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

( Figs 4, 11, 16, 27C, 31, 32, 44)

‘Korukoura meadsi’ McGuinness 2001: 604; Hitchmough 2002:125.

Charopidae sp. 34 (NMNZ M.151454) Hitchmough et al. 2007: 85; Spencer et al. 2009: 216; Mahlfeld et al. 2012: appendix 1.

Material examined: New Zealand, North Island, Hawke’s Bay, W of Cape Kidnappers, ‘ Cape Sanctuary’ : MA73638 , holotype ( Fig. 31), 39°40′09.181″S, 177°02′27.397″E, K. Mahlfeld and T. Quinnell, 16 July 2020 ; MA73639 and NMNZ M.151454, paratypes, grasses in Knightia excelsior R.BR. grove, 39°39′35.080″S, 177°02′59.372″E, M.J. Meads, 11 July 1983 .

Other material examined: Known only from type material.

Description: Shell small, depressed subglobose, thin, and fragile, 1.87 mm wide and 937 μm high at three whorls, sparsely ribbed, loosely coiled with a silky sheen. Shell colour translucent off-white; spire flat and umbilicus narrow, about one-quarter of the maximal shell diameter (D/U ratio 5.35). Protoconch of nearly 1.5 convex whorls, 536 μm wide, sculptured with five to six widely spaced, thin, low spiral cords. Teleoconch of 1.5 rapidly expanding, convex whorls with a round base. Sculpture consisting of widely spaced, prominent primary axials traversed by fine spiral lirae; spirals approximately twice the width of secondary costae and forming microscopic beads at intersections with them, ~15 costellae per interstitial space. Each primary axial is crested with a long, filmy periostracal lamella that is slightly more extended outwards along the section of the axials of the whorl periphery. Suture deep. Aperture oblique, rotundly lunate, lip simple. Short columella reflected.

Reproductive anatomy: Ovotestis bilobed; lobes consisting of smaller lobules. Hermaphroditic duct swollen basally; prostate about twice as long as albumen gland; uterus about half as long as prostate; free oviduct terminates in a papilla-like structure at lower end of female genital tract. Vagina a simple tube of less than half the length of the free oviduct. Spermatheca obovate, on a slim, long stalk that is only slightly swollen at base. Vas deferens entering penis apically near the retractor muscle. Apical phallic lumen containing a free-hanging epiphallic papilla; lumen otherwise simple and devoid of pilasters. An appendage enters lumen immediately below epiphallic papilla; this blind duct is nearly as large as the upper part of the penis. Top half of the glandular structure tapering rapidly into a narrow papilla, which terminates about the midpoint of the entire appendage. Flagellum entering male lumen through a simple pore.

Etymology: Named after the Cape Sanctuary at Cape Kidnappers.

Distribution: Hawke’s Bay, ‘Cape Sanctuary’ reserve near Cape Kidnappers.

Ecology: Possibly rewarewa ( Knightia excelsior ) and kanuka ( Kunzea ericoides R.Br. ) forest litter and in moss.

Related species: The combination of emergent bulbous apex, compact squarish shell architecture, light brown to off-white shell colour, and a coarsely ribbed teleoconch with prominent axials, each crested by a filmy but conspicuous lamella, distinguishes this species from any of the other Sinployea species. The entrances of the glandular penial appendages are different in

Sinployea systematics and biogeography • 41 Calymna costulata and S. capensis ; in the former there is a recess, and in the latter there is a papilla as in S. accelerata ( Fig. 4). A juvenile shell from Motu River (NMNZ M.195396) is potentially another new, closely related species. The teleoconch spirals are much more widely spaced.

Conservation status: During a field trip in July 2020, we collected a total of 17 samples close to the site where we collected S. capensis , including sites with different microhabitats and forest canopy tree species. Only two samples, one from moss, under a kanuka canopy above a rewarewa patch, and one in kanuka litter a few metres from the other site, both at ~ 140 m a.s.l., produced specimens of this rare species. Sample sizes ranged from 2.5 to 5 L of leaf litter. Taking the entire area of the Cape Sanctuary reserve as an approximation of area of occupancy could lead to an overestimation of the real distribution of S. capensis . Three hundred and fifty-four samples made within a distance of 80 km from Cape Kidnappers, which represents collecting for the last 100 years, with the bulk of the sampling done within the last 50 years ( Fig. 32), produced S. capensis except for the 1983 records. This information suggests that S. capensis is probably a local endemic restricted to the Cape Sanctuary. In order to determine its range within the Sanctuary, much more collecting is required from different habitat types and at different seasons. The Cape Sanctuary has a predator-proof fence, and pest control there is intensive, hence the habitat of this rare snail species is relatively secure. We recommend continuing to rank this species as ‘Threatened: Nationally Critical’, with the qualifier ‘Data Poor: Size and Trend’ and ‘Biologically Sparse’.

Southern, tightly coiled species of Sinployea

This group includes Sinployea maitai , Sinployea canaliculata , Sinployea charopiformis , Sinployea cresswelli , Sinployea australis , and Sinployea fiordlandica .