Lissothuria caboblanquensis Arriaga-Ochoa & Alvarado

Laguarda-Figueras, Alfredo, 2014, Lissothuria caboblanquensis n. sp., a new species of sea cucumber (Holothuroidea: Dendrochirotida: Psolidae) from Costa Rica, Zootaxa 3802 (1), pp. 144-150 : 146-149

Lissothuria caboblanquensis Arriaga-Ochoa & Alvarado

Figures 1–4

Material examined. Holotype ICML-UNAM 10165, 15 mm total length (TL), August 3rd, 2012, Collected in La Colindancia, Cabo Blanco, Costa Rica, Pacific Ocean (9°34.763’N, 85°8.816’W), 17 m depth by J. Nivia; Paratypes ICML-UNAM 10166, 2 specimens, total length 10 mm each, same data as the holotype; MZUCR-783, six specimens, from 6.4 up to 13 mm TL, same data as the holotype.

Type locality. La Colindancia, Cabo Blanco, Costa Rica, Pacific Ocean (9°34.763’N, 85°8.816’W).

Diagnosis. Dorsal scale covering completely, with 12 to 13 scales between the mouth and anus, 10 narrow valves surrounding the oral shield; the anus is surrounded by a varying number of rounded small valves. Ten short tentacles, the two most ventral are smaller. Sole elongated, fringed by three rows of closely crowded tube feet, which form a continuous margin, midventral radius with a double row of tube feet throughout. Ossicles of dorsal surface are knobbed baskets, towers complex with spiny apex, and hourglasses well developed. Ossicles of sole are perforated plates, which are smooth or knobbed; baskets with knobbed margin. Tentacles with irregular, perforated, flattened rods and few rosettes.

Description of holotype. 17 mm total length (TL) and 5 mm high at the central part of the body (15 mm sole length, 5 mm wide). Elongated body; well calcified test. Mouth and anus slightly elevated ( Fig. 1A ). Tentacles contracted. Dorsal surface with thick imbricating scales approximately 900 µm in diameter; 13 scales between oral and anal openings, the marginal scales are smaller ( Fig. 3A , B–D, E). Scales perforated for passage of tube feet ( Fig. 1 B); 10 narrow valves surrounding the oral opening; anal valves are small and rounded varying in number ( Fig. 3 E). Dorsal tube feet distributed in all dorsal surface, those located in the ambulacra are numerous and conspicuous. Sole elongated, fringed by three rows of closely crowded tube feet, which form a continuous margin, midventral radius with a double row of tube feet throughout ( Fig. 3 C). Ten dendritic tentacles, the two ventral most are smaller than the rest. Calcareous ring simple, low, radial and interradial plates about the same size and slightly calcified. Color in alcohol white to pale cream, tentacles white. Well-developed gonads. Ossicles of dorsal surface (apart from scales) are towers with spiny apex, some of them tend to be more or less geometric although most are asymmetric or irregular, the base may be smooth or irregular, the base measures between 80 and 120 µm in diameter, the height can be up to 130 µm ( Fig. 1 D). Small baskets are 40 to 60 µm in diameter, the base and the edge of which are usually knobbed ( Fig. 1 E); elaborated hourglass shaped ossicles, these may be lower than 70 µm in diameter by 40 µm high, or may have the same ratio in diameter and height (90 µm or more) ( Fig. 1 C). There are also perforated plates; end plates appear to be vestigial in the dorsal tube feet ( Fig. 1 F).

Sole ossicles are perforated plates in various shapes with smooth or knobbed margin, they reach up to 150 µm in length ( Fig. 2 A–B), and there are also small shallow baskets 40 to 60 µm in diameter, with knobbed edges and sometimes small knobs in the center ( Fig. 2 C). Tentacles generally with flat and perforated rods, most times wider in the center than at the end portions or irregular lengths up to 200 µm; there are also elaborate small rosettes 10 to 20 µm wide ( Fig. 2 D–F).

Paratype variations. Specimens slightly smaller than the holotype, 11–13 mm TL and 3 mm high in the central part of the body (8–10 mm sole length, 4 mm wide) ( Figs. 3A , B, D, E). Elongated body; well calcified test. 12 scales between oral and anal openings. Mouth, anus and internal morphology same as in the holotype. Tentacles contracted. Dorsal scales approximately 800 µm in diameter. Shape and size of the ossicles are the same as in the holotype, except that in the smaller paratype (11 mm TL) ossicles are more abundant.

Etymology. The name refers to the type locality Cabo Blanco, Costa Rica. This is the first protected natural reserve that runs the Costa Rica Conservation Model since its establishment in 1963; we dedicated this species on its 50th anniversary of creation.

Habitat. Inhabits rocky reef with stone blocks, specimens were found attached to rocks at 13 m depth.

Geographical distribution. Only known from its type locality ( Fig. 4 ).

Figures

FIGURE 2. Holotype of Lissothuria caboblanquensis sp. nov., ICML-UNAM 10165; A) Smooth perforated plates from the sole; B) Knobbed perforated plates from the sole; C) Small shallow baskets from the sole; D) Flattened perforated rods from the tentacles; E) curved perforated rod from the tentacles; F) Small rosettes from the tentacles. Scale for all ossicles: 50 µm.

FIGURE 4. Distribution map of Lissothuria caboblanquensis sp. nov.

FIGURE 1. A) Holotype of Lissothuria caboblanquensis sp. nov., ICML-UNAM 10165, showing dorsal, ventral and lateral views, scale: 5 mm; B) Dorsal scale showing the perforation for the tube feet, scale: 500 µm; C) Elaborated hourglass shaped ossicles from the dorsal side; D) Different towers shaped bodies from the dorsal side; E) Baskets of the dorsal surface; F) Perforated plates of the dorsal surface, scale for C, D, E and F: 50 µm.

FIGURE 3. A) Dorsal view of paratype of Lissothuria caboblanquensis sp. nov., ICML-UNAM 10166, scale: 2 mm; B) Lateral view of paratype; C) Detail of the sole margin (anterior part of body) showing the three rows of tube feet, scale: 1 mm; D) Detail of the dorsal scales of the body, scale: 2 mm; E) Detail of valves of the anal shield, scale: 500 µm.