Prototrochus roniae, O’Loughlin, Mark & Macintosh, Hugh, 2015

O’Loughlin, Mark & Macintosh, Hugh, 2015, New Prototrochus species of sea cucumber from Australia (Echinodermata: Holothuroidea: Synaptida: Myriotrochidae), Zootaxa 3995 (1), pp. 264-270 : 266-269

Prototrochus roniae sp. nov.

Figs 1–3 , Table 1

Material examined. Holotype — SAMA K4516, Australia, Great Australian Bight, continental slope, 34.603726ºS 131.068390ºE, collected by multicorer, sample W13/005580, 1479 m, Southern Surveyor SS2013_RC19 stn. 0 6, 10 April 2013.

Other material. NMV F151838 (permanent slide mount), Western Australia, Indian Ocean, Two Rocks (north of Perth), continental slope, 31.661667ºS 114.981111ºE, collected by grab, 403 m, CSIRO cruise Southern Surveyor SS07/2005 stn. 136, 4 August 2005.

Description. Prototrochid species, incomplete specimen (anterior part only), 0.95 mm long (preserved in 95% ethanol); calcareous ring diameter 0.45 mm. Tentacles lack ossicles. Body wall with numerous myriotrochid wheels; rims rounded; diameters of wheels 65–104 µ m; wheel hub diameters 16–23 µ m; spokes 12–15; teeth 31– 35.

Distribution. Great Australian Bight, continental slope, 34.60ºS 131.07ºE, 1479 m.

Etymology. Named roniae for Roni Robbins, with appreciation of her dedicated and productive partnership with Roger Bamber as ARTOO Marine Biology Consultants.

Remarks. Prototrochus roniae sp. nov. is distinguished in the key above from the other five Australasian species of Prototrochus . Ossicle dimension of the second myriotrochid specimen (NMV F151838) are: wheel diameters 64–96 µ m; wheel hub diameters 16 µ m; spokes 10–14; teeth 21–24. All dimensions agree well with those of the holotype except the inner wheel rim teeth number. We provisionally refer this part-specimen to Prototrochus roniae sp. nov. on the evidence that the few ossicles that we could measure are similar to those of the holotype. We have not considered this specimen in the data given in the table and the distribution.

Figures

FIGURE 1. Prototrochus roniae sp. nov. holotype part-specimen (SAMA K 4516). A, photo of anterior end; scale bar 100 µ m. Prototrochus robbinsae sp. nov. holotype part-specimen (NMV F 151834). B, photo of anterior end showing part of calcareous ring and three tentacles; arrow indicates groove for nerve penetrating radial plate; scale bar 100 µ m long; C, enlarged view of tentacle illustrating lobed margin of tentacle and absence of tentacle ossicles.

FIGURE 2. Photos of wheels from the Australian slope species of Prototrochus Beljaev & Mironov, 1982; scale bars each 50 µ m long). A, Prototrochus roniae sp. nov. holotype (SAMA K 4516); B, outline of parameters of wheel in A; C, Prototrochus robbinsae sp. nov. holotype (NMV F 151834); D, Prototrochus burni O’Loughlin (in O’Loughlin & VandenSpiegel, 2007) holotype (NMV F 94697); E, Prototrochus staplesi O’Loughlin (in O’Loughlin & VandenSpiegel, 2007) holotype (NMVF 94698); F, Prototrochus taniae O’Loughlin (in O’Loughlin & VandenSpiegel, 2007) holotype (NMV F 59591).

FIGURE 3. Geographical and depth distribution of Australasian species of Prototrochus Beljaev & Mironov, 1982.