A3 EUD 345). East Kalimantan, Maratua Island, Danau Kakaban marine lake, 2°08.44’N – 118°30.60’E, 0.5m, 21/X/2003, coll. L.J. Bell, DKK012 ( MNHN A3 EUD 327); East Kalimantan, Maratua Island, Danau Haji Buang, marine lake, 2°12.630’N – 118°35.681’E, 1m, 25/09/2006, coll. L.J. Bell, HBM042 ( MNHN A3 EUD 333).

The colonies form clusters of dense lobes, some of them occasionally ramified. The lobes are dirty yellow or greenish, the heads translucent ( Fig. 11 C). Dark spots are placed dorsally and ventrally at the base of the oral siphon. Dark pigment cells are sometimes present in the upper part of the thorax, and some may be scattered on the abdomen. Colonies in a resting state are more deeply pigmented than those with extended functional zooids. The largest lobes of the colonies reach 15mm in length. There is not a pronounced constriction between the thorax and abdomen. The number of stigmata is difficult to count, up to 32 in the first half row and 24 in the third row. The larva ( Fig. 11 D) has a trunk 0.5mm long with 3 short adhesive papillae and thick vesicles between them, the larvae are very contractile.

The colonies collected from Mansuar Lake are particularly pale, this may be due to the different sea water characteristics in this isolated lake with salinity and pH lower than in lakes with larger communications with the lagoon water.

E. viride essentially differs from E. laysani by the smaller size of its larvae, and the dark pigment spots at the siphons. The lobes of the colonies are more densely packed, and more coated with epibionts at their base, but this is variable. A molecular analysis would be necessary to better isolate these two species

Figures

FIGURE 11. Eudistoma laysani: A, colony; B, stained larva, scale bar: 0.5 mm. Eudistoma viride: C, colony; D, stained larva, scale bar = 0.25 mm.