Camaena detianensis 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 : 35-38

Taxon classification Animalia Stylommatophora Camaenidae

Camaena detianensis Zhou & Lin sp. n. Figs 3B, 4B, 5B, Table 3

Holotype.

[FJIQBC 18472] Shell height 38.5 mm, shell width 61.4 mm, height of aperture 22.5 mm, width of aperture 26.2 mm, 21 May 2013, collected from the type locality.

Paratype.

[FJIQBC 18473- 18482] 10 specimens: all live snails including 4 adults and 6 juveniles. Shell height 34.2-40.4 (38.46 ± 2.49) mm, width 55.0-62.5 (59.60 ± 2.41) mm, height of aperture 19.6-23.9 (22.44 ± 1.67) mm, width of aperture 24.2-28.1 (25.86 ± 1.58) mm, 21 May 2013, collected from holotype locality.

Type locality.

Detian Falls, Daxin, Guangxi, China (22°51'29.54"N, 106°43'13.51"E).

Etymology.

Named for the type locality, adjective.

Description.

Shell. Shell sinistral, large, thick, solid, non-transparent and depressed-globular. 5.5 whorls, the front whorls increasing and convex rapidly. Spire arched. Body whorl expanding with an acute carina at periphery and a shallow groove-like depression above and below the carina, obviously near the aperture. Apex quite blunt. Growth lines on protoconch visible when using 15 × magnification. Suture line deep. Surface dark brown and slightly red with obvious malleation. Spiral bands absent. The upper part of the periphery of body whorl with countless thick growth lines, convex, and the lower part smooth. Spire ribs below the periphery relatively obvious. Aperture lunate. Peristome reflected, white and not sharp. Columellar margin reflected. Umbilicus partly covered by reflected columellar lip. Inner lip attached to the body whorl tightly, forming translucent, smooth and thick callus. Umbilicus obvious and round. A hump beside umbilicus absent.

Soft body. Foot and tentacles are dark brown, and the head color is relatively light.

Reproductive system. Penis slightly long, slender and smooth. Epiphallus long and thin. Penis retractor muscle short, wide and flat. Flagellum very slender and long. Va gina smooth and slender. Vas deferens slender. Bursa copulatrix oval. Pedunculus of bursa copulatrix quite long, expanded at the base. Inner penial wall supporting several longitudinal, dense, and curly pilasters with narrow space. Verge long conical with many shallow, longitudinal and narrow pilasters. A shallow transverse microgrooves at the apical 1/3, surrounding the verge. A harelip-like crack at the end of verge. Verge opens terminally.

Ecology.

The species was found on limestone in Daxin county of Guangxi province. It generally lives in primeval forest or forest with a good ecological environment, and cannot be found in gardens near the forest. The population density of this new species in field is relatively low.

Remarks.

The key characters of Camaena detianensis sp. n. and the other eight sinistral Camaena are presented in the identification key. The carina and groove above and below the carina of Camaena detianensis sp. n. are typical features, which are different from other species of Camaena except for Camaena hahni . There is no obvious groove-like depression above and below the periphery of Camaena hahni .

The differences of shell between the new species and Camaena cicatricosa were as follows: (1) Camaena detianensis sp. n. is quite large, and the largest width can reach 62.5 mm, while the maximum width of shell of Camaena cicatricosa is less than 50 mm (2) The shell of this species is dark brown without spiral bands, while the shell of Camaena cicatricosa is yellowish brown, and contains many annular spiral bands (3) There is an acute carina at periphery of body whorl of the new species, and groove-like depression above and below the carina, but Camaena cicatricosa has no obvious carina.

The new species has similar appearance with Camaena hahni , both of which have semi-open umbilicus and a distinct carina at periphery of body whorl, but there still exist differences (1) Camaena hahni is relatively small, and the width of shell of mature specimen is generally between 45.0-47.0 mm. While the new species is very large, and the width of shell is generally between 55.0-62.5 mm (2) Compared to the new species, Camaena hahni has a sharper carina, but there is no obvious groove-like depression above and below the carina (3) The growth lines and spire ribs of Camaena hahni are thicker, and the shell surface is very rough, while that of the new species is relatively finer (4) The new species has thicker callus, while Camaena hahni has thinner callus.

A dissection of reproductive system shows that the pilasters of penis wall and verge shape of Camaena detianensis sp. n. is similar to that of Camaena cicatricosa , both of which have longitudinal and curly pilasters on the penis wall with narrow spaces, and the verge is conical with many longitudinal pilasters, while Camaena hahni has longitudinal and transverse pilasters on the penis wall, and verge is semicircle and small. There is an annular microgroove on verge, and a harelip-like crack at the end of verge in the new species, which is a diagnostic feature differing from other sinistral Camaena species.

COI gene p-distances between this new species and other seven sinistral species were 0.073-0.189 (Table 3). On the phylogenetic tree, this new species and Camaena cicatricosa are mutually sister groups, and p-distance of the two species is 0.073-0.086. According to above information, it is reasonable that the species is recognized as a new species ( Criscione and Köhler 2014).