Cyclophorus takumisaitoi T. Hirano, 2019

Cyclophorus takumisaitoi T. Hirano View in CoL , sp. nov.

urn:lsid:zoobank.org:act:6D497FF9-5849-49BB-8162-665FADA40C34

Etymology. The name refers to the malacologist and evolutionary biologist Takumi Saito, who collected individuals of this species together with Tu Van Do and Takahiro Hirano.

Conchological description. Medium-sized Cyclophorus species, overall shell shape rounded, aperture typically circular. Shell height 22.7 to 25.0 mm (mean = 23.8 mm), shell breadth 27.1 to 29.2 mm (mean = 28.0 mm). Number of whorls 5 to 5.25. Early whorls without bluish colouration. Shape of body whorl uncompressed or slightly compressed; rounded or well-rounded. Lip reflected and simple. Lip colour orange, peach or yellow. Wing-shaped projection at columellar margin absent. Peripheral band not distinguishable from background colouration, or absent. Colour pattern generally variable. Typical elements of pattern above position of peripheral band: zig-zag stripes and flames in lighter shades of brown. Typical elements of pattern below position of peripheral band: spiral bands in darker shades of brown.

Type specimens. VNM076 ( Fig 12a View Fig 12 ; holotype), soft body in ethanol (previously in formalin) and dry shell; NHMUK 20180455 (ethanol-preserved frozen tissue sample NHMUK Barcode 014041344); GenBank accession numbers MN153344 (COI), MN153393 (16S), MN153440 (28S); male individual; shell height 25.0 mm, shell breadth 28.2 mm, number of whorls 5.25. VNM078 ( Fig 12b View Fig 12 ; paratype), soft body in ethanol (previously in formalin) and dry shell; NHMUK 20180456 (ethanol-preserved frozen tissue sample NHMUK Barcode 014041345); GenBank accession numbers MN153346 (COI), MN153395 (16S), MN153442 (28S); male individual; shell height 23.2 mm, shell breadth 27.1 mm, number of whorls 5. VNM077 ( Fig 12c View Fig 12 ; paratype), soft body in ethanol (previously in formalin) and dry shell; NHMUK 20180457 (ethanol-preserved frozen tissue sample NHMUK Barcode 014041346); GenBank accession numbers MN153345 (COI), MN153394 (16S), MN153441 (28S); male individual; shell height 23.4 mm, shell breadth 28.0 mm, number of whorls 5.25.

Locality and sampling data. VNM076, VNM078, VNM077: Vietnam, Hoa Binh, Cuc Phuong National Park (20.38493˚, 105.52280˚); 26 May 2016; leg. Tu Van Do, Takahiro Hirano & Takumi Saito.

Diagnosis. Cyclophorus takumisaitoi sp. nov. can be differentiated from all herein characterised Cyclophorus species based on DNA sequence data. Diagnostic nucleotide substitutions of the cytochrome c oxidase subunit I (COI) gene: 241:A, 319:C, 349:T, 430:G, 499:A (numbers indicate the position in the studied COI fragment).

Remarks. The studied material of C. takumisaitoi has been found in northwestern Cuc Phuong National Park in southeastern Hoa Binh province ( Fig 4 View Fig 4 ). None of the other herein characterised species is known to occur sympatrically with this species. Cyclophorus cucphuongensis occurs in central and eastern Cuc Phuong National Park. The shell shape of C. cucphuongensis is similar to that of C. takumisaitoi ( Fig 2 View Fig 2 ). The shell of C. cucphuongensis is slightly larger than that of C. takumisaitoi ( Fig 3a View Fig 3 ). The lip of C. cucphuongensis tends to have a more yellowish colour than that of C. takumisaitoi , which tends to be more reddish. The wing-shaped projection at the columellar margin is present in C. cucphuongensis , while being absent in C. takumisaitoi , and the shell colouration of C. cucphuongensis is more vivid with a more prominent peripheral band. Furthermore, C. paracucphuongensis occurs in western Cuc Phuong National Park. The shell shape of C. paracucphuongensis is similar to that of C. takumisaitoi ( Fig 2 View Fig 2 ). The shell of C. paracucphuongensis is slightly larger than that of C. takumisaitoi ( Fig 3a View Fig 3 ). The lip of C. paracucphuongensis tends to have a more yellowish colour than that of C. takumisaitoi , which tends to be more reddish. The shell colouration of C. paracucphuongensis is more vivid with a more prominent peripheral band.