Holothuria (Halodeima) nigralutea O’Loughlin, 2007

O’Loughlin, P. Mark, Paulay, Gustav, Vandenspiegel, Didier & Samyn, Yves, 2007, New Holothuria species from Australia (Echinodermata: Holothuroidea: Holothuriidae), with comments on the origin of deep and cool holothuriids, Memoirs of Museum Victoria 64, pp. 35-52 : 46-47

Holothuria (Halodeima) nigralutea O’Loughlin sp. nov.

Figures 4–7 , Tables 1, 3–5.

Material examined. Holotype: Western Australia, off Point Cloates, 22.86° S, 113.51° E, 100 m, Southern Surveyor , SS 10/2005 stn 135, 9 Dec 2005, NMV F120437 .

Paratypes: Type locality and date, F111290 (1); Dampier, 95– 90 m, 19.79°S, 115.47°E, SS05/2007 stn 29, 12 Jun 2007, F146582 (1).

Comparative material examined. H. (Halodeima) atra Jäger, 1833 . Fiji, F113579 (1); New Caledonia, Noumea, F95939 (1); N Australia, Gulf of Carpentaria, E Bremer I., F112194 (1).

H. (Halodeima) edulis Lesson, 1830 . Lectotype, Indonesia, Moluccan Is , Lesson and Garnot, 1825, MNHN EcHh 543; N Australia, Gulf of Carpentaria, Bremer I., F95094 (1); Great Barrier Reef, Heron I., F95093 (1); F95095 (1); F113599 (1); Pacific Ocean, Wake Atoll, UF E4670 .

Description (preserved specimens). Holotype 155 mm long, up to 35 mm high, up to 40 mm wide; paratype 145 mm long, up to 30 mm high, up to 45 mm wide; body length/width ratio less than 4; oval in tranverse section, not tapering from mid-body, rounded anteriorly and posteriorly; live body form short, squat, narrow anterior neck, narrow posterior tail (see photo of paratype). Body wall thick, soft-leathery, 2–5 mm thick, wrinkled, surface smooth to slightly rugose. Mouth ventral, surrounded by an irregular collar of about 60 inconspicuous papillae. Tentacles 20, peltate, with long thin tubular ampullae extending off calcareous ring plates, subequal, up to 20 mm long. Anus terminal, lacking anal teeth, with few anal papillae dorsally, with paired anal tube feet ventrally. Dorsal and lateral papillae inconspicuous in size but conspicuous in colour, flat or nipple-like, about 0.5 mm diameter, scattered irregularly, 2–10 mm apart (holotype), lacking ampullae.Tube feet scattered irregularly over ventrum, 1–5 mm apart (holotype), retracted or slightly exposed, about 0.4 mm diameter, lacking ampullae. Left dorsolateral radial plate of calcareous ring 12 mm wide and 6 mm high, with 4 anterior points, posterior margin with shallow rounded indentation. Left dorso-lateral interradial plate 4 mm high and wide, anterior margin with spire, posterior margin with rounded indentation. Tuft of small stone canals/ madreporites on each side of dorsal mesentery, extending freely in coelom, up to 25 per tuft, each up to 3 mm long, some stone canals branched. Holotype with 4 sac-like polian vesicles, up to 5 mm long, 1 branched; paratype with 4 tubular, thin, polian vesicles, 3, 8, 10, 25 mm long, 2 branched from common base. Longitudinal muscles flat, broadly attached, with narrowly free edges, up to 5 mm wide dorsally, up to 15 mm wide ventrally. Gonad tubules long, thin, multiple branching, extending half of body length. Respiratory trees extending to anterior end. Cuvierian organ absent. Gut contents calcareous detritus, with fragments up to 6 mm long.

Ossicles. Dorsal body wall with numerous rosettes, few tables; tables variable in form and size, 48–64 μ m, commonly 56 μ m long; disc reduced, typically 28 μ m wide, smooth with a single central perforation; spire typically 20 μ m wide, with 4 pillars united by a single cross-beam; crown widely spinous, typically 40 μ m wide, with 16–20 large spines; rosettes plate-like, variable in form, with obtusely angular branches arising from primary rod, 24–48 μ m long, frequently 2 small terminal and 2 large, lateral perforations (frequently with transverse bridging connection), but with up to 8 perforations. Papillae with rods, some mesh-like ossicles; rods up to 160 μ m long, variably bluntly spinous, curved, with some distal perforations; papilla apex with irregular small rods resembling those in madreporite, some anastomosing to form an irregular open mesh. Ventral body wall with numerous rosettes, fewer tables; tables same as dorsal; rosettes larger than dorsally, up to 10 perforations, up to 40 μ m long. Tube feet with endplates, perforated plates, tables, rosettes; endplates multilayered, up to 480 μ m wide; perforated plates smooth, thin, subrectangular, formed from primary rod with perpendicular lateral branches, up to 128x104 μ m, typically with 2 large lateral perforations mid-rod; tables and rosettes as in ventral body wall. Oral body wall with rosettes, tables, rods; tables similar to dorsal; rosettes frequently larger than dorsal ones, up to 56 μ m long; rods same as in tentacles, up to 184 μ m long. Anal body wall with rosettes, few tables, some rods; tables and rosettes as in ventral body wall; rods frequently with lateral branches, branches frequently joined to form lateral and terminal perforations, rods up to 88 μ m long, intergrade with rosettes. Tentacle rods up to 344 μ m long, frequently curved, thick to thin, coarsely or finely spinous, spines close or sparse, rare branches, with rare, mostly terminal perforations. Stone canal/madreporite ossicles massed irregular rods, some branched, some anastomosing to create perforations, some with an irregular, perforated mesh, up to 134 μ m long. Respiratory tree with numerous irregular rods, up to 160 μ m long, frequently with small node in middle of rod, and with branches at ends and node, variable in length and form, some branches joined to create terminal or lateral perforations.

Ossicles absent from tentacle ampullae, polian vesicles, gonad tubules, longitudinal muscles, circular muscles, and wall of cloaca.

Colour. Live colour (paratype): black on pale yellow; with scattered, small, brown spots at papillae. Preserved colour: variable pattern of black over pale yellow; with small red-brown spots around papillae and tube feet, spots irregularly distributed all over body, such spots always associated with papillae or tubefeet;interiorbodywallwithscattered,superficial, irregular black spots, that are not associated with papillae or tube feet.

Distribution. Off Point Cloates, Western Australia; 100 m.

Etymology. From the Latin niger (black) and luteus (yellow), referring to the black and yellow live colour (feminine).

Remarks. This species is assigned to Holothuria Linnaeus, 1767 , and provisionally referred to the subgenus Halodeima Pearson, 1914 , as diagnosed in Rowe (1969). Samyn et al. (2005) suggested that Halodeima might need to be raised to generic rank, but added that “revision of Holothuriidae will depend on further comparative taxonomic studies as well as on more detailed phylogenetic analyses before any of the changes proposed can be solidified into a new classification”. This work is progressing, and it remains premature to raise Halodeima to generic status or erect a new genus (see below).

The type species of Halodeima Pearson, 1914 is Holothuria atra Jäger, 1833 (by original designation). Rowe (1969) considered the following species to constitute Halodeima : H. chilensis Semper, 1868 ; H. edulis Lesson, 1830 ; H. floridana Pourtalés, 1851 ; H. grisea Selenka, 1867 ; Stichopus kefersteini Selenka, 1867 ; H. mexicana Ludwig, 1875 ; H. pulla Selenka, 1867 ; Halodeima stocki Cherbonnier, 1964 . Pawson (1978) added H. manningi . Samyn (2003), Pawson (1995) and Paulay (1989, 2003) also listed H. signata Ludwig, 1875 as a valid species of Halodeima .

Molecular data indicate that H. (Halodeima) nigralutea is most closely related to H. (Halodeima) edulis Lesson (see below), and the morphology of these species is closely similar. Distinguishing characters are listed in Table 3. In describing his new species Lesson (1830) referred principally to its widespread commercial use, but he noted: cylindrical rounded thin slightly rugose sinuous form; ventral cover of irregularly distributed papillae; upper body deep sooty black colour; under body and sides pleasant red colour, speckled with black spots. Cherbonnier (1951) gave a more detailed description and illustrated the ossicles of the lectotype of H. edulis . He noted it had 6 polian vesicles, ranging in size from large to very small. The specimens of H. edulis examined in this study are in accord with these features. Féral and Cherbonnier (1986) illustrated live colour (p. 82 only).

Both specimens of H. nigralutea have ossicles in the respiratory trees. No ossicles were encountered in the respiratory tree of the lectotype of H. edulis . Ossicles were noted in only 1 of 7 specimens of H. edulis from northern Australia (NMV F95095), as they were in a specimen from Wake Atoll (UF E4670) (GP). Presence or absence of respiratory tree ossicles in H. edulis appears to be a variable character.

Figures

Figure 4. Bayesian phylogram of species studied together with selected outgroup taxa, with posterior probability values (10 million generations, GTR-I-Gamma, and uninformative prior) above branches, and parsimony bootstrap values (100 replicates) below.

Figure 5. a, live paratype of Holothuria (Halodeima) nigralutea O’Loughlin sp. nov, from Western Australia, off Point Cloates (220 mm long; NMV F111290; photo by Karen Gowlett-Holmes). b, preserved holotype of H. (Halodeima) nigralutea, from Western Australia, off Point Cloates (148 mm long; upper dorsal, lower ventral; oral end right; NMV F120437; photos by David Staples). c, lectotype of Holothuria edulis Lesson, 1830 from Indonesia, Moluccan Is (160 mm long; MNHN EcHh 543; upper dorsal, lower ventral; photos by Yves Samyn). d, live H. (Halodeima) edulis, from Japan, Okinawa (not collected, photo by Gustav Paulay). e, live H. (Halodeima) edulis, from northern Australia (not collected, photo by Neville Coleman). f, live atypical “grey” form of H. (Halodeima) edulis, from Japan, Okinawa (UF E3882, photo by Gustav Paulay).

Figure 6. Holothuria (Halodeima) nigralutea O’Loughlin sp. nov. (SEM of ossicles from NMV F111290). A, dorsal body wall; B, ventral body wall; C, anal body wall; D, tube feet; E, tentacles; F, respiratory trees; G, madreporite.

Figure 7. Holothuria (Halodeima) edulis Lesson, 1830 (SEM of ossicles from NMV F113599). A, dorsal body wall; B, anal body wall; C, oral body wall; D, ventral body wall; E, tentacles; F, tube feet; G, madreporite.