Pyura elongata Tokioka, 1952

Monniot, Françoise, 2009, Some ascidians from Indonesian marine lakes (Raja Ampat Islands, West Papua), Zootaxa 2106, pp. 13-40 : 35-37

Pyura elongata Tokioka, 1952

Figures 18A , 19 )

Material. Indonesia. West Papua, Danau A Gam marine lake, 00°26.970’S – 130°29.149’E, 0.5m, 02/XII/ 2007,coll. L.J. Bell and L.E. Martin, DAG 0 94 ( MNHN S2 PYU 430).

Description. The largest specimen is 7cm large, the other 4.5cm in width. The siphonal lining is bright red, the tunic is brown-red covered with epibionts except the siphons ( Fig. 18A ). The tunic is thick but not hard. The body wall is colourless except the siphons which are red. The muscles ( Fig. 19 B) are strong, in bundles in the main part of the body but in dense thin parallel fibres on the ventral side ( Fig. 19 B). The 6 folds are high ( Fig. 19 A) with up to 22 vessels, widely separated anteriorly. The gut forms a single loop ( Fig. 19 B) with a narrow stomach partially covered with several hepatic diverticula. The gonads are straight, of the pyurid shape ( Fig. 19 B), with lobes slightly attached to the body wall. There are no endocarps. A large cloacal velum is curved at its anterior margin.

All characters correspond well with previous descriptions, including the shape of the spinules in lamellas ( Fig. 19 C) lining the internal side of the siphons. The entire external surface of the tunic appears velvety due to a dense cover of thin stick-like spinules, as seen in electron microscopy ( Fig. 19 D). Spinules commonly extend on the body surface of many pyurid species but their density is exceptional here. They were probably not seen before as they cannot be seen with naked eye on this large size species.

Pyura elongata is widely distributed in the indo-pacific. Pyura scortea Kott, 1985 is considered here as a junior synonym.

Figures

FIGURE 19. Pyura elongata: A, right part of the branchial sac; B, body opened along the ventral line; C, spinules of the siphonal lining, scale bar = 10 µm; D, spinules covering the external tunic surface of the body, scale bar = 100 µm.

FIGURE 18. A, Pyura elongata. B, Pyura vittata.