Monniotus ramosus Millar, 1988

Monniot, Françoise, 2012, Some ascidians from the southern coast of Madagascar collected during the “ AtimoVatae ” survey, Zootaxa 3197, pp. 1-42 : 22

Monniotus ramosus Millar, 1988

( Figure 18 )

Monniotus ramosus Millar, 1988: 826 fig 1, Mozambique.

Stations. TR 1 (MNHN A1 MON 6).

Madagascar, Tulear. Vasseur col. 1964 (MNHN A1 MON 4).

A single colony of about thirty zooids was collected during the Atimo Vatae survey (Fig; 18A), but a second colony from Tulear comes from P. Vasseur material. The dichotomic ramification of the colonies is that described and figured n by Millar. Several ramified lobes arise from a common base; each group measures about 3.5cm. The thorax ( Fig. 18 C) and the abdomen ( Fig. 18 B) are enclosed independently in a sandy tunic but their post-abdomens are united in a common peduncle.

The colony from the south of Madagascar is only female with ovaries and larvae. The colony from Tulear is male with a short double row of testis vesicles in the post-abdomen at a short distance from the gut loop. All zooids have 15 rows of stigmata, without parastigmatic vessels ( Fig. 18 D). The larvae 1.2mm long are as described and figured by Millar.

This species is recollected for the first time. Its distribution is restricted to Madagascar. Other species of Monniotus are known from the Pacific Ocean: M. australis ( Kott, 1957) and M. radiatus Kott, 1992 from Australia have only 10 rows of stigmata and parastigmatic vessels. M. papillosus Monniot F. & Monniot C., 2001 from New Guinea has 18 rows of stigmata with parastigmatic vessels. M. pacificus Monniot F.& Monniot C., 2001 from Palau has 20 rows of 40 stigmata, high papillae and an areolated stomach. M. paucistigma Monniot F. & Monniot C., 2008 from New Guinea has only 4 rows of stigmata, papillae both on transverse and parastigmatic vessels.

Figures

FIGURE 18. Monniotus ramosus: A, colony; B, abdomen; C, thorax; D, Branchial sac. Scale bars: B, C, = 2 mm; D = 1 mm.