Sinployea fiordlandica 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 fiordlandica Climo, Mahlfeld & Roscoe sp. nov.

( Figs 16, 33B, 35, 45) Sinployea ‘fiordlandica’ McGuinness 2001: 594; Hitchmough 2002: 130.

Charopidae sp. 29 (NMNZ M.081649) Hitchmough et al. 2007: 60; Spencer et al. 2009: 216; Mahlfeld et al. 2012: appendix 1.

Material examined: New Zealand, South Island , Fiordland, NMNZ: M.081649, holotype ( Figs 33B, 35), Doubtful

Sound , Mount Troup Ridge, 900 m a.s.l., 45°28′27.702″S, 167°08′01.132″E, P.C. Mayhill, February 1985 .

Other material examined: New Zealand, South Island , Fiordland , NMNZ: M.085028, WSW of Manapouri , Centre Pass, Dusky Track, 1100 m a.s.l., 45°36′00.744″S, 167°08′33.399″E, P.C. Mayhill, February 1986 .

Description: Shell small, thin, and fragile, 2.1 mm wide and 950 μm high at three whorls, moderately finely ribbed, moderately tightly coiled, narrowly umbilicate and low spired. Shell coloured dorsally with brown flammulations covering most of the shell, base chiefly lighter coloured. Spire flat; protoconch of 1.25 convex whorls, translucent, 581 μm wide; sculpture consisting of seven to eight thin, crisp, widely spaced spiral lirae. Teleoconch of ~1.75 moderately rapidly expanding, convex whorls (aperture broken); 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 very fine periostracal lamella, often worn off (102 axials on first teleoconch whorl). Umbilicus 503 μm wide (D/U ratio 4.17); spirals prominent around umbilical

46 • Mahlfeld et al.

well. Suture deep. Aperture lunate; columella short, oblique, and reflected; lip simple.

Reproductive anatomy: Unknown.

Etymology: After Fiordland, southwestern South Island.

Distribution: South Island, Fiordland, Dusky and Doubtful Sounds.

Ecology: Temperate montane beech ( Nothofagus Blume ) forest to subalpine shrublands?

Related species: The combination of finely ribbed shell, broad brown flammulations, a light-coloured shell base, a moderately open umbilicus, and a large protoconch distinguishes this from other NZ Sinployea species. Sinployea waipoua has similar fine ribbing and colour pattern to S. fiordlandica , but a smaller protoconch. Both species are closest in shell morphology to each other. Sinployea australis is not as finely ribbed and has unicoloured pale buff shells.

Conservation status: Only one sample was taken from Mount Troup in 1985, and since then no further survey has taken place in the area. Twenty-one samples are known from the Doubtful

Sound area , and two samples were taken from Centre Pass ,

Dusky Sound in 1986 and 1996. The collection sites are 15 km apart. Another 34 collection events have taken place in the Dusky Sound area based on Te Papa molluscs collection data. The high number of other collection events from Fiordland, Otago, and Southland ( Fig. 2) indicate that S. fiordlandica is a Fiordland endemic. The species was ranked in the 2010 NZTCS assessment as ‘At Risk: Naturally Uncommon’, with the qualifiers ‘Data Poor’ and ‘Biologically Sparse’ ( Mahlfeld et al. 2012). We recommend continuing with this threat ranking and adjusting the qualifiers to the new subcategories of ‘Data Poor: Size and Trend’ .