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25 April 2023 A new species of Anauchen Pilsbry, 1917 from Guangxi, China (Gastropoda: Stylommatophora: Hypselostomatidae)
Zhe-Yu Chen
Author Affiliations +
Abstract

Anauchen whitteni sp. nov. is described and illustrated based on specimens collected in Guangxi Zhuang Autonomous Region, southwestern China. The new species is diagnosed by havinh four apertural barriers and a rounded body whorl.

INTRODUCTION

Anauchen Pilsbry, 1917 is a group of small pulmonate snails with more than ten species distributed in China, Vietnam, Thailand, and Cambodia (Bavay & Dautzenberg, 1904; Yen, 1939; Panha & Burch, 2005; Burch & Panha, 2002; Vermeulen et al., 2007, 2019). This genus differs from other hypselostomatids by lacking an angular lamella and bearing only a simple lamella on the parietal side (Pilsbry, 1917; Panha & Burch, 2005).

In the present paper, a new species of Anauchen is described from Guangxi and distinguished from its congeners. The type material derives from the yields of two recent field trips conducted by R.-X. Lin, Z.-A. Shi and the author.

MATERIAL AND METHODS

Small brushes with warm water and alcohol were used to remove the dirt on the surface of the shells. Shells were photographed using a Canon® 5D Mark IV camera attached with a Laowa® 25mm f/2.8 2.5-5X Ultra Macro lens. The final high DoF (depth of field) images were stacked from 30 to 50 single photos using Zerene Stacker® 1.04. The shells were measured with digital vernier calipers to the nearest 0.01 mm. Morphological terminology followed Pilsbry (1917) and Vermeulen et al. (2019).

Type specimens deposited in mollusc collection of the Museum of Hebei University (HBUMM, Baoding, China) and author's private collection (CZY, Wuhan, China). Specimens of Anauchen angulinus (Gredler, 1885) (CZY/13, Mawei Town [麻尾镇], Dushan County [独山县], Guizhou Province, 09-APR-2019, leg. Lu Qiu; CZY/3, Small Three Gorges scenic spot [小三峡景区], Hechi City [河池市], Guangxi Zhuang Autonomous Region, 15-JUN-2020, leg. Ran-Xi Lin) were used for comparison.

TAXONOMY

Family Hypselostomatidae Zilch, 1959 Anauchen Pilsbry, 1917

  • Anauchen Pilsbry, 1917 (1916-1917): 188.

  • Anauchen Schileyko, 1998: 139, fig. 158.

  • Type species: Boysidia gereti Bavay & Dautzenberg, 1904, by original designation.

  • Remarks: Anauchen angulinus (Gredler, 1885) is the only species of this genus previously recorded from China (Gredler, 1885, 1887a, b; Yen, 1939). Specimens from Guizhou and Guangxi show variability: individuals with three teeth (parietal and columellar lamellae, lower plica) occur mixed with individuals with a single tooth (parietal lamella) in same localities. Therefore, it is possible that the former is a variant or immature form of Anauchen gereti (Bavay & Dautzenberg, 1904). Boysidia pentadens Chen, Wu & Zhang, 1999 previously recorded from Yunnan, should be assigned within the genus Anauchen, based on original description and subsequent illustrations (Chen et al., 1999; Qian & Zhou, 2014; Chen et al., 2016). However, this species is similar to Anauchen messageri (Bavay & Dautzenberg, 1904) in general shape and dentition.

  • Fig. 1.

    Shell of Anauchen whitteni sp. nov. (holotype).

    img-z2-6_89.jpg

    Fig 2.

    Microstructure of Anauchen whitteni sp. nov. (A) Protoconch. (B) Surface of the body whorl.

    img-z2-8_89.jpg

    Anauchen whitteni sp. nov. Figs 1, 2

  • Type material: Holotype; HBUMM; empty shell; CHINA, “Collected from the rocks, Mt. Nanshe [南蛇山], Yizhou District [宜州区], Hechi City [河池市], Guangxi Zhuang Autonomous Region, China. 24°30′22″N, 108°38′51″E, 270 m, 2022-VII-18, leg. Ran-Xi Lin & Zi-Ang Shi”. – Paratypes; HBUMM/2; two empty shells; same collection data as of holotype. – Paratypes; CZY/2; two worn empty shells; “Collected from the rocks, Mt. Laoren [老人山], Diecai District [叠彩区], Guilin City [桂林市], Guangxi Zhuang Autonomous Region, China. 25°17′33″N, 110°17′16″E, 240 m 2022-III-14, leg. Zhe-Yu Chen”.

  • Cross diagnosis: The lack of a basal plica allows Anauchen whitteni sp. nov. to be easily distinguished from most Anauchen species. Anauchen chatnareeae Panha & Burch, 2003 and Anauchen srakeoensis Panha & Burch, 2004 have the similar dentition like the new species, however, their developed keels or free last whorl cannot be found in the new species. The new species resembles Anauchen angulinus and Anauchen gereti in general shape, but can be distinguished from the latter by its darker color and the presence of two palatal plicae.

  • Etymology: This name is dedicated to late Dr Tony Whitten, a famous biological conservationist in East and Southeast Asia who provided crucial support for karst biodiversity study.

  • Description: Shell very small, thin, elongate-conical, light yellowish-brown, marbled with occasional whitish growth-lines, ca. 5.25 - 5.5 whorls. Surface with extremely fine grid-like sculpture. Protoconch with 1.25 whorls, somewhat dull and waxy matte, with very fine and well-spaced spiral threads. Upper whorls slowly increasing, each of nearly similar height. Body whorl approximately twice as high as penultimate whorl. Both whorls convex, ventral side of the body whorl flatter than dorsal side. Suture deeply impressed. Entire surface with very fine, not completely continuous, regular, and increasingly spaced spiral threads. Teleoconch with some scattered, unevenly spaced, flat growth lines. Aperture circular to somewhat elliptic, significantly downward sloping. Peristome attached to the body whorl, parietal side not reflected, other part strongly expanded. Four apertural barriers present. Parietal lamella fin-shaped, white, distinct, and elevated, with a rounded profile, steeper on the inside. Upper palatal plica small, ridge-shaped, somewhat oblique. Lower palatal plica longer and higher, rounded or nearly triangular. Columellar lamella small, short, similar to the upper palatal plica. Umbilicus open, relatively narrow, with penultimate whorl visible inside.

  • Measurements (holotype): Shell height: 3.41 mm; shell width: 2.87 mm; shell diameter (top view; excluding the dilated peristome): 2.64 mm; umbilicus width: 0.68 mm.

  • Distribution: China (North Guangxi).

  • Remarks: The new species is a rock dweller, as it has been recorded for its relatives (Tongkerd et al., 2004; Vermeulen et al., 2019). Compared to other species described in the recent decades, Anauchen whitteni sp. nov. is closest to the genus diagnosis defined by Pilsbry (1917), namely, those species with a horny or white shell, absence of an angular lamella, peristome attached to the body whorl and a rounded, rather than keeled body whorl.

  • ACKNOWLEDGEMENTS

    Thanks go to Ran-Xi Lin and Lu Qiu for sharing the materials, to Adrienne Jochum, Barna Páll-Gergely and Jaap J. Vermeulen for valuable comments on the manuscript. This study was partially supported by the Tony Whitten Conservation Award 2021.

    This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited (see  https://creativecommons.org/licenses/by/4.0/).

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    Zhe-Yu Chen "A new species of Anauchen Pilsbry, 1917 from Guangxi, China (Gastropoda: Stylommatophora: Hypselostomatidae)," Revue suisse de Zoologie 130(1), 89-92, (25 April 2023). https://doi.org/10.35929/RSZ.0090
    Accepted: 2 November 2022; Published: 25 April 2023
    KEYWORDS
    Anauchen
    Asia
    land snail
    new species
    taxonomy
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