Broscosoma bicoloratum Kavanaugh and Liang 2021, sp. nov.
Creators: name: Kavanaugh, David H.
name: Liang, Hongbin
Publisher: name: Zenodo
Year: 2021
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Coleoptera
Carabidae
Broscosoma
Broscosoma bicoloratum

description: 3. Broscosoma bicoloratum Kavanaugh and Liang, sp. nov.
Figures 7c, 8c, 15, 16, 42, 48-50
Type material. Holotype, a male, in IOZ, labeled: “ CASENT 10265704 ”/ “ CHINA, Yunnan, Gongshan County, Dulongjiang Township, NW slope of Heipu Yakou, 3350m ” N27.77437º / E098.44793º ”/ “ 13 August 2006, Stop # DHK-2006-075, D.H. Kavanaugh & J.A. Miller collectors”/ “HOLOTYPE Broscosoma bicoloratum Kavanaugh & Liang, CH-04 Kavanaugh & Liang sp. nov. designated 2021” [red label]. Paratypes (a total of 29): two males and one female (CAS, IOZ) labeled: same as holotype except first label: “ CASENT 10265703 ” and “ CASENT 10265705 ” and “ CASENT 10265706 ”, respectively; three males and five females (CAS, IOZ) labeled: “ CASENT 1006243 ”, “ CASENT 1006245 ”, “ CASENT 1008140 ” and “ CASENT 1008141 ” to “ CASENT 1008145 ”, respectively/ “ CHINA, Yunnan Province, Gaoligong Shan, Nujiang Prefecture, Nujiang State Nature Reserve, Dulong / Gongshan Yakou area, 21 airkm W of Gongshan ”/ “ 3300-3680m, 16-17 July 2000, Stop #00-24C, D.H. Kavanaugh, C.E. Griswold, H.-B. Liang, D. Ubick & D.-Z. Dong collectors”; one female (IOZ) labeled: “ CASENT 1025606 ”/ “ CHINA, Yunnan, Gongshan County, Cikai Township, southeastern slope of Heipu Yakou, 3365m ” / N27.77032º / E098.44674º ”,/ “ 11 August 2006, Stop # DHK-2006-069B, D.H. Kavanaugh, D.Z. Miller, D.-Z. Dong & Y. Liu collectors”; one male and two females (CAS, IOZ) labeled: “ CASENT 1025709 ”to “ CASENT 1025710 ” to “ CASENT 1025711 ”, respectively/ “ CHINA, Yunnan, Gongshan County, Cikai Township, southeastern slope of Heipu Yakou, 3365m ”/ “ N27.77032º / E098.44674º “ 11 August 2006, Stop # DHK-2006-072, Y. Liu collectors”; two males and three females (CAS, IOZ) labeled:, “ CASENT 1026544 ” to “ CASENT 1026545 ” and “ CASENT 1026546 ” and “ CASENT 10265548 ”, respectively/ “ CHINA, Yunnan, Gongshan County, Cikai Township, southeastern slope of Heipu Yakou, 3365m ” / N27.77032º / E098.44674º ”/ “ 13 August 2006, Stop # DHK-2006-074, D.-Z. Dong & Y. Liu collectors”; one male and one female (CAS, IOZ) labeled: “ CASENT 1033874 ” and “ CASENT 1033875 ”, respectively/ “ CHINA, Yunnan, Gongshan County, Cikai Township, headwaters South Fork Qiqi He on SE slope below Qiqi-Dulong Yakou, 3570 m,”/ “ N27.69490° / E098.45646°, 27 September 2007, Stop# 2007-053, D.H. Kavanaugh, H.B. Liang, & H.L. Shi collectors”; one male (IOZ) labeled: “ CASENT 1033984 ”/ “ CHINA, Yunnan, Gongshan County, Cikai Township, Qiqi Trail SE of Qiqi-Dulong Yakou, 3525 m, N27.69367° / E098.46004°,”/ “ 29 September 2007, Stop# 2007-057, D.H. Kavanaugh & H.B. Liang collectors”; three males and one female (CAS, IOZ) labeled: “ CASENT 1034174 ”to “ CASENT 1034176 ” and “ CASENT 1034177 ”, respectively/ “ CHINA, Yunnan, Gongshan County, Cikai Township, Qiqi-Dulong Yakou, 3675 m, N27.69659° / E098.45398°,”/ “ 27 September 2007, Stop# HBL-2007-05A, H.B. Liang, H.L. Shi, & X.J. Feng collectors”; one male (IOZ) labeled: “ CASENT 1033899 ”/ “ CHINA, Yunnan, Gongshan County, Cikai Township, Qiqi-Dulong Yakou, 3675 m, N27. 69653° / E098.45393°, 27-29 September 2007,”/ Stop# 2007-054, D.H. Kavanaugh, H.B. Liang, & H.L. Shi collectors, in pitfall trap ”; one male (IOZ) labeled: “ CASENT 1034187 ”/ “ CHINA, Yunnan, Gongshan County, Cikai Township, Qiqi-Dulong Yakou, 3675 m, N27.70401° / E098.45398°, 27-29 September 2007,”/ Stop# HBL-2007-05B, H.B. Liang, H.L. Shi, & X.J. Feng collectors, in pitfall traps ”. All paratypes also bear the following label: “ PARATYPE Broscosoma bicoloratum Kavanaugh & Liang, sp. nov. designated 2021” [yellow label].
Type locality. CHINA, Yunnan, Gongshan County, Dulongjiang Township, NW slope of Heipu Yakou, 3350 m.
Derivation of species name. The species epithet, bicoloratum, is an adjective derived from the Latin words, bis, meaning two, and coloratus, meaning colored. The name refers to the distinct color difference in dorsal view between the forebody (black) and the elytra (metallic green or bluish-green) in members of this species.
Diagnosis. Adults of this species (Fig. 15a) can be distinguished from those of other species in the region by the following combination of character states: size moderate, BL = 9.6 to 10. 8 mm; head and pronotum black to piceous, without metallic reflection (except a few specimens with a faint metallic green band across anterior part of pronotum anterior to the anterior transverse impression); head with tempora distinctly convex behind eyes (Fig. 7c); genal ridge varied, extended from base of head to just anterior to temporal constriction or to below ventral margin of eye; antennomeres 3 and 4 glabrous except for apical whorl of setae; pronotum globose anterior to sub-basal constriction (Fig. 7c), lateral margination absent, basolateral setae absent; elytral silhouette ovoid, with humeri indistinct, elytral microsculpture effaced or extremely faintly impressed; metatrochanters asetose (except unisetose unilaterally in very few specimens); male protarsi with tarsomeres 1 to 3 with ventral pads of adhesive setae; male genitalia as in Fig. 16.
Description. Fig. 15a. Size medium, BL male = 10.3–10. 8 mm, female = 9.6–10. 8 mm, ratio EL/PL of male and female = 2.1–2.2. Body color black or dark piceous, last visible abdominal sternite dark brown or rufous brown, antennae with all antennomeres rufous brown, femora black, dark piceous, or reddish brown, tibiae and tarsi reddish brown. Head and pronotum without metallic reflection (except a few speciemens with a faint metallic green band across anterior part of pronotum anterior to the anterior transverse impression), elytra with distinct green or greenish-blue metallic reflection, venter without metallic reflection.
Head. Fig. 7c. Eyes medium-sized, their diameter equal to or slightly greater than length of tempora. Frontal furrows deeply impressed, narrow to broad, arcuate, slightly convergent anteriorly and posteriorly, long, extended posteriorly beyond middle of eyes, rugulose, impunctate. Vertex with post-temporal sulcus deep, sharply defined, very sparsely and finely punctate to moderately punctate. Tempora obliquely convex. Genal ridges present, extended from base of head anteriorly to slightly beyond the post-temporal constriction or to the ventral margins of the eyes. Clypeus with one pair of setae. Supraorbital setae present, one pair. Eustipes of maxilla with two setae, the dorsobasal seta distinctly more than half as long as ventrobasal seta. Mentum with tooth present, simple, paramedial region shallowly foveate, one pair of mental setae present. Glosal sclerite (ligula) with one pair of setae. Submentum with one or two pairs of setae. Gula without transverse grooves. Antennomeres 3 and 4 without pubescence, ratio A3/A5 = 1.1–1.2.
Pronotum. Fig. 7c. Globose anterior to sub-basal constriction with base distinctly pedunculate, widest at middle of discal region, ratio PL/PW = 1.1–1.2, disk markedly convex; apical, lateral, and basal margination absent; anterior transverse impression shallow, broad and vaguely delineated, coarsely punctate both at bottom and on slopes of depression; median longitudinal impression moderately impressed; posterior transverse impression deep, sharply delineated; anterior region sparsely to densely punctate and rugulose; pronotal base coarsely punctate and rugulose; one pair of midlateral pronotal setae present at mid-length of discal region; basolateral pronotal setae absent.
Elytra. Elytral silhouette ovoid, short, widest at middle, ratio EL/EW male = 1.5–1.6, female = 1.5, greatest elevation above lateral margin (in lateral view) posterior to middle; humeri narrow, sloped, indistinct; lateral margins markedly arcuate, or markedly arcuate and faintly angulate sub-basally; parascutellar striole present, short, distally merged in a distinct jog with free base of stria 1. Eight elytral striae present; stria 1 moderately deeply and sharply impressed, striae 2 to 3, 4, or 5 moderately or shallowly impressed in basal two-thirds of striae and successively more shallowly impressed in apical third and laterally, lateral striae indistinct in some specimens, striae 8 merged with lateral groove throughout its length or nearly so; stria 1 moderately punctate at least in basal half, striae 2 to 8 moderately to coarsely punctate in basal half and successively more finely and sparsely punctate in apical half and laterally. Elytral microsculpture effaced or only very faintly impressed. Parascutellar seta present at base of stria 2 in most specimens, on base of interval 3 or near base of stria 3 in a few specimens, discal setae absent, umbilicate series of elytral setae comprised of one post-humeral and two preapical setae.
Hindwings. Vestigial, incapable of supporting flight.
Thoracic venter. Metepisternum ratio ML/MW = 1.5–1.7.
Legs. Hind trochanter asetose. Tarsomeres without dorsal pubescence; tarsomere 5 with two or more pairs of setae ventrally; male protarsi with pads of adhesive setae on tarsomeres 1 to 3 ventrally, male mesotarsi with pads of adhesive setae on tarsomeres 1 and 2 ventrally.
Abdomen. Sternite VI of male with one to three pairs of apicoparamedial setae, of female with one pair of setae.
Male genitalia: As in Fig. 16.
Comments. This is one of four species in the study area members of which have the elytra with distinct metallic reflection but the forebody (head and pronotum) without metallic reflection or with that reflection confined to the pronotal area anterior to the anterior transverse impression. Most members of B. bicoloratum have the pronotum without a trace of metallic reflection, but a few specimens have that anterior area with a faint metallic green band. That green band is found elsewhere only in all members of B. viridicollare, which are generally larger, have the elytral microscupture moderately distinctly impressed (effaced or nearly so in B. bicoloratum), and median lobe of the male genitalia longer, slightly less arcuate, and with the apical lamella slightly broader (Fig. 35c). Broscosoma gaoligongense members also have the forebody without metallic reflection, but they have the parascutellar setiferous pore inserted near the base of stria 3 (near base of stria 2 in most B. bicoloratum specimens), have the metatrochanter unisetose (asetose in most specimens of B. bicoloratum, but with a seta present unilaterally in a few specimens) and the eyes (Fig. 7d) slightly less convex (more convex in B. bicoloratum). Members of the fourth species, Broscosoma gongshanense, have the eyes less convex (Fig. 7e), the tempora shorter and nearly straight (tempora longer and distinctly more convex in B. bicoloratum), and the discal portion of the pronotum very slightly more elongate. The male genitalia of these two species are quite similar but differ in the shapes of the sclerites of the internal sac of the median lobe.
Among Broscosoma species known from outside the study area, members of only one species, Broscosoma monticola Habu, 1973, from Nepal, have the forebody without metallic reflection and markedly contrasting with the very distinct metallic reflection seen on the elytra in most specimens. However, B. monticola members have the genal ridge confined to the region from the post-temporal groove to the base of the head (extended anteriorly to ventral margin of eye in most B. bicoloratum specimens) and the median lobe of the male genitalia with a large protuberance on the ventral margin (see Habu 1973, fig. 6), which is absent from the median lobe of B. bicoloratum males.
Habitat distribution. In daytime, members of this species have been found under stones in moist alpine meadow areas (Fig. 42a) and along roadcuts and trails through bamboo and Rhododendron thickets (Fig. 42b). The beetles are active on the surface at night in the same areas, particularly in areas with a cover layer of mosses. Our records document occurrence of this species at moderately high elevations in the 3300 to 3675 m range (Fig. 49).
Geographical distribution within the Gaoligong Shan. Fig. 15b. We examined a total of 30 specimens (16 males and 14 females) from the northern part of the Gaoligong Shan in Gongshan County. Our records are all from the crest of the range and adjacent western and eastern slopes (in Core Areas 1 and 2, respectively (Fig. 48) (see Type material above for exact collection data).
Overall geographical distribution. This species has been recorded only from the crest of the Gaoligong Shan in Gongshan County in western Yunnan Province China.
Geographical relationships with other Broscosoma species. Members of this species have been found together only with those of Broscosoma gongshanense (described below) at one or more sites (Fig. 50). Broscosoma ribbei occurs in the same general area but mainly at lower elevations.
description: Published as part of Kavanaugh, David H. & Liang, Hongbin, 2021, Inventory of the Carabid Beetle Fauna of the Gaoligong Mountains, Western Yunnan Province, China: Species of the Tribe Broscini (Coleoptera: Carabidae)., pp. 85-182 in Proceedings of the California Academy of Sciences 67 (4) on pages 109-113, DOI: 10.5281/zenodo.11067355