Arinia zangke Xiang, He, Lu & Chen, 2025

Xiang, Hong Quan, Lu, Yi Zhi, He, Yue Ming & Chen, Hui, 2025, Two new species of land snails (Mollusca: Gastropoda) from China, Ecologica Montenegrina 88, pp. 215-221 : 217-221

Arinia zangke Xiang, He, Lu & Chen , sp. nov.

https://zoobank.org/ urn:lsid:zoobank.org:act:62BE5BE2-8D9C-4909-88C3-F4C1202EAD27

Fig. 2 A–K

Material examined. Holotype: NCUXLB 25040201, shell height 4.0 mm ( Fig. 2 A–B ). Guiding County [OiOE县], Qiannan Buyi and Miao Autonomous Prefecture [ Ŕ 南布IJdzaedzh治州], Guizhou Province, China, 26.63°N, 107.22°E, April 2025, collected by Xiao-Bo Qian.

Paratypes: 2 specimens, NCUXLB 25040202, 03, shell height 4.2–4.5 mm ( Fig. 2 C–I ), April 2025, locality and habitat same as holotype.

Diagnosis. Shell small, ovoid, apex domed. Shell color white. Spiny projections of the ribs high, slender, trough-shaped, folded almost horizontally, ribs above the aperture abruptly becoming very low and very closely spaced. Peristome double, the inner peristome, slightly protruding, the outer peristome is strongly expanded, but not reflected.

Description. Shell small, ovoid, apex domed, last whorl widest when removing the expanded ribs and peristomes. Shell color white. Whorls 6–6.5, slightly convex. Last 1/8 whorls (including interspace between the outer and inner peristomes) expanded upward and ascending onto the penultimate whorl in right lateral view. Last whorl distinctly keeled at the base, reinforced by spiny ribs. Suture impressed. Protoconch consisting of 1.5 whorls, glossy, almost smooth. Axial ribs developed on the teleoconch, strongly developed as spines on most whorls; ribs on the whorls (except above the aperture) highly protruded, ribs on first 1/4 whorls of the teleoconch low, closely spaced, folded at the periphery as little spines; ribs on the subsequent whorls (except above the aperture) highly protruded and strongly folded at the periphery as spines, widely spaced (3 ribs per mm), not synchronized with those on the previous whorls; upper margin of the ribs above the spiny projection (between the suture and spines) distinct, prominently protruded (particularly below the suture on upper whorls); spiny projections of the ribs high, trough-shaped, folded almost horizontally, slightly wider, arising at some distance below the suture (arising near periphery of a whorl), ribs above the aperture (ribs on the last 1+1/8 to last 3/4 whorls around the constriction) abruptly becoming very low and very closely spaced, without spiny projections, becoming less folded at the periphery, slightly elevated just below the suture. Aperture oval. Peristome double, the inner peristome, slightly protruding, not sharp, the outer peristome is strongly expanded, but not reflected; upper insertion of the peristome distinctly ascending towards aperture; aperture without columellar lamella, a short columellar lamella from ventrolateral right inside the last whorl ( Fig. 2J ); with a short parietal lamella from lateral right to ventrolateral right inside the last whorl ( Fig. 2K ). Umbilicus closed in adult. Operculum unknown.

Differential diagnosis. This species can be easily distinguished from all species of the genus by the features of a domed apex and a shell surface with developed, thin, and sharp single-humped ribs. Additionally, it can be differentiated from species of the genus Sinoarinia due to the absence of the characteristic strongly ascending last whorl, which partially covers the penultimate whorl.

Etymology. The species name "zangke " comes from an ancient term used in Guizhou. We suggest the Chinese common name as "牂牁DDZDz".

Distribution and ecology. The species lives on slopes with dense forests in the region and prefers to concentrate near stones under the fallen leaves in the forest ( Fig. 3 A–C ).

Discussion

The genus Arinia H. Adams & A. Adams, 1856 is a widely distributed across Southeast Asia ( Zilch 1953; Vermeulen 1996; Vermeulen et al. 2007; Páll-Gergely and Hunyadi 2018). In previous studies, some scholars assigned certain China and Vietnam species to the genus Sinoarinia Chen & Wu, 2020 , which shares similarities with Arinia ( Chen and Wu 2020) . However, based on morphological comparisons, the new species described herein belong to the Arinia genus. As for Sinoennea fengshiyangi sp. nov., it may represent the longest recorded Sinoennea species in China and occupies a unique habitat. It has only been found in the dry, hot river valley of Yuanjiang County. This species exhibits a distinctive microhabitat preference, inhabiting roots systems of cacti along valley slopes. Notably, the researchers in this study do not consider these cacti to be native (at least most are nonnative), as cactus cultivation fields occur nearby, where locals plant and harvest species such as dragon fruit for sale. Some cacti in the valley were likely dispersed by birds feeding on fruits from surrounding areas. Historically, the valley supported scattered native shrublands, and prior to the arrival of cacti, these snails probably depended primarily on these shrubs for survival. After cacti became established, their superior water retention capacity made them favorable microhabitats, prompting the snails to colonize them. The discovery of these two new species contributes to a better understanding of the biodiversity in the Yunnan-Guizhou Plateau region.

Acknowledgments

We sincerely thank the editor, Dr. Vladimir Pešić, for his guidance throughout the review process, and Dr. Barna Páll-Gergely for their constructive feedback, which significantly improved the quality of this manuscript.

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Figures

Figure 2. (A, B) holotype, Arinia zangke sp. nov. (C–I) paratype, Scale bars = 1 mm. (J) columellar lamella. (K) parietal lamella.

Figure 3. (A) Type locality of Arinia zangke sp. nov. (B, C) Living specimens of Arinia zangke sp. nov. on the fallen leaves. (D) Type locality of Sinoennea fengshiyangi sp. nov.