taxonID	type	description	language	source
294B256410778618D69BFB33B4C6FB59.taxon	type_taxon	Type species. Pterocyclos rupestris Benson, 1832 by monotypy. The specimen that matches best with the original description and figures (Benson, 1832: 13, pl. 2, fig. 1 A – C) is here designated as the lectotype UMZC 2359.1 (Fig. 3 A, no operculum) to stabilise the name. The other specimens become the paralectotypes UMZC 2359.2 (4 shells, Fig. 3 B). The type locality is from “ outlying rocks of the Rajmahal range of Hill, India ”. Subsequently, based on differences in the shell colour, Benson (1832: 13) also recognised three varieties (var. 1 – 3) in the same lot of specimens. However, only the syntype UMZC 2359.3 of “ var. 3 ” (1 shell, Fig. 3 C) could be distinguished from the others.	en	Sutcharit, Chirasak, Tongkerd, Piyoros, Panha, Somsak (2014): The land snail genus Pterocyclos Benson, 1832 (Caenogastropoda: Cyclophoridae) from Thailand and Peninsular Malaysia, with descriptions of two new species. Raffles Bulletin of Zoology 62: 330-338, DOI: 10.5281/zenodo.5458831
294B256410778618D69BFB33B4C6FB59.taxon	diagnosis	Diagnosis. Apertural lip narrow to wide, wing-shaped and overhanging the accessory respiratory structure. This last structure varies from notch-like to completely tubular in shape. The last whorl is usually completely attached to the penultimate whorl (only in a few species is the last whorl partly separated from the penultimate whorl). Operculum calcareous with a shallow to deep concave profile, inside covered with a corneous layer, and outside with many calcareous counterclockwise multilamellae. These characters made Pterocyclos s. s. different from the other known pterocyclini genera. External features. Animal shows blackish patches and / or mottles scattered on a whitish body, faded near mantle cavity (Fig. 2 A – C). Head with pair of long cephalic tentacles (ct), each containing dark eyespot at outer base (Fig. 2 A). Anterior body short with genital groove on right side running downwards from anterior end of pallial cavity. Posterior body long, foot broad, with operculum attached dorsally of posterior body. Animal dioecious, male has both long conical external penis (p) on right side below tentacles, and sperm groove (sg) passed along to tip of external penis (Fig. 2 A); female shows only vaginal groove (vg) on right side (Fig. 2 B). Lung cavity (lc) has large vein (v) and reticulated vessels. Ctenidium and osphradium absent. Mantle collar (mc) smooth and slightly thickened. Columellar muscle (cm) broad and thickened (Fig. 2 B). Genitalia. Testis (te) with branched tubules, bright orange, located around 2 – 3 whorls from apex. Vas deferens (vd) thin, straight tube, connected between testis and prostate gland (pg). Narrow sperm groove connected from genital opening on the right side of snail to tip of external penis. Long cylindrical shaped external penis situated posteriorly below tentacles (Fig. 2 A). Female: Ovary (ov) bright orange colour and multi-lobulate glands embedded with brownish digestive glands. Oviduct (od) with thin tube, connected between ovary and uterus (ut) (Fig. 2 B). Radula morphology. Typical taenioglossate radula were observed (Fig. 2 D, E), teeth arranged in v-shaped row, each transverse row contained 7 teeth (2 - 1 - 1 - 1 - 2). Central tooth large, symmetrical triangular shape, with 2 – 4 well developed cusps on each side. Lateral and marginal teeth slightly slender, inclining to central tooth, with 3 – 4 cusps. Shape of teeth and number of cusps vary among species.	en	Sutcharit, Chirasak, Tongkerd, Piyoros, Panha, Somsak (2014): The land snail genus Pterocyclos Benson, 1832 (Caenogastropoda: Cyclophoridae) from Thailand and Peninsular Malaysia, with descriptions of two new species. Raffles Bulletin of Zoology 62: 330-338, DOI: 10.5281/zenodo.5458831
294B256410778618D69BFB33B4C6FB59.taxon	discussion	Remarks. Two different spellings, viz. Pterocyclos and Pterocyclus, are widely used in the literature and both attributed to Benson (1832). However, the name Pterocyclus is an unjustified emendation that has been erroneously used as a valid name (e. g., Nevill, 1878; Fischer, 1885; Kobelt & Möllendorff, 1897; Kobelt, 1902, 1911). Wenz (1938) was the first to place Pterocyclus in the synonymy of Pterocyclos. In addition, he attributed the authorship of Pterocyclus to Crosse (1868). However, it now seems that Agassiz (1848: 908) was responsible for this unjustified emendation. Hence, the proper authorship and date of the name Pterocyclus is “ Agassiz, 1848 ” (ICZN, 1999: Art. 50.5). Nomenclaturally, Pterocyclus Agassiz, 1848 [Mollusca, Gastropoda] is a junior homonym of Pterocyclus Gray, 1846 [Aves, Passeriformes, Tomaliidae]. Thus, it should not be used as valid generic name (ICZN, 1999, Arts. 23, 52), even if Pterocyclus Gray, 1846 is itself a junior subjective synonym of Garrulax Lesson, 1831 (Deignan et al., 1964; Sibley & Monroe, 1999).	en	Sutcharit, Chirasak, Tongkerd, Piyoros, Panha, Somsak (2014): The land snail genus Pterocyclos Benson, 1832 (Caenogastropoda: Cyclophoridae) from Thailand and Peninsular Malaysia, with descriptions of two new species. Raffles Bulletin of Zoology 62: 330-338, DOI: 10.5281/zenodo.5458831
294B256410758618D441FB13B073FE59.taxon	description	(Figs. 1, 3 E, F; Table 1)	en	Sutcharit, Chirasak, Tongkerd, Piyoros, Panha, Somsak (2014): The land snail genus Pterocyclos Benson, 1832 (Caenogastropoda: Cyclophoridae) from Thailand and Peninsular Malaysia, with descriptions of two new species. Raffles Bulletin of Zoology 62: 330-338, DOI: 10.5281/zenodo.5458831
294B256410758618D441FB13B073FE59.taxon	materials_examined	Other material examined. Teluk Ewa, Pulau Langkawi, Kedah, Malaysia: CUMZ 3880 (64 shells), 4582 (44 shells, Fig. 3 E, F), 4583 (70 shells), 4584 (3 shells). Gua Cerita, Northern Island, Pulau Langkawi, Kedah, Malaysia: CUMZ 3879 (9 shells).	en	Sutcharit, Chirasak, Tongkerd, Piyoros, Panha, Somsak (2014): The land snail genus Pterocyclos Benson, 1832 (Caenogastropoda: Cyclophoridae) from Thailand and Peninsular Malaysia, with descriptions of two new species. Raffles Bulletin of Zoology 62: 330-338, DOI: 10.5281/zenodo.5458831
294B256410758618D441FB13B073FE59.taxon	discussion	Remark. Pterocyclos blandi was described by Benson (1851) in one of the two papers (out of nearly 60) in which Benson dealt with land snails and provided illustrations of specimens (Naggs, 1997). The species identification is unambiguous and there are no type specimens. The species differs from all other Pterocyclos species by its depressed and thick shell, and transparent periostracum. The shell colour is usually uniform brown to purplish, rarely with variegated brown zigzag pattern, apertural lip whitish; upper part of the apertural lip broadly expanded and wing-shaped; lower part of the apertural lip thickened and not expanded. Accessory respiratory structure triangular, overhanging by the upper part of the apertural lip. Operculum calcareous, slightly concave inside, and multilamellae outside. The species was not found in the limestone areas of Perlis, Kedah, Perak and Kelantan in Malaysia, and in southern Thailand. This suggests that P. blandi has a limited distribution and is possibly endemic to Langkawi Islands, Perlis, Malaysia, where the species seems to be declining due to exploitation of the limestone quarries.	en	Sutcharit, Chirasak, Tongkerd, Piyoros, Panha, Somsak (2014): The land snail genus Pterocyclos Benson, 1832 (Caenogastropoda: Cyclophoridae) from Thailand and Peninsular Malaysia, with descriptions of two new species. Raffles Bulletin of Zoology 62: 330-338, DOI: 10.5281/zenodo.5458831
294B256410758618D693FE13B09EFB67.taxon	description	(Figs. 1, 3 G)	en	Sutcharit, Chirasak, Tongkerd, Piyoros, Panha, Somsak (2014): The land snail genus Pterocyclos Benson, 1832 (Caenogastropoda: Cyclophoridae) from Thailand and Peninsular Malaysia, with descriptions of two new species. Raffles Bulletin of Zoology 62: 330-338, DOI: 10.5281/zenodo.5458831
294B256410758618D693FE13B09EFB67.taxon	materials_examined	Type specimens. Holotype UMZC 1032 (height 8.8 × diameter 17.2 mm, Fig. 3 G) (no other material was available).	en	Sutcharit, Chirasak, Tongkerd, Piyoros, Panha, Somsak (2014): The land snail genus Pterocyclos Benson, 1832 (Caenogastropoda: Cyclophoridae) from Thailand and Peninsular Malaysia, with descriptions of two new species. Raffles Bulletin of Zoology 62: 330-338, DOI: 10.5281/zenodo.5458831
294B256410758618D693FE13B09EFB67.taxon	discussion	Remark. Pterocyclos subalatus has been described in detail, based on two shells (Sykes, 1903). Because of its relatively small size (diameter about 15 mm), and its thick and brownish periostracum, this species superficially resembles the genus Cyclotus. However, the holotype clearly shows the typical characters of Pterocyclos, i. e., the expanded apertural lip, with thin channel and shortly expanded of apertural lip at suture area, operculum low cup shape, and multilamellae outside. This species clearly differs from P. spaleotes and P. umbraticus because its last whorl is not disconnected from the penultimate whorl, while its accessory respiratory structure has a shallow channel. It further differs from P. umbraticus by having a smooth shell surface and much smaller shell size.	en	Sutcharit, Chirasak, Tongkerd, Piyoros, Panha, Somsak (2014): The land snail genus Pterocyclos Benson, 1832 (Caenogastropoda: Cyclophoridae) from Thailand and Peninsular Malaysia, with descriptions of two new species. Raffles Bulletin of Zoology 62: 330-338, DOI: 10.5281/zenodo.5458831
294B25641075861ED6E6FAFDB72CF8E3.taxon	description	(Figs. 1, 2 D, 3 H – J; Table 1)	en	Sutcharit, Chirasak, Tongkerd, Piyoros, Panha, Somsak (2014): The land snail genus Pterocyclos Benson, 1832 (Caenogastropoda: Cyclophoridae) from Thailand and Peninsular Malaysia, with descriptions of two new species. Raffles Bulletin of Zoology 62: 330-338, DOI: 10.5281/zenodo.5458831
294B25641075861ED6E6FAFDB72CF8E3.taxon	materials_examined	Type specimens. The specimen herein designated as the lectotype NMW 1955.158. 01107 (height 11.4 × diameter 22.8 mm; Fig. 3 H, no operculum), to stabilise the name, is the shell figured in the original description (Tomlin, 1932, pl. 26 text figure). The other specimen from the same lot of the lectotype becomes the paralectotype NMW 1981.118. 02705 (1 shell, Fig. 3 I, no operculum). Other material examined. Topotypes from Batu Cave, Kuala Lumpur, Malaysia (03 ° 14.276 ' N, 101 ° 41.079 ' E): CUMZ 4585 (35 specimens in ethanol, Fig. 3 J), 4747 (52 shells).	en	Sutcharit, Chirasak, Tongkerd, Piyoros, Panha, Somsak (2014): The land snail genus Pterocyclos Benson, 1832 (Caenogastropoda: Cyclophoridae) from Thailand and Peninsular Malaysia, with descriptions of two new species. Raffles Bulletin of Zoology 62: 330-338, DOI: 10.5281/zenodo.5458831
294B25641075861ED6E6FAFDB72CF8E3.taxon	discussion	Remark. Pterocyclos spaleotes is only known from its type locality, despite several surveys in nearby areas. Originally, it was described from two shells without an operculum, which leads Tomlin (1932) to assign it to the genus Rhiostoma Benson, 1860. However, after examining the types (Fig. 3 G, H) and topotypic specimens (Fig. 3 I), this generic placement seems untenable. The unique characters of P. spaleotes are: the small and thin shell, the corneous and transparent periostracum, and the surface with a variegated brown zigzag colour pattern and a dark brown peripheral band. The last whorl is usually partially disconnected from the penultimate whorl. Aperture rounded, with a white lip and a little expansion of the upper part. The accessory respiratory structure has a short, tubular shape. The operculum is calcareous, slightly concave inside and multilamellae outside. Pterocyclos spaleotes clearly differs from any Rhiostoma species by the shape of its accessory respiratory structure located on the sutural area, and by its calcareous, low cupshaped and multilamellae operculum. Moreover, P. spaleotes has been recorded (type locality) much further south than Rhiostoma, which does not occur south of the limestone karst in Perlis, Malaysia. Finally, preliminary analysis of the DNA sequence of a fragment of the cytochrome oxidase subunit I gene supports the transfer of Rhiostoma spaleotes to Pterocyclos (Tongkerd, unpublished data).	en	Sutcharit, Chirasak, Tongkerd, Piyoros, Panha, Somsak (2014): The land snail genus Pterocyclos Benson, 1832 (Caenogastropoda: Cyclophoridae) from Thailand and Peninsular Malaysia, with descriptions of two new species. Raffles Bulletin of Zoology 62: 330-338, DOI: 10.5281/zenodo.5458831
294B25641073861ED5E6F879B10FF7BB.taxon	description	(Figs. 1, 3 K)	en	Sutcharit, Chirasak, Tongkerd, Piyoros, Panha, Somsak (2014): The land snail genus Pterocyclos Benson, 1832 (Caenogastropoda: Cyclophoridae) from Thailand and Peninsular Malaysia, with descriptions of two new species. Raffles Bulletin of Zoology 62: 330-338, DOI: 10.5281/zenodo.5458831
294B25641073861ED5E6F879B10FF7BB.taxon	materials_examined	Type specimens. Holotype ZMA Mol. 135622 (height 13.2 × diameter 29.4 mm, Fig. 3 K) (no other material was available).	en	Sutcharit, Chirasak, Tongkerd, Piyoros, Panha, Somsak (2014): The land snail genus Pterocyclos Benson, 1832 (Caenogastropoda: Cyclophoridae) from Thailand and Peninsular Malaysia, with descriptions of two new species. Raffles Bulletin of Zoology 62: 330-338, DOI: 10.5281/zenodo.5458831
294B25641073861ED5E6F879B10FF7BB.taxon	discussion	Remarks. Benthem Jutting (1949) described this species based on a number of shells. We have examined the holotype, which clearly does not show the typical characters of Cyclotus and, therefore, we suggest transferring the species to Pterocyclos. The shell has a relatively large, short channel-like accessory respiratory structure at the apertural lip, and the upper part of the apertural lip is expanded near the suture. In contrast, Cyclotus usually has a relatively small shell (diameter 10 – 30 mm), no accessory respiratory structure or only a short sutural tube, and has a corneous or thin calcareous, plate-shaped operculum (Kobelt, 1902, 1911; Wenz, 1938). Because of these differences, we suggest the re-assignment of this species to Pterocyclos. The characters by which P. umbraticus differs from the other Pterocyclos species are the chevron-shaped, zigzag sculpture on the upper shell surface, and the accessory respiratory structure that forms a nearly complete tube. In addition, this species tends to live in non-limestone forests of highland areas (altitude about 200 – 1600 m) in Pahang (Benthem Jutting, 1949).	en	Sutcharit, Chirasak, Tongkerd, Piyoros, Panha, Somsak (2014): The land snail genus Pterocyclos Benson, 1832 (Caenogastropoda: Cyclophoridae) from Thailand and Peninsular Malaysia, with descriptions of two new species. Raffles Bulletin of Zoology 62: 330-338, DOI: 10.5281/zenodo.5458831
294B25641070861DD5D1FF53B1B2FBB9.taxon	description	(Figs. 1, 3 L – P; Table 1)	en	Sutcharit, Chirasak, Tongkerd, Piyoros, Panha, Somsak (2014): The land snail genus Pterocyclos Benson, 1832 (Caenogastropoda: Cyclophoridae) from Thailand and Peninsular Malaysia, with descriptions of two new species. Raffles Bulletin of Zoology 62: 330-338, DOI: 10.5281/zenodo.5458831
294B25641070861DD5D1FF53B1B2FBB9.taxon	materials_examined	Type specimens. Holotype CUMZ 4595 (height 13.9 × diameter 25.4 mm; Fig. 3 L). Type locality: Tam Sumano, Patthalung, Thailand (7 ° 35 ' 183 " N, 99 ° 52 ' 80 " E). Paratypes CUMZ 4588 (11 specimens in ethanol, Fig. 3 M), NHMUK (2 shells), NMW (2 shells), SMF (2 shells) are from the type locality. Other material examined. Gua Cenderawasih, Perlis, Malaysia CUMZ 3881 (44 shells), 4592 (7 shells, Fig. 3 N). Sungi Jenis, Perlis, Malaysia: CUMZ 3878 (27 shells). Gua Kelam, Perlis, Malaysia: CUMZ 3877 (39 shells), 4587 (6 shells). Wang Kelian, Perlis, Malaysia: CUMZ 3875 (4 shells). Perlis State Park, Malaysia: CUMZ 4586 (10 shells). Khao Loop-chang, Padang Besar, Songkhla: CUMZ 3876 (4 shells). Tam Tone-din, Kuan-Don, Satun: CUMZ 4590 (19 shells; Fig. 3 O, P), 4591 (16 shells), 4866 (4 shells). Tarutao National Park, Satun: CUMZ 4589 (14 shells), 4593 (3 shells), 4749 (6 shells), 4750 (43 shells). Tam Kantiphol, Tung Wa, Satun: CUMZ 4596 (6 shells). Tam Phaya Hong, Kong Ra, Patthalung: CUMZ 4870 (13 shells). Tam Puttha Kodome, Srinagarindra, Patthalung: CUMZ 3812 (9 shells).	en	Sutcharit, Chirasak, Tongkerd, Piyoros, Panha, Somsak (2014): The land snail genus Pterocyclos Benson, 1832 (Caenogastropoda: Cyclophoridae) from Thailand and Peninsular Malaysia, with descriptions of two new species. Raffles Bulletin of Zoology 62: 330-338, DOI: 10.5281/zenodo.5458831
294B25641070861DD5D1FF53B1B2FBB9.taxon	etymology	Etymology. The specific epithet is from the Latin word “ diluvium ” meaning “ inundation or flood ”. This is a commemorative name referring to the most devastating flooding in the history of the Kingdom of Thailand in the year 2011.	en	Sutcharit, Chirasak, Tongkerd, Piyoros, Panha, Somsak (2014): The land snail genus Pterocyclos Benson, 1832 (Caenogastropoda: Cyclophoridae) from Thailand and Peninsular Malaysia, with descriptions of two new species. Raffles Bulletin of Zoology 62: 330-338, DOI: 10.5281/zenodo.5458831
294B25641070861DD5D1FF53B1B2FBB9.taxon	diagnosis	Diagnosis. This new species differs from P. blandi by having a larger shell, a triangular shaped accessory respiratory device, an upper apertural-lip that is only slightly expanded, and a white to brown shell colour. It differs from the other newly described species, viz. P. frednaggsi Sutcharit & Panha, new species, by having a white to brown shell, a thin periostracum, a triangular shaped accessory respiratory device, and a narrow peripheral band. The differences from Rhiostoma asiphon Möllendorff, 1893, are the white to brownish shell colour, the low, cup-shaped operculum, and the triangular accessory respiratory structure.	en	Sutcharit, Chirasak, Tongkerd, Piyoros, Panha, Somsak (2014): The land snail genus Pterocyclos Benson, 1832 (Caenogastropoda: Cyclophoridae) from Thailand and Peninsular Malaysia, with descriptions of two new species. Raffles Bulletin of Zoology 62: 330-338, DOI: 10.5281/zenodo.5458831
294B25641070861DD5D1FF53B1B2FBB9.taxon	description	Description. Shell medium to large, depressed, thickened, and widely umbilicated. Apex acute; spire nearly flat; suture wide; whorl 4 – 5 convex becoming increasingly regular. Shell surface with thin growth lines; periostracum thin, corneous to brownish colour. Last whorl rounded and stout, narrow dark brown peripheral band usually present. Shell colour monochrome white, brown or brown zigzag pattern. Aperture rounded with white lip; upper peripheral-lip is slightly expanded near suture. Apertural tube structure triangular shaped, connected with a radial ridge parallel to apertural lip margin. Operculum calcareous, slightly concave inside and multilamellae outside.	en	Sutcharit, Chirasak, Tongkerd, Piyoros, Panha, Somsak (2014): The land snail genus Pterocyclos Benson, 1832 (Caenogastropoda: Cyclophoridae) from Thailand and Peninsular Malaysia, with descriptions of two new species. Raffles Bulletin of Zoology 62: 330-338, DOI: 10.5281/zenodo.5458831
294B25641070861DD5D1FF53B1B2FBB9.taxon	distribution	Distribution. Pterocyclos diluvium Sutcharit & Panha, new species, has only been located in limestone areas. It is mainly distributed in southern Thailand in Trang, Patthalung, Satun, Krabi, and Songkhla Provinces. In Malaysia, it was recorded from limestone hills in Perlis and Kedah.	en	Sutcharit, Chirasak, Tongkerd, Piyoros, Panha, Somsak (2014): The land snail genus Pterocyclos Benson, 1832 (Caenogastropoda: Cyclophoridae) from Thailand and Peninsular Malaysia, with descriptions of two new species. Raffles Bulletin of Zoology 62: 330-338, DOI: 10.5281/zenodo.5458831
294B25641070861DD5D1FF53B1B2FBB9.taxon	discussion	Remarks. This new species is superficially similar to R. asiphon with which it could easily be misidentified. Under the name “ Rhiostoma asiphon ”, not in the sense of Möllendorff (1893, 1894), several specimens were reported from many localities from Peninsular Malaysia (Benthem Jutting, 1960). We examined those specimens and revisited all mentioned localities, and confirmed none of them could be identified as R. asiphon s. s. Moreover, the type specimens of R. asiphon (lectotype SMF 130509 and paralectotypes SMF 130510, 130511, 130512) are clearly distinct from this new species. Especially, with the purplish to black shell colour, the calcareous cup-shaped operculum, and notch shaped apertural tube structure. Intraspecific variation was observed in the specimens from Tam Tone-din, Satun (CUMZ 4590). This population tended to show a wide range of shell colour variation from dark brown (Fig. 3 P) to white (Fig. 3 O). However, the unique accessory respiratory structure and the operculum suggest that the observed colour variation is likely to reflect intraspecific patterns, although this requires further corroboration, such as from molecular data, for confirmation.	en	Sutcharit, Chirasak, Tongkerd, Piyoros, Panha, Somsak (2014): The land snail genus Pterocyclos Benson, 1832 (Caenogastropoda: Cyclophoridae) from Thailand and Peninsular Malaysia, with descriptions of two new species. Raffles Bulletin of Zoology 62: 330-338, DOI: 10.5281/zenodo.5458831
294B25641070861CD662FBB3B65AFA79.taxon	description	(Figs. 1, 2 A – C, E, 3 Q – S; Table 1)	en	Sutcharit, Chirasak, Tongkerd, Piyoros, Panha, Somsak (2014): The land snail genus Pterocyclos Benson, 1832 (Caenogastropoda: Cyclophoridae) from Thailand and Peninsular Malaysia, with descriptions of two new species. Raffles Bulletin of Zoology 62: 330-338, DOI: 10.5281/zenodo.5458831
294B25641070861CD662FBB3B65AFA79.taxon	materials_examined	Type specimens. Holotype CUMZ 4594 (height 12.1 × diameter 27.8 mm; Fig. 3 Q). Type locality: Bukit Chintamanis, Pahang, Malaysia (03 ° 26.798 ' N, 102 ° 00.987 ' E). Paratypes CUMZ 4581 (18 specimens in ethanol, Fig. 3 R), 4571 (29 shells), NHMUK (2 shells), NMW (2 shells), SMF (2 shells) are from the type locality. Other material examined. Gua Pulai, Gua Musang, Kelanta, Malaysia CUMZ 4597 (9 shells, Fig. 3 S), 4944 (4 specimens in ethanol).	en	Sutcharit, Chirasak, Tongkerd, Piyoros, Panha, Somsak (2014): The land snail genus Pterocyclos Benson, 1832 (Caenogastropoda: Cyclophoridae) from Thailand and Peninsular Malaysia, with descriptions of two new species. Raffles Bulletin of Zoology 62: 330-338, DOI: 10.5281/zenodo.5458831
294B25641070861CD662FBB3B65AFA79.taxon	etymology	Etymology. The specific epithet “ frednaggsi ” comes from Fred Naggs, malacologist at the Natural History Museum, London, who has enthusiastically encouraged and continuously supported land snail research in Thailand and other Southeast Asian countries.	en	Sutcharit, Chirasak, Tongkerd, Piyoros, Panha, Somsak (2014): The land snail genus Pterocyclos Benson, 1832 (Caenogastropoda: Cyclophoridae) from Thailand and Peninsular Malaysia, with descriptions of two new species. Raffles Bulletin of Zoology 62: 330-338, DOI: 10.5281/zenodo.5458831
294B25641070861CD662FBB3B65AFA79.taxon	diagnosis	Diagnosis. Pterocyclos frednaggsi Sutcharit & Panha, new species, differs from P. blandi by having a thick and yellowish periostracum, a broad, dark brown peripheral band, a channel shaped accessory respiratory structure, and a slight expansion of the upper part of the apertural lip. It differs from P. spaleotes by having a larger shell, a thicker periostracum, and a broad, dark brown peripheral band. The differences from P. diluvium Sutcharit & Panha, new species, include the broad, dark brown peripheral band and the channel shaped accessory respiratory structure. This new species is superficially similar to P. umbraticus, but differs from this latter species by its relatively smooth shell surface, the broad dark brown peripheral band, and the fact that its distribution is limited to the lowland limestone area (altitude less than 200 m amsl). In contrast, P. umbraticus has a chevron-shaped, zigzag shell sculpture and tends to live in non-limestone forests of highland areas (altitude about 200 – 1600 m amsl) at Maxwell’s Hill and Gunung Brinchang, Pahang (Benthem Jutting, 1949).	en	Sutcharit, Chirasak, Tongkerd, Piyoros, Panha, Somsak (2014): The land snail genus Pterocyclos Benson, 1832 (Caenogastropoda: Cyclophoridae) from Thailand and Peninsular Malaysia, with descriptions of two new species. Raffles Bulletin of Zoology 62: 330-338, DOI: 10.5281/zenodo.5458831
294B25641070861CD662FBB3B65AFA79.taxon	description	Description. Shell medium sized, depressed, thickened, widely umbilicated. Apex acute; spire flattened to slightly elevated; suture wide; 4 – 5 convex and regularly increasing whorls. Shell surface with thin growth lines; periostracum brown and corneous. Last whorl rounded, stout, with a broad dark brown peripheral band. Shell colour brownish or with a variegated, dark brown zigzag pattern on early whorl. Aperture rounded. Apertural lip white, upper part slightly expanded near suture. Accessory respiratory structure channel-like to short tubular shaped. Operculum calcareous, slightly concave inside, and multilamellae outside. Radula. Central tooth with well developed central cusp and two smaller lateral cusps on each side; central cusp small with pointed tip; four smaller lateral cusps on both sides with dull to pointed head. Lateral teeth have three cusps; outer cusp large, elongate shape, and two smaller inner lateral cusps with curved tips. Inner marginal teeth have three cusps; central cusp large and convex head, and flanked with smaller and pointed head of one inner and one outer lateral cusps. Outer marginal cusp bicuspid, each cusp with pointed head (Fig. 2 E).	en	Sutcharit, Chirasak, Tongkerd, Piyoros, Panha, Somsak (2014): The land snail genus Pterocyclos Benson, 1832 (Caenogastropoda: Cyclophoridae) from Thailand and Peninsular Malaysia, with descriptions of two new species. Raffles Bulletin of Zoology 62: 330-338, DOI: 10.5281/zenodo.5458831
294B25641070861CD662FBB3B65AFA79.taxon	distribution	Distribution. This limestone dwelling species is known from the type locality and from Gua Musang, Kelantan, Malaysia.	en	Sutcharit, Chirasak, Tongkerd, Piyoros, Panha, Somsak (2014): The land snail genus Pterocyclos Benson, 1832 (Caenogastropoda: Cyclophoridae) from Thailand and Peninsular Malaysia, with descriptions of two new species. Raffles Bulletin of Zoology 62: 330-338, DOI: 10.5281/zenodo.5458831
294B25641070861CD662FBB3B65AFA79.taxon	discussion	Remarks. Specimens of this species from Gua Musang, Kelantan (Fig. 3 S) have slightly larger and darker shells with a narrower peripheral band than typical shells. However, the unique shape of the short tubular accessory respiratory structure and the multilamellae operculum suggest that these atypical forms represent intraspecific geographic variation.	en	Sutcharit, Chirasak, Tongkerd, Piyoros, Panha, Somsak (2014): The land snail genus Pterocyclos Benson, 1832 (Caenogastropoda: Cyclophoridae) from Thailand and Peninsular Malaysia, with descriptions of two new species. Raffles Bulletin of Zoology 62: 330-338, DOI: 10.5281/zenodo.5458831
