Polycarpa gradata Monniot, 2002

Monniot, Françoise, 2012, Some ascidians from the southern coast of Madagascar collected during the “ AtimoVatae ” survey, Zootaxa 3197, pp. 1-42 : 35

Polycarpa gradata Monniot, 2002

( Figures 28A , 29 )

Polycarpa gradata Monniot C., 2002: 80 figs 13–14A, Mozambique, Madagascar Tulear, Djibouti.

Stations. TR 7 (MNHN S1 POL.B 561). TA 22 (MNHN S1 POL.B 560). TA 33 (MNHN S1POL.B 559).

The individuals are almost separated along their whole length only united at their base ( Fig. 28A ). Up to twenty specimens can be grouped in a single mass. The tunic is smooth and naked, ochre in formalin. Both siphons are apical; epibionts are often settled at the base of the body. The individuals of a same group have not the same development stage and the basal part of the body which does not contains organs is more or less long. The largest individuals reach 5.5cm in length. The body wall is opaque; of an orange colour more reddish on the siphons. The internal side of the body wall is covered with leaf-shaped endocarps ( Fig. 29 A). The branchial tissue is thin with 4 folds on each side ( Fig. 29 B). The gut loop is closed with a short stomach internally folded and a long rectum ending in a lobed anus. Several specimens were eviscerated. An average of 11 elongated polycarps is lined on each side of the body. The atrial siphon has numerous thread-like processes at the base of the lining.

This species is only recorded from the western Indian Ocean from Djibouti to Mozambique and Madagascar.

Figures

FIGURE 29. Polycarpa gradata: A, dissection; B, branchial sac.

FIGURE 28. A, Polycarpa gradata. Scale bar = 1 cm. B, Symplegma rubra, part of in situ colony (photo P. Laboute).