Holothuria (Holothuria) mammata Grube 1840

Holothuria (Holothuria) mammata Grube, 1840

(Fig. 34)

non Holothuria tubulosa Gmelin, 1791 — $ Nobre 1924: 89, 1930: 23, 70 [misidentification]; Nobre 1938: 143–144, figs. 58.1, 69.1 [based on Nobre 1924, 1930]; $ Marques 1983: 4, fig. 8 [misidentification]; Pereira 1997: 333 [based on previous misidentifications]; $ Morton et al. 1998: 98, 169, figs. 5.2T, 8.8R [misidentification]; $ Wirtz 2009: 46 [misidentification]; Micael & Costa 2010: 323 [based on previous misidentifications]; $ Micael et al. 2010: 329 [misidentification]; Micael et al. 2012: 4 [based on previous misidentifications];

non Holothuria dakarensis Panning, 1939 — $ Rowe 1969: 153, 154 [misidentification]; Pérez-Ruzafa et al. 1992b: 154–155, 1999: 57, 2002: 287–288 [based on Rowe 1969];

Holothuria mammata Grube, 1840 —? $ Pawson & Shirley 1977: 915, 919; $ Borrero-Pérez et al. 2009: 51–69, figs. 1–7, 2010: 900, 2011: 1–12, figs. 1–4.

Type locality: Mediterranean Sea.

See: Tortonese (1965: 57, fig. 18); Borrero-Pérez et al. (2009).

Occurrence: Northeast Atlantic and the Mediterranean Sea, from south of Portugal to the Azores, Madeira, Selvagens and Canaries (Borrero-Pérez et al. 2009).

Depth: 0–77 m (Perrier 1902, herein); a common presence in the low intertidal and infralitoral of the Azorean shores.

Habitat: sand, mud, gravel to hard substrata, on sea-grass prairies and in large tide-pools (Hérouard 1923, Pérez-Ruzafa et al. 1992b, 2002).

Larval stage: planktotrophic (Domínguez-Godino et al. 2018).

Commercial value: edible (Borrero-Pérez et al. 2009).

Material examined: DBUA-ECH 394 (Poços, S„o Vicente, SMG, AZO, c. 37°50’06”N, 25°40’10”W, 1996.07. 17, 13 m; 1 spm, TL = c. 200 mm); DBUA-ECH 397 (Lajes, PIX, AZO, 38°23’22”N, 28°15’04”W, 2010.09.24, 1– 2 m; 10 spms, TL = 109–230 mm); DBUA-ECH 406 (Santa Cruz, FLS, AZO, 39°27’17.79”N, 31°07’30.48”W, 2011.04.23, intertidal; 14 spms, TL = 80–330 mm).

Description: body cylindrical, flattened ventrally. Tegument smooth, not thick. Mouth subventral and anus terminal. Dorsal surface with large mammillate papillae organized in six irregular longitudinal rows. Presence of a collar of small oral papillae. Ventral surface with tube-feet organized more or less in three longitudinal series (middle one somewhat subdivided in two). Most animals eviscerated. Cuvierian tubules inconspicuous. Table discs spinose, arched and somewhat reduced; tables with tetrabasal spires, of moderate height, crowded by acicular spines. Buttons, thick with a rugose appearance, covered by numerous small pointed knobs and with three or more pairs of small holes. Colour: uniform dark brown.

Remarks: in general, H. mammata can be easily distinguished from other shallow-water Holothuria species known to occur in the Azores by their inability to eject Cuvierian tubules (see remarks under H. sanctori). Among the sea cucumbers inhabiting the Azorean shallow waters, H. mammata differs also by its well developed spinose ossicles. Though closely resembling Mediterranean H. tubulosa, this species is distinct by the presence of a Cuvierian organ, relatively larger dorsal papillae and relatively larger tables (Rowe 1969).

Holothuria mammata is one of the most common elements of the Azorean shallow-water biota, particularly in relatively protected bays both natural (e.g., natural lagoon in Lajes, Pico Island; Ávila et al. 2011) and manmade (e.g., port of Ponta Delgada, S„o Miguel Island; personal observation). However, it was only in 2009 that this species was identified with certainty in the archipelago by Borrero-Pérez and co-workers. Historically, H. mammata was frequently confused with a closely similar species from the Mediterranean Sea, H. tubulosa (Gmelin 1791). Both species present a high degree of morphological variability, and in some cases the individuals may present intermediate diagnostic characters. Borrero-Pérez et al. (2009) showed that Atlantic records of H. tubulosa were a result of misidentifications with H. mammata, given that the former is restricted to the Mediterranean Sea. Thus, historical reports of H. tubulosa from the Azores should be considered as H. mammata. Another similar species, H. dakarensis Panning, 1939, was at one time included in the Azores echinoderm fauna by Rowe (1969). Pawson & Shirley (1977) believed that Rowe based his statement on specimens from Faial Island, deposited in the collection of the British Natural History Museum. On re-examination of this material, the authors concluded the animals belonged either to H. mammata or H. tubulosa. As the latter is restricted to the Mediterranean Sea these specimens are more likely to belong to H. mammata. Furthermore, Borrero-Pérez et al. (2009) also showed that in the Eastern Atlantic H. dakarensis is restricted to southern latitudes along the African coasts, from Senegal and Cape Verde to Angola.