Figures 2 a–f, 3 a–d.
Material examined. Holotype. Antarctica, Scotia Sea, South Georgia, 55.06 ºS 35.24 ºW, 116 m, ICEFISH 2004 stn 47 –BT– 25, S. Lockhart, 12 Jun 2004, NMV F 168623.
Paratypes. From type series (type locality on same date), NMV F 104996 (5); Shag Rocks, 53.63 ºS 40.91 ºW, 206 m, BAS 2006 stn SR–EBS– 4, NMV F 168627 (1).
Other material. Antarctic Peninsula, N of Bransfield Strait, 227–231 m, US AMLR 2006 stn 33 – 18, USNM 1132590 (2); N of D’Urville I., 238 m, US AMLR 2006 stn 39–52, USNM 1132592 (1); N of D’Urville I., 238 m, US AMLR 2006 stn 39–52, USNM 1132593 (8).
Diagnosis. Psolus species up to 22 mm long, 9 mm high, 11 mm wide; high to low convex body, slightly tapered posteriorly, lacking oral and anal cones; scales obscured by close cover of large and small apically spinous pillars on the scales, up to 0.5 mm high; lacking 5 discrete oral valves, oral scales numerous, apically pointed, marginally spinous; tentacles 10, 8 large, 2 small ventrally; calcareous ring with distally rounded radial and interradial anterior projections, radial projections larger, concave radial and interradial posterior indentations; thin calcareous sole, single outer peripheral series of small tube feet, zig-zag to double series of larger inner peripheral tube feet, lacking mid-ventral tube feet; bi-lobed dorsal madreporite; single ventral polian vesicle; gonad tubules unbranched.
Dorsal and lateral multilayered ossicles only. Sole with irregular round to oval perforated plates and shallow bowls, commonly 136 µ m long, frequently with upturned margin, surface and marginal knobs. Largest tentacle ossicles irregularly oval or triangular or elongate thick perforated plates, surface smooth, bluntly denticulate margin, up to 560 µ m long. Largest tube feet support ossicles up to 320 µ m long, elongate curved narrow perforated plates, bluntly denticulate margin, rare sparse surface knobs.
Colour (preserved). White to off-white, slightly translucent sole.
Distribution. Antarctic Ocean, South Georgia, Shag Rocks, Antarctic Peninsula, 116– 238 m.
Etymology. Named for Caroline Harding (Museum Victoria Entomology Department), with appreciation of her generous collaborative assistance in doing both the montage photography of specimens and ossicles in this study, and the preparation of the figures.
Remarks. Psolus carolineae sp. nov. is distinguished from all other Antarctic Psolus species by the distinctive apically spinous pillars that arise from and closely cover the dorsal and lateral scales.