Pyura viarecta Kott, 1985

Monniot, Francoise, 2021, New records of deep-sea ascidians (Tunicata, Ascidiacea) from the New Caledonia region, Zootaxa 4996 (3), pp. 443-468 : 458

Pyura viarecta Kott, 1985

Figure 15

Station: Kanacono CP 4676. One specimen.

Pyura viarecta Kott, 1985 : Heron Island; Monniot F. & Monniot C. 2003: Nouvelle Calédonie. Embedded with coarse sand the round body 14 mm in diameter has a few hold-fast rhizoids. The internal layer of the tunic is thin. Extracted from the tunic the body is ovoid with the dorsal body wall thicker due to a more developed musculature than ventrally. Eighty oral tentacles with two orders of ramifications alternate with smaller ones. The dorsal tubercle is thick, protruding C-shaped with horns inwardly rolled. The posterior part of the branchial sac is missing gone out through a hole possibly made by depressurization but the anterior part remains against the prepharyngeal band ( Fig. 15A ). The dorsal lamina has pointed languets. On each side seven branchial folds are composed of about 10 to 12 longitudinal vessels each separated by two vessels, and three oval stigmata are in a mesh between the folds. The digestive loop is long and open ( Fig. 15B ) ending in a narrow lobed anus. The stomach was damaged but parts of the hepatic gland remain with round papillae. There is one gonad on each side ( Fig. 15B ) with eight lobes on the right side and 6 lobes on the left. The hermaphrodite lobes are well separated from each other and only attached to the body wall by the long central common duct. They gonads are not fully mature and each has an endocarp. No endocarps were found on the body wall and none on the gut. The rim of the atrial velum wears round lobes.

This species is well characterised by its sandy tunic, seven branchial folds per side and the long gonads with lobes not linked to the body wall. Described from New Zealand it is found for a second time at depth in New Caledonia.

Figures

FIGURE 15. Pyura viarecta. A, body ventrally opened; B, same body, branchial sac removed. Scale bars = 1cm.