Ascidia curvata (Traustedt, 1882)

Bonnet, Nadia Y. K. & Rocha, Rosana M., 2011, The family Ascidiidae Herdman (Tunicata: Ascidiacea) in Bocas del Toro, Panama. Description of six new species, Zootaxa 2864, pp. 1-33 : 13-14

Ascidia curvata (Traustedt, 1882)

( Fig. 8 )

Material examined. DZUP ASC 159—2 ind.; STRI Bay; on polyethylene plate; 08/vii/2008; DZUP ASC 161—2 ind.; STRI Bay; on polyethylene plate; 18/x/2008. DZUP ASC 24—3 ind.; Solarte; 0.5 m; 04/viii/2003. DZUP ASC 22—1 ind.; San Cristobal island; 0–1.0 m; 12/viii/2003. DZUP ASC 61—4 ind.; City; 19/viii/2006.

The species is very common and individuals are usually directly attached to mangrove roots or on the shells of bivalves that are on the roots, with siphons oriented downwards. Aggregations of 15–20 individuals are common. Individuals are usually 4.0–5.0 cm long but can be 8.0 cm in length. The tunic is transparent, thick and smooth, occasionally encrusted. This is a well known species, so a complete description can be found in Van Name (1945) and Monniot (1983).

The body wall is transparent, yellowish at the anterior region especially between siphons in freshly preserved animals. The oral siphon has eight round, large and short lobes, very thin and transparent and, in live animals, with a yellow spot between each; the atrial siphon has six similar lobes. Lobe margins are plain. The spots between siphons may be orange or red in animals fixed in formalin. The musculature is conspicuous and both siphons have a band of dense circular fibers at the margin forming a sphincter. Longitudinal fibers do not form bands.

Musculature on the right side is slender, with fibers in many directions covering the entire dorsal-ventral extension of the body, but not so dense that internal structures are not visible. Along the ventral margin and the posterior region to the atrial siphon the fibers are mainly transverse. On the left side, longitudinal fibers extend from the siphons and transverse fibers are very short and slender in the dorsal region.

The pleated pharynx extends beyond the posterior margin of the stomach and has 30–42 complete longitudinal vessels on the left, and 41–54 on the right, with 5–9 longitudinal stigmata per mesh. Primary papillae are slightly curved and large, some with lateral protrusions. Very small papillae in a transverse line indicated the formation of a new vessel; also some minute button-like intermediary papillae may be seen. The prepharyngeal groove has a double membrane, the anterior with or without projections along the margin. The area between the prepharyngeal groove and tentacles have papillae. The neural ganglion is close to the dorsal tubercle.

The renal accumulation vesicles are small, white or transparent spheres, both on the atrial wall of the esophagus, stomach and rectum as well as on the externally facing wall. The atrial epithelium that covers the alimentary canal facing the atrial cavity is mostly covered by minute papillae and the anterior margin of the stomach, the ascending portion of the intestine and the primary intestinal loop have large irregularly shaped papillae.

Both gonads are spread over both intestinal loops and are visible from outside and inside the atrial cavity. The gonoducts are attached to the rectum and open at the level of the anus.

Remarks. Ascidia curvata is known from 11 locations in the Caribbean ( Van Name 1945; Millar 1962; Monniot 1983; Goodbody 1984a, 2000, 2003; Rocha et al. 2005) as well as in Bermudas ( Berrill 1932; Van Name 1945), northeastern ( Lotufo 2002), southeastern ( Marins et al. 2010) and southern Brazil ( Rocha & Nasser 1998).

Figures

FIGURE 8. Ascidia curvata (Traustedt, 1882). A. Animals in the field. B. Right side of body (without tunic). C. Left side of body (without tunic). Scale bar: B, C = 1.0 cm.