taxonID	type	description	language	source
038587FD0362FFC4745BFC05961FFAAB.taxon	description	(figs 1, 2, 3 A, B, 4 A, B, 5, 11 A)	en	Pholyotha, Arthit, Sutcharit, Chirasak, Lin, Aung, Panha, Somsak (2022): Multigene phylogeny reveals the ribbed shell morphotypes in the land snail genus Sarika (Eupulmonata: Ariophantidae), with description of two new species from Thailand and Myanmar. Contributions to Zoology 91 (2): 97-132, DOI: 10.1163/18759866-BJA10027, URL: http://dx.doi.org/10.1163/18759866-bja10027
038587FD0362FFC4745BFC05961FFAAB.taxon	materials_examined	Material examined. Type material: the type specimens could not be traced. Non-type material: Attaran Valley [Attaran River valley in Mawlamyine city, Mon State, Myanmar], NHMUK 1888.12.4.1518 - 19 (two shells). Attaran Valley, Tenasserim, NHMUK 1903.7. 1.1096 (one shell). Mergui, NHMUK 1988.12. 4.1514 (one shell; fig. 3 A). Pathen Mountain, Mawlamyine city, Mon State, Myanmar, 16 ° 13 ’ 46.8 ” N 97 ° 56 ’ 20.3 ” E, CUMZ 7941. Pha Paung Cave, Mawlamyine city, Mon State, Myanmar, 16 ° 17 ’ 11.1 ” N 97 ° 54 ’ 06.5 ” E, CUMZ 7942. Diagnostic characteristics. Shell depressed; body whorl obtusely angulated; shell ribbed with irregular-sized dash-shaped nodules arranged on radial ribs. Animal with four mantle edges. Genitalia with straight epiphallic caecum, large penial retractor muscle and cuboidal penial pilasters. Spermatophore: head filament with smooth longitudinal folds; tail filament bearing three spines near sperm sac and about two-thirds of its length with branching spines. Description. Shell (fig. 3 A, B). Shell depressed, large (width up to 32.5 mm, height up to 17.3 mm) and rather thin to slightly solid. Shell colour yellowish brown to brownish. Whorls 6 – 6 ½, increasing regularly. Embryonic shell nearly smooth with very weak radial wrinkles. Spire dome-shaped; apex slightly protruding; suture impressed. Body whorl large and slightly shouldered to obtusely angulated. Upper shell surface sculptured with distinct radial ribs, crossed by spiral lines and with series of irregular-sized dash-shaped nodules arranged on radial ribs, and then radial ribs gradually disappearing below periphery towards umbilicus. Aperture crescent-shaped, little descending, well oblique, and with simple margin. Columellar margin simple and slightly reflected near umbilicus. Umbilicus narrowly opened. Genital organs (fig. 4 A, B). Atrium (at) enlarged and very short. Penis (p) cylindrical, elongate, and with thin penial sheath covering penis near atrium. Inner surface sculptured, finely folded from atrium to middle of penis and then transformed to cuboidal penial pilasters (pp). Epiphallus (e) cylindrical, and slightly shorter than penis. Epiphallic caecum (ec) straight, smaller diameter than proximal epiphallus, and located at middle of epiphallus. Penial retractor muscle (prm) large, thickened and attached at tip of epiphallic caecum. Flagellum (fl) large, irregular slender, enlarged at the tip, and same length as epiphallus. Vas deferens (vd) thin tube. Vagina (v) short cylindrical and about half of penis length. Dart apparatus (da) enlarged, cylindrical and joined to atrium at vaginapenis junction. Gametolytic sac (gs) elongate bulbous (containing one spermatophore inside); gametolytic duct (gd) enlarged cylindrical. Free oviduct (fo) enlarged cylindrical, slightly longer than vagina, and proximally encircled with brownish tissue. Oviduct large lobules; prostate gland running alongside oviduct. Spermatophore (fig. 5). Spermatophore long and needle-shaped (fig. 5 A). Sperm sac (ss) enlarged and elongate oval. Head filament (hf) elongate with smooth longitudinal folds (fig. 5 B). Tail filament (tf) very long tube, and region close to sperm sac bearing three spines: spine I simple and very short; spine II longer than spine I with branching into small spinules; spine III longest with complicated branching into small spinules (fig. 5 C). Region furthest away without spine; terminal part ca. two-thirds of its length with series of branching spines arranged in single row (fig. 5 D, E). Radula (fig. 11 A). Teeth arranged straight and with half row formula: 1 – (16 – 17) – 54. Central tooth symmetrical tricuspid with large mesocone and small ectocones. Lateral teeth asymmetrical tricuspid with large mesocone, and nearly absent to very small endocone and ectocone. Marginal teeth started around tooth number 16 or 17; inner teeth elongate bicuspid with lanceolate endocone and small ectocone; and outermost teeth gradually reduced in size. External features (fig. 2). Living snails with reticulated skin, dark grey to black eye stalks, and pale to dark grey body. Four well-developed mantle edges with pale creamy-grey to dark grey colour. Right shell lobe short and left shell lobe wanting. Dorsal lobes large and broad: anterior and posterior left dorsal lobes smaller than right dorsal lobe. Caudal fossa and caudal horn present. Distribution (fig. 1). Based on our survey, this species has a narrow distribution with two populations being found on isolated limestone hills near Attaran River in Mawlamyine city, Mon State, Myanmar. According to the literature, this species was recorded from the top of Muleyit, Attaran Valley, and Mergui, Yanglaw, Tenasserim Valley (Blanford & Godwin-Austen, 1908). Remarks. Helix theodori Philippi, 1846 was previously classified in the genus Hemiplecta because the shell morphology has strong radial striae on the dorsal shell surface; however, its taxonomic position has been uncertain since the first examination of the genitalia was done by Godwin-Austen (1907) based on two specimens from the Attaran [Mon State] (Godwin-Austen, 1907, 1918; Blanford & Godwin-Austen, 1908). Godwin-Austen (1907) reported that the genitalia of this species were similar to those of Sarika, but its genitalia have no epiphallic caecum near the penial retractor muscle. In this study, however, we discovered that the genitalia of this species have a straight epiphallic caecum with thickened penial retractor muscle in which the diameter of penial retractor muscle is slightly smaller than the diameter of epiphallic caecum (yellow arrow in fig. 4 A). Moreover, our phylogeny indicated that Sarika theodori is grouped with the three other ribbed shell species and other species of Sarika, and not in a clade of Hemiplecta (fig. 2).	en	Pholyotha, Arthit, Sutcharit, Chirasak, Lin, Aung, Panha, Somsak (2022): Multigene phylogeny reveals the ribbed shell morphotypes in the land snail genus Sarika (Eupulmonata: Ariophantidae), with description of two new species from Thailand and Myanmar. Contributions to Zoology 91 (2): 97-132, DOI: 10.1163/18759866-BJA10027, URL: http://dx.doi.org/10.1163/18759866-bja10027
038587FD0366FFC8745BFAE89782FED9.taxon	description	(figs 1, 2, 3 C, D, 4 C, D, 6, 7, 11 B)	en	Pholyotha, Arthit, Sutcharit, Chirasak, Lin, Aung, Panha, Somsak (2022): Multigene phylogeny reveals the ribbed shell morphotypes in the land snail genus Sarika (Eupulmonata: Ariophantidae), with description of two new species from Thailand and Myanmar. Contributions to Zoology 91 (2): 97-132, DOI: 10.1163/18759866-BJA10027, URL: http://dx.doi.org/10.1163/18759866-bja10027
038587FD0366FFC8745BFAE89782FED9.taxon	materials_examined	Material examined. Type material: the type specimens could not be traced. Non-type material: see supplementary table S 5.	en	Pholyotha, Arthit, Sutcharit, Chirasak, Lin, Aung, Panha, Somsak (2022): Multigene phylogeny reveals the ribbed shell morphotypes in the land snail genus Sarika (Eupulmonata: Ariophantidae), with description of two new species from Thailand and Myanmar. Contributions to Zoology 91 (2): 97-132, DOI: 10.1163/18759866-BJA10027, URL: http://dx.doi.org/10.1163/18759866-bja10027
038587FD0366FFC8745BFAE89782FED9.taxon	description	Diagnostic characteristics. Shell depressed; shell colour generally two-tones (brownish above) or monochrome whitish to brownish; shell ribbed with regular-sized, dash-shaped nodules arranged on radial ribs. Animal with four mantle edges. Genitalia with straight epiphallic caecum and cuboidal penial pilasters. Spermatophore: head filament with smooth longitudinal folds; tail filament bearing three spines near sperm sac and about seven-tenths of its length with branching spines. Description. Shell (fig. 3 C, D). Shell depressed to conoid-depressed, large (width up to 38.5 mm, height up to 20.5 mm), and moderately solid. Shell colour generally two-tone with yellowish to dark brown above and whitish below periphery (seldomly monochrome whitish to brownish), and brownish peripheral band sometimes present. Whorls 6 – 6 ½, increasing normally. Spire dome-shaped; apex slightly protruding; suture impressed. Embryonic shell nearly smooth with very weak radial wrinkles. Last whorl large and well-rounded. Upper shell surface sculptured with regular and distinct radial ribs, crossed by spiral lines and with series of regular-sized dash-shaped nodules arranged on radial ribs, and then radial ribs gradually disappearing below periphery towards umbilicus. Aperture crescent-shaped, obliquely opened with simple peristome. Columellar margin simple and slightly reflected near umbilicus. Umbilicus narrowly opened. Genital organs (fig. 4 C, D). Atrium (at) enlarged, very short. Penis (p) elongate, cylindrical, with thin penial sheath covering near atrium. Inner surface sculptured as very finely folded to nearly smooth from atrium to middle of penis, and then gradually transforming to cuboidal penial pilasters (pp). Epiphallus (e) cylindrical, slightly shorter than penis, and distal epiphallus (between epiphallic caecum and flagellum) usually stained with dark colour in adult specimens (see yellow dot lines in fig. 4 C). Epiphallic caecum (ec) straight, smaller diameter than proximal epiphallus, and located at middle of epiphallus. Penial retractor muscle (prm) thin and attached at head of epiphallic caecum. Flagellum (fl) slender, longer than epiphallus, and enlarged at the tip. Vas deferens (vd) thin tube. Vagina (v) short cylindrical, and about half of penis length. Dart apparatus (da) enlarged and joined to atrium at vagina and penis junction. Gametolytic sac (gs) elongate bulbous (containing one spermatophore inside); gametolytic duct (gd) enlarged cylindrical. Free oviduct (fo) enlarged cylindrical, slightly longer than vagina, and proximally encircled with yellowish or brownish tissue. Oviduct large lobules; prostate gland running alongside oviduct. Spermatophore (fig. 6). Spermatophore long and needle-shaped (fig. 6 A). Sperm sac (ss) enlarged and elongate oval. Head filament (hf) elongate and with smooth longitudinal folds (fig. 6 B). Tail filament (tf), region close to sperm sac bearing three spines: spine I simple and slender; spines II and III almost similar in size, longer than spine I and with branching into small spinules (fig. 6 C). Region furthest away without spine; terminal part ca. seven-tenths of its length with series of long branching spines arranged in single row (fig. 6 D), and then transformed to series of short and delicate branching spines covering terminal part of tail filament (fig. 6 E). Radula (fig. 11 B). Teeth arranged straight with half row formula: 1 – (20 – 21) – 72. Teeth shape is similar to those of S. theodori. Central tooth symmetrical tricuspid; lateral teeth asymmetrical tricuspid. Marginal teeth started around tooth number 20 or 21 and with elongate bicuspid. External features (figs 2, 7). Living snails with reticulated skin. Eye stalks and body with whitish, creamy-grey to dark grey colour. Four well-developed mantle lobes with same colour as body. Right shell lobe short and left shell absent. Dorsal lobes large and broad: anterior and posterior left dorsal lobes smaller than right dorsal lobe. Caudal fossa and caudal horn present.	en	Pholyotha, Arthit, Sutcharit, Chirasak, Lin, Aung, Panha, Somsak (2022): Multigene phylogeny reveals the ribbed shell morphotypes in the land snail genus Sarika (Eupulmonata: Ariophantidae), with description of two new species from Thailand and Myanmar. Contributions to Zoology 91 (2): 97-132, DOI: 10.1163/18759866-BJA10027, URL: http://dx.doi.org/10.1163/18759866-bja10027
038587FD0366FFC8745BFAE89782FED9.taxon	distribution	Distribution (fig. 1). Sarika siamensis has a wide distribution, currently known from Thailand, Myanmar, Laos, Malaysia, Singapore, Cambodia, and southern China (Prasankok & Panha, 2011; Abu-Bakar et al., 2014; Tan et al., 2016; Inkhavilay et al., 2019; Boonmachai & Nantarat, 2020; Dumidae et al., 2020; Sutcharit et al., 2020 b). Its distribution in Vietnam and other countries needs further studies. All records of S. siamensis come from sandstone, rocky, limestone, mountainous habitats, and human disturbed areas (Prasankok & Panha, 2011; Tan et al., 2016; Inkhavilay et al., 2019; Boonmachai & Nantarat, 2020; Dumidae et al., 2020; Sutcharit et al., 2020 b).	en	Pholyotha, Arthit, Sutcharit, Chirasak, Lin, Aung, Panha, Somsak (2022): Multigene phylogeny reveals the ribbed shell morphotypes in the land snail genus Sarika (Eupulmonata: Ariophantidae), with description of two new species from Thailand and Myanmar. Contributions to Zoology 91 (2): 97-132, DOI: 10.1163/18759866-BJA10027, URL: http://dx.doi.org/10.1163/18759866-bja10027
038587FD0366FFC8745BFAE89782FED9.taxon	discussion	Remarks. Pfeiffer (1856 a) described this species from “ Siam ” [Thailand] based on specimens in the Cuming collection; however, the type specimen could not be located in the NHM, London collection. This species has been classified to the Indian genus Cryptozona since the classification of Panha (1996); however, its generic position has been uncertain. Most studies on this species have concentrated at the population level because this species is the most widespread species in mainland Southeast Asia (Prasankok & Panha, 2011; Tan et al., 2016; Inkhavilay et al., 2019; Boonmachai & Nantarat, 2020; Dumidae et al., 2020; Sutcharit et al., 2020 b) and is currently reported as the intermediate host for the rat lungworm that causes eosinophilic meningitis in human (Vitta et al., 2016; Dumidae et al., 2020). There were no records of S. siamensis in Myanmar until our survey in 2016, where a S. siamensis population was discovered in an urban area (Hpa-An City, Myanmar), but we could not find them in suburban or rural areas. In addition, Macrochlamys kelantanensis Möllendorff, 1902, a widespread species in Malaysia and Thailand, was also found at same locality with S. siamensis (Pholyotha et al., 2020 b). Thus, we consider that this population of S. siamensis has recently expanded its range into Myanmar, possibly associated with anthropogenic activities due to the high mountain barrier to snail dispersal covering from northern Thailand and extending along the Myanmar border (Gupta 2005). An accidental introduction through horticultural trade activities or association with human activities has been reported in Singapore (Tan et al., 2016), Chintamanis in Malaysia (Prasankok & Panha, 2011), Yunnan in China (Sutcharit et al., 2020 b), and Kampong Speu in southern Cambodia (Sutcharit et al., 2020 b). In addition, S. siamensis exhibits a rather wide range of shell colour variation from monotone whitish (fig. 7 B, C) or two-tone, much paler beneath (fig. 7 A, D), and with or without a peripheral band (fig. 7 C, D). This species also exhibits a rather wide range of body colour variation from whitish (fig. 7 A) to creamy-grey (fig. 7 C) or grey (fig. 7 B, D). In the past, there were some examples of taxonomic problems from these variations of S. siamensis. A white unbanded variety with faintly decussated shells was erroneously recorded as S. hainesi (Marten, 1860; Marten, 1867; Tryon, 1886), while a large, pale yellowish shell with a reddish band was also erroneously described as S. birmana (Pfeiffer, 1857) (Marten, 1860; Marten, 1867; Morelet, 1875). In this study, we examined all the variations in S. siamensis and found that the genitalia of these morphs were identical. In addition, our molecular phylogeny also supported that all these morphs were grouped together within the S. siamensis clade (fig. 2).	en	Pholyotha, Arthit, Sutcharit, Chirasak, Lin, Aung, Panha, Somsak (2022): Multigene phylogeny reveals the ribbed shell morphotypes in the land snail genus Sarika (Eupulmonata: Ariophantidae), with description of two new species from Thailand and Myanmar. Contributions to Zoology 91 (2): 97-132, DOI: 10.1163/18759866-BJA10027, URL: http://dx.doi.org/10.1163/18759866-bja10027
038587FD036AFFCC745BFEC695C4FA46.taxon	description	(figs 1, 2, 8 A, B, 9 A, B, 10, 11 C) Type material examined. Holotype. CUMZ 7943 (fig. 8 A; width 29.3 mm, height 16.7 mm). Paratypes. Same locality as holotype: CUMZ 7944 (fig. 8 B, width 28.5 mm, height 16.1 mm), NHMUK 0000 (two shells), and ZRC 0000 (two shells). Limestone outcrop in Cha Lae, Thong Pha Phum District, Kanchanaburi Province, Thailand, 14 ° 56 ’ 31.1 ” N 98 ° 40 ’ 10.4 ” E, CUMZ 7945. Type locality. Wat Pa Tham Sukho Prang Phe, Sangkhla Buri District, Kanchanaburi Province, Thailand 15 ° 02 ’ 12.7 ” N 98 ° 34 ’ 58.2 ” E. Etymology. The specific name “ costabilis ” is from the Latin word meaning “ riblike ”, which refers to shell surface with transversely dashed ribs that characterises this species within the genus Sarika. Diagnostic characteristics. Shell large, depressed; body whorl obtusely angulated; shell ribbed with nodules arranged on radial ribs. Animal dark creamy-grey body and four mantle edges. Genitalia with short and straight epiphallic caecum and cuboidal penial pilasters. Spermatophore: head filament with smooth longitudinal folds; tail filament bearing three spines near sperm sac and with branching spines on middle and terminal part. Description. Shell (fig. 8 A, B). Shelldepressed, large size (width up to 29.3 mm, height up to 16.7 mm), and rather solid; shell colour yellowish-brown. Whorls 6 – 6 ½, increasing regularly; near aperture opening slightly sloping downwards. Spire dome-shaped; apex slightly protruding; suture impressed. Embryonic shell nearly smooth with very weak radial wrinkles. Body whorl large and obtusely angulated. Upper shell surface sculptured with distinct radial ribs, crossed by spiral lines, and with series of nodules arranged on radial ribs, and then radial ribs gradually disappearing below periphery towards umbilicus. Aperture crescent-shaped, little descending, and lip little thickened. Columellar margin simple and slightly reflected near umbilicus. Umbilicus narrowly opened. Genital organs (fig. 9 A, B). Atrium (at) enlarged and very short. Penis (p) elongate, cylindrical, with thin penial sheath covering near atrium. Inner surface sculptured, very finely folded to nearly smooth from atrium to one-third of penis, and then gradually transformed to cuboidal penial pilasters (pp). Epiphallus (e) cylindrical, slightly shorter than penis. Epiphallic caecum (ec) short, straight, diameter nearly equal to proximal epiphallus, and located at middle of epiphallus. Penial retractor muscle (prm) thin and attached at tip of epiphallic caecum. Flagellum (fl) very long approximately twice of epiphallus length, slender and enlarged at the tip. Vas deferens (vd) thin tube. Vagina (v) cylindrical and slightly shorter than half of penis length. Dart apparatus (da) enlarged cylindrical and joined to atrium at vagina and penis junction. Gametolytic sac (gs) elongate bulbous (containing one spermatophore inside); gametolytic duct (gd) cylindrical and enlarged at based. Free oviduct (fo) enlarged cylindrical, approximately two times of vagina length. Oviduct large lobules; prostate gland running alongside oviduct. Spermatophore (fig. 10). Spermatophore long and needle-shaped (fig. 10 A). Sperm sac (ss) enlarged and elongate oval. Head filament (hf) elongate with smooth longitudinal folds (fig. 10 B). Tail filament (tf), region close to sperm sac bearing three spines: spine I very small and simple; spine II longer than spine I with bifurcating into spinules; spine III longest with complicated branching into small spinules (fig. 10 C). Region furthest away with series of ten branching spines arranged in row located in middle (red dashed line in fig 10 A; fig. 10 D); terminal part about one-tenth of its length, composed of series of short to long delicate branching spines arranged in multiple rows, and covering terminal part of tail filament (fig. 10 E). Radula (fig. 11 C). Teeth arranged in wide, straight, and with half row formula: 1 – (19 – 20) – 70. Central tooth symmetrical tricuspid with large mesocone and small ectocones. Lateral teeth asymmetrical tricuspid with large mesocone, and small endocone and ectocone. Marginal teeth started around tooth number 19 or 20; inner teeth elongate bicuspid with lanceolate endocone and minute ectocone; and outermost teeth gradually reduced in size. External features (fig. 2). Living snails with reticulated skin, dark grey to black eye stalks, and pale to dark creamy-grey body. Four well-developed mantle lobes with same colour as body. Right shell lobe short and left shell lobe absent. Dorsal lobes large and broad; anterior and posterior left dorsal lobes smaller than right dorsal lobe. Caudal fossa and caudal horn present. Distribution (fig. 1). Sarika costabilis sp. nov. is endemic to Thailand and, currently known from a few limestone localities in mountainous areas in Kanchanaburi Province (fig. 1). We extended our survey in other karstic habitats in Thailand, but we could not find this species elsewhere. Remarks. Among the Sarika species with a ribbed shell, the distinguishing character of S. costabilis sp. nov. is the obtusely angulated last whorl with descending aperture, genitalia with short and large epiphallic caecum and long flagellum, and spermatophore with branching spines at the middle and terminal part of tail filament. In contrast, S. siamensis has a well-rounded last whorl, aperture not descending, genitalia with long epiphallic caecum and short flagellum, and spermatophore having spines nearly the entire tail filament length. Shell morphology of S. costabilis sp. nov. is somewhat similar to S. theodori, but the latter species have long epiphallic caecum, short flagellum, and spermatophore having spines about two-thirds of the tail filament length. Compared with other ariophantids with ribbed shells, S. costabilis sp. nov. can be distinguished from Hemiplecta textrina (Benson, 1856) by a coarse shell sculpture and descending aperture. In contrast, the shell sculpture of H. textrina is slightly coarse and its aperture is simple (Blanford & Godwin-Austen, 1908; Sutcharit & Panha, 2021). This new species can be separated from H. auriettae (Tapparone-Canefri, 1889) by its small and narrow umbilicus. In contrast, the umbilicus of H. auriettae is slightly widely opened and shows all whorls (Blanford & Godwin-Austen, 1908; Sutcharit & Panha, 2021). However, the anatomical data of H. textrina and H. auriettae are unavailable for further comparison. Sarika costata species group: species with a shell surface having fine radial ribs without fine impressed spiral lines and with five mantle lobes.	en	Pholyotha, Arthit, Sutcharit, Chirasak, Lin, Aung, Panha, Somsak (2022): Multigene phylogeny reveals the ribbed shell morphotypes in the land snail genus Sarika (Eupulmonata: Ariophantidae), with description of two new species from Thailand and Myanmar. Contributions to Zoology 91 (2): 97-132, DOI: 10.1163/18759866-BJA10027, URL: http://dx.doi.org/10.1163/18759866-bja10027
038587FD036EFFCE76BCFA439789FB3F.taxon	description	(figs 1, 2, 8 C, D, 9 C, D, 11 D) Type material examined. Holotype. CUMZ 7946 (fig. 8 C, width 10.8 mm, height 7.2 mm). Paratypes. Same locality as holotype: CUMZ 7947 (fig. 8 D, width 10.9 mm, height 7.0 mm). Other material examined. Phra (Buddha) Cave, Tanintharyi Township, Tanintharyi Division, Myanmar, 11 ° 13 ’ 46.2 ” N 99 ° 10 ’ 34.3 ” E, CUMZ 7948. Type locality. Kala Island, Myeik Township, Myeik District, Tanintharyi Division, Myanmar, 12 ° 25 ’ 54.3 ” N 98 ° 29 ’ 56.3 ” E. Etymology. The specific name “ costata ” is from the Latin word meaning “ ribbed ”, which refers to the shell surface having fine radial ribs that characterises this species within the genus Sarika. Diagnostic characteristics. Shell medium, globosely depressed; body whorl well-rounded; shell ribbed with smooth radial ribs; aperture narrowly crescent-shaped. Animal pale grey body, black stripes behind long tentacles and five mantle edges. Genitalia with straight epiphallic caecum, cuboidal, and irregularly oblique-folded penial pilasters. Description. Shell (fig. 8 C, D). Shell globosely depressed, medium size (width up to 12.4 mm, height up to 8.0 mm) and rather thin to slightly solid. Shell colour yellowish-brown to brownish. Whorls 6 – 6 ¼, increasing regularly. Spire much elevated; apex slightly protruding; suture impressed, slightly wider near aperture opening. Embryonic shell rather smooth; later whorl with very weak radial ridges. Body whorl large and well-rounded. Upper shell surface sculptured with regular, distinct, and smooth radial ribs, and then radial ribs disappearing below periphery. Aperture crescent-shaped, narrow, well oblique, and with simple lip. Columellar margin simple and slightly reflected near umbilicus. Umbilicus narrowly opened. Genital organs (fig. 9 C, D). Atrium (at) enlarged and very short. Penis (p) elongate and cylindrical. Inner surface sculptured with very finely longitudinal pilasters (pp) to nearly smooth, about one-third of penis length, covered with cuboidal pilasters in middle part, and then transformed to irregular folds arranged in oblique row about one-third of penis length. Epiphallus (e) elongate, cylindrical, and same length as penis. Epiphallic caecum (ec) straight, slightly smaller diameter than epiphallus and located at middle of epiphallus. Penial retractor muscle (prm) thin and attached at tip of epiphallic caecum. Flagellum (fl) slender, same length as epiphallus, and enlarged at the tip. Vas deferens (vd) thin tube. Vagina (v) cylindrical and slightly shorter than penis. Dart apparatus (da) enlarged, very long, and joined to atrium at vagina and penis junction. Gametolytic sac (gs) bulbous; gametolytic duct (gd) elongate cylindrical. Free oviduct (fo) enlarged cylindrical, slightly shorter than vagina. Oviduct large lobules; prostate gland running alongside oviduct. Radula (fig. 11 D). Teeth arranged straight with half row formula: 1 – (11 – 12) – 50. Central tooth symmetrical tricuspid with large mesocone and small ectocones. Lateral teeth asymmetrical tricuspid with large mesocone, and small endocone and ectocone. Marginal teeth started around tooth number 11 or 12; inner teeth elongate bicuspid with lanceolate endocone and small ectocone; and outermost teeth gradually reduced in size. External features (fig. 2). Living snails with reticulated skin, dark grey eye stalks, and very pale grey body with black stripes behind long tentacles. Five well-developed mantle lobes with same colour as body. Right shell lobe moderately elongate; left shell lobe short. Dorsal lobes large and broad; anterior and posterior left dorsal lobes smaller than right dorsal lobe. Caudal fossa and caudal horn present. Distribution (fig. 1). Sarika costata sp. nov. is known from two localities, Kala Island and on the mainland at Phra Cave in Tanintharyi Region, Myanmar. Its distribution range needs further studies. We could not find this species in Thailand. Remarks. Regardless of the genitalia and mantle characters, Sarika costata sp. nov. differs from S. theodori, S. siamensis, and S. costabilis sp. nov. by having small and smooth radial ribs, while the three latter species have relatively larger shell with nodules or dash-shaped nodules arranged on radial ribs. Moreover, this new species has five mantle edges and the inner wall of the penis is sculptured with cuboidal and folded penial pilasters, while the other three species have four mantle edges, and the inner wall of the penis is sculptured with only cuboidal penial pilasters. Compared with the medium-sized species with costulate striation on the shell surface from Thailand and Myanmar, the shell morphology of S. costata sp. nov. is similar to Khasiella pansa (Benson, 1856). Khasiella pansa was described from the Irrawaddy Valley and recorded from the Mergui Archipelago (Benson, 1856; Blanford & Godwin-Austen, 1908); however, the anatomical data of K. pansa needs further studies. In comparison, this new species has a smaller shell size, well-rounded body whorl, and narrowly crescent-shaped aperture, while K. pansa has a slightly larger, subangulate body whorl, and wider aperture (Benson, 1856; Hanley & Theobald, 1876; Blanford & Godwin-Austen, 1908).	en	Pholyotha, Arthit, Sutcharit, Chirasak, Lin, Aung, Panha, Somsak (2022): Multigene phylogeny reveals the ribbed shell morphotypes in the land snail genus Sarika (Eupulmonata: Ariophantidae), with description of two new species from Thailand and Myanmar. Contributions to Zoology 91 (2): 97-132, DOI: 10.1163/18759866-BJA10027, URL: http://dx.doi.org/10.1163/18759866-bja10027
