Cycloryx Godwin-Austen, 1914

Aravind, Neelavar Ananthram & Páll-Gergely, Barna, 2023, Two Extraordinary Alycaeid Species From Northeastern India (Gastropoda: Caenogastropoda: Cyclophoroidea), Acta Zoologica Academiae Scientiarum Hungaricae 69 (4), pp. 353-363 : 354-356

Genus Cycloryx Godwin-Austen, 1914

Type species: Cyclostoma constrictum BENSON, 1851 , by original designation.

Remarks: The genera Pincerna (type species: Alycaeus liratula Preston, 1907 ) and Cycloryx Godwin-Austen, 1914 have been synonymized because of their similar conchological traits, such as the ovately conoid shells shape, the regular ribbing on the upper whorls and the short sutural tube (PÁLL-GERGELY 2017), and this classification was followed in the genus-level revision of the Alycaeidae ( PÁLL-GERGELY et al. 2020) . Later, GITTENBERGER et al. (2022) treated the Bhutanese species as Cycloryx based on our unpublished molecular data. The Chinese, Lao, and Vietnamese species are maintained as Pincerna until molecular data become available ( PÁLL-GERGELY 2023), but the Himalayan species certainly belong to Cycloryx .

Cycloryx cf. pemaledai Gittenberger et Sherub, 2022

( Fig. 1 )

Cycloryx pemaledai Gittenberger et Sherub in GITTENBERGER et al., 2022: 76, figs 2, 9.

Material examined: India, North Sikkim, 2 km north of Lachen , towards Gurudongmar Lake , 27.74487°N, 88.54439°E, altitude 2749 m a.s.l., leg. Aravind N.A., 27 November 2019, locality code: “SOIL-75 Sikkim (AR)” (2 shells, ATREE/2019 /LS6001, ATREE/2019 /LS6002) .

Description of the Indian shells: Shell conical ovoid, yellowish-ochre, whorls 3.75–4, bulging, separated by a deep suture; protoconch consisting of ca. 1.5 whorls, finely granu- late, with some faint spiral striae in Specimen2; R1 consisting of 2.1–2.25 whorls, finely, regularly ribbed, ribs thread-like, there are ca. 32 ribs on last half whorl of R1, rib density rather uniform on entire R1; area between ribs with extremely fine spiral striation except for the terminal ca. quarter whorl of R1, where spiral striae are replaced by a granular surface; R2 nearly smooth, with 10–14 breathing tunnels, spiral striation re-appears on R 2 in Specimen1, but not in Specimen2; tube short, relatively thick; breathing tunnels are more closely spaced than ribs at the end of R1; transition between R1 and R2 visible due to change in rib morphology, and the slight change in rib density, but inconspicuous; transition between R2 and R3 indicated by a shallow constriction; R2 and R3 less than quarter whorl together, R2 slightly longer than R3; R3 shorter than that of any other Cycloryx species, with 4–5 thread-like ribs, R3 ribs similar in morphology to R1ribs, near the suture curved backwards; spiral striation nearly (but not entirely) absent on R3, there are some additional microscopic radial lines between the R3 ribs; aperture only slightly oblique to shell axis in lateral view, rounded; peristome very thin, inner peristome slightly expanded, outer peristome only visible as a reflected lobe above umbilicus; umbilicus open, rounded, very narrow, partly covered by lobe-like reflected outer peristome, but above and below the lobe is a narrow slit which makes umbilicus visible.

Measurements: H = 3.3–3.6 mm, D = 2.7–3 mm.

Operculum and anatomy: Unknown.

Differential diagnosis: Differs from all congeners by the shorter R3. Simi- larly high-spired species ( C. elegans , C. khungoensis , C. constrictus , C. costatus ) are smaller, and the only one which is similar in size ( C. tenellus ) is known from the Shan Hills and has different sculpture (initial whorls smooth, end of R1 with widely-spaced ribs).

Distribution and ecology: This species was described from northeastern Bhutan, and its current record from Sikkim is the first record for India. The dis- tance between the two known localities is approximately 115 km in a straight line. The snails in India were collected from the soil and leaf litter samples from the slopes with lots of moss, dry litter and shrubs. The habitat is covered with Rhododendron shrubs along the slopes, at an altitude of ca. 2750 m a.s.l.

Remarks: Our specimens from Sikkim largely match with typical Cycloryx pemaledai described from northeastern Bhutan in terms of general shell shape (including the characteristically short R3 for this species) and rib density. However, based on the photos in the original description, the Indian shells are slightly wider with more rounded whorls. Nevertheless, we do not inter- pret these differences as sufficient for species-level distinction.

Figures

Fig. 1. Cycloryx cf. pemaledai Gittenberger et Sherub, 2022 from Sikkim, India (Specimen1). (Photos: B. Páll-Gergely)