Sinployea waipoua Climo, Mahlfeld & Roscoe sp. nov.

(Figs 16, 23A, 24, 44) Sinployea ‘Waipoua’ McGuinness 2001: 595; Brook 2002: 93.

Charopidae sp. 28 (NMNZ M.098308) Hitchmough et al. 2007:128; Spencer et al. 2009: 216; Mahlfeld et al. 2012: appendix 1.

Material examined: New Zealand, North Island, Northland, NMNZ: M.098308, holotype (Figs 23A, 24), NW of Dargaville, Waipoua Forest, Kawerua Road, 35°37′15.289″S, 173°28′41.060″E, P.C. Mayhill, November 1986.

Other material examined: New Zealand, North Island, Northland: halfway between Waipoua and Whangarei, S of Parakao, Ruahuia Viaduct, 35°44′22.693″S, 173° 57′23.942″E, I.J. Payton, 31 December 1970, forest litter (Payton collection); Tutamoe, Pupurangi Sanctuary, K. Mahlfeld and D.J. Roscoe, 26 September 2015, old growth forest, 596 m a.s.l. (Open Lab collection); Waipoua Forest, just N of Waipoua River bridge, K. Mahlfeld and D.J. Roscoe, 2 October 2015, under treefern and nikau [Rhopalostylis sapida] fronds, below road on bank above river, 114 m a.s.l. (near type locality; Open Lab collection).

Description: Shell small, thin, and fragile, ~ 2 mm wide (aperture partly broken) and ~ 1 mm high at three whorls, moderately finely ribbed, loosely coiled, narrowly umbilicate, and low spired. Shell of translucent pale buff background with brown flammulations covering most of the shell including base. Spire broadly convex. Protoconch of 1.125 convex whorls, translucent, 465 μm wide; sculpture consisting of six thin, crisp, widely spaced spiral lirae. Teleoconch of ~1.625 moderately rapidly expanding, convex whorls, slightly flattened ab- and adapically. Sculpture consisting of numerous calcareous, thin, primary axials traversed by fine spiral lirae; spirals approximately one-third of the width of primary axials and forming microscopic beads at intersections with even finer secondary axials, about five axials per interspace. Primary axials crested with a very fine periostracal lamella, often worn off (85 axials on first teleoconch whorl). Umbilicus 408 μm wide (D/U ratio of ~4.9); spirals prominent around umbilical well. Suture moderately deep. Aperture obliquely oval; columella short and a little curved and reflected, partly covering umbilicus; lip simple.

Reproductive anatomy: Unknown.

Etymology: After Waipoua Forest and in appreciation of Te Roroa iwi members for their kaitiakitanga and manākitanga (K.M. and D.J.R. were guided by Dawn Birch and Laurie Joseph around Maunganui Bluff and parts of Waipoua Forest).

Distribution: New Zealand, North Island, Northland, Waipoua, and Tutamoe.

Ecology: Habitat information is available for the Tutamoe locality, where the species was found in mixed broadleaf/podocarp old growth forest litter at 596 m a.s.l. and near the type locality, where the species was found in leaf litter from under treeferns and nikau palms (Rhopalostylis sapida).

Related species: The combination of finely ribbed and chiefly brown shell with a small protoconch distinguishes this species from S. solemi, which has more coarsely ribbed shells with a dorsal colour pattern of brown zigzag bands. Sinployea kaipara has a colour pattern of broad brown maculations rather than zigzag bands, has a slightly wider umbilicus, and is a little more tightly coiled. Sinployea fiordlandica has similar ribbing and colour pattern to S. waipoua but is flatter and has a deeper suture and is more tightly coiled.

Conservation status: In>70 samples in Te Papa collections from Waipoua Forest, S. waipoua was found only once. Two more records were found in private collections from near Parakao and Tutamoe. As shown in Figures 2 and 16, it is likely that S. waipoua is a Waipoua–Tutamoe endemic, allopatric with the other Northland Sinployea species. Previous assessment had this species ranked as ‘Data Deficient’, with the qualifier ‘one locality’ (OL). A change in ranking to ‘Naturally Uncommon’, with the qualifiers ‘Data Poor: Size and Trend’ and ‘Biologically Sparse’ is suggested here.