Cyclosomus sumatrensis Bouchard

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 : 517-519

Cyclosomus sumatrensis Bouchard

Figures 11 , 14G , 15C , 16F , 17F , 22

Cyclosomus sumatrensis Bouchard, 1903 a:174 . HOLOTYPE, sex and present location unknown (see notes below). Type locality: Indonesia, Sumatra, Palembang. Andrewes (1930:364); Csiki (1932:1295); Lorenz 2005:452).

Notes on types and nomenclature. Andrewes (1930:364) reported on his study of the unique type of C. sumatrensis in the Förster collection, which was housed at that time in the Museum of the Lycée at Mulhouse, Strasbourg ( France). Our efforts to borrow and study the Bouchard holotype were facilitated by Thierry Deuve, who contacted colleagues in several institutions in Strasbourg on our behalf. According to Mary Meister (Zoological Museum of Strasbourg (ZMSC)), the insects from the Lycée at Mulhouse collection were at one time offered to the ZMSC but a transfer was never completed. Efforts to learn whether or not the Mulhouse collection still exists have failed thus far. It seems likely that the collection, including the holotype of C. sumatrensis , has been lost or destroyed. However, this species is geographically and morphologically distinct enough from other Cyclosomus species that we see no need to designate a neotype until the loss of the holotype can be confirmed.

Diagnosis. Adults of C. sumatrensis can be distinguished from those of other Cyclosomus species in Asia by the following combination of character states: Body size medium for genus, BL males = 7.7 to 8.1 mm, females = 7.1 to 7.4 mm; body form ( Fig. 11 ) slightly elongate ovoid; pronotum ( Fig. 14G ) relatively narrow (ratio PWM/PL = 2.25 to 2.43), disc piceous to black with lateral pale bands slightly narrower than average for genus, distinctly defined, and slightly narrowed basally, apical angles narrower and less broadly rounded, lateral margins smoothly arcuate, not sinuate near anterior angles; elytra ( Fig. 11 ) with pattern of dark maculae more extensively developed and less varied than average for genus, with middle transverse dark band thick and extended from midline at least across interval 8, also onto interval 9 in some specimens, preapical dark spot present; elytral striae deeply impressed and intervals slightly to moderately 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. 16F ), apical lamella rounded and of medium length in dorsal aspect ( Fig. 17F ); specimen from West Malaysia or northern Indonesia ( Fig. 22 ).

Andrewes (1930) distinguished members of C. sumatrensis from those of C. flexuosus on the basis of their smaller size, narrower form, and deeper elytral striae, as well as minor differences in elytral color pattern. He concluded that C. sumatrensis was probably a distinct species closely related to C. flexuosus , but suggested that additional material might show it to be only a “variety” of the latter. Specimens of C. sumatrensis can be confused only with those of C. flexuosus , but members of these species are easily distinguished by the setae of the epipleura, which are long only in the humeral and subhumeral regions and progressively and distinctly shorter toward the apex in C. sumatrensis specimens but longer throughout the epipleural length in C. flexusosus members. Specimens of C. sumatrensis are also slightly smaller (7.1 to 8.1 mm compared with 8.2 to 9.8 mm for C. flexuosus specimens), and males have the apical lamella of the median lobe longer and narrower in dorsal aspect (compare Fig. 17F with Fig. 17B ).

Habitat distribution. Unknown, but presumed to be restricted to the sandy shores of medium to large rivers at low elevation, like members of most other species of the genus.

Geographical distribution. We have examined a total of 14 specimens (six males and eight females) from the following localities: INDONESIA: Java: East Java (Kediri, Kras [one female; IRSNB], [one female; MFNB], [five males and three females; NHMUK], [one female; NHRS]) ; Sumatra: Bengkulu (Mana [“ Manna ”] 1902, M. Knappert collector [one female; NHMUK]) ; North Sumatra (Deli Serdang [“ Deli ”], 1894, W. Reisch collector [one female; MFNB]) . MALAYSIA: Pahang: Taman Negara (5 January 1992, J. Nielsen collector [one male; CAS]) .

The known geographical range of C. sumatrensis ( Fig. 22 ) extends from the Malaysian portion of the Malay Peninsula south to Sumatra and Java. It was previously known only from Sumatra, Indonesia and specimens reported here from the Malay Peninsula and Java represent new records for these areas.

Geographical variation. We found slight individual variation ( Figs. 11A, B ) in development of the dark color pattern of the elytra within the largest sample of this species (from Kras, East Java). Specimens from all other localities were similar to at least some specimens from that sample, so we recognized no particular geographical variation.

Geographical relationships with other Cyclosomus species. No other congeneric species is known to occur in Malaysia or Indonesia; and the nearest Cyclosomus records are for C. inustus , in Cambodia, across the Gulf of Thailand and more than 800 km distant to the northeast, and C. flexuosus in Sri Lanka, across the Bay of Bengal and more than 1600 km distant to the west.

Figures

FIGURE 11. Cyclosomus sumatrensis Bouchard, dorsal habitus. A. Dark male (Kras, Kediri, East Java, Java, Indonesia); B. Pale male (Taman Negara, Pahang, Malaysia). 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 15. Prosternal intercoxal process, 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 (Cinkona, Anamalia Hills, Tamil Nadu, India); C. C. sumatrensis Bouchard (Taman Negara, Pahang, Malaysia); D. C. verspertilio Cueva-Dabkoski and Kavanaugh sp. nov. (New Delhi, Delhi, India). 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 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.