Camaena obtecta (Fischer, 1898)

Ding, Hong-Li, Wang, Pei, Qian, Zhou-Xing, Lin, Jun-Hong, Zhou, Wei-Chuan, Hwang, Chung-Chi & Ai, Hong-Mu, 2016, Revision of sinistral land snails of the genus Camaena (Stylommatophora, Camaenidae) from China based on morphological and molecular data, with description of a new species from Guangxi, China, ZooKeys 584, pp. 25-48 : 30-32

Taxon classification Animalia Stylommatophora Camaenidae

Camaena obtecta (Fischer, 1898) Figs 3B, 4B, Table 4

Helix (Camaena) cicatricosa var. obtecta Fischer, 1898: 315, pl. 17, figs 5-6.

Type locality.

Vietnam: Luc Chu and Cao Bang

Material examined.

See Table 4.

Diagnosis.

Shell sinistral, large, thick, solid, depressed-globular, yellowish brown to dark brown, with obtuse apex and low dome-shaped spire; 5 1/2 rapidly increasing and slightly convex whorls separated by deep suture; body whorl expanded, descending in front; periphery bluntly angulate in front of aperture, becoming round behind peristome. Surface with thick growth lines, fine spiral ribs, and weak malleation. Aperture ovate-lunate, white inside, with curved margin. Peristome white, expanded, reflected, thickened and glossy; columellar margin strongly expanded; inner lip thick, callous. Basal lip straight, forming an obtuse angle at junction with straight and oblique columellar lip. Umbilicus completely covered by reflected columellar lip and thickened callus when fully matured. Hump beside umbilicus present. Color pattern of numerous wavy, reddish brown spiral bands of various thickness; subperipheral and subsutural bands much wider (Fig. 3B).

Penis short, swollen, with a rounded bulge in correspondence of verge. Epiphallus medium with short, thin and wide penis retractor muscle. Flagellum elongated, tapering distally. Vas deferens long and thin. Vagina short and thickened. Bursa copulatrix clavate with long and thin pedunculus, apparently expanded at basal one-third its length. Verge conic, with irregular and curly wrinkles. Inner penial wall supporting transverse and narrowly spaced pilasters (Fig. 4B).

Distribution.

This species has previously been recorded from Cao Bang and Luc Chu in northern Vietnam. Luc Chu is the area north of Cao Bang to the border with China according to Billet (1898). In addition, it is now recorded from Longbang and Buhaitun, in Jinxi, southwestern Guangxi, China, approximately 20 km north of Cao Bang (Fig. 1).

Ecology.

This species inhabits forests on limestone, including degraded forests.

Comparative remarks.

This species is characterized in having a hump beside the completely covered umbilicus, thick shell, ovate-lunate aperture, transverse only pilasters on inner penial wall, and a conic verge with irregularly curly wrinkles. It differs from Camaena cicatricosa by having a larger shell, a completely covered umbilicus, humped base beside umbilicus, more convex whorls and ovate-lunate aperture. It forms a well-differentiated clade in the phylogenetic tree (Fig. 2) and exhibits sufficient morphological differences to justify elevation to full species rank.