Polyclinum constellatum? Savigny, 1816

Monniot, Françoise, 2016, Ascidians (Tunicata) of the French Guiana Expedition, Zootaxa 4114 (3), pp. 201-245 : 204-205

Polyclinum constellatum? Savigny, 1816

Figure 2 .

Stations. CP 4309; CP 4408.

Entirely covered with sand the small colonies (5 to 7mm in diameter) contain a single system of zooids around a central common cloacal opening. The oral siphon has 6 long pointed lobes ( Fig. 2 B). The atrial siphon opens by a short narrow tube ( Fig. 2 B) extended dorsally into a languet having longitudinal and transverse muscular fibres. Below the atrial siphon the body wall wears a button-like protrusion. The branchial sac has 11 to 12 stigmatal rows ( Fig. 2 A). On the right side an average of 22 stigmata per row was counted and 12 round papillae on the transverse vessel between 2 rows. The dorsal languets are long and pointed. The abdomen has the common shape of the genus as does the post-abdomen which is appended by a thin peduncle ( Fig. 2 B) The larva 0.55mm in length has a tail in a half circle, 3 adhesive papillae, 4 pairs of thick ampullae, and small vesicles on the ventral and dorsal sides ( Fig. 2 C). A crystal is present in the central mass of the body.

The colonies from Guiana only differ from the widely distributed P. constellatum by their small size. The species is cosmopolitan and has been recorded from a large area of the western Atlantic from Florida to Brazil ( Monniot F. 1983; Rocha & Costa 2005).

Figures

FIGURE 2. Polyclinum constellatum (stained with hemalum). A: branchial sac; B, zooid; C, larva. Scale bars: A – B = 2.5 mm; C = 0.25 mm.