Cladodactyla crocea ( Lesson, 1830 )

O’Loughlin, P. Mark, Mackenzie, Melanie, Paulay, Gustav & VandenSpiegel, Didier, 2014, Four new species and a new genus of Antarctic sea cucumbers with taxonomic reviews of Cladodactyla, Pseudocnus, Paracucumidae and Parathyonidium (Echinodermata: Holothuroidea: Dendrochirotida), Memoirs of Museum Victoria 72, pp. 31-61 : 37-40

Cladodactyla crocea ( Lesson, 1830)

Figures 2 , 3 , 4 ; table 1

Holothuria (Cucumaria) crocea Lesson, 1830: 153–154 , pl. fig. 1.

Cladodactyla crocea .— Brandt, 1835: 43.— Wyville Thomson, 1878: 57–61, fig. 1.— Panning, 1957: 27–29, figs 10–13.

Cucumaria crocea .— Théel, 1886: 58–61, pl. 3 fig. 5, pl. 12 figs 1, 2 (see Remarks).— Ludwig, 1898: 15–24, pl. 1 figs 6–13.— Vaney, 1908a: 296.— 1908b: 23–24.— Ekman, 1925: 75–81, figs 15, 16.

Cucumaria croceoida Vaney, 1908a: 299 .— 1908b: 31, pl. 5 figs 64–66.

Cucumaria crocea var. croceoides . — Ekman, 1925: 81–85, fig. 17.

Material examined. South-west Atlantic Ocean , Falkland Islands, Discovery Expedition, RRS William Scoresby, WS stn 231, 50°10'S 58°42'W, 159–167 m, 4 Jul 1928, NHMUK 2013.1 (1) ; W of Falkland Is , WS stn 867, 51°10'S 64°16'W, 148–150 m, 30 Mar 1932, NHMUK 2013.2 (1) ; WS stn 869, 52°16'S 64°14'W, 187 m, 31 Mar 1932, NHMUK 2013.3 (1) ; Falkland Is , US AMLR 2004 Icefish stn 17– OT20, 52°22'S 58°52'W, 78 m, S. Lockhart, 31 May 2004, NMV F105017 (4) ( UF tissue sequence codes MOL AF 501, 502) ; Icefish stn 18–OT14, 52°08'S 58°05'W, 93 m, S. Lockhart, 28 May 2004, NMV F106967 (3) ( UF tissue sequence code MOL AF 504 ) ; Icefish stn 21– OT16, 52°43'S 59°97'W, 120 m, S. Lockhart, 30 May 2004, NMV F105002 (3) ( UF tissue sequence code MOL AF 503 ) ; Burdwood Bank , Icefish stn 5–BT4, 54°47'S 59°18'W, 303 m, S. Lockhart, 21 May 2004, NMV F160031 (1) ( UF tissue code MOL AF542 ) ; Falkland Is , Challenger stn 315, 51°40'S 57°50'W, 9–22 m, 26–28 Jan 1876, USNM E10614 (2) ; Tierra del Fuego , Cape Penas, Eltanin stn 966, 53°40'S 66°20'W, 81 m, 10 Feb 1964, USNM E33519 (46).

Description. Body cylindrical, rounded orally and anally, up to 100 mm long 30 mm diameter (live, in Wyville Thompson 1878; 47 mm long preserved, in Ekman 1925); body wall soft, leathery, dorso-lateral radial body wall thick, soft, “puffy”; dorsal marsupium created by elongate indentation / invagination between dorsal radii; 10 equal tentacles; ring not calcified in larger specimens; tube feet restricted to radii in paired zig-zag rows, smaller and more numerous in dorso-lateral than in ventral radii, outer ventro-lateral rows of tube feet fewer and more spaced, dorsal tube feet absent in small specimens, often withdrawn into pits in preserved specimens; dorso-lateral radial tube feet do not cross inter-radius at anterior and posterior ends of marsupium; single polian vesicle; paired, unbranched tufts of hermaphroditic gonad tubules, genital papilla anterior mid-dorsal in marsupium; 2 respiratory trees, each divided basally into 2 sub-equal or unequal dendritic branches creating 4 trees, extending about two-thirds length of coelom.

Mid-body wall ossicles absent from largest specimens; in smaller specimens ossicles absent from marsupium wall but mid-lateral body wall with thick rods and spinous plates, rods frequently with single to numerous distal perforations, frequently with distal and lateral spines and branches, plates irregularly oval to round, with two larger central perforations, surface and margin with sharp spines, rods and plates intergrade, up to 296 µm long. Dorsal tube foot endplates up to 280 µm diameter, endplate support ossicles curved, distally perforate, spinous rods up to 136 µm long. Ventral tube feet endplates with irregular perforations, diameter about 360 µm, endplate support rods as in body wall but curved, about 168 µm long. Tentacle ossicles irregular thick rods with distal and sometimes lateral perforated extensions, with marginal denticulations around perforated parts, up to 272 µm long. Introvert lacking ossicles. Peri-anal body wall ossicles spinous rods and plates as in body wall, up to 176 µm long, and some larger oval plates with spinous margin, plates up to 240 µm long, no spinous crosses detected.

Colour. Live: body orange yellow, tentacles white. Preserved: body pale brown to grey to cream to pink with brown spots variably evident.

Distribution. South-west Atlantic Ocean, Falkland Islands ( Malvinas), Burdwood Bank, Tierra del Fuego, 0– 303 m.

Remarks. The synonymy above is selective and does not include the comprehensive list of early references provided by Ludwig 1898. Théel (1886) provided good illustrations (pl. 3 fig. 5) of the ossicles of Cladodactyla crocea but reported them as Cucumaria laevigata , and wrongly reported two small ventral tentacles for Cladodactyla crocea . Lampert (1886) was confused in his discussion of Cucumaria crocea and illustrated ossicles of Pentactella laevigata Verrill, 1876 . Cladodactyla crocea is distinguished from the other Cladodactyla species by the combination of: presence of a dorsal external marsupium; dorso-lateral radial tube feet series not continuous anteriorly and posteriorly across the dorsal inter-radius to create a complete border to the marsupium; 10 equal tentacles; tentacle ossicles rods not plates; absence of introvert ossicles; presence of tube feet support rod ossicles; lack of spinous crosses in the peri-anal body wall.

Ekman (1925) found variations in body wall ossicle form, and in the presence or absence of ossicles, in specimens that he judged to be Cucumaria crocea and Cucumaria croceoida Vaney, 1908 . Ekman could distinguish two groups, but acknowledged that there was an overlap, and thus relegated Vaney’s species to a variety of Lesson’s. We observed similar variations among specimens of Cladodactyla crocea , and thus judge that the variety croceoides should not have formal status and refer it to the synonymy of Cladodactyla crocea .

Figures

Figure 2. Maximum likelihood tree for Cladodactyla–Heterocucumis–Staurocucumis clade, based on COI sequences, T92+G+I model, 100 bootstrap replicates, Laevocnus laevigatus as outgroup. Filled circles>0.95 bootstrap support; hollow circles>0.70 bootstrap support.

Figure 3. Cladodactyla crocea (Lesson, 1830). a, in situ photo of lateral view of live specimen with juveniles on the dorsal marsupium (Falkland Islands; photo by SMSG); b, dorsal view of 35 mm long preserved specimen showing thickened marsupial dorsal radial rims with numerous very small tube feet (NMV F105017); c, dorsal view of 8 mm long preserved specimen showing invaginated marsupium with enclosed embryos (NMV F160031).

Figure 4. SEM images of ossicles from specimens of Cladodactyla crocea (Lesson, 1830). Main figure with spinous rods and plates from the dorso-lateral body wall of a 15 mm long specimen (NMV F105002); top left box with spinous rods from the lateral body wall of a 28 mm long specimen (NMV F106967).