Camaena lingyunensis Zhou & Lin

Ai, Hong-Mu, Lin, Jun-Hong, Wang, Pei, Zhou, Wei-Chuan & Hwang, Chung-Chi, 2016, Descriptions of two new species of the genus Camaena from Guangxi, China (Gastropoda, Stylommatophora, Camaenidae), ZooKeys 634, pp. 29-45 : 34-35

Taxon classification Animalia Stylommatophora Camaenidae

Camaena lingyunensis Zhou & Lin sp. n. Figs 3A, 4A, 5A, Table 3

Holotype.

[FJIQBC 19280] Shell height 29.0 mm, shell width 52.5 mm, height of aperture 21.3 mm, width of aperture 27.0 mm, 24 April 2014, collected from the type locality.

Paratype.

[FJIQBC 19281- 19293] 13 specimens: 2 empty adult shells, 11 live snails including 9 adults and 2 juveniles. Results of adult measurements: shell height 24.0-34.0 (27.40 ± 2.96) mm, width 49.8-59.5 (53.00 ± 2.77) mm, height of aperture 18.0-25.0 (20.75 ± 1.74) mm, width of aperture 22.0-31.0 (26.35 ± 2.57) mm, 24 April 2014, collected from type locality.

Type locality.

Kasuo, Lingyun, Guangxi, China (24°17'47.33"N, 106°39'6.53"E).

Etymology.

The name of the new species refers type locality.

Description.

Shell. Shell sinistral, large, slightly thin, semi-translucent, hard and fragile, flat globose. 4.75 whorls, the upper whorls increasing fast and slightly convex. Spire relatively low. Body whorl rapidly expanded, convex, with a weakly obtuse angulated margin at periphery. Shell fawn with countless light chestnut spiral bands. Spiral bands slender and dense below the periphery of body whorl, forming wide area of bands. Growth lines dense and thick on the surface. Apex quite blunt. Growth lines on protoconch visible when using 15 × magnification. Suture line shallow. Aperture lunate, slightly descending in front view. Peristome reflected, sharp and white. Columellar lip reflected, slightly covering the umbilicus. Inner lip attached to the body whorl, forming translucent, thin and smooth callus. Umbilicus open and round. The first whorl can be seen through the umbilicus. Hump beside umbilicus absent.

Soft body. Foot hazel. Tentacles darker. White band from the head to the neck.

Reproductive system. Penis slightly swollen, short. Epiphallus long and thick. Penis retractor muscle very slender and long. Flagellum medium length, thick basally, tapering distally. Vas deferens long and thin. Vagina thick and slightly short. Bursa copulatrix oval. Pedunculus of bursa copulatrix quite long, expanded at basal half, while smooth and slender at the end. Inner penial wall supporting transverse, smooth, and dense pilasters proximally and several longitudinal, thin, curly, and widely-spaced pilasters distally. Verge conical and smooth, with eight transverse wrinkles basally. An obvious longitudinal crack on the verge, and six smooth and longitudinal pilasters with wide space in the crack. Verge opens laterally.

Ecology.

This species was found on limestone in Lingyun county of Guangxi province. It generally inhabits mountaintops with clouds and mists, but cannot be found at the foot of the mountain.

Remarks.

The key characters of Camaena lingyunensis sp. n. and the other eight sinistral Camaena species are presented in an identification key. This species is clearly different from other species, with a more oblate shape, lower spire, thinner and more fragile shell, and lighter colouration. The umbilicus of the new species is fully open, and the first whorl can be seen from the umbilicus, which significantly is distinguished from Camaena poyuensis (Zhou, Wang & Ding, 2016) and Camaena obtecta (Fischer, 1898) without an umbilicus, Camaena inflata and Camaena connectens (Dautzenberg & Fischer, 1906) with a narrow umbilicus, and Camaena cicatricosa and Camaena detianensis sp. n. with a semi-open umbilicus. The new species is similar with another sinistral snail, Camaena seraphinica , which also has a fully open umbilicus, but with a relatively higher and arched spire, wide and beautiful red spiral bands, and colour spots and no forged trace on the surface. Furthermore, the base region colour of the body whorl around the umbilicus is white. Differently, the new species has a flat and low spire with an inconspicuous forged trace, and contains countless slender spiral bands. The base region colour of the body whorl is the same as the shell surface with slender spiral bands.

Some sinistral Camaena species have the same features as the new species on penial wall, such as Camaena hahni , Camaena poyuensis and Camaena inflata ( Ding et al. 2016), while the verge of these species is significantly different from the new species. The surface of verge of Camaena hahni , Camaena poyuensis and Camaena inflata all contains transverse or longitudinal microgrooves, but in the new species it is conical and smooth, and does not have any microgrooves except for a longitudinal crack, from which six longitudinal and smooth pilasters can be seen. There are six longitudinal and deep cracks on verge of Camaena poyuensis , but the cracks cannot be riven.

COI gene p-distances between this new species and the other seven sinistral species are 0.098-0.178 (Table 3). On phylogenetic tree, Camaena lingyunensis sp. n. is adjacent to Camaena cicatricosa and Camaena detianensis sp. n. However, the shells of the three species were greatly distinct as follows: (1) the fawn shell color of Camaena lingyunensis sp. n. is much lighter than the dark tawny shell color of Camaena cicatricosa and brown shell color Camaena detianensis sp. n. (2) The spire of Camaena lingyunensis sp. n. is low and flat, while the spires of the latter two are relatively high and arched (3) the Camaena lingyunensis sp. n. has countless light chestnut and slender spiral bands on the body whorl while Camaena detianensis sp. n. has no spiral bands (4) the umbilicus of Camaena lingyunensis sp. n. is fully open, while that of the latter two are semi-open.