Psolus heardi O’Loughlin & Skarbnik-López, 2015

O'Loughlin, P. Mark, Skarbnik-López, Jessica, Mackenzie, Melanie & VandenSpiegel, Didier, 2015, Sea cucumbers of the Kerguelen Plateau, with descriptions of new genus and species (Echinodermata: Holothuroidea), Memoirs of Museum Victoria 73, pp. 59-93 : 81

Psolus heardi O’Loughlin & Skarbnik-López sp. nov.

Zoobank LSID. http://zoobank.org:act: FF1FB240-6E7D-44BA- 9AF3-B1FADA9EE993

Psolus sp. nov. (HOL 23).—Hibberd & Moore, 2009: 120,

Tables 1–3, 6; figures 1, 9, 10.

Material examined. Holotype. Southern Ocean , S Kerguelen Plateau, NE Heard Island, NW of Shell Bank, ANARE Aurora Australis, HRD 93, stn. 71–S, epibenthic sled, -50.72 75.07, 514–528 m, coll. T. Stranks, 28 Sep 1993, NMV F84986 .

Paratypes. Holotype locality and date, NMV F198493 (7) .

Other material (AAD species code: HOL 23). Southern Shell Bank, AAD Southern Champion cruise 46 haul 111, beam trawl, -51.81 76.31, 247 m, AAD; southern Shell Bank, SC 46(114), -51.81 76.06, 410 m, AAD; southern Shell Bank, SC 46(115), -51.81 75.98, 557 m, AAD. Description. Preserved body up to 12 mm long (excluding tentacles), body up to 5 mm high, body flat ventrally, domed dorsally, lacking oral and anal cones, mouth with anterior orientation, dorsal and lateral body with conspicuous imbricating scales, lacking tube feet, ventro-lateral scales projecting slightly over a soft sole. Discrete sole, lacking scales, peripheral series of large tube feet, series not continuous anteriorly, rare mid-ventral tube feet. Tentacles dendritic, 10, ventral pair small. Calcareous ring solid, cucumariid-like, digitiform anterior projection and deep posterior notch on both radial and inter-radial plates, lacking posterior prolongations. Longitudinal muscles narrow, flat. Gonad comprises 2 tufts of sac-like tubules, one on each side of the dorsal mesentery, hermaphrodite, coelomic bood-protecting.

Dorsal and lateral ossicles imbricating scales and cups; scales irregularly oval, up to about 1 mm long, scales are perforated plates with mesh-like secondary layering, finely spinous dorsal surface layer; cups irregular, shallow to deep, predominantly four perforations in cross form, sometimes small corner perforations, cups variably knobbed or with short digitiform projections, some incipiently bridged, cups typically 140 µ m long. Sole with irregular, marginally knobbed, perforated, shallow, concave plates, up to about 8 perforations, up to about 360 µ m long; plates inter-grade with shallow cups, similar to dorsal cups, predominantly 4 large perforations, sometimes smaller corner ones, margin knobbed, some secondary knobs and developments, cups about 140 µ m long. Tentacle ossicles thick, perforated rods and plates, irregular, curved, variably knobbed and digitate margins, some surface knobs, plates and rods up to 320 µ m long; small thin curved plates, about 50 µ m long; rare fine irregular crosses, about 50 µ m long; small rosette-like ossicles, about 100 µ m long.

Distribution. Southern Ocean, Kerguelen Plateau, NE Heard Island, Shell Bank, 247–557 m,

Etymology. Named heardi with reference to Heard Island.

Remarks. We provisionally assign this new species to the currently suppressed Psolus Oken, 1815 , pending an appeal to the ICZN (see Introduction). While Psolus heardi O’Loughlin & Skarbnik-López sp. nov. satisfies the general diagnostic criteria for referral to Psolus , we are aware that emerging phylogenetic data do not support the family Psolidae and provide evidence that the genera Psolus Oken and Psolidium Ludwig, 1887 are polyphyletic (Gustav Paulay pers. comm.). Psolus heardi O’Loughlin & Skarbnik-López sp. nov. differs from all other Psolus species by having a combination of: coelomic brood-protecting habit; poorly defined ventrolateral margin overlapping the sole; dorsal scales that are single-layered with mesh-like secondary layering that has fine dorsal surface spines; shallow, irregular, marginally knobbed cups that are similar dorsally and in sole. “Other material” refers to lots that were identified in the AAD by comparison with voucher specimens that were identified by Mark O’Loughlin. These lots are held (unregistered) in the AAD and the determinations not confirmed by Mark O’Loughlin.