Pyura curvigona, Tokioka, 1950

Monniot, Françoise, 2009, Some ascidians from Indonesian marine lakes (Raja Ampat Islands, West Papua), Zootaxa 2106, pp. 13-40 : 33-35

Pyura curvigona ? Tokioka, 1950

( Figures 15 B, 16, 17)

Pyura curvigona Tokioka, 1950: 147 , fig. 23, pl.10 figs 4–6; 1967: 199, figs 88–89; Tokioka & Nishikawa, 1975: 339, figs 37–40; Millar, 1975:312; Kott, 1985:296, figs 143a–b, 144. Cole & Vorontsova, 1998: 4, fig. 3.

Material. Indonesia. West Papua, Gam Island,, NW. Gam Island, Danau Ctenophore marine lake, 00°27.289’S – 130°29.580’E, 1m, 26/X/2007, coll. L.J. Bell and L.E. Martin, DCG 0 35 ( MNHN S2 PYU 433).

Information supplied by the collector indicate that specimens settled in exposed locations are red, those under overhangs are pale. Both specimens studied here are brown, 55mm and 35mm in size. The apertures are iridescent ( Fig. 15 B), densely covered with long spinules which have an enlarged round base ( Figs 16 A,B).These spinules constitute one of the main characteristics of the species with the wide rectum. The internal organs ( Fig. 17 A,B) are those reported in previous descriptions: poorly ramified oral tentacles, 6 branchial folds ( Fig. 17 B), a long digestive loop with an enlarged rectum and endocarps in a row along its whole external side. The liver has small digitate lobes at the cardiac side of the stomach and a cauliflower massive lobe at the pyloric end. The gonads are curved ( Fig. 17 A) and each lobe wears several endocarps. The heart is long and wide. In the smallest specimen only 4 small endocarps are spaced along the ventral side of the heart, and look like dermato-branchial bridges, but in the largest specimen the endocarps are well developed and form a continuous line along the heart ( Fig. 17 A). No other endocarps were detected elsewhere on the body wall. The latter structure is similar to that described and figured for Pyura gangelion ( Savigny, 1816) by Monniot C. (2001) and its junior synonym Pyura albanyensis Michaelsen, 1927 described by Monniot C. (1989), but they have different spinules.

The spinule shape and the enlarged rectum in a Pyura with 6 branchial folds indicate these specimens as P. curvigona , but the presence of endocarps on the heart is disturbing as they have not been reported before. As they are few and hardly visible in one specimen, it is possible that they have been previously overlooked or their presence variable.

Figures

FIGURE 16. Pyura curvigona? spinules of the internal side of the siphons: A, with SEM, B, in light microscopy. A, B, scale bar = 100 µm.

FIGURE 17. Pyura curvigona?: A, Body opened along the ventral line; B, branchial sac.

FIGURE 15. A, Polycarpa insulsa. B, Pyura curvigona?