Broscosoma furvum Kavanaugh and Liang, 2021

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)., Proceedings of the California Academy of Sciences 67 (4), pp. 85-182 : 116-121

5. Broscosoma furvum Kavanaugh and Liang , sp. nov.

Figures 7a , 10a , 18 , 19 , 40b , 48-50

Type material. Holotype, a male, in IOZ, labeled: “ CASENT 1017819 ”/ “ CHINA, Yunnan, Fugong County, Lumadeng Township, second cirque S of Shibali Yakou at border post “31”, N27.20333º / E098.69303º ”/ “ 3710m, 17 August 2005, Stop #DHK2005-095, H.B. Liang, D.Z. Dong & J.F. Zhang collectors”/ HOLOTYPE Broscosoma furvum Kavanaugh & Liang sp. nov. designated 2021” [red label]. Paratypes (a total of 13): five males and seven females ( CAS, IOZ) labeled: same as holotype except first label “ CASENT 1017818 ”, “ CASENT 1017820 ” to “ CASENT 1017823 ” and “ CASENT 1017811 ” to “ CASENT 1017817 ”, respectively/ “ CHINA, Yunnan, Fugong County , Lumadeng Township , second cirque S of Shibali Yakou at border post “31”, N27.20333º / E098.69303º ”/ “ 3710m, 17 August 2005, Stop #DHK2005-095, H.B. Liang, D.Z. Dong & J.F. Zhang collectors”; one male ( CAS) labeled: “ CASENT 1020001 ”/ “ CHINA, Yunnan, Fugong County, Lumadeng Township , first cirque S of Shibali Yakou, 3725m ”/ “ N27.20520º / E098.69590º, 17 August 2005, Stop #DHK2005-094, D.H. Kavanaugh collector”. All paratypes also bear the following label: “PARATYPE Broscosoma furvum Kavanaugh & Liang , sp. nov. designated 2021” [yellow label].

Type locality. China, Yunnan, Fugong County, Lumadeng Township, second cirque S of Shibali Yakou at border post “31”, 27.20333º/98.69303º, 3710m.

Derivation of species name. The species epithet, furvum , is an adjective derived from the Latin word, furvus, meaning dark or dusky. The name refers to the dark brown to black dorsal body color, with no trace of metallic reflection, of members of this species.

Diagnosis. Adults of this species ( Fig. 18a ) can be distinguished from those of other species in the region by the following combination of character states: size moderate, BL = 10.6 to 11. 1 mm; dorsum of body piceous, without any trace of metallic reflection; antennomeres 3 and 4 glabrous except for apical whorl of setae, distinctly darker than antennomeres 1 and 2; genal ridge evident, extended from base of head to ventral margin of eye ( Fig. 10a ); pronotum anterior to sub-basal constriction ( Fig. 7a ) longitudinally slightly ovoid in dorsal view, basolateral setae absent; elytral silhouette ovoid, with humeri indistinct; metatrochanters unisetose; male protarsi with tarsomeres 1 to 3 with ventral pads of adhesive setae; male genitalia as in Fig. 19 , with median lobe longer and more slender and with apical lamella distinctly bent ventrally in lateral view.

Description. Fig. 18a . Size medium, BL male = 10.6–11. 1 mm, female = 10.6–10. 9 mm, ratio EL/PL male = 2.2, female = 2.2–2.3. Body color black or piceous, last visible abdominal sternite black, piceous, or dark brown, antennae with antennomeres 3 and 4 slightly darker brown than antennomeres 1 and 2 and 5 to 11, femora, tibiae, and tarsi dark brown or tarsi lighter brown in some specimens. Head, pronotum, elytra, and venter without metallic reflection.

Head. Fig. 7a . Eyes medium-sized, their diameter slightly greater than length of tempora. Frontal furrows deeply impressed, narrow, short, linear, and distinctly divergent posteriorly, or medium length, arcuate, and slightly convergent anteriorly and posteriorly, extended posteriorly to middle of eyes or less, faintly rugulose, impunctate. Vertex with post-temporal transverse sulcus deep, sharply defined, smooth and impunctate or very sparsely and finely punctate. Tempora obliquely convex. Genal ridges distinctly present, extended from base of head to ventral margins of 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 = 1.0–1.1.

Pronotum. Fig. 7a . Disc anterior to sub-basal constriction slightly longitudinally ovoid in dorsal view with base distinctly pedunculate, widest at middle of discal region, ratio PL/PW = 1.2– 1.3, disk markedly convex; apical margination absent; lateral margination present, narrow, delineated only on pronotal base; basal margination absent; anterior transverse impression shallow, broad and vaguely delineated, smooth; median longitudinal impression distinct, but finely and shallowly impressed or moderately impressed; posterior transverse impression deep, sharply delineated; anterior region faintly and sparsely rugulose; pronotal base coarsely and densely 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, female = 1.5– 1.6, greatest elevation above lateral margin (in lateral view) posterior to middle; humeri narrow, sloped, indistinct; lateral margins markedly arcuate; parascutellar striole present, short, distally merged in a distinct jog with free base of stria 1. Eight striae present; stria 1 moderately deeply and sharply impressed, striae 2 to 3, 4, or 5 shallowly impressed in basal two-thirds of striae and successively more shallowly impressed to indistinct in apical third, striae 3 to 8 successively more shallowly impressed to indistinct laterally and apically (striae striae 3 or 4 to 8 obliterated or nearly so 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 3, 4, or 5 moderately punctate in basal two-thirds and successively more shallowly and sparsely punctate in apical third, striae 3 to 8 successively more shallowly and sparsely punctate laterally and apically. Elytral microsculpture evident, comprised of finely impressed isodiametric sculpticells. Parascutellar seta present near base of stria 3 in most specimens (near base of stria 2 in a few specimens), discal setae absent, umbilicate series comprised of one post-humeral and two preapical setae.

Hindwings. Vestigial, incapable of supporting flight.

Thoracic venter. Metepisternum ratio ML/MW = 1.4–1.5.

Legs. Hind trochanters unisetose. 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 both male and female with one pair of apicoparamedial setae.

Male genitalia. As in Fig. 19 .

Comments. This is the only Broscosoma species in the study area members of which have the full dorsum of the body without a trace of metallic reflection. Its members are also among the largest of any of the species in the area, overlapping in size only with those of B. viridicollare and the largest members of B. bicoloratum and B. ribbei , all of which have at least the elytra distinctly metallic green or bluish-green.

Among Broscosoma species known from outside the study area, only four have members with similar or larger body size and without dorsal metallic reflection at least in most members. The known body size ranges for three of these, Broscosoma dostali Deuve, 2006 , Broscosoma herculaneum Deuve, 2011 , and Broscosoma mourzinei Deuve, 2011 , all known only from Sichuan, are larger and non-overlapping with the size range of B. furvum specimens. Members of B. dostali also have the eyes and tempora more convex, the pronotum shorter and more globose (more elongate in B. furvum ), and the median lobe of male genitalia with the apical lamella narrower and more symmetrical in lateral aspect (see Deuve 2006, fig. 9) (broader and distinctly expanded ventrally in B. furvum ). Members of B. herculaneum have the head more generally punctate, the submentum with three pairs of setae (one or two pairs in B. furvum ), the pronotum with the medial impression distinctly impressed but not extended to the pronotal base (deep and extended well onto the pronotal base in B. furvum ), the elytra with only stria 1 impressed, the others effaced and represented only by punctures (at least two striae impressed on center of elytral disc in B. furvum ), and the median lobe of the male genitalia with the apical lamella narrower and slightly less expanded ventrally (see Deuve 2011a, fig. 61). Members of B. mourzinei have the eyes less convex and smaller, their diameter about equal to length of the tempora (eyes slightly more convex and their diameter slightly greater than the length of the tempora in B. furvum ), the submentum with three pairs of setae, the pronotal base finely and densely punctate (base more coarsely punctate in B. furvum ), the elytra with only stria 1 impressed, and the median lobe of the male genitalia of similar shape except with the apical lamella slightly narrower and more symmetrical in lateral aspect (see Deuve 2011b, fig. 16). Members of the fourth species, Broscosoma rolex Morvan, 1995 , known from Nepal, are of similar size to B. furvum members but have the elytral silhouette more slender (slightly broader in B. furvum ), elytra with slight metallic reflection in some specimens, and the median lobe of male genitalia distinctly thicker subapically and with the apical lamella narrower and more symmetrically rounded in lateral aspect (see Morvan 1995, fig. 7).

Habitat distribution. Members of this species were collected under large stones on the crest of the range and on the east-facing slope just below it in an area of scattered Rhododendron and bamboo thickets interspersed with moist herbaceous meadow vegetation and stabilized talus ( Fig. 40b ). This species has been found only at high elevation, with our records documenting its occurrence in the 3710 to 3725 m range ( Fig. 49 ).

Geographical distribution within the Gaoligong Shan. Fig. 18b . We examined a total of 14 specimens (seven males and seven females), all from the northcentral part of the Gaoligong Shan in Fugong County on the eastern side of the range in Core Area 3 ( Fig. 48 ) (see Type material above for exact collection data) .

Overall geographical distribution. This species currently is known only from the northcentral part of the Gaoligong Shan, in western Yunnan Province, China.

Geographical relationships with other Broscosoma species. Members of this species have been found syntopic only with those of Broscosoma viridicollare at the type locality ( Fig. 50 ).

Figures

FIGURE 7. Forebody, Broscosoma species, dorsal aspect. a. B. furvum sp. nov. (CASENT1020001; first cirque S of Shibali Yakou, Fugong County, Yunnan, China); b. B. viridicollare sp. nov. (CASENT1022787; 8.5 km above Shibali, Lishadi Twonship, Fugong County, Yunnan, China); c. B. bicoloratum sp. nov. (CASENT1026704; slope NW of Heipu Yakou, Dulongjiang Townhip, Gongshan County, Yunnan, China); d. B. gaoligongense Deuve and Wrase (CASENT1027285; just W of Fenxue Yakou, Pianma Township, County, Yunnan, China); e. B. gongshanense sp. nov. (CASENT1008139; Dongshaofang area, Gongshan County, Yunnan, China).

FIGURE 10. Head, Broscosoma species, lateral aspect. a. B. furvum sp. nov. (CASENT1020001; first cirque S of Shibali Yakou, Fugong County, Yunnan, China); b. B. gaoligongense Deuve and Wrase (CASENT1027285; just W of Fenxue Yakou, Pianma Township, County, Yunnan, China); c. B. purpureum sp. nov. (CASENT1015871; Moqie Wang, Dulongjiang Township, Gongshan Yunnan, China). White arrows denote endpoints of genal ridge.

FIGURE 18. Broscosoma furvum sp. nov. a. Habitus (CASENT1020001; first cirque S of Shibali Yakou, Fugong County, Yunnan, China), dorsal aspect, scale line = 1.0 mm; b. Map showing locality records (blue circles) for this species in the Gaoligong Shan region, scale line = 100 k.

FIGURE 19. Male genitalia, Broscosoma furvum sp. nov. (CASENT1023548; 1.0 km E of Shibali Yakou, Lishadi Township, Fugong County, Yunnan, China). a. Right paramere, lateral aspect; b. Left paramere, lateral aspect; c. Median lobe, left lateral aspect; d. Median lobe, ventral aspect; scale line = 1.0 mm.

FIGURE 40. Photographs of habitats for broscine species in the Gaoligong Shan region. a. SW slope of Kawakarpu Shan on slope NE of Chukuai Lake, 3950 m, 27.982°/098.480°, Bingzhongluo Township, Gongshan County, Yunnan (habitat for Brosocodera chukuai sp. nov.); b. Second cirque S of Shibali Yakou at border post “31”, 3710 m, 27.203°/098.693°, Lumadeng Township, Fugong County, Yunnan (habitat for Brosocodera chukuai sp. nov., Broscosoma furvum sp. nov., and Broscosoma viridicollare sp. nov.). Photos by David H. Kavanaugh.

FIGURE 48. Chart showing the representation of broscine species in project-designated Core Areas (see Fig. 3) in the Gaoligong Shan region.

FIGURE 49. Chart illustrating the altitudinal ranges of broscine species represented in the Gaoligong Shan region. Green bars mark the elevational range recorded for each species.

FIGURE 50. Chart illustrating the co-occurence (syntopy) of broscine species in samples from the same habitats and at the same sites in the Gaoligong Shan region. Incidents of syntopy marked in black represent confirmed co-occurrence, those marked in grey not confirmed by records but likely.