Sinployea solemi Climo, Mahlfeld & Roscoe, 2025

Mahlfeld, Karin, Climo, Frank & Roscoe, David, 2025, Systematics, conservation status, and biogeography of 16 new species of Sinployea Solem, 1983 (Gastropoda: Charopidae) from New Zealand, Zoological Journal of the Linnean Society 204 (1) : -

Sinployea solemi Climo, Mahlfeld & Roscoe sp. nov.

( Figs 16, 19A, 20, 44) Sinployea ‘paucilamellata’ McGuinness 2001: 595; Brook 2002: 92.

Charopidae sp. 27 (NMNZ M.058110) Hitchmough et al. 2007: 41; Spencer et al. 2009: 216; Mahlfeld et al. 2012: appendix 1.

Material examined: New Zealand, North Island , Northland, SE of Cape Reinga: MA152583 , holotype ( Fig. 20), Pandora Road, 34°27′27.6″S, 172°46′12.3″E, J.F. Goulstone, 11 May 1991 ; NMNZ M.115995, paratypes, at entrance to Tapotupotu Bay Road, 34°26′30.49″S, 172°42′04.6″E, P.R. Jamieson, 2 January 1975 .

Other material examined: New Zealand, North Island, Northland, NMNZ:M.058110, SE of Cape Reinga, at entrance to Tapotupotu Bay Road, 34°26′30.49″S, 172°42′04.6″E, P.R. Jamieson, 2 January 1975 ; M.058119 (badly damaged shell), NNE of Whangarei, W of Ngunguru, Hugh Crawford Reserve , 60 m a.s.l., 35°37′54″S, 174°28′10″E, P.C. Mayhill, September 1978 ; M.115991 (badly damaged shell), Great Barrier Island , 36°06′07.495″S, 175°24′41.358″E, D. Hunt, January 1987 ; MA: MA96903 , Unuwhao, Waihi Stream , 34°25′31.8″S, 172°53′5.6″E, J.F. Goulstone, 10 May 1991 ; MA96904 , Spirits Bay, Waterfall Gully , 34°25′53″S, 172°52′9″E, J.F. Goulstone, 10 May 1991 ; Kapowairua , at edge of swamp under ferns and manuka [ Leptospermum ], 34°25′54.303″S, 172°51′52.091″E, K. Mahlfeld, 25 March 2018 , 21 m a.s.l. (Open Lab collection).

Description: Shell small, thin, and fragile, 1.5 mm wide and 860 μm high at 2.5 whorls, medium-coarsely ribbed, loosely coiled, very narrowly umbilicate and low spired (spire ~100 μm high). Colour pattern of wider to narrow brown axial colour bands, forming zigzags along shell periphery, and merging to form a brown shell base. Protoconch of 1.25 convex whorls, translucent, 475 μm wide, sculptured with five to six thin, crisp, widely spaced spiral lirae. Teleoconch of 1.375 rapidly expanding, convex whorls; base a little flattened. Sculpture consisting of moderately widely spaced, sharp primary axials, ~50 on first teleoconch whorl. Axials traversed by fine spiral lirae; spirals approximately one-third of the width of primary axials and forming microscopic beads at intersections with secondary axials, ~6–10 axials per interspace. Primary axials crested with a very fine periostracal lamella, often worn off. Umbilicus very narrow, 268 μm wide (Diameter/Umbilicus ratio 5.6); partly covered by reflected columellar lip. Aperture obliquely ellipsoid, slightly flattened dorsally and ventrally, 760 μm high; lip simple. Suture moderately deep for NZ Sinployea .

Reproductive anatomy: Unknown.

Etymology: Named after Alan Solem for his work on Pacific snails.

Notes: Teleoconch ribbing ranges from very coarse in the west of the distributional range (Tapotupotu and Pandora) to moderately fine (Kapowairua and Unuwhao) in the east, northernmost NZ. Similar patterns of W–E shell variation from Cape Reinga to North Cape, occur in Phrixgnathus sciadium ( Pfeiffer, 1857) , Delos Hutton, 1904 , Allodiscus , and Climocella .

One specimen collected from Kapowairua resembles S. solemi but has more protoconch spirals, is coarsely ribbed on the teleoconch, and has a wider umbilicus than other specimens of S. solemi from nearby. This particular shell is also repaired in two places on the teleoconch. The shell is difficult to place but could be part of the variation within S. solemi . The shells from Ngunguru, NE of Whangarei, and Great Barrier Island, Hauraki Gulf, are badly damaged but could be conspecific with S. solemi . More observations are needed to gauge shell variation in this species.

Distribution: New Zealand, Northland, Te Paki, and Cape Reinga area. Specimens known from Ngunguru and Matawaia, NW of Whangarei in Northland, Great Barrier Island in Hauraki Gulf, and Ohinau Island off E Coromandel Peninsula are potentially conspecific.

Ecology: Subtropical coastal mixed broadleaf forest.

Related species: The combination of coarsely ribbed shell with brown narrow zigzag axial bands, brown base, very narrow umbilicus, and smaller protoconch distinguishes this species from other colour-patterned North Island species. Sinployea waipoua and S. capensis shells also have smaller protoconchs, but shells of the former are chiefly brown with few narrow light flashes, and in the latter they are uniformly pale buff. The remainder of northern North Island species, S. mangamuka , S. imperforata , and S. karangahake , have larger protoconchs and different shell architectures.

Conservation status: A rank of ‘Data Deficient’, qualifiers ‘Data Poor: Recognition, Trend, and Size’, is proposed here because of the variations in teleoconch ribbing and the species being potentially more widespread in coastal areas of eastern Northland. The proposed ranking changes the umbrella category from ‘Threatened’ to ‘Insufficient Information’.