Aplidium antillense ( Gravier, 1955 )

Rocha, Rosana Moreira Da, Gamba, Gustavo Antunes & Zanata, Thais Bastos, 2012, Aplidium (Ascidiacea, Polyclinidae) in central coast, Brazil, Zootaxa 3565, pp. 18-30 : 19-21

Aplidium antillense ( Gravier, 1955)

( Fig. 2 , 6A )

Amaroucium antillense Gravier, 1955: 618 , Martinique.

Aplidium antillense Monniot, 1972: 953 , fig. 2, Bermuda; 1983: 414, fig. 1A, Guadeloupe; Sanamyan & Gleason, 2009: 51 , fig. 1, 2, USA (Atlantic).

Material examined: DZUP APL- 24 1 colony, Naufrágio Reliance, Salvador, Bahia, 13°00'39"S, 38°32'02"W, 5–9 m, Col. R. M. Rocha, 13.12.2007; DZUP APL- 25 1 colony, Pier Salvador, Salvador, Bahia, 12°54’49”S, 38°29’28”W, 1−3m, Col. I. M. Neves, 03.03.2012; DZUP APL- 26 1 colony, Marina Mercado Modelo , Salvador, Bahia, 12°58’21”S, 38°30’56”W, 1−3m, Col. I. M. Neves, 0 3.03.2012.

Colonies cushion-shaped with rounded profile, 4.5 cm in diameter and 5 mm thick ( Fig. 6A ). The tunic is soft, gelatinous and contains sand, especially at the base. Transparency helps in locating the zooids that are scattered in the colony. Five reduced circular cloacae were observed in one of the specimens.

Zooids are perpendicular to the surface of the colonies, light yellow but transparent. The thorax and abdomen measure approximately 2 mm each, and the post-abdomen measures 8 mm in length, reaching nearly to the base of the colony. The oral siphon is conical with six very short triangular lobes, while the atrial siphon is small, circular and opens at the level of the first or second row of stigmata. The atrial languet is long, narrow and pointed, projecting from the top edge of the atrial opening. Thorax musculature comprises 10 delicate longitudinal fibers extending to the end of the post-abdomen. The 15 oral tentacles are all very short, arranged in a single circle. The pharynx has eight or nine rows of stigmata, each with 10?12 stigmata on each side. The dorsal lamina is subdivided into short triangular languets to the left of the dorsal axis. The esophagus is flattened laterally. The stomach is short, wide and has 13−14 external longitudinal folds, some of which may be discontinuous. The duodenum is narrow, as long as the stomach, followed by a curved post-stomach at the end of the intestinal loop. The intestine is narrow and starts with long and narrow rectal caeca. The anus is smooth and opens at the level of the fifth or sixth row of stigmata ( Fig. 2 A). The ovary is in the anterior portion of the post-abdomen, just after the intestinal loop, with 3–7 oocytes. Fertilization of oocytes appears to occur in the ovary. The testis has 16−45 spherical or oval follicles arranged in pairs (anterior region) or aligned ( Fig. 2 B, C). One to three larvae are incubated in the thorax, at the side of the pharynx. The larvae found were immature.

Remarks. This is the first report of A. antillense for Brazil. This species was first described in Martinique and subsequently it was found in some other places in the Caribbean, Bermuda and in the United States along the Atlantic coast ( Monniot, 1972; 1983; Goodbody, 2003; 2004; Sanamyan & Gleason, 2009). According to Goodboby (2003), the species “is relatively common on piers and boats in the vicinity of the town [Port Royal] and is sometimes fairly abundant on the iron framework of the old wrecked boat, the BOND, at the entrance to the Port Royal Lagoon. It was abundant on the undersurface of the hull of a boat, which had been moored at the University marine laboratory...”. We also found the species in similar settings (shipwrecks and marinas), which indicate its probable non-native condition both in Jamaica and in Brazil.

Although the description of Guadeloupe specimens says that A. antillense has 12−13 rows of stigmata ( Monniot, 1983), F. Monniot (personal communication) rechecked the specimens deposited in her collection and corrected it to 8−9 rows. Aplidium antillense resembles A. exile , with the main difference being the stomach with more longitudinal folds (22−24) in the latter.

Figures

FIGURE 2. Aplidium antillense. A, zooid, thorax and abdomen. B, post-abdomen, detail of female and male follicles. C, postabdomen. Scales: 1 mm.

FIGURE 6. A, Aplidium antillense at shipwreck Reliance, Salvador, Bahia. B, Aplidium elongatum below two colonies of Didemnum psammatodes (Sluiter, 1895), Island Pacotes, Vila Velha, Espírito Santo. C, Aplidium elongatum in cross section. D, Aplidium lobatum at Praia da Barra, Salvador, Bahia. E, F, Aplidium selenium at Quebramar norte, Salvador, Bahia.