Laeocathaica Moellendorff , 1899

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

Genus Laeocathaica Moellendorff, 1899

Laeocathaica Möllendorff, 1899: 86; Richardson 1983: 77; Schileyko 2004: 1686.

Type species.

Helix (Plectotropis) christinae H. Adams, 1870 (by original designation).

Description.

Shell sinistral, strongly depressed to broadly conic, moderately solid, of 5-10.5 almost flat whorls. Last whorl abruptly descending in front, angulated to strongly keeled; rarely rounded. Coloration consists of whitish, corneous, or chestnut background and mostly with one or two dark sub-peripheral bands; besides, usually there are several fulvous, diffuse radial streaks. Protoconch usually with fine radial threads and/or fine granules that each is formed by a low hump deposited in a shallow socket. Sculpture of teleoconch whorls varying from fine, silky radial striation to rather strong ribbing; on basal surface below keel or angle this sculpture becomes much weaker. Aperture rounded to peach-shaped, oblique, margins usually more or less reflexed. Within aperture a ring-like thickening present. Apertural teeth absent or with one tuberculiform basal tooth and sometimes with another one on palatal wall. During postembryogenesis several sets of teeth, different from those developed at adult stage in shape and/or number, present and remained to adult stage. Umbilicus moderate to very wide, ratio of umbilicus diameter to maximum diameter 0.21-0.50. Height 3.5-14 mm, maximum diameter 10.0-29.5 mm.

On left and right side of mantle edge, no leaf-shaped appendage present. Head wart between ommatophores present, weak, or developed. Jaw arcuate, with 3-8 more or less projecting ribs.

Slender vas deferens entering epiphallus at penial retractor muscle insertion. Penis generally clavate, rarely subcylindrical. Penis internally divided into three regions: the proximal part with narrow or thick longitudinal pilasters, among which one pair or two pairs of adjacent pilasters fuse into one Y-shaped fork or two Y-shaped forks (not in Laeocathaica christinae , L. phaeomphala , and L. qingchuanensis Wu, sp. nov.). The median part, composed of fine pilasters that weave into network or covered by isolated tongue-like/diamond-like granules erecting on penial wall. The distal part, near epiphallic opening, with mini-pilasters crowded and forming several short and thick pilasters. Epiphallic papilla absent. Penial sheath always present, surrounding proximal penis. Dart sac always present. Accessory sac presents at ventral dart sac, internally solid or narrowly empty. Mucous glands 2-12, each simply or complicatedly branched, entering accessory sac separately before being united into a common duct inside wall of accessory sac. Proximal section of dart sac with 0-2 PAS that if present, each has a tiny opening leading to dart chamber. Vagina between atrium and dart sac elongated only in a few species. Bursa copulatrix duct subcylindrical throughout (modified from Schileyko 2004).

Distribution.

China: S Gansu, W Hubei, W Shaanxi, Chongqing, Sichuan.

Remarks.

Laeocathaica species are granulate on the protoconch, which is smooth in actual observation due to erosion or weathering. In the original description of Laeocathaica filippina , Heude (1882) first mentioned the irregular white radiate stripes (1882), which were particularly noted by Möllendorff (1899) as "die stets vorhandenen Jugendlippen (the ever-present juvenile lips)" that joined the definition of Laeocathaica . Möllendorff (1899) also noticed in Euhadra haplozona Möllendorff, 1899 and Euhadra eris Möllendorff, 1899 such "ever-present juvenile lips" exist. The juvenile lips, which have remained on the mature shell, may be frequent and weak such as those of L. minwui Páll-Gergely, 2022 (Fig. 11A ) and many other species, or sparse and strong as those of Laeocathaica dityla (Fig. 13D ) and L. parapolytyla Wu, sp. nov. (Fig. 25 ). Regarding the genital organs, the Y-shaped forks present on the proximal part of inner wall of the penis were observed exclusively in most anatomically studied Laeocathaica species among the Chinese dart-sac-bearing camaenids.

Figures

Figure 11. A Laeocathaica minwui Pall-Gergely, 2022, SMF 24255 a B L. christinae (H. Adams, 1870), HBUMM 01251 - spec. 1.

Figure 13. A, B Laeocathaica dejeana (Heude, 1882) A SMF 23919, lectotype B NHMUK 1902.5.13.1 - 2 C-E L. dityla Moellendorff, 1899 C SMF 9086, lectotype D SMF 9087, paratype E HBUMM 00698 - spec. 1.

Figure 25. Laeocathaica parapolytyla Wu, sp. nov. A-E paratypes HBUMM 06640 - spec. 2 - 6 F holotype, HBUMM 06640 - spec. 1 G-I paratypes HBUMM 06640 - spec. 7 - 9. Both A, H show four views B-G, I show apical view only.