Cyclosomus suturalis (Wiedemann)

Kavanaugh, David H. & Cueva-Dabkoski, Mollie, 2023, A Review of Genus Cyclosomus Latreille (Coleoptera: Carabidae: Lebiinae: Cyclosomini) in Asia., Proceedings of the California Academy of Sciences 67 (21), pp. 493-537 : 519-522

Cyclosomus suturalis (Wiedemann)

Figures 12 , 14H , 16G , 17G , 18B , 22

Scolytus suturalis Wiedemann, 1819:169 . LECTOTYPE, here designated, a male, in ZMUC, labeled: “Type” [red label]/ “Bengala Westermann flexuosus F. suturalis Wied.” [handwritten]/ “ ZMUC 00022690”/ “ LECTOTYPE Scolytus suturalis Wiedemann 1819 design. by D.H. Kavanaugh & M. Cueva-Dabkoski 2023” [red label]. Paralectotypes examined: 1 male, also in ZMUC, labeled: “Mus. Westerm.”/ “TYPE” [red label]/ “ S. flexuosus var. S. suturalis Wied. Bengal May 1809 ” [handwritten]/ PARALECTOTYPE Scolytus suturalis Wiedemann 1819 design. by D.H. Kavanaugh & M. Cueva-Dabkoski 2023” [yellow label]/ “ Cyclosomus marginatus Motschulsky det. D.H. Kavanaugh 2023 ”. Type locality: “Bengal” [area which now includes West Bengal (eastern India) and Bangladesh].

Cyclosomus flexuosus, Chaudoir 1876:32 .

Cyclosomus suturalis (Wiedemann) , Chaudoir (1876:32); Andrewes (1921:166, 1924:464); Csiki (1932:1295); Lorenz (2005:452).

Notes on types and nomenclature. Chaudoir (1876:32) considered C. suturalis as a junior synonym of C. flexuosus , but Andrewes (1921:166) confirmed its status as a distinct species. In that same paper, Andrewes recognized C. marginatus as a junior synonym of C. suturalis . This difference of opinion between these two superb taxonomists can possibly be explained by the fact that the type series of C. suturalis includes two specimens, which are not, in our view, conspecific. Thus, they may have examined different specimens in making their assessments. The male specimen that we have selected as lectotype actually resembles some small male specimens of C. flexuosus in size and elytral color pattern. The female specimen we designate as paralectotype appears to be a specimen of C. marginatus , with the size and elytral color pattern matching the lectotype of that species. If Chaudoir had studied the male specimen and Andrewes the female specimen, their respective opinions are quite understandable. Because of variation in elytral color pattern seen in each of these species, Wiedemann’s original description is insufficient to distinguish between specimens of C. flexuosus , C. marginatus , and C. suturalis . By selecting the male specimen as lectotype of C. suturalis , we are able to recognize Motschulsky’s C. marginatus as the valid name for a distinct species (see above). If we had chosen the female specimen as lectotype, then C. marginatus would have remained a junior synonym of C. suturalis and the male specimen would represented a new species currently without a name.

Diagnosis. Adults of C. suturalis can be distinguished from those of other Cyclosomus species in Asia by the following combination of character states: Body size medium to large for genus, BL males = 8.2 to 9.1 mm, female = 9.2 mm; body form ( Fig. 12A, C ) slightly elongate ovoid; pronotum ( Fig. 14H ) relatively broader (ratio PWM/PL = 2.44 to 2.50), disc rufopiceous to black, lateral pale bands well-defined, slightly narrowed at least in apical half and broadened basally, apical angles slightly narrowed and less broadly rounded, lateral margins smoothly arcuate, not sinuate near anterior angles; elytra with pattern of dark maculae less varied, with middle band of average ( Fig. 12A ) to distinctly greater than average ( Fig. 12C ) thickness for the genus and extended from midline to interval 6 in most specimens, onto interval 7 and part of interval 8 in some specimens, preapical dark spot present, striae deeply impressed and intervals flat or slightly convex; elytral epipleura with long setae only in humeral and subhumeral areas, setae in apical two-thirds distinctly shorter; male median lobe with apical lamella extended in line with ventral curvature of shaft in lateral aspect ( Fig. 16G ), apical lamella short and bluntly triangular in dorsal aspect ( Fig. 17G ); specimen from eastern India to westernmost Yunnan ( Fig. 22 ).

Specimens of C. suturalis are most similar to those of C. acutangulus and atypical specimens of C. inustus that have the elytral preapical dark spot present. Refer to the key and Diagnosis sections for each of those species for distinguishing features.

Habitat distribution. Specimens from Yunnan were collected at night on the upper sandy banks of the Longchuan River ( Fig. 18B ) at an elevation of 734 m (H.B Liang, personal communication).

Geographical distribution. Fig. 22 . We examined a total of seven specimens (four males and three females) from the following localities: CHINA: Yunnan: Mangshi, Zhefang Township ( Longchuan Jiang at Nongkan village , 24.16534°/98.10266°, 734 m, 22 May 2020, H.B. Liang and Y. Xu collectors [two males and two females; IOZ]) . BANGLADESH / INDIA: “ Bengala ” ([one male; ZMUC]) . BANGLADESH / INDIA / MYANMAR: “India Or.” ([one female; MNFB]) . INDIA: Sikkim: Melli ( Teesta River valley , 240 m, 14 October 1918, H. Stevens collector [one male; NHMUK]) .

This species ranges from the type area, “Bengala” or “Bengal” (no specific locality), which includes present-day eastern India and/or Bangladesh, at least to westernmost Yunnan Province, China. The westernmost confirmed limit of the species is in Sikkim and the easternmost limit in western Yunnan. Andrewes’ records from northern India ( Andrewes 1921) may have been based on misidentified specimens of C. vespertilio , which is described below.

Geographical variation. We found some individual variation ( Figs.12A, C ) in development of the dark color pattern of the elytra within the sample of this species from Mangshi, Yunnan, China. Specimens from all other localities were similar to one or more of the specimens from that sample, so we recognized no particular geographic variation.

Geographical relationships with other Cyclosomus species. Because of the uncertainty with regard to where the exactly the type specimen was collected in “Bengala”, the northwestern limits to the range of this species remain unclear. Cyclosomus marginatus is also known only from the similarly vague “ India Or.,” again without specific locality, so it is possible that these species co-occur or at least overlap in their geographical ranges. Whether or not the range of C. suturalis overlaps those of C. flexuosus and/or C. vespertilio cannot yet been confirmed. The range of C. inustis approaches that of C. suturalis at least in northern Indochina so there is at least potential for co-occurrence of these species, although the two have not yet been found near each other.

Figures

FIGURE 12. Cyclosomus suturalis (Wiedemann). A. Scolytus suturalis Wiedemann, lectotype male, dorsal habitus; B. Labels associated with lectotype; C. Dark male ((Longchuan Jiang at Nongkan village, Zhefang Township, Mangshi, Yunnan, China). Scale lines = 1.0 mm.

FIGURE 14. Pronota, Cyclosomus spp., dorsal aspect. A. C. acutangulus Kavanaugh and Cueva-Dabkoski (Bhalukpong, Arunachal Pradesh, India); B. C. flexuosus (Fabricius) (Hetauda, Bagmati Province, Nepal); C. C. inustus Andrewes, holotype (Hong Kong, China); D. C. marginatus Motschulsky (India); E. C. pallidus Kavanaugh and Cueva- Dabkoski sp. nov. (Karachi, Sindh Province, Pakistan); F. C. philippinus Heller (Pili, Zambales Mountains, Luzon, Philippines); G. C. sumatrensis Bouchard (Taman Negra National Park, Pahang, Malaysia); H. C. suturalis (Wiedemann), lectotype (“Bengala”, India); I. C. vespertilio Cueva-Dabkoski and Kavanaugh sp. nov. Scale lines = 0.5 mm.

FIGURE 16. Male genitalia, Cyclosomus spp., left lateral aspect. A. C. acutangulus Kavanaugh and Cueva-Dabkoski (Longchuan Jiang at Longjiang Bridge, Wuhe Township, Tengchong County, Yunnan, China); B. C. flexuosus Dejean (Karaikal, Puducherry, India); C. C. inustus Andrewes (“China”); D. C. marginatus Motschulsky (“Bengal”, India); E. C. philippinus Heller (Pili, Zambales Mountains, Luzon, Philippines); F. C. sumatrensis Bouchard (Taman Negara, Pahang, Malaysia); G. C. suturalis (Wiedemann), lectotype (“Bengala”, India); H. C. verspertilio Cueva-Dabkoski and Kavanaugh sp. nov. (New Delhi, Delhi, India). Scale lines = 0.5 mm.

FIGURE 17. Male genitalia, Cyclosomus spp., dorsal aspect. A. C. acutangulus Kavanaugh and Cueva-Dabkoski (Longchuan Jiang at Longjiang Bridge, Wuhe Township, Tengchong County, Yunnan, China); B. C. flexuosus Dejean (Karaikal, Puducherry, India); C. C. inustus Andrewes (“China”); D. C. marginatus Motschulsky (“Bengal”, India); E. C. philippinus Heller (Pili, Zambales Mountains, Luzon, Philippines); F. C. sumatrensis Bouchard (Taman Negara, Pahang, Malaysia); G. C. suturalis (Wiedemann), lectotype (“Bengala”, India); H. C. verspertilio Cueva-Dabkoski and Kavanaugh sp. nov. (New Delhi, Delhi, India). Scale lines = 0.5 mm.

FIGURE 18. Photographs of habitats for Cyclosomus species. A. C. acutangulus Kavanaugh & Cueva-Dabkoski (Longchuan Jiang just below bridge at Menglian village, Wuhe Township, Tengchong County, Yunnan, China; photograph by David H. Kavanaugh); B. C. suturalis (Wiedemann) (Longchuan Jiang at Nongkan village, Zhefang Township, Mangshi, Yunnan, China; photograph by Hong-Bin Liang).

FIGURE 22. Map showing distribution of locality records for Cyclosomus specimens examined. White triangles = C. sumatrensis Bouchard; yellow highlighted area with black question mark = type area for C. suturalis (Wiedemann); white circles = other localities for C. suturalis; white squares = C. vespertilio Cueva-Dabkoski and Kavanaugh sp. nov. Modified from Wikimedia Commons, World Atlas of the World, at URL: <http://upload.wikimedia.org/wikipedia/ commons/8/8f/Whole_world_-_land_and_oceans_12000.jpg>. Scale line = 500 km.