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 Author Setyastuti, Ana Research Center for Oceanography, National Research and Innovation Agency (BRIN). Jalan Pasir Putih I, Ancol Timur, Jakarta Utara, 14430, Indonesia Author Solis-Marin, Francisco Alonso Colección Nacional de Equinodermos “ Dra. Ma. Elena Caso Muñoz ”, Laboratorio de Sistemática y Ecología de Equinodermos, Instituto de Ciencias del Mar y Limnología (ICML), Universidad Nacional Autónoma de México (UNAM), Ciudad de México, C. P. 04510, México Author Lüter, Carsten Museum fuer Naturkunde, Leibniz Institute for Evolution and Biodiversity Science. Invalidenstr. 43, 10115, Berlin, Germany text Zootaxa 2024 2024-09-06 5506 2 227 244 http://dx.doi.org/10.11646/zootaxa.5506.2.4 journal article 10.11646/zootaxa.5506.2.4 1175-5326 13746857 55527A8F-3454-49A2-AD65-ECBAE234C03D Labidodemas semperianum Selenka, 1867 ( Figures 5–8 ) Labidodemas semperianum Selenka, 1867: 309 , pl. 17, figs. 1–3; Massin et al ., 2004: 1833 , figs. 9A–J, 10A–H, map 6 (synonymy and records 1970–2003). Type material . Lectotype MCZ 736 (the dissected specimen, 75 mm long), paralectotype MCZ 736 (the nondissected specimen, 90 mm long) ( Massin et al . 2004 ). The Syntype ZMG (no number given by Selenka, 1867 ) are untraceable ( Massin et al. 2004 ). Type locality . Formerly Hawaiian Islands (as Sandwich Islands ), but now Society Islands according to the designation of lectotype ( Massin et al . 2004 ) . Material examined . MZB Hol.385 ( one specimen ), 68x 19 mm in ethanol, collected in Batulawang , Situbondo , Jawa Timur , by diving, found under a rock, 5 m depth , coll. by Tim Teripang LIPI 2018 . External description . Body cylindrical; colour in ethanol white uniformly ( Figs. 5A, B ). Body soft to the touch, 1–2 mm thick. Mouth and anus terminal; mouth brown, surrounded by 16 potato-digitate tentacles. Anal papillae present, not calcified. Dorsal papillae small, conical shape, yellow, scattered over the surface. Ventral tube feet are very long ( 3 mm ), white to yellowish, arranged in three rows in the ambulacral areas with a zigzag pattern. Internal description . Calcareous ring small ( Fig. 5C ), with radial pieces twice wider than interradial pieces ( 2 mm wide and 2 mm high). Cuvierian tubules present, not expelled during collection, adhesive, bulbous and thick, brownish, branched, distal part of the tube with spherules, more than 10 attachment sites. Tentacle ampullae present, short. Single Polian vesicle, sac-like. Stone canal not observed. Gonad one tuft, branched. Respiratory trees arise from a single stalk. Longitudinal muscles flat and completely attached to the body wall. Inner body wall whitish, intestine filled with gravel and coral rubble. FIGURE 5. Labidodemas semperianum Selenka, 1867 . MZB Hol.385 (68x19 mm in ethanol). Specimen photograph. A: dorsal; B: ventral; C: calcareous ring. FIGURE 6. Labidodemas semperianum Selenka, 1867 . MZB Hol.385. Ossicles dorsal body wall, A: tables; B: pseudo-button. Ossicles ventral body wall, C: tables; D: buttons. FIGURE 7. Labidodemas semperianum Selenka, 1867 . MZB Hol.385. Ossicles dorsal papillae, A: tables; B: buttons, pseudobuttons and rods; C: plate. Ossicles ventral tube feet, D: tables; E: endplate. Ossicles . Dorsal body wall with tables and buttons; tables disc 60–80 µm across, disc rims mostly spinous, perforated by 4–6 central holes; table spire low (20–30 µm), ending in four to six long spines, some of them bifurcated distally; table crown generally larger than table disc ( Fig. 6A ). Pseudo-buttons only a few; 60–80 µm long; knobbed ( Fig. 6B ). Ventral body wall holds tables and buttons ( Figs. 6C, D ) similar to those in dorsal body wall. Dorsal papillae with tables, buttons, pseudo-buttons, rods and plates; tables disc 55–90 µm across, disc rims spinous; perforated by four to five central holes and a variable number of peripheral holes; spire low, single crossbeam, ending in four to six long spines with distal bifurcation; table crown wider than table disc ( Fig. 7A ). Buttons 40–50 µm long, sometimes with knobbed; pseudo-buttons 60–100 µm long; rods 50–90 µm long ( Fig. 7B ); small plate observed in heaps with rods and buttons, 100 µm across ( Fig. 7C ). Ventral tube feet only with tables and large end plates. Tables 60–80 µm across, with four to five central holes, crown sometimes with only three spines, tables reduced to the (spiny) disc or with a reduced crown also observed ( Fig. 7D ). Endplate reaching 500 µm across ( Fig. 7E ). FIGURE 8. Labidodemas semperianum Selenka, 1867 . MZB Hol.385. A: tentacle rods; B: ossicles of anal papillae. Tentacles with only rods, thin, smooth or spiny, 30–60 µm long ( Fig. 8A ). Ossicles of anal papillae consist of a mixture of table discs, 40–50 µm across, irregular rods and reduced buttons, 30–45 µm long ( Fig. 8B ). Remarks . The specimen examined in the present study possesses Cuvierian tubules with more than 10 attachment sites. Such had never been observed before in this species. On the other hand, L. semperianum in the present study has few buttons and pseudo-buttons in the body wall and dorsal papillae, similar to the study of Massin et al . (2004) . Ecology . Found in shallow waters, less than 30 m depth ( Lane et al . 2000 ), under coral rocks. Depth range . 1–30 m depth. Geographic distribution . The following new locality is added here since Massin et al . (2004: 1835 , map 6) publication: Situbondo-East Java , Indonesia (present study).