Laeocathaica parapolytyla Wu, 2023

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

Laeocathaica parapolytyla Wu sp. nov.

Figs 2A, B , 25 , 27 , 42G, H , 48I, J

Type material.

Holotype HBUMM06640-spec.1, 1 dissected; town of Wenxian, Gansu Province, 1269 m a.s.l., near point (32.944391°N, 104.685604°E); 2011-VIII-09, coll. Wu, M., Xu, Q. and Budha, P.; DNA voucher HBUMM06639. Paratypes HBUMM06640-spec.2-9 (apex of spec.9 was removed for SEM observation), same data as holotype. HBUMM00532, Xinglongcun, Zhongzhaixiang, Wenxian, Gansu Province, near point (33.232415°N, 104.419075°E); 1998-V-19, coll. Chen, D.-N. and Zhang, G.-Q.

Measurement of holotype.

Shell height 6.9 mm, maximum diameter 15.6 mm, aperture height 3.9 mm, aperture breadth 5.8 mm, umbilicus diameter 5.0 mm, protoconch whorls 11/2, whorls 87/8.

Diagnosis.

Protoconch with dense radially-arranged threads, visible through umbilicus. Beneath carina a clear chestnut band present. Mucous glands four or five. Penis with two pairs of pilasters fusing into two Y-shaped forks. Vagina between atrium and dart sac not elongated. Proximal accessory sac absent.

Description of shell.

Sinistral, depressed, thin but somewhat solid. Shell with 81/8-93/8 fairly flat whorls. Suture impressed. Protoconch 11/2-13/4 whorls, with densely arranged radial threads that may be invisible because of weathering or erosion. Periphery distinctly angulate. Growth lines indistinct. Spiral grooves are absent throughout. Aperture oblique, roundly square, descending in front. Peristome not expanded and indistinctly reflexed at lower part. Within aperture a ring-like thickening present, basally with a flat tooth. Columella oblique. Umbilicus abruptly broadened after penultimate whorl, ~ 1/4 of maximum diameter. Protoconch visible through umbilicus. Shell apically in intermittent yellowish white and pale chestnut patches except white carina. In umbilical view shell distinctly paler in greyish yellow, just beneath carina a clear chestnut band present, umbilical region brownish.

General anatomy.

Eversible head wart prominent. Jaw arcuate, with four projecting ribs.

Anatomy of genital organs.

Penial sheath covering ~ 1/5 of penis. Penis distally fairly expanded. Inside penis, two high pilasters fusing into one Y-shaped fork at proximal 1/4, another pair of pilasters fusing into one Y-shaped fork at middle part. Fine pilasters on distal end of penis merging into ~ 7 thick and short folds. Epiphallic papilla absent. Vas deferens narrow throughout. Vagina between atrium and dart sac not elongated. Vagina between dart sac and insertion of bursa copulatrix duct ~ 1/2 length of dart sac. Dart sac ~ 1/2 length of penis. Accessory sac small but externally distinguishable, internally solid, ventrally inserting into dart sac at distal 1/3, together with mucous glands opening to dart chamber. Mucous glands four or five, each singly tubular or bifurcated. Proximal accessory sac absent. Bursa copulatrix duct equally thick.

Etymology.

The name of this new species is made up of para - meaning similar to and polytyla from Laeocathaica polytyla Möllendorff, 1899, which is conchologically close to the new species.

Ecology.

On rocks of local hill.

Distribution.

Only known from the type locality.

Remarks.

The new species exhibits a large intraspecific change in size (Fig. 25 ), which is also showed in Laeocathaica polytyla (Fig. 24A, B ). Laeocathaica parapolytyla Wu, sp. nov. looks like a flattened and sharply carinate L. polytyla , but has slightly different coloring and coarser growth lines. The terminal genitalia of these two species are similar, but in the new species the penis internally has two pairs of pilasters that fuse into two Y-shaped forks, while in Laeocathaica polytya the penis has only one Y-shaped fork formed by adjacent pilasters.

Figures

Figure 2. A distribution map of all known species of Laeocathaica Moellendorff, 1899 except L. anceyi (Moellendorff in Ancey, 1889), L. hisanoi Pall-Gergely, 2022, and L. leucorhaphe Moellendorff, 1899 whose precise localities are not known; white dots: the localities where no Laeocathaica species was ever found B distribution of the new species described in this paper, yellow dots: L. qingchuanensis Wu, sp. nov., green dot: L. zhengpingliui Wu, sp. nov., brown dots: L. parapolytyla Wu, sp. nov., white dot: L. qiminglii Wu, sp. nov., pink dot: L. cheni Wu, sp. nov., blue dots: L. qishilii Wu, sp. nov., orange dots: L. nordsiecki Wu, sp. nov. C distribution of L. carinifera (H. Adams, 1870) (green dots), L. qingchuanensis Wu, sp. nov. (yellow dots), and L. stenochone Moellendorff, 1899 (blue dots) D distribution of L. amdoana Moellendorff, 1899 (green dots), L. distinguenda Moellendorff, 1899 (pink dots), and L. tropidorhaphe Moellendorff, 1899 (blue dots) C equivalent to the larger box in (A), B, D equivalent to the smaller box in (A).

Figure 24. A, B Laeocathaica polytyla Moellendorff, 1899 A SMF 9098, lectotype B HBUMM 05437 - spec. 1 C, D L. potanini Moellendorff, 1899 C SMF 9082, paratype D HBUMM 00633 - 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.

Figure 27. Genital anatomy of Laeocathaica parapolytyla Wu, sp. nov., HBUMM 06640 - spec. 1, holotype A general view B ventral view of dart sac apparatus. Abbreviations: AS - accessory sac; At - atrium; BCD - bursa copulatrix duct; DS - dart sac; Ep - epiphallus; FO - free oviduct; MG - mucous glands; P - penis; PR - penial retractor muscle; PS - penial sheath; Va - vagina; VD - vas deferens.

Figure 42. Internal view of penis A, B Laeocathaica dolani (Pilsbry, 1934), HBUMM 00069 - spec. 1 A general view B proximal penis C L. christinae (H. Adams, 1870), HBUMM 01251 a-spec. 1, general view D L. phaeomphala Moellendorff, 1899, HBUMM 05433 - spec. 1 E L. odophora Moellendorff, 1899, HBUMM 08430 - spec. 1 F L. pewzowi Moellendorff, 1899, ZIN RAS No. 4, " Aegista pewzowi Schalf. " G, H L. parapolytyla Wu, sp. nov., HBUMM 06640 - spec. 1, holotype G general view H proximal part. Arrows indicate the position where two penial internal pilasters fuse into one distal pilaster.

Figure 48. SEM micrographs A, B Laeocathaica qishilii Wu, sp. nov., HBUMM 08298, paratype A protoconch B teleoconch C, D L. qiminglii Wu, sp. nov., HBUMM 08448, paratype C protoconch D teleoconch E, F L. phaeomphala Moellendorff, 1899, CZG 202008 - w 3, subadult E protoconch F teleoconch G, H L. filippina (Heude, 1882), HBUMM 04166 G protoconch H teleoconch I, J L. parapolytyla Wu, sp. nov., HBUMM 06640 - spec. 9, paratype I protoconch J teleoconch.