Ascidia sydneiensis Stimpson, 1855

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 : 24-25

Ascidia sydneiensis Stimpson, 1855

( Fig. 15 )

Material examined. DZUP ASC 116—1 ind.; Casa Blanca; 0.5 m, mangrove roots; 25/vii/2008; DZUP ASC 160— 1 ind.; 05/vi/2009. DZUP ASC 123—1 ind.; Marina; 1.0 m, inside brick; 05/iii/2009. DZUP ASC 38—5 ind.; STRI dock; 1.0 m; 12/viii/2003. DZUP ASC 111—1 ind.; Hospital Point; 20/viii/2006. DZUP ASC 113—7 ind.; Baía Honda; mangrove roots; 23/viii/2006; DZUP ASC 117—6 ind.; mangrove roots; 0.5–1.0 m; 28/vii/2008. DZUP ASC 109—3 ind.; Solarte; mangrove roots; 15/viii/2006; DZUP ASC 112—1 ind.; mangrove roots; 23/viii/2006. DZUP ASC 124—1 ind.; Crawl Cay; 14/vi/2009. DZUP ASC 39—2 ind.; San Cristobal island; 0–1.0 m, mangrove roots; 12/viii/2003; DZUP ASC 36—2 ind.; San Cristobal island; 0.4 m, mangrove roots; 12/viii/2003; DZUP ASC 37—1 ind.; San Cristobal island; 0–1.0 m, mangrove roots; 12/viii/2003. DZUP ASC 118—5 ind.; Popa island; 0.5 m, mangrove roots; 30/vii/2008. DZUP ASC 110—1 ind.; City; 19/viii/2006; DZUP ASC 163—1 ind.; City; 12/vii/2009.

Although few were found during the survey of August 2003, the species is very common both on mangrove prop roots and artificial substrates. Individuals are usually 4.5–5.0 cm long (occasionally to 7.5 cm). Color of living animals is variable and may be white, yellow, red, wine or cream. The color comes from the right side of the body wall, because the tunic is transparent. Conical or more elongated tunic projections occur mainly on the posterior region and are used for attachment. The tunic is usually heavily encrusted with algae and other invertebrates. Siphon position and length are also variable. The oral siphon typically has 7–8 lobes with indented margins, or long projections and a red spot between each two lobes. Each lobe is in the end of an aggregation of longitudinal muscle fibers, and between these muscle bands the tunic forms a marked longitudinal crest when the animals is contracted. The atrial siphon has six triangular lobes, with projections and a dark spot between each (red in living animals). Some individuals lack lobes on the margin of the siphons but still have aggregations of projections where the lobes should be. The neural ganglion is close to the dorsal tubercle. The primary papillae are flat, long and curved, with a basal expansion; intermediate papillae are absent. The alimentary canal is always large and most of the space is occupied by the dilation of the rectum that forms a round sac. The border of the anus is multilobed. Renal accumulation vesicles are absent in the examined material. The ovary is ramified into elongated lobes on the primary and secondary intestinal loops. The testicle has small and irregular follicles, usually inside the primary loop and on the secondary loop. From the outside, the testicular follicles are visible on the dilation of the intestine.

Remarks. This species is widely distributed in all oceans.

Figures

FIGURE 15. Ascidia sydneiensis Stimpson, 1855. A. Animal in the field. B. Right side of body (without tunic). C. Left side of body (without tunic). Scale bar: B, C = 1.0 cm.