Cyphochilus peninsularis Arrow, 1938 Figs 14, 38-40, 89 Cyphochilus peninsularis Arrow, 1938: 268. Type material examined: Lectotype by present designation: BMNH; 1 ♂; THAILAND: // 1937-647 (P) // Type (P circular label, red border) // Peninsular Siam [THAILAND]/ Nakon Sri Tamarat / Kao Luang / 5800 ft / March 30th 1922 / H.M. Pendlebury (P) // Cyphochilus / peninsularis / Type ♂ Arrow (H) //. (Fig. 14). – Paralectotype by present designation: BMNH; 1 ♀; //1937-647 // Cyphochilus / peninsularis / Co-type ♀ Arrow (H) // Peninsular Siam / Nakon Sri Tamarat / Kao Luang / 5800 ft / March 30th 1922 / H.M. Pendlebury (P) // 1937-647 (P) //. – Paralectotype by present designation: BMNH; 1 ♂; // Co-type (P circular label, yellow border // March 29th 1922 / H.M. Pendlebury (P) // Peninsular Siam / Nakon Sri Tamarat / Kao Luang / 5800 ft // March 24th 1922 / H.M. Pendlebury (P) // 1938-437 (P) //. – Paralectotype by present designation: MHNG; 1 ♂; // Peninsular Siam / Nakon Sri Tamarat / 9 m Kao Luang / 5800 ft / March 29th 1922 / H.M. Pendlebury (P) // 1937-437 (P) //. (Fig. 89). Redescription of the lectotype male: Size – BL: 20.8 mm, BW: 8.7 mm, BWX: 11 mm, situated in the distal third of elytra. Color – Integument dark brown while legs and appendices light brown-reddish; dorsal surface with scales uniformly whitish, denser along sides of pronotum and margins of elytra where they are yellowish. Head – CW/L: 3.1; anterolateral edges of clypeus rounded, lateral edges of clypeus straight and subparallel; frons large, making eyes not prominent (F/O: 4.9); antennal club longer than antennomeres 2-7 (A2-7/CL: 0.7). Pronotum – Transverse (PnW/L: 1.8), strongly convex, slightly concave just behind eyes; apical angles flattened, acute and protuberant; basal lateral margins sinuate, basal angles acute and sharp. Elytra – With four striae visible, not covered by scales but not elevated. Thoracic sterna – Surface with long, yellowish-brown pubescence and scales; mesosternum developed anteriorly (MstL: 0.65 mm) visible between the mesocoxae in lateral view. Abdomen – Sternites with sparse scales including median part of the eight sternite; pygidium convex with apical margin largely reflected and with corresponding ventrite quite large. Legs – Protibia bidentate being the third basal tooth almost not visible; slender apical tooth much longer than the middle tooth. Aedeagus – Parameres strongly asymmetric (Figs 38-40). Variability: BL: 20.5-22.7 mm. Female: Antennal club ovate, much shorter than in the males and of preceding antennomeres (A2-7/CL: 1.5). Type locality: Nakhon Sri Thammarat is a city in southern Thailand (8°26′11″ N, 99°57′47″ E), capital of the homonymous Province and District. The locality is about 610 km South of Bangkok, on the east coast of the Malay Peninsula. Distribution: The species is known only from one locality in the Southern Thailand on the Malay Peninsula. Remarks: Arrows (1938) described the species based on 8 specimens, of which only 5 could be found. Cyphochilus peninsularis is quite distinct morphologically from its congeners. It is easily recognizable by the long antennal club in the males, the mesosternum developed between mesocoxae and by the unique morphology of the parameres.

Published as part of Sabatinelli, Guido, 2020, Taxonomic notes on the genus Cyphochilus Waterhouse, 1867 (Coleoptera, Scarabaeoidea, Melolonthinae) with description of 10 new species, pp. 157-181 in Revue suisse de Zoologie 127 (1) on pages 172-173, DOI: 10.35929/RSZ.0014, http://zenodo.org/record/5743429