Leptoclinides coronatus, Oliveira & Carvalho & Rocha, 2019

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 : 2-6

Leptoclinides coronatus sp. nov.

urn:lsid:zoobank.org:act:0689D2DB-DD99-4CBB-82F0-C75FF8602BE4

Fig. 1

Etymology

The name of this species refers to the crown-like arrangement of the lobes on the surface of the colony around the common cloacae.

Material examined

Holotype

BRAZIL • 1 colony; Espírito Santo, Guarapari, Escalvada Island ; 20º41′58.77″ S, 40º24′82″ W; 8 m depth; 28 Mar. 2017; R. M. Rocha leg.; DZUP LEP- 018, slide DZUP DID 3.84.

1 Characteristics based on Paiva et al. (2015). 2 Characteristics based on Michaelsen (1923).? no information available.

Paratypes

BRAZIL • 1 colony; Espírito Santo, Guarapari, Ilha Rasa de Terra ; 20º40′32″ S, 40º22′1″ W; 12–15 m depth; 27 Mar. 2017; R. M. Rocha leg.; DZUP LEP- 016, slide DZUP DID3.82 • 1 colony; same collecting data as for holotype; DZUP LEP-020 • 1 colony; same collecting data as for holotype but 29 Mar. 2017; DZUP LEP-019 .

Description

Colonies were found exposed on granitic substrate between 8 and 15 m. They have an orange and white marbled appearance, and colony shape follows that of the substrate ( Fig. 1A ). Colonies can be 2–5 cm in diameter and 1–2 mm thick. Color in fixed specimens becomes grayish. Common cloacal apertures are wide, white with conical projections with many spicules along the margin ( Fig. 1B ). The tunic is cartilaginous with a smooth surface. Spicules are 20–30 µm in diameter, uniformly, but not densely, distributed throughout the tunic. Spicules are star-like with 6 conical rays in cross section and, at the base, the rays are separated from one another by a matrix covered by small, rounded projections ( Fig. 1C ).

Zooids are about 1.6 mm long, with the thorax twice the length of the abdomen. The oral siphon is tubular, 0.44 mm long, with six short and rounded lobes, sometimes not easily visible. On each side of the thorax there are eight muscular fibers that extend from the oral siphon to just anterior to the rectal esophageal peduncle. The atrial siphon is long and oriented downward ( Fig. 1D ). Occasionally the atrial opening appears short, probably due to the position of the zooid within the colony. Both siphons have conspicuous circular musculature.

The pharynx has 10 stigmata per row on each side, except the last row, which has fewer stigmata (about 8–9). Stigmata are narrowly fusiform and slightly wider at the center. The thoracic organ is round, not raised, normally smaller than the size of the fold and located at the level of the fourth row of stigmata, almost in the middle of the thorax. The thoracic organ is often full of spicules.

The abdomen is vertical, with a short and narrow esophagus. The stomach is large, elongate, and it is not overlapped by the intestinal loop ( Fig. 1E ). The testis has six rounded follicles. The sperm duct is spiral, with 4–6 counter-clockwise turns.

The larval trunk is ovoid and ~ 0.7 mm in length. The tail curves ¾ of the way around the trunk. Three adhesive papillae are equally spaced with short, wide peduncles. Two pairs of large ectodermal ampullae are centrally located, and there is also one single dorsal and ventral ampullae, both smaller, for a total of six ampullae. The sensorial vesicle is posterior and the statocyte either anterior or ventral to the ocellus. Mature larvae have four rows of stigmata in the pharynx, with 10 stigmata in the first three rows and nine stigmata in the last. No pigment or ectodermal vesicles are present.

Remarks

Leptoclinides coronatus sp. nov. is very distinctive in comparison with the other congeners found in coastal Brazil. Leptoclinides crocotulus and L. latus are orange, but uniformly so and without swaths of white. Leptoclinides crocotulus is also different by the different shape and smaller (12 µm) size of spicules, the different size and shape of the siphons, smaller lateral thoracic organ and three testicular follicles with two or three turns of the sperm duct ( Paiva et al. 2015). It is also different from L. latus , which has a globular-type spicule, an atrial languet and fewer turns of the sperm duct.

The Australian L. imperfectus (Kott, 1962) is marbled with orange and gray on a white background, but differs more clearly from L. coronatus sp. nov. in having papillae on the surface of the colony, a very long esophago-rectal peduncle, 6–8 testicular follicles and seven turns of the sperm duct and slightly smaller larvae (trunk ~ 0.6 mm long) with four pairs of ectodermal ampullae ( Kott 2001). Also marbled, L. marmoreus Brewin, 1956 differs in having a smooth-margin cloaca and nine turns of the sperm duct ( Brewin 1956), while L. marmoratum ( Sluiter, 1909) is not orange, but rather gray or dark blue, has longer (3 mm) zooids and spicules in a narrow layer under the bladder cells, in addition to small groups of spicules scattered around the tunic ( Sluiter 1909; Millar 1975).

Distribution

Type locality: Brazil: Espírito Santo.

Figures

Fig. 1. Leptoclinides coronatus sp. nov., holotype (DZUP LEP-018). A. Colony in situ. B. Detail of the cloaca with lobes. C. Spicules. D. Thorax. E. Abdomen. F–G. Larvae in different stages in the same colony. Scale bars: D–G = 0.1 mm.