Sarika solemi Pholyotha & Panha, 2020

Pholyotha, Arthit, Sutcharit, Chirasak, Tongkerd, Piyoros & Panha, Somsak, 2020, Integrative taxonomic revision of the land snail genus Sarika Godwin-Austen, 1907 in Thailand, with descriptions of nine new species (Eupulmonata, Ariophantidae), ZooKeys 976, pp. 1-100 : 1

Sarika solemi Pholyotha & Panha sp. nov. Figs 1 , 44 , 45B , 46C-F , 47C, D , 48B

Sarika aff. hainesii [sic]: Solem 1966: 38, 39, fig 5a (non Pfeiffer 1856a: 32); Sutcharit and Panha 2008: 96.

Type material.

Holotype CUMZ 7297 (Fig. 46C , width 24.4 mm, height 13.5 mm). Paratypes CUMZ 7298 (15 shells and 26 specimens preserved in ethanol; Fig. 46D , width 24.8 mm, height 12.7 mm), NHMUK 20200288 (two shells), SMF (two shells), ZRC.MOL.017030 (two shells).

Other material examined.

Thailand-Western. Ban Nam Ok Hu, Tha Song Yang, Tak, 17°08'01.2"N, 98°22'01.8"E: CUMZ 7504. Mae Usu Cave, Tha Song Yang, Tak, 17°18'14.7"N, 98°09'20.8"E: CUMZ 7505. Thailand-Northern. Mountain area in Mae Na Toeng, Pai, Mae Hong Son, 19°34'40.5"N, 98°25'55.9"E: CUMZ 7300. Wat Pang Kham, Pang Mapha, Mae Hong Son, 19°41'03.3"N, 98°12'30.5"E: CUMZ 7501. Huai Nam Dang, Mae Taeng, Chiang Mai, 19°18'48.9"N, 98°36'19.2"E: CUMZ 7299. Kew Mae Pan, Chom Thong, Chiang Mai, 18°33'21.1"N, 98°28'56.0"E: CUMZ 7503 (Fig. 46E, F ). Doi Inthanon, Chom Thong, Chiang Mai, 18°35'16.9"N, 98°29'13.4"E: CUMZ 7502. Mountain area in Chom Thong, Chiang Mai, 18°32'05.2"N, 98°31'02.8"E: CUMZ 7911.

Type locality.

The limestone karsts with dry forest near Mae La Na Cave, Pang Mapha, Mae Hong Son, Thailand, 19°34'25.5"N, 98°13'01.8"E.

Diagnosis.

Shell large, depressed and yellowish brown to brown with obtusely angulated to angulated body whorl. Animal with creamy-grey body and five mantle lobes. Genitalia with a long straight epiphallic caecum and long pseudo-verge. Inner penial sculpture with irregularly short folded pilasters in proximal part, then reticulated pilasters in the middle, and cuboidal pilasters in distal end.

Description.

Shell. Shell depressed, large size (shell width up to 26.5 mm, shell height up to 15.0 mm) and rather thin. Surface rather smooth and polished; shell colour yellowish brown to brown. Whorls 6- 6½, increasing regularly; body whorl large and obtusely angulated to angulated. Spire moderately to very much elevated; suture impressed. Aperture crescent-shaped and obliquely opened. Peristome simple. Columellar margin simple and slightly reflected near umbilicus. Umbilicus narrowly opened (Fig. 46C-F ).

Genital organs. Atrium short. Penis cylindrical with thin penial sheath covering proximal penis. Proximal penis rather slender; distal penis enlarged with pseudo-verge inside. Inner sculpture of penis proximally with very finely longitudinal penial pilasters to nearly smooth surface, then changed to irregularly short folded pilasters, modified to reticulated pilasters in middle, and modified to cuboidal pilasters at distal end. Pseudo-verge long conic, approximately one-third of total penis length. Epiphallus long cylindrical and narrower than distal penis. Epiphallic caecum very long, straight, and almost same diameter as epiphallus. Penial retractor muscle thin and attached at tip of epiphallic caecum. Flagellum long slender, and approximately as long as penis. Vas deferens thin tube connecting distal epiphallus, and free oviduct (Fig. 47C, D ).

Vagina cylindrical and approximately one-fourth of penis length. Dart apparatus large, long cylindrical, and located on atrium at vagina and penis junction. Gametolytic organ (sac and duct) small and long duct. Free oviduct cylindrical and proximal end encircled with thick tissue (Fig. 47C ).

Radula . Teeth with half row formula: 1-(12-13)-54. Central tooth symmetrical tricuspid; lateral teeth asymmetrical tricuspid; marginal teeth elongate bicuspid. Marginal teeth starting at approximately row number 12 or 13 (Fig. 48B ).

External features. Animal with reticulated skin and dark creamy mixing with grey to dark grey body, very pale grey foot sole and pale grey caudal horn. Five mantle lobes well developed and same colour as body (Fig. 45B ).

Etymology.

The specific name solemi is named in honor of Dr. Alan Solem, who first discovered and described the genitalia of this species but under the name Sarika aff. hainesii .

Distribution.

Sarika solemi sp. nov. seems to be restricted to western and northern Thailand along the Tenasserim Ranges (Fig. 44 ). This species occurs in forested mountains and is highly abundant in limestone habitats.

COI analysis.

The ML and BI analyses showed that the individuals of S. solemi sp. nov. (n = 3) formed a monophyletic group with high support (Fig. 1 ; BS = 95%, PP = 1). The mean intraspecific genetic distance of S. solemi sp. nov. was 2.9% (Table 2 ).

Remarks.

Solem (1966) examined and described the genitalia of specimens from northern Thailand and referred them to as " Sarika aff. hainesii ". In this study, we collected and examined several new specimens from northern Thailand and found that the genitalia were identical with those described and illustrated in Solem (1966: 38, 39, fig 5a). We here recognised these populations as new species. Sarika solemi sp. nov. has similar shell morphology to S. hainesi s.s., but the distinguishing characters are the number of mantle lobes and genitalia. This new species has five mantle lobes and genitalia with very long epiphallic caecum and long pseudo-verge, while S. hainesi s. s. has four mantle lobes, and genitalia with shorter epiphallic caecum and without pseudo-verge.

Sarika solemi sp. nov. is a variable species in terms of body whorl with obtusely angulated periphery (Fig. 46C, D ) to obvious angulated periphery (Fig. 46E, F ). All shell morphs are identical in genital characters and form a well-supported clade in COI analysis.

Figures

Figure 1. Maximum likelihood tree showing the relationships among species of Sarika based on the mitochondrial COI gene sequences. Numbers by the nodes are the ML bootstrap values (left) and Bayesian posterior probabilities (right); shown only for the nodes supported by ML or BI (≥ 70 % and ≥ 0.95). Each clade colour refers to a genus.

Figure 44. Geographic distribution of Sarika dugasti and S. solemi sp. nov. based on the specimens examined herein.

Figure 45. Living snails of Group III: Sarika dugasti group. A Sarika dugasti specimen CUMZ 7563 and B S. solemi sp. nov. paratype CUMZ 7298. Not to scale.

Figure 46. Shells of Group III: Sarika dugasti group. A, B Sarika dugasti A syntype MNHN-IM- 2000 - 27884 and B specimen CUMZ 7542, C-F S. solemi sp. nov. C holotype CUMZ 7297 D paratype CUMZ 7298, and E, F specimen CUMZ 7503.

Figure 47. Genitalia. A, B Sarika dugasti specimen CUMZ 7542 A general view of the genital system and B internal structure of the penis C, D S. solemi sp. nov. paratype CUMZ 7298 C general view of the genital system and D internal structure of the penis. White arrowheads indicate the ends of the penes.

Figure 48. Representative SEM images of the radula. A Sarika dugasti specimen CUMZ 7574 and B S. solemi sp. nov. paratype CUMZ 7298. Central tooth indicated by ' C'; Yellow colour indicates lateral teeth with the transition to marginal teeth.