Sarika khmeriana Pholyotha & Panha, 2020

Pholyotha, Arthit, Sutcharit, Chirasak, Thach, Phanara, Chhuoy, Samol, Ngor, Peng Bun & Panha, Somsak, 2020, Land snail genus Sarika Godwin-Austen, 1907 (Eupulmonata: Ariophantidae) from Cambodia, with description of three new species, European Journal of Taxonomy 674 (674), pp. 1-21 : 11-15

Sarika khmeriana Pholyotha & Panha sp. nov.

urn:lsid:zoobank.org:act:13BEB7E0-40BD-480C-ABA7-72798C9E6AF2

Table 1 ; Figs 4 A–B, 5, 6A–F

Diagnosis

Sarika khmeriana sp. nov. can be characterized by a large, depressed shell, rounded on the periphery. Shell colour dark brownish and usually with pale brownish (to whitish) umbilical area. Animal has dark grey body and left shell lobe is absent. Genitalia have rather long epiphallic caecum and inner wall of penis sculptured with triangular prism penial pilasters. Spermatophore head filament with irregularly serrated longitudinal folds; tail filament bearing two spines near sperm sac and branching spines along the entire tail filament length.

Etymology

The specific epithet ‘ khmeriana ’ refers to the Khmer Empire, of which Cambodia is the residual state.

Material examined

Holotype

CAMBODIA • 1 shell (width 24.2 mm, height 12.3 mm); Kampot Province, Dang Tong District, limestone outcrops near Totong Temple, locality code C041; 10°41′59.8″ N, 104°31′30.1″ E; CUMZ 7904 .

Paratypes

CAMBODIA • 6 shells, 11 alcohol-preserved specimens; same collection data as for holotype; CUMZ 7905 • 2 shells; same collection data as for preceding; NHMUK • 2 shells; same collection data as for preceding; ZRC .

Other material

CAMBODIA • 24 shells, 17 alcohol-preserved specimens; Kampot Province, Banteay Meas District, limestone outcrops at Prasat Phnom Totong Temple, locality code C042; 10°41′47.9″ N, 104°31′25.5″ E; CUMZ 7906 .

Description

SHELL ( Fig. 4 A–B). Depressed, large (shell width up to 24.2 mm, shell height up to 12.3 mm), rather thin, semi-translucent. Shell colour dark brownish on upper surface and at periphery; below periphery surrounding umbilicus pale to very pale brownish. Shell surface smooth, glossy; more glossy below periphery; suture rather shallow with narrow, whitish subsutural band. Spire slightly elevated; whorls 6–6½, increasing regularly; last whorl broadly rounded on periphery. Aperture obliquely crescentshaped; peristome simple. Columellar margin simple, slightly reflected near umbilicus. Umbilicus somewhat narrow and deep.

EXTERNAL FEATURES ( Fig. 5A ). Living animals have monochrome dark grey body with pale grey foot sole. Caudal foss present; caudal horn elevated and large. Mantle edge well developed with three dorsal lobes and one shell lobe (see Pholyotha et al. 2018: fig. 1). Shape and size of dorsal lobes and right shell lobe (left shell lobe absent) similar to previous species.

GENITALIA ( Fig. 5 B–C). Atrium (at) enlarged, very short. Penis (p) cylindrical, with thin penial sheath covering proximal penis. Inner sculpture of penis very finely folded to nearly smooth then gradually transformed to triangular prism (rhombic base and acute angle on top) penial pilasters (pp) near epiphallus. Epiphallus (e) cylindrical, elongate, about two times penis length. Epiphallic caecum (ec) large, similar diameter as penis, straight and located near middle of epiphallus. Penial retractor muscle (prm) thin, attached at tip of epiphallic caecum. Flagellum (fl) slender, somewhat long, about 1.5 times epiphallus length. Vas deferens (vd) a thin tube. Vagina (v) cylindrical, similar length as penis. Dart apparatus (da) cylindrical, rather large, long, attached to atrium at penis and vagina junction. Gametolytic sac (gs) enlarged, bulbous (spermatophore inside); gametolytic duct (gd) long, cylindrical. Free oviduct

(fo) cylindrical, longer than vagina, proximal end encircled with thickened tissue. Oviduct large lobules; prostate gland running alongside oviduct.

SPERMATOPHORE ( Fig. 6 A–F). Sperm sac (ss) enlarged, elongate-oval. Head filament (hf) enlarged (most was missing) with irregularly serrated longitudinal folds. Tail filament (tf) very long tube, region close to sperm sac bearing two spines. Spine I simple, short; spine II with complicated branching into small, numerous spinules. Spines on tail filament starting just after spine II, with complicated branching into spinules, arranged alternate ( Fig. 7D ) or opposite ( Fig. 7F ).

RADULA ( Fig. 5D ). Teeth arranged in wide-angle U-shape with half row formula: 1–(13–14)–55 teeth. Central tooth symmetrical tricuspid with triangular-shaped mesocone; ectocones very small. Lateral teeth asymmetrical tricuspid; mesocone large, pointed cusp; endocone small, located near the tip; ectocone larger than endocone, pointed cusp, located in middle of tooth. Marginal teeth occurring around tooth numbers 13–14, obliquely bicuspid; endocone elongate, pointed cusp; ectocone small, pointed cusp. Outermost teeth gradually reduced in size as cusps to small teeth.

Distribution

This new species is known from two locations very close to each other, on limestone outcrops. Totong Mountain (type locality) is a small karst with an old quarry, surrounded by housing areas and is adjacent to paddy fields ( Fig. 1 ). The second locality, Prasat Phnom Totong, about 500 m south of the type locality, is a very large and active mining site of a cement factory.

Remarks

Sarika khmeriana sp. nov. is quite similar in terms of shell shape with S. lactoconcha sp. nov., but this species is distinct in possessing dark brown shell on upper surface and pale brownish (to whitish) surrounding umbilicus, and left shell lobe absent (four mantle lobes); whereas S. lactoconcha sp. nov. has a monochrome pale milky shell, and well-developed left shell lobe (five mantle lobes).

This new species differs from S. resplendens in having a thin penial retractor muscle and the entire tail filament of spermatophore has branching spines, whereas the genitalia of S. resplendens (see Godwin-Austen 1907: fig. 3) have a large and thickened penial retractor muscle, and the tail filament of spermatophore is without a branching spine. Compared with other species of Sarika from Cambodia, S. khmeriana sp. nov. is rounded on the periphery while S. bocourti is obtusely angulated on the periphery, and this new species has a larger shell diameter than S. benoiti . Sarika khmeriana sp. nov. also differs from M. despecta (Mabille, 1887) from northern Vietnam in having an elevated spire and narrower umbilical opening.

Figures

Fig. 4. Shells of Sarika spp. A. Sarika khmeriana Pholyotha & Panha sp. nov., holotype (CUMZ 7904). B. Sarika khmeriana Pholyotha & Panha sp. nov., paratype (CUMZ 7905). C. S. nana Pholyotha & Panha sp. nov., holotype (CUMZ 7907). D. S. nana Pholyotha & Panha sp. nov., paratype (CUMZ 7908). E. Macrochlamys excepta (Mabille, 1887), syntype (MNHN-IM-2000-27886). F. M. zero (Mabille, 1887), syntype (MNHN-IM-2000-27782).

Fig. 5. Sarika khmeriana Pholyotha & Panha sp. nov., paratype (CUMZ 7905). A. Living snail. B. Beneral view of genital system. C. Internal structure of penis. D. Representative SEM image of the radula. Central tooth indicated by ‘C’; yellow arrow heads indicate lateral teeth with the transition to marginal teeth; white arrow heads indicate the end of penis.

Fig. 6. SEM images of spermatophores. A–F. Sarika khmeriana Pholyotha & Panha sp. nov., paratype (CUMZ 7905). A. General view of spermatophore. B. Head filament. C–F. Detail of tail filament. G–J. S. nana Pholyotha & Panha sp. nov., paratype (CUMZ 7908). G. General view of spermatophore. H. Head filament. I–J. Detail of tail filament.

Fig. 7. Sarika nana Pholyotha & Panha sp. nov., paratype (CUMZ 7908). A. Living snail. B. General view of genital system. C. Internal structure of penis. D. Representative SEM image of the radula. Central tooth indicated by ‘C’; yellow arrow heads indicate lateral teeth with the transition to marginal teeth; white arrow heads indicate the end of penis.

Fig. 1. Geographic distribution of Sarika spp. in Cambodia based on new specimens examined herein. (modified from GinkgoMaps-project http://www.ginkgomaps.com).