Labidodemas javaensis, Setyastuti & Solis-Marin & Lüter, 2024

Setyastuti, Ana, Solis-Marin, Francisco Alonso & Lüter, Carsten, 2024, Sea cucumbers of the genus Labidodemas (Holothuroidea: Holothuriida: Holothuriidae) from Indonesia, with the description of a new species and a revised key to the genus, Zootaxa 5506 (2), pp. 227-244 : 235-240

publication ID	https://doi.org/ 10.11646/zootaxa.5506.2.4
publication LSID	lsid:zoobank.org:pub:55527A8F-3454-49A2-AD65-ECBAE234C03D
DOI	https://doi.org/10.5281/zenodo.13746668
persistent identifier	https://treatment.plazi.org/id/5C8E23B1-A355-4D87-A913-42223E612FEE
taxon LSID	lsid:zoobank.org:act:5C8E23B1-A355-4D87-A913-42223E612FEE
treatment provided by	Plazi
scientific name	Labidodemas javaensis
status	sp. nov.

Treatment

Labidodemas javaensis sp. nov.

( Figures 9–13 View FIGURE 9 View FIGURE 10 View FIGURE 11 View FIGURE 12 View FIGURE 13 )

Type material. Holotype MZB Hol. 413; 85x 30 mm in ethanol; under a rock, 3 m depth; coll. by Tim Teripang P 2O LIPI, 1 July 2018.

Type locality. Bilik Sajile , Baluran National Park, East Java, Indonesia.

External morphology of holotype. Medium-sized specimen (85 x 30 mm), body cylindrical, worm-like. Colour in living animals and ethanol is similar, uniformly white, with dark brown colour at the anterior and posterior parts ( Figs. 9A–D View FIGURE 9 ). Body wall 2–4 mm thick, firm, smooth to the touch. Mouth terminal, surrounded by 20 dendritic tentacles, yellowish ( Fig. 9E View FIGURE 9 ). Anus terminal, encircled by 8–10 anal papillae, arranged solitary. Dorsal papillae small, yellowish, spread over the surface. Ventral tube feet numerous, yellowish, longer than dorsal papillae, 3–4 mm, spread in three rows (ambulacral).

Internal morphology of holotype. Calcareous ring composed of huge quadrangular radial pieces and slender interradial pieces, posterior margin of radial pieces pronounced concave, anterior side with deep median notch ( Fig. 9F View FIGURE 9 ). Radial pieces three times wider and higher than interradial pieces (radial pieces 3 mm wide and high). Cuvierian tubules absent. Tentacle ampullae present, 4–5 mm long. Single Polian vesicle, tube-like, 10 mm long. Gonad one tuft, branched. Respiratory trees arise from a single stalk. Longitudinal muscles medially attachment, margins free, flat.

Ossicles of holotype. Dorsal body wall and dorsal papillae hold tables, rods and pseudo-buttons ( Figs. 10 View FIGURE 10 , 11 View FIGURE 11 ). Table discs rounded with spiny edges, usually perforated by four central holes, occasionally up to six central holes; rarely with peripheral holes, but if present, usually 2–4 holes; four short pillars united by a single cross beam, ending in a regular or irregular crown with 4–5 huge spines, usually with distal bifurcation, the crown of spines always wider than disc; disc 40–70 µm across ( Figs. 10A View FIGURE 10 , 11A View FIGURE 11 ). In dorsal papillae also present tables with very spinous disc rims, mostly with reduced pillars and ending in reduced crowns with numerous small spines, discs 40–55 µm across ( Fig. 11B View FIGURE 11 ). Rods observed in several shapes, smooth tri-radiate rods, 60–100 µm long ( Fig. 10B View FIGURE 10 ); smooth with or without perforations, 40–100 µm long ( Figs. 10C–D View FIGURE 10 , 11E View FIGURE 11 ); rugose surface rods only found in papillae, straight or tri-radiate, 50–70 µm long ( Fig. 11D View FIGURE 11 ). Pseudo-buttons rarely found, 100–110 µm long ( Figs. 10E View FIGURE 10 , 11C View FIGURE 11 ).

Ventral body wall only present regular tables, discs 65–80 µm across ( Fig. 10F View FIGURE 10 ). Ventral tube feet with a few regular tables, discs 50–100 µm across ( Fig. 12A View FIGURE 12 ), and very numerous tables similar to those in dorsal papillae, 40–60 µm across ( Fig. 12B View FIGURE 12 ); large rods with smooth surface very rare, 180 µm long ( Fig. 12D View FIGURE 12 ); large perforated plates many, 400–450 µm across ( Fig. 12E View FIGURE 12 ). pseudo-buttons only a few, 60–65 µm long ( Fig. 12C View FIGURE 12 ).

Tentacles only present rods, straight or slightly curved, smooth or rugose surface with blunt spines, 35–50 µm long ( Fig. 13A View FIGURE 13 ). Anal papillae always with tables disc with reduced pillars and crowns, spiny rims and more squarish, 25–45 µm across ( Fig. 13B View FIGURE 13 ); tri-radiate rods with spiny surfaces, 40–60 µm long ( Fig. 13C View FIGURE 13 ); straight rods with smooth surface, 45–60 µm long ( Fig. 13E View FIGURE 13 ); slightly curved and straight rods with spiny surfaces, 40–55 µm long ( Fig. 13D View FIGURE 13 ); spiny surface rods with perforations, 45–55 µm long ( Fig. 13F View FIGURE 13 ). Longitudinal muscles devoid ossicles.

Remarks. The new species is characterised by having a ribbon-like calcareous ring, three rows of ventral tube feet, and ossicle assemblage that undoubtedly belongs to Labidodemas Selenka, 1867 .

Three main characters specific to L. javaensis sp. nov. are (1) most table discs devoid of peripheral holes with rim of the discs very spiny, (2) dorsal papillae and ventral tube feet always with two types of tables (i.e. regular table with crown spines always bifurcate distally and smaller table size with very spiny disc and crown), (3) the present of tri-radiate shape of rods in the dorsal body wall and anal papillae.

The ossicle assemblages show that Labidodemas javaensis sp. nov. is closely related to L. quadripartitum Massin, Samyn & Thandar, 2004 , but several differences warrant its new species status. Table 1 View TABLE 1 lists the character differences between both species and the other two closer-related species ( L. semperianum Selenka, 1867 and L. pseudosemperianum Massin, Samyn & Thandar, 2004 ).

Etymology. Named after its type locality and regional occurrence, Java, Indonesia.

Ecology. A nocturnal animal, it hides under the rocks during the day.

Depth range. 3–7 m depth.

Geographic distribution. At present only known from the type locality.