Cyclophorus courbeti Ancey, 1888

Cyclophorus courbeti Ancey, 1888 View in CoL [ 92]

Conchological description. Medium to large-sized Cyclophorus species, overall shell shape rounded, aperture typically circular. Shell height 21.1 to 34.6 mm (mean = 30.0 mm), shell breadth 25.8 to 43.1 mm (mean = 36.1 mm) (sub-group I: shell height 31.6 to 34.6 mm (mean = 33.2 mm), shell breadth 36.9 to 43.1 mm (mean = 40.5 mm); sub-group II: shell height 21.1 to 26.7 mm (mean = 24.1 mm), shell breadth 25.8 to 31.4 mm (mean = 28.1 mm)). Number of whorls 4.75 to 5.5 (sub-group I: 5.25 to 5.5; sub-group II: 4.75 to 5.25). Early whorls without bluish colouration. Shape of body whorl usually slightly compressed or uncompressed; usually rounded or sub-angular (sub-group I: usually slightly compressed or uncompressed; usually rounded; sub-group II: slightly compressed or uncompressed; rounded or sub-angular). Lip usually reflected and simple (sub-group I: reflected and simple; sub-group II: reflected and simple, or unreflected and duplicated). Lip colour ivory, white, orange, peach or yellow (sub-group I: ivory, orange, peach, white or yellow; sub-group II: ivory or white). Wing-shaped projection at columellar margin absent. Peripheral band usually dark brown (sub-group I: usually dark brown; sub-group II: dark brown). Colour pattern generally variable. Typical elements of pattern above position of peripheral band: zig-zag stripes, spiral lines and spiral bands in different shades of brown or in white (sub-group I: zig-zag stripes, spiral bands and spiral lines in different shades of brown or in white; sub-group II: zig-zag stripes and spiral lines in different shades of brown). Typical elements of pattern below position of peripheral band: spiral lines, spiral bands and flames in different shades of brown (sub-group I: spiral lines, spiral bands and flames in darker shades of brown; sub-group II: spiral lines, spiral bands and flames in different shades of brown).

Displayed specimens. VNM019 ( Fig 5a View Fig 5 ; sub-group I), specimen in ethanol; NHMUK 20110591 (ethanol-preserved frozen tissue samples NHMUK Barcode 014041333, NHMUK Barcode 014041350); GenBank accession numbers MN153306 (COI), MN153355 (16S), MN153403 (28S); sex of individual not determined (parts of soft body damaged); shell height 32.2 mm, shell breadth 39.0 mm, number of whorls 5.25. VNM022 ( Fig 5b View Fig 5 ; sub-group II), specimen in ethanol; NHMUK 20110540/2; GenBank accession numbers MN153309 (COI), MN153358 (16S); female individual; shell height 24.8 mm, shell breadth 29.0 mm, number of whorls 5.25 . VNM021 ( Fig 5c View Fig 5 ; sub-group II), specimen in ethanol; NHMUK 20110540/1 (ethanol-preserved frozen tissue samples NHMUK Barcode 014041331, NHMUK Barcode 014041348); GenBank accession numbers MN153308 (COI), MN153357 (16S), MN153405 (28S); sex of individual not determined (parts of soft body damaged); shell height 26.7 mm, shell breadth 31.4 mm, number of whorls 5.25. VNM023 ( Fig 5d View Fig 5 ; sub-group II), specimen in ethanol; NHMUK 20110541 (ethanol-preserved frozen tissue samples NHMUK Barcode 014041332, NHMUK Barcode 014041349); GenBank accession numbers MN153310 (COI), MN153359 (16S), MN153406 (28S); sex of individual not determined (parts of soft body damaged); shell height 22.6 mm, shell breadth 26.3 mm, number of whorls 4.75.

Locality and sampling data. VNM019: Vietnam, Lang Son, Trung Quan commune (22.13137˚, 106.58715˚); 23 May 2011; leg. Hao Van Luong, Fred Naggs & Sang Van

Pham. VNM022, VNM021, VNM023: Vietnam, Bac Kan, Bang Van commune (22.47878˚, 106.04597˚); 19 May 2011; leg. Jonathan Ablett, Hao Van Luong, Fred Naggs & Sang Van Pham.

Diagnosis. Cyclophorus courbeti 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: 10:C, 25:C, 40:G, 127:A, 184:G, 214:A, 292:C, 294:C, 436:A, 493:T, 508:C, 514:G, 604:A, 638:A, 652:C, 653:C (numbers indicate the position in the studied COI fragment).

Remarks. Despite extensive effort, we were unable to locate type material of this species (see also [ 107]). Our determination was thus based on the description and figure in Ancey [ 92]. The description and the depicted shell matched sub-group I in size, shape (but the studied material of sub-group I had a less pronounced keel, which was, however, present in sub-group II) and colouration. The type locality given in Ancey [ 92] is “upper Tonkin, in the region of Lang Son and Bac Ninh” (original: “Haut-Tonkin, dans la région de Lang-son et de Bac-Ninh”), and our studied samples of sub-group I were collected from a locality in this area. We regard the material from eastern Thailand, which has been determined as C. courbeti by Nantarat et al. [ 47] (also included in the phylogenies of [ 6] and this study, herein THA011), as belonging to a different species. The studied material of C. courbeti has been found in northern Lang Son province (sub-group I) and in northeastern Bac Kan province (sub-group II) ( Fig 4 View Fig 4 ). Another herein characterised species, C. subfloridus (sub-group II), occurs sympatrically with C. courbeti (sub-group I) in northern Lang Son province. The shell shape of C. subfloridus is generally less compressed than that of C. courbeti ( Fig 2 View Fig 2 ). The shell of C. subfloridus sub-group II is smaller than that of C. courbeti sub-group I ( Fig 3b View Fig 3 ) and the early whorls show a bluish colouration, while those of C. courbeti sub-group I lack a bluish colouration. The lip of C. subfloridus sub-group II tends to have a more whitish colour than that of C. courbeti sub-group I, which tends to be more yellowish or reddish.