Sclerothyone oloughlini, Martins & Tavares, 2019

Martins, Luciana & Tavares, Marcos, 2019, Two new species of Sclerothyone from the southwestern Atlantic Ocean, with a key to genera and species of Sclerothyoninae (Holothuroidea: Dendrochirotida: Sclerodactylidae), Zootaxa 4658 (2), pp. 375-382 : 379

Sclerothyone oloughlini sp. nov.

( Figs 2–3 ; Table 1 )

Type material. Ilha bela, São Paulo , Brazil, 23°46’S, 43°00’W, 2.ix. 1970, 150 m, holotype 10mm ( MZUSP 1884 ). Paratypes: same data as the holotype, 2 spms 4–6 mm ( MZUSP 1889 ). Cabo Frio, Rio de Janeiro , Brazil, 23°36’ S, 43°23’ W, 4.ix. 1970, 475m, 4 spms, 3–5 mm ( MZUSP 1887 ). Campos Basin , Rio de Janeiro , Brazil, 21°20’S, 40°15’W, Campos Basin Monitoring Program coll., xii.1991 to i. 1992, 185m, 3 spm 5–10 mm ( MZUSP 1888 ) .

Etymology. This species is named in honor of Dr. Peter Mark O’Loughlin, in recognition for his enthusiasm and contributions to the systematics of Holothuroidea.

Diagnosis. Body barrel-shaped. Tube feet in double rows restricted to ambulacra. Calcareous ring plates undivided; posterior processes subdivided, long, length up to two times height of calcareous ring plate. Body wall with multilocular, two pillared tables; handles present and two-pillared tables; circular disc without handle. Plates (near the anus); tentacles with rods, introvert with rosettes. Tube feet with two pillared supporting tables, arched plates and end plates.

Description. Body barrel-shaped ( Fig. 2a ). Ten dendritic tentacles ventral-most pair smaller. Anal papillae absent. Tube feet in double rows restricted to ambulacra. Radial and interradial plates of the calcareous ring of same length, entire, united at the base only ( Fig. 2b ). Radial plates notched anteriorly for the passage of the radial nerves and radial canal; posterior processes subdivided. Interradial plates arrow-shaped, with an anterior depression. Longitudinal muscles thin, split in the anterior region of the body; retractor muscle short, flat, attached to the muscular process ( Fig. 2b ). Internal organs degraded (i.e Polian vesicle, stone canal and madreporite not observed). Color white in ethanol.

Ossicles: Body wall with two-pillared tables; circular disc with handle, multiperforated and undulating margin; spire short, ending in a crown of teeth (60–110 μm long, Fig. 3 a–b); two-pillared tables; circular disc without handle (30–40 μm long, Fig. 3 c–d) and plates near anus (100–200 μm long, Fig. 3e ). Tentacles with curved rods, perforated along entire length (150–220 μm long, Fig. 3f ); introvert with rosettes (20–60 μm long, Fig. 3g ). Tube feet with twopillared supporting tables; table disc curved, with four central holes, one perforation in both ends; short spire ending in four blunt teeth (80–100 μm long, Fig. 3h ); arched plates (60–100 μm long, Fig. 3i ) and end plates circular (up to 100 μm long).

Type locality. Brazil, São Paulo, Ilha Bela , 23°46’S, 43°00’W, 150 m.

Distribution. Brazil (São Paulo and Rio de Janeiro), between 150- 475m.

Remarks. Sclerothyone oloughlini sp. nov. stands apart from Sclerothyone reichi sp. nov. and S. unicolumnus in that the multilocular tables from the body wall have handles ( Fig. 3a, b ), whereas these are absent in the latter two species. The new species differs from S. velligera in having multilocular tables from body wall ( Fig. 3 a–d) instead of four-holed tables, and in having tentacles provided with rods only ( Fig. 3f ), whilst in S. velligera the tentacles provided with rod and plates.

Figures

FIGURE 2. Sclerothyone oloughlini sp. nov., holotype (MZUSP 1884). (A) lateral view of the body wall; (B) calcareous ring (longitudinal muscle in white arrow and retractor muscle black arrow). Scale bars: A, 5mm; B; 3 mm.

FIGURE 3. Sclerothyone oloughlini sp. nov., holotype (MZUSP 1884). SEM pictures of the ossicles. (A–B) tables with handles [white arrow] and (C–D) tables without handles from body wall (E) plate from anus; (F) rod from tentacles; (G) rosette from introvert; (H) supporting table from tube feet and (I) arched plate from tube feet. Scale bars: A–B, 50 μm; C–D, 20 μm; E–F,100 μm, G–I, 50 μm.