Pterocyclos frednaggsi Sutcharit & Panha, 2014

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, pp. 330-338 : 336-337

Pterocyclos frednaggsi Sutcharit & Panha , new species

( Figs. 1 , 2A – C, E , 3Q – S ; Table 1)

Type specimens. Holotype CUMZ 4594 (height 12.1 × diameter 27.8 mm; Fig. 3Q ). Type locality: Bukit Chintamanis , Pahang, Malaysia (03°26.798' N, 102°00.987' E) . Paratypes CUMZ 4581 (18 specimens in ethanol, Fig. 3R ), 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. 3S ), 4944 (4 specimens in ethanol) .

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.

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).

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. 2E ).

Distribution. This limestone dwelling species is known from the type locality and from Gua Musang, Kelantan, Malaysia.

Remarks. Specimens of this species from Gua Musang, Kelantan ( Fig. 3S ) 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.

Figures

Fig. 1. Distribution map of Pterocyclos species examined in this study. The numbered locality names are detailed in Table 1. The approximate type locality of Pterocyclos subalatus, and Pterocyclos umbraticus, are indicated by locality numbers 3 and 5, respectively.

Fig. 2. A–C, General anatomy of Pterocyclos frednaggsi Sutcharit & Panha, new species, from Gua Musang, Kelantan, Malaysia CUMZ 4944, showing: A, right side of male with testis and external penis; B, right side of female with ovary and vaginal groove; C, left side of female with lung cavity and heart. D, E, Radula morphology of: D, Pterocyclos spaleotes, topotype specimen CUMZ 4585; E, Pterocyclos frednaggsi Sutcharit & Panha, new species, paratype CUMZ 4581.

Fig. 3. A–D, Shell and operculum of Pterocyclos rupestris: A, lectotype UMZC 2359.1; B, paralectotype UMZC 2359.2; C, syntype of var. 3 UMZC 2359.3; D, operculum from same lot of the paralectotype (showing top, side and bottom views). E, F, Specimens of P. blandi from Langkawi Island, Perlis, Malaysia CUMZ 4582. G, Holotype UMZC 1032 of P. subalatus. H–J, Pterocyclos spaleotes: H, lectotype NMW 1955.158.01107, I, paralectotype NMW 1981.118.02705; J, topotype specimen CUMZ 4585. K, Holotype ZMA Moll. 135622 of P. umbraticus. L–P, Pterocyclos diluvium Sutcharit & Panha, new species: L, holotype CUMZ 4595, M, paratype CUMZ 4588, N, specimen from Gua Cenderawasih, Perlis, Malaysia CUMZ 4592; and O, P, specimens from Tam Tone-din, Kuan-Don, Satun, Thailand CUMZ 4590 showing a: O, uniform whitish shell; and P, dark brown colour patterns. Q–S, Pterocyclos frednaggsi Sutcharit & Panha, new species: Q, holotype CUMZ 4594; R, paratype CUMZ 4581; S, specimen from Gua Pulai, Gua Musang, Kelantan, Malaysia CUMZ 4597.