Traumatophora triscalpta (Martens, 1875)

Wu, Min, 2019, A taxonomic note on the helicoid land snail genus Traumatophora (Eupulmonata, Camaenidae), ZooKeys 835, pp. 139-152 : 139

Traumatophora triscalpta (Martens, 1875) Figs 1, 2, 3, 4, 5, 6

Helix triscalpta Martens, 1875a: 2; Martens 1875b: 185-186; Heude 1882: 35-36, pl. 15, figs 7, 7a, 7b; Gredler 1884: 137; Möllendorff 1884: 388.

Helix (Traumatophora) triscalpta Pilsbry 1890: 6, 8, pl. 1, figs 1-8.

Stegodera (Traumatophora) triscalpta Schmacker and Boettger 1894: 173.

Traumatophora triscalpta Yen 1939: 126, pl. 13, fig. 7; Yen 1942: 271-272; Yen 1943: 297; Schileyko 2003: 1512, fig. 1949.

Material examined.

Helix triscalpta von Martens, 1875, syntypes, ZMB/Moll-109875; Poyang-Yu (Lake Poyang), Kiangsi Province, China; 3 dried shells (major diameter of three shells: 31.0 mm, 30.5 mm, 26.3 mm. Measurement made by Christine Zorn); leg. von Martens. Tianmushan, Zhejiang Province, China; 1 fully matured empty shell (HBUMM06875 specimen-1) and 1 full matured animal (HBUMM06875 specimen-2, body whorl was partially removed to take out whole soft parts), May, 2016; coll. Zhou, Dakang (Beijing Botanical Garden). A piece of foot of HBUMM06875 specimen-2 was cut off and preserved in 99.7% alcohol at -20 °C.

Description.

Shell (Figs 2, 3). Clearly depressed; thick and solid; dextral. Whorls convex. Suture impressed. Umbilicus approximately one fifth of shell major diameter. Bottom-umbilicus transition changed gently. Columella oblique. Columellar lip only slightly covering umbilicus. Protoconch smooth. On teleconch spiral furrows absent. Aperture strongly oblique; not sinuate at peristome. Body whorl descending abruptly in front. Shell surface without ribs. Growth lines fine and broken into granules which are distributed evenly on whorls except on protoconch (Fig. 2B); not accompanied by irregular thickenings. Shell not perforated. Adult shell not hairy or scaly. Adult body whorl rounded at periphery; with bottom convex. Ring-like thickening within aperture absent. Aperture with three baso-palatal lamellar teeth (Figs 2C, 3 A–C). Palatal tooth near columella shortest, approximately half length of other two teeth. Outer surface of body whorl with longitudinal depressions corresponding to teeth (Figs 2A, D, 3 A–C). Peristome thin; white; narrowly and uniformly reflexed. Callus indistinct. Shell dull to somewhat glossy; uniformly in reddish brown; bandless. Measurements (HBUMM06875, n = 2): shell height 17.8-18.2 mm, shell breadth 35.4-37.2 mm, aperture height 10.4-11.0 mm, aperture width 16.6-17.5 mm, embryonic shell whorls 1.250-1.500, whorls 5.000-5.125, shell height/ breadth ratio 0.20-0.22.

General anatomy. Eversible head wart between ommatophore insertions absent. Tentacles and dorsum leaden-black. Sole and the remaining lower lateral side creamy white. Jaw arcuate; with 12 more or less projecting ribs (Fig. 4C).

Genitalia (Figs 4-6). A sheet of membrane (in Fig. 4A, the remnant membrane after dissection is arrowed), growing on oviducts and tightly connected with vas deferens, wrapping dart apparatus completely. Penis sheath very short; only restrictedly present near insertion on dart sac. Penis very short; moderately thick; externally simple. Penial retractor muscle inserting on penis-epiphallus transition. Epiphallus as thick as the most swollen part of penis; approximately two times longer than penis. Flagellum approximately three times longer than penis; tapering. Epiphallic papilla absent. Penis internally with four pilasters. Penial pilasters uniformly-spaced; thickest at two thirds of their entire length distally (Fig. 5B). Dart sac tiny (Fig. 5D). Dart in dart sac not observed (maybe lost or regenerating) in HBUMM06875 specimen-2. Accessory sac developed; large in size; interiorly with pilasters; transversally with developed sphincter muscles (Figs 5E, 6A, B). Mucous glands nine; extending distally to more than half of bursa copulatrix duct (longest in the subfamily Bradybaeninae); each thicker than penis; in volume larger than rest of genitalia (Fig. 4A); connected to each other by nerve fibres (Fig. 5C). Each mucous gland duct entering accessory sac through a separate pore; through papilla or not (Figs 5E, 6A, B). Vagina approximately as long as accessory sac; entering dart sac chamber. A ball-shaped proximal accessory sac (Figs 4A, 5A, D, E, 6A), about 1.5 mm in diameter, with opening leading to dart sac chamber near entrance of vagina. Gonad glands palm-shaped; with short peduncles (Fig. 4B). Measurement in HBUMM06875 specimen-2: DS– 2.1 mm long; AS– 4.1 mm long; MG– 30.9 mm (average of 5 mucous glands); P– 6.9 mm; Ep– 10.3 mm; Fl– 19.1; VD– 22.0 mm; PR– 3.2 mm; Va– 3.2 mm; FO– 4.9 mm; BC plus BCD– 37.5 mm.

Distribution.

Extant distribution: Jiangxi (type locality: around Boyanghu; Lushan), Hubei (Ou-tang =Wudangshan Mts., Tong-san in Sei-zo), Fujian (Foochow= Fuzhou. Yen 1942), Zhejiang (Tianmushan Mts. This study). Pleistocene: Jiangsu (Chenkiang: Chiao-shan =Zhengjiang: Jiaoshan) (Fig. 1).

Ecology.

Perhaps this species is among the rarest bradybaenine species in China, although the extant distribution range is large and covers Jiangxi, Hubei, Fujian and Zhejiang. Traumatophora triscalpta was known from higher altitudes of 1200-1500 m ( Pilsbry 1890).

Taxonomic remarks.

In this study, the Traumatophora specimens from Zhejiang are identified as T. triscalpta based on the original description and comparison of the type material (Fig. 3). I follow Yen (1943) in treating T. triscalpta and T. fraterminor (originally described as Helix triscalpta fraterminor Gredler, 1884: 137. T. triscalpta fraterminor Yen 1939: 126, pl. 13, fig. 8; Zilch 1974. T. fraterminor Yen 1943: 297) as two distinct species, although the only known difference between them is that the latter species is "smaller in diameter and higher in altitude, obtusely angulated at periphery" ( Pilsbry 1890). However, considering the frequency of convergence events in the evolution of shell morphology in the helicoids, it is reasonable to treat these two taxa that show detectable differences in shell morphology as two species. Traumatophora fraterminor is distributed between Hwang-tchou ( today’s Huangshi, Hubei Province) and Kiou-Kiang ( today’s Jiujiang, Jiangxi Province) (Pilsbry, 1890) (Fig. 1). Report of a Pleistocene fossil from Zhenjiang, Jiangsu as T. fraterminor (sensu Yen 1943) is somewhat doubtful because the relevant specimen was a juvenile shell.