Figures 2 M, 14
Type material. Holotype NMNZ M. 310256 and 5 paratypes (4 NMNZ M.118653, 1 MNHN IM- 2012-2523).
Type locality. New Zealand, North Island, E of Mercury Islands, 36 º 30.27 ’S, 176 º 30.45 ’E, 990–1100 m.
Material examined. New Zealand. North Island: E of Mercury Islands, 36 º 30.27 ’S, 176 º 30.45 ’E, 990–1100 m, R/V Kaharoa, 15.06.1999, 2 dd (holotype NMNZ M. 310256, and one specimen M. 151361); SE of Aldermen Islands, 37 º04.30’S, 176 º 26.60 ’E, 807–872 m, R/V Tangaroa, 23.01.1981, 5 dd (paratypes); E of North Cape, 34 º25.00’S, 173 º 13.10 ’E, 254–327 m, R/V Tangaroa, 27.01.1981, 3 dd (NMNZ M. 118465); W of White Island, 37 º 10.90 ’S, 176 º 38.70 ’E, 685–705 m, R/V Tangaroa, 23.01.1981, 1 dd (NMNZ M. 308003); E of Poor Knights Islands, 35 º28.00’S, 175 º03.00’E, 282 m, R/V Acheron, 14.02.1974, 1 dd (NMNZ M.036043).
Description (holotype) (Fig. 14 A–C). Shell small, fusiform, with high elevated spire (LWL /SL 0.51) and attenuated short canal. Shell consisting of nearly two protoconch whorls and 6.25 convex, angulated, teleoconch whorls. Protoconch (Fig. 14 F, paratype) paucispiral, globose, sculptured with microscopic spiral threads, diameter 930 Μm, height 890 Μm, transition to teleoconch weakly demarcated by onset of two spiral cords. Suture impressed. Besides inconspicuous, strongly sinuous, growth lines with deep broad anal sinus on whorl periphery, axial sculpture consisting of narrow, closely spaced, ribs matching the growth lines in shape, 12 on penultimate whorl, 13 on last whorl. Axial ribs running from suture to suture on spire whorls, although rather low above shoulder, and becoming obsolete on shell base at transition to canal; on first teleoconch whorl, 10 narrow, closely spaced, weakly sinuous, and slightly prosocline, axial ribs; on second whorl, axial ribs and anal sinus becoming progressively deeper, reaching the adult profile by last half of second whorl. Spiral sculpture consisting of a narrow subsutural cord, appearing on second whorl and progressively shifting abapically, strong keel on shoulder, with thin riblet below, and another strong abapical keel; on shell base, 4 additional, narrow, broadly spaced cords (interspaces twice as broad as cords), and 8, closer spaced, cords on canal. Axial ribs forming strong beads when intersecting the shoulder and two abapical-most spiral cords. Aperture low, elongate, 0.41 (together with canal) of SL. Outer lip partially chipped, sinuous in profile (Fig. 14 B), slightly concave on subsutural ramp, and nearly evenly convex in middle part, concave at transition to short and relatively broad, nearly straight, canal. Columella short, nearly straight, smooth. Callus narrow, of thin transparent glaze overlying parietal region. Siphonal notch absent. Canal weakly differentiated from aperture, recurved abaxially. Shell colour off-white. Periostracum transparent, yellowish, peeling (absent on most part of holotype).
Measurements (holotype, largest specimen): SL 9.0 mm, LWL 4.8 mm, AL (with canal) 3.7 mm, SW 3.0 mm.
Distribution. New Zealand, off North Island, shells in 282- 990 m.
Etymology. Aotearoa is the New Zealand name for Maori language. It is used as noun in apposition.
Remarks. There is little variation in the material examined. Hortia aotearoa resembles H. paradrillia, from New Caledonia, and differs in having a broader shell with shorter canal and more closely spaced spiral keels.