Leptoclinides torosus F. Monniot, 1983

Oliveira, Livia M., Carvalho, João Paulo & Rocha, Rosana M., 2019, Leptoclinides (Ascidiacea, Didemnidae) from Brazil: new records and two new species, European Journal of Taxonomy 572, pp. 1-16 : 10-12

Leptoclinides torosus F. Monniot, 1983

Fig. 4

Leptoclinides torosus F. Monniot, 1983: 17 , fig. 5; pl. 1D.

Material examined

BRAZIL • 2 colonies; Bahia, Boa Viagem shipwreck; 12º55′56″ S, 38º30′50″ W; 7–8 m depth; 3 Aug. 1999; R.M. Rocha leg.; DZUP LEP-001 , slides DZUP DID3.29 to DZUP DID3.31 , DZUP DID-171 • 1 colony; Espírito Santo, Escalvada Island ; 20º41′59″ S, 40º24′82″ W; 8 m depth; 28 Mar. 2017; R.M. Rocha leg.; DZUP LEP-017 , slide DZUP DID3.83 .

Description

Colonies were found on exposed granitic substrate around 8 m deep. Brazilian specimens form black colonies in situ ( Fig. 4 A–B) that when fixed turn whitish brown. Colonies are 2.5–6.0 cm wide and 2–4 mm thick. The tunic is firm, smooth and has no encrustations. Spicules are star-shaped, usually 35 µm in diameter; however, the larger ones can reach 70 µm in diameter. The spicules are uniformly distributed in low density in the tunic, with 8–10, usually conical rays in cross section. Between the conical rays there are granulated areas that resemble very short truncated rays ( Fig. 4C ).

Zooids are ~ 1.2 mm long, with a 0.5 mm long thorax and 0.7 mm long abdomen. The thorax has 7–8 longitudinal muscle fibers on each side ( Fig. 4D ). The oral siphon is 0.25 mm long, tubular and with six short, rounded lobes along the margin. In some zooids the oral siphon is difficult to see, appearing as though it has no lobes. The atrial siphon is tubular and arises from the base of the thorax, with many circular muscle fibers (19–20) along its length. The siphon opens at the level of the fourth row of stigmata, usually downward oriented. In some zooids, the atrial and oral siphons are about the same length. The thoracic organ is circular, not salient, usually less than or the same size as the stigmata and is at the level of the third (sometimes between the third and fourth) row of stigmata. The pharynx has 12–13 stigmata on each side, in the first three rows, and 10–12 in the last row ( Fig. 4E ). The abdomen is horizontal, the esophagus short and narrow. The stomach is globular and is not overlapped by the intestinal loop. The testis has four, rarely five, follicles, overlain by six tightly coiled turns of the sperm duct. One specimen (DZUP DID-171, from Bahia) had a testis with four follicles and only four turns of the sperm duct.

Larvae were only found in specimens from Bahia in August. They were immature and so some structures were not visible. The larval trunk was 0.65–0.75 mm long and the pharynx had 9–10 stigmata per half row.

Remarks

The type location for L. torosus is Guadalupe ( Monniot 1983), and here we report it for the first time in the southern Atlantic. In our samples, the colonies were thinner, and spicules were not distributed in the same way as in Guadalupe (restricted to the level of the abdomens), nor did they have papillae of spicules on the surface as in Monniot (1983). Otherwise, the color of the colony, spicule shape, number of testicular follicles, turns of the sperm duct and larval size all agree with the original description of the species.

Distribution

Type locality: Guadeloupe ( Monniot 1983). Additional records: Brazil: Bahia and Espírito Santo (this study).

Figures

Fig. 4. Leptoclinides torosus F. Monniot, 1983. A. Colony in situ. B. Detail of the surface of the colony (DZUP LEP-017). C. Spicule. D–E. Thorax. Atrial siphon inadvertently removed during dissection in E. F. Abdomen (DZUP DID-171). Scale bars: D–F = 0.1 mm.