Laeocathaica stenochone 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

Laeocathaica stenochone Moellendorff, 1899

Figs 2A, C , 31 , 32 , 43E, F , 46C, D , 50B , 51

Laeocathaica stenochone Möllendorff, 1899: 91, pl. 5, fig. 4; - Wiegmann 1900: 100, pl. 3, figs 89,90; - Gude 1902: 6; - Yen 1939: 148, pl. 15, fig. 30; - Yen 1942: 283; - Chen and Zhang 2004: 314, fig. 301.

Laeocathaica subsimilis - Sturany 1900: 21 ( Möllendorff 1901: 302).

Laeocathaica (Laeocathaica) stenochone - Zilch 1968: 175; - Richardson 1983: 79.

Laeocathaica carinifera - Páll-Gergely et al. 2022: 50, fig. 12D.

Museum material.

ZIN RAS No. 5, Laeocathaica stenochone Möllendorff., 1 fully mature soft part and 1 subadult, Zwischen dem Dorf Yu-Lin-guan und der Stadt Wen-hsien, 1885-IX-6-8, coll. Potanin, det. Möllendorff. SMF 9071, lectotype; Hsi-gu-tsheng (= town of Zhouquxian) [西固城], SO-Gansu, China; ex Potanin 577, Slg. O. v. Möllendorff. SMF 8951, paratype; Zw. Yue-ling-guan u. Wen-hsien ; Slg. O. v. Möllendorff, ex potanin 730. SMF 9072, paratype, A shell with immature aperture; same data as lectotype. SMF 24270 , paratype, not full matured at aperture;? Sy-tshuan; ex Beresowski 908c, Slg. O. v. Möllendorff .

New material.

HBUMM05495, many fma; 1 fma dissected; 5 km away from Hejiawan Bridge , along the road to Bikou , Wenxian , Gansu Province , near point (32.769664°N, 105.22781°E), shrubs, limestones, loess, near farmland, 2006-IX-28, coll. Wu, M., Liu, J.-M., Zheng, W. and Gao, L.-H.; DNA voucher HBUMM05492. HBUMM05764, HBUMM05764a, HBUMM05767, HBUMM05769, HBUMM05772, HBUMM05774c: many fma and juvs; Bikou, along the road from Datang Hydropower Station to Hejiawan Bridge; 2006-IX-28, coll. Liu, J.-M. and Zheng, W. HBUMM08431, 1 fma dissected; near Shichuanba [石川坝], Wenxian, Gansu Province, near 33.17534°N, 105.019362°E; 2019-X-12, coll. Li, Q.-M.; DNA voucher HBUMM08431a .

Distribution.

Gansu: Huixian [徽县], Wenxian, Wudu, Zhouqu (type locality).

Additional information of shell.

The protoconch is radially and regularly covered with dense thick granules (~ 25 - ~ 55 µm long) on the first 11/4 whorls. On the remaining protoconch whorls granules are indistinct and replaced by crowded radial threads. Spiral grooves are only indistinctly present on the apical side of body whorl.

General anatomy.

Eversible head wart indistinct. Jaw arcuate, with three projecting ribs.

Anatomy of genital organs.

Penial sheath very short, covering ~ 1/10 of penis. Penis tubular, equally thick. Inside penis, two high pilasters forming one Y-shaped fork at proximal 1/5, besides with two pilasters parallelly merging into one thickest pilaster. Fine pilasters on distal end of penis merging into ~ 6 thick folds, among which one is thicker than the others. 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. Love dart ~ 9 mm long, apically 2-bladed, subsequently rounded. Accessory sac small, internally solid, inserting into dart sac at middle part, opening to dart chamber. Mucous glands ~ 5, each complicatedly branched. Proximal accessory sacs two, symmetrical, separated apically and touching ventrally, each with an opening leading to proximal dart chamber near dart chamber opening. Bursa copulatrix duct of even diameter. Bursa copulatrix ovate, very small.

Remarks.

Geographically, the distribution of Laeocathaica carinifera in the Yangtze valley in Chongqing and Sichuan does not overlap those of L. stenochone and L. qingchuanensis Wu, sp. nov., both of which occur along the Bailongjiang River (Fig. 2C ). In terms of shell morphology, Laeocathaica stenochone close to L. carinifera and L. qingchuanensis Wu, sp. nov. can be distinguished (Fig. 50B ). Laeocathaica stenochone shows a particular protoconch and teleoconch sculpture (Fig. 46C, D ), which is completely different from those of L. carinifera (Fig. 45I, J ). In molecular analysis based on present combination of 16S + ITS2 sequences (Fig. 51 ), Laeocathaica stenochone (voucher HBUMM08431a) cannot be distinguished from L. carinifera (voucher HBUMM05103, HBUMM05131) because they share the same ITS2 sequence and show only 3-site difference in 16S sequence, suggesting they are possibly genetically very close species. However, L. stenochone and L. carinifera cannot be treated as one species (see Discussion).

Compared to Laeocathaica carinifera , L. stenochone has a symmetrical dart sac apparatus, short penial sheath, and significantly longer and evenly slender penis (Fig. 32 ), in which the Y-shaped fork is present more proximally (Fig. 43E, F ).

The specimens HBUMM08433 (8 fma, Wufengxi [五凤溪], Jintang County [金堂县], Chengdu [成都], Sichuan Province; coll. Li, Q.-M., 2019-XI; DNA voucher HBUMM08433a) that show a very similar shell to Laeocathaica stenochone could represent a different species to L. carinifera and L. stenochone due to a different genital trait.

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 31. Laeocathaica stenochone Moellendorff, 1899 A SMF 9071, lectotype B SMF 8951, paratype C HBUMM 05495 - spec. 1.

Figure 32. Genital anatomy of Laeocathaica stenochone Moellendorff, 1899, HBUMM 05495 - spec. 1 A general view B left view of dart sac apparatus C ventral view of dart apparatus. Abbreviations: AS - accessory sac; At - atrium; BC - bursa copulatrix; BCD - bursa copulatrix duct; DS - dart sac; Dt - love dart; DtC - a chamber containing love dart; Ep - epiphallus; FO - free oviduct; MG - mucous glands; P - penis; PAS - proximal accessory sac; PR - penial retractor muscle; PS - penial sheath; Va - vagina; VD - vas deferens. Asterisk * indicates the opening of proximal accessory sac.

Figure 43. Internal view of penis A, B Laeocathaica polytyla Moellendorff, 1899, HBUMM 05437 - spec. 1 A general view B proximal penis C L. potanini Moellendorff, 1899, HBUMM 00633 - spec. 1, general view D L. prionotropis Moellendorff, 1899, HBUMM 05549 - spec. 1, general view E, F L. stenochone Moellendorff, 1899, HBUMM 05495 - spec. 1 E general view F proximal penis G L. carinifera (H. Adams, 1870), HBUMM 08443 - spec. 2, general view. Arrows indicate the position where two penial internal pilasters fuse into one distal pilaster.

Figure 45. SEM micrographs A, B Laeocathaica potanini Moellendorff, 1899, HBUMM 00633 A protoconch B teleoconch C, D L. dityla Moellendorff, 1899, HBUMM 00698 C protoconch D teleoconch E, F L. qingchuanensis Wu, sp. nov., HBUMM 01179 a-spec. 6, paratype E protoconch F teleoconch G, H L. christinae (H. Adams, 1870), HBUMM 01251 a G protoconch H teleoconch I, J L. carinifera (H. Adams, 1870), HBUMM 04162 I protoconch J teleoconch K, L L. polytyla Moellendorff, 1899, HBUMM 05437 K protoconch L teleoconch.

Figure 46. SEM micrographs A, B Laeocathaica distinguenda Moellendorff, 1899, HBUMM 05479 A protoconch B teleoconch C, D L. stenochone Moellendorff, 1899, HBUMM 05495 C protoconch D teleoconch E, F L. prionotropis Moellendorff, 1899, HBUMM 05549 E protoconch F teleoconch G, H L. amdoana Moellendorff, 1899, HBUMM 05640 G protoconch H teleoconch I, J L. tropidorhaphe Moellendorff, 1899, HBUMM 05664 I protoconch J teleoconch K, L L. cheni Wu, sp. nov., HBUMM 08368, paratype, juvenile K protoconch L teleoconch.

Figure 50. Scatter plots of canonical variate 1 against canonical variate 2 (Canonical Variate Analysis), showing the shell morphological relationships among A Laeocathaica distinguenda Moellendorff, 1899 (green dots; a, average shape), L. amdoana Moellendorff, 1899 (blue dots; b, average shape) and L. tropidorhaphe Moellendorff, 1899 (orange dots; c, average shape) B L. qingchuanensis Wu, sp. nov. (green dots; a, average shape), L. stenochone Moellendorff, 1899 (orange dots; b, average shape) and L. carinifera (H. Adams, 1870) (blue dots; c, average shape). Encircled dots: 1, SMF 8959, lectotype; 2, HBUMM 05436 - spec. 1; 3, SMF 8952, lectotype; 4, SMF 9074, lectotype; 5, paratype of L. dangchangensis Chen & Zhang, 2004; 6, SMF 9071, lectotype; 7, syntype, NHMUK 1870.7.16.7. Data for 5 from fig. 7 D, 6 and 7 from fig. 12 in Pall-Gergely et al. 2022.

Figure 51. Bayesian phylogram of camaenid species (for detail see in Table 1) based on the concatenated partial mitochondrial 16 S and partial ITS 2 sequences. The tree is rooted with Helix pomatia. Numbers near nodes indicating Bayesian posterior probabilities and Maximum-likelihood bootstrap values are given as BPP ⁄ BP. Black or orange part shows the topology where the result yielded by using Bayesian-Inference method agrees with that by using Maximum-likelihood method or not, respectively. An asterisk indicates the branch is exactly one third shortened in length. Scale bar is for substitutions per site.