Laeocathaica cheni Wu, 2023

Wu, Min, Shen, Wang & Chen, Zhong-Guang, 2023, Land snail diversity in central China: revision of Laeocathaica Moellendorff, 1899 (Gastropoda, Camaenidae), with descriptions of seven new species, ZooKeys 1154, pp. 49-147 : 49

Laeocathaica cheni Wu sp. nov.

Figs 2A, B , 37B , 39 , 44F-H , 46K, L , 49F , 51

Type material.

Holotype HBUMM05553b-spec.1, fma, dissected; Hengdan, Wenxian, Gansu Province; north side of Baishuijiang River, along 212 Guodao, near point (32.864025°N, 104.859517°E); hillside, bushes; 2006-IX-29; coll. Wu, M., Liu, J.-M., Zheng, W. and Gao, L.-H. Paratypes HBUMM05553b-spec. 2-7, 8 fma, 1 dissected (anatomy no. sp3); same data as holotype. HBUMM05576a- spec. 1-2, 2 fms, South bank of Baishuijiang River, Hengdan, Wenxian, Gansu Province; near point (32.863381°N, 104.854879°E); hilltop, bushes; 2006-IX-29; coll. Wu, M., Liu, J.-M., Zheng, W. and Gao, L.-H. HBUMM08420, 1 fma with fully mature shell but immature genitalia, dissected, a slope near X496 (32.969442°N, 104.654191°E), Wenxian, Gansu Province; 2019-X-13; coll. Li, Q.-M.; DNA voucher HBUMM08420a. HBUMM08428, 3 fma (1 dissected) and 1 juv, same data as HBUMM08420; DNA voucher HBUMM08428a. HBUMM08368, 2 fma and 3 juvs, not dissected; Gansu Province; 2019; coll. Li, Q.-S.; DNA voucher HBUMM08368a.

Measurement of holotype.

Shell height 9.0 mm, maximum diameter 19.3 mm, aperture height 5.6 mm, aperture breadth 7.3 mm, umbilicus diameter 7.1 mm, protoconch whorls 15/8, whorls 91/8.

Diagnosis.

Protoconch with elongated granules. Umbilicus suddenly narrowed from penultimate whorl, more than 1/3 maximum diameter, through which protoconch is visible. Beneath carina a chestnut band present. Mucous glands four. Proximal 1/2 of penis with ~ 5 thin internal pilasters, two of them fusing into a Y-shaped fork at middle part. Distal region of penis with tongue-shaped papillae. Vagina between atrium and dart sac not elongated. Proximal accessory sacs two, symmetrical, each with a pore leading to dart chamber.

Description of shell.

Sinistral, depressed, somewhat solid. Shell with 9-95/8 fairly flat whorls. Suture impressed. Protoconch 11/2-15/8 whorls, with fine granules (each ~ 20 µm long) almost invisible because of weathering or erosion. Growth lines thick or rib-like above but fine below carina. Above periphery a whitish carina present. Aperture oblique, peach-shaped, descending. On ring-like thickening within aperture, a very blunt tooth present near columella. Peristome almost not expanded, just minutely reflexed at lower part. Columella oblique. Umbilicus brownish, more than 1/3 of maximum diameter, suddenly narrowed from penultimate whorl. Protoconch visible through umbilicus. Whorls apically yellowish brown with intermittent darker brown patches. In umbilical view shell yellowish white with several brownish patches, and just beneath carina a thick chestnut band present.

General anatomy.

Eversible head wart weakly present. At mantle edge leaf-shaped appendage absent. On internal body wall of head region between ommatophorous insertions with neither glands nor tiny pits. Body greyish brown, central dorsum with pale longitudinal stripes. Sole dirty white. Jaw arcuate, with ~ 8 more or less projecting ribs.

Anatomy of genital organs.

Penial sheath short but well developed. Penis distally expanded, externally simple. Inside penis, proximal 1/2 with ~ 5 internal pilasters, two of which fuse into one Y-shaped fork at middle of penis; distal 1/2 with tongue-shaped (HBUMM05553b) or diamond-shaped papillae (HBUMM08428) that are erect or inclined towards atrium. Fine pilasters on distal end of penis merging into ~ 6 more or less thick short folds. Epiphallic papilla absent. Vas deferens narrow throughout. Vagina between atrium and dart sac not elongated. Accessory sac tiny, internally solid, inserting into dart sac medially, opening to dart chamber. Mucous glands four, each a single tube or simply branched. Proximal accessory sacs two, symmetrical, dorsally separated and ventrally touching each other, each with a ventral pore leading to proximal dart chamber. Love dart ~ 7 mm long, apically 2-bladed or rhombic (HBUMM08428-spec.1) then rounded. Bursa copulatrix duct equally narrow.

Etymology.

This new species is named in honor of Prof Chen, De-Niu, who works on land mollusks in the Institute of Zoology, Chinese Academy of Sciences, Beijing.

Ecology.

This species is found on exposed slate rocks of the hill side.

Distribution.

Only known from the type locality.

Remarks.

The new species is conchologically close to L. zhengpingliui Wu, sp. nov., but the new species has a much more depressed spire and relatively much larger aperture. In the genitalia, the middle part of penis, i.e., the distal 1/2 of the penis of the new species is occupied with regular tongue/diamond-shaped papillae (Fig. 44F, H ), while in L. zhengpingliui Wu, sp. nov., the middle part is clearly short (only ~ 1/6 of the penis length) and does not have such tongue/diamond-shaped papillae (Fig. 44D ).

Figures

Figure 2. A distribution map of all known species of Laeocathaica Moellendorff, 1899 except L. anceyi (Moellendorff in Ancey, 1889), L. hisanoi Pall-Gergely, 2022, and L. leucorhaphe Moellendorff, 1899 whose precise localities are not known; white dots: the localities where no Laeocathaica species was ever found B distribution of the new species described in this paper, yellow dots: L. qingchuanensis Wu, sp. nov., green dot: L. zhengpingliui Wu, sp. nov., brown dots: L. parapolytyla Wu, sp. nov., white dot: L. qiminglii Wu, sp. nov., pink dot: L. cheni Wu, sp. nov., blue dots: L. qishilii Wu, sp. nov., orange dots: L. nordsiecki Wu, sp. nov. C distribution of L. carinifera (H. Adams, 1870) (green dots), L. qingchuanensis Wu, sp. nov. (yellow dots), and L. stenochone Moellendorff, 1899 (blue dots) D distribution of L. amdoana Moellendorff, 1899 (green dots), L. distinguenda Moellendorff, 1899 (pink dots), and L. tropidorhaphe Moellendorff, 1899 (blue dots) C equivalent to the larger box in (A), B, D equivalent to the smaller box in (A).

Figure 37. A Laeocathaica zhengpingliui Wu, sp. nov., HBUMM 05553 - spec. 1, holotype B L. cheni Wu, sp. nov., HBUMM 05553 b-spec. 1, holotype C L. qingchuanensis Wu, sp. nov., HBUMM 01179 a-spec. 1, holotype D L. nordsiecki Wu, sp. nov., HBUMM 08446 - spec. 1, holotype.

Figure 39. Genital anatomy of Laeocathaica cheni Wu, sp. nov., HBUMM 05553 b-spec. 1, holotype A general view B ventral view of dart apparatus C left view of dart sac apparatus. Abbreviations: AS - accessory sac; At - atrium; BC - bursa copulatrix; BCD - bursa copulatrix duct; DS - dart sac; DtC - a chamber containing love dart; Ep - epiphallus; MG - mucous glands; P - penis; PAS - proximal accessory sac; PR - penial retractor muscle; PS - penial sheath; Va - vagina; VD - vas deferens. Asterisk * indicates the opening of proximal accessory sac.

Figure 44. Internal view of penis A, B Laeocathaica tropidorhaphe Moellendorff, 1899 A general view, HBUMM 05619 - spec. 1 B proximal penis, HBUMM 05664 - spec. 1 C L. qishilii Wu, sp. nov., general view, HBUMM 08298 - spec. 1, holotype D L. zhengpingliui Wu, sp. nov., general view, HBUMM 05553 - spec. 1, holotype E L. qingchuanensis Wu, sp. nov., general view, HBUMM 01179 - spec. 1, holotype F-H L. cheni Wu, sp. nov. F, G HBUMM 05553 b-spec. 1, holotype F general view G proximal penis H HBUMM 08428 - spec. 1, paratype, partial internal view of distal penis. Arrows indicate the position where two penial internal pilasters fuse into one distal pilaster.

Figure 46. SEM micrographs A, B Laeocathaica distinguenda Moellendorff, 1899, HBUMM 05479 A protoconch B teleoconch C, D L. stenochone Moellendorff, 1899, HBUMM 05495 C protoconch D teleoconch E, F L. prionotropis Moellendorff, 1899, HBUMM 05549 E protoconch F teleoconch G, H L. amdoana Moellendorff, 1899, HBUMM 05640 G protoconch H teleoconch I, J L. tropidorhaphe Moellendorff, 1899, HBUMM 05664 I protoconch J teleoconch K, L L. cheni Wu, sp. nov., HBUMM 08368, paratype, juvenile K protoconch L teleoconch.

Figure 49. Habitats (excluding D) A, B Laeocathaica qishilii Wu, sp. nov., border of Jiuzhaigou County and Wen County C L. nordsiecki Wu, sp. nov., Guoyuanxiang, Jiuzhaigou D L. qiminglii Wu, sp. nov., an indoor photograph E L. qingchuanensis Wu, sp. nov., Dagou Nature Reserve, Qingchuan County F L. cheni Wu, sp. nov., Hengdan, Wenxian.

Figure 51. Bayesian phylogram of camaenid species (for detail see in Table 1) based on the concatenated partial mitochondrial 16 S and partial ITS 2 sequences. The tree is rooted with Helix pomatia. Numbers near nodes indicating Bayesian posterior probabilities and Maximum-likelihood bootstrap values are given as BPP ⁄ BP. Black or orange part shows the topology where the result yielded by using Bayesian-Inference method agrees with that by using Maximum-likelihood method or not, respectively. An asterisk indicates the branch is exactly one third shortened in length. Scale bar is for substitutions per site.