Broscosoma purpureum 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 : 136-140

10. Broscosoma purpureum Kavanaugh and Liang , sp. nov.

Figures 6c , 9d , 10c , 28 , 29 , 45b , 48-50

Type material. Holotype, a male, in IOZ, labeled: “ CASENT 1015338 ”/ “ CHINA, Yunnan, Gongshan County, Dulongjiang Township , 0.5km N of Kongdang, 1500m, N27.88111º / E098.34063º,”/ “ 25 October 2004 ”/ “Stop #DHK-2004-057 A, D.H. Kavanaugh collector”/ “HOLOTYPE Broscosoma purpureum Kavanaugh & Liang sp. nov. designated 2021” [red label] . Paratypes (a total of 52): one male and three females ( CAS, IOZ) labeled: same as holotype except first label “ CASENT 1015337 ” and “ CASENT 1015339 ” to “ CASENT 1015341 ”, respectively ; 18 males and eight females ( CAS, IOZ) labeled: “ CASENT 1014590 ” to “ CASENT 1014602 ”, “ CASENT 1016705 ” to “ CASENT 10116708 ” and “ CASENT 10116730 ” and “ CASENT 1014603 ” and “ CASENT 1016709 ” to “ CASENT 10116715 ”, respectively/“ CHINA, Yunnan, Gongshan County, Dulongjiang Township , 0.5km N of Kongdang, 1500m, N27.88111º / E098.34063º, 25 October 2004 ”/ “Stop #DHK-2004-057C, D.H. Kavanaugh, Q.-B. Hou, H.-B. Liang, D.-Z. Dong & G. Tang collectors” ; three females ( CAS, IZO) labeled: “ CASENT 1017017 ” to “ CASENT 1017019 ”, respectively/ “ CHINA, Yunnan, Gongshan County, Dulongjiang Township, 0.6 km N of Dizhengdang village on Dulong Jiang , N28.08442º / E098.32652º ”/ “ 1880m, 29 October 2004, Stop #DHK-2004-061B, D.H. Kavanaugh, G. Tang & D.-Z. Dong collectors” ; three males and three females ( CAS, IOZ) labeled: “ CASENT 1014626 ” to “ CASENT 1014628 ” and “ CASENT 1014629 ” to “ CASENT 1014631 ”, respectively/ “ CHINA, Yunnan, Gongshan County, Dulongjiang Township, Bapo , 1412m, N27.73902º / E098.34975º ”/ “ 26 October 2004, Stop #LHB-2004-033, H.-B. Liang collector” ; one female ( IOZ) labeled: ” CASENT 1015009 ”/ “ CHINA, Yunnan, Gongshan County, Dulongjiang Township, Bapo , Mulangdang , 1355m, N27.75256º / E098.34745º ”/ “ 4 November 2004, Stop #LHB-2004-046, H.-B. Liang collector” ; three males and two females ( CAS, IOZ) labeled: “ CASENT 1016094 ” to “ CASENT 1016096 ” and “ CASENT 1016097 ” to “ CASENT 1016098 ”, respectively/ “ CHINA, Yunnan, Gongshan County, Dulongjiang Township, west bank of Dulongjiang at Elideng village , 1640m, N28.00287º / E098.32145º ” / “ 3 November 2004, Stop #DHK-2004-073, D.H. Kavanaugh, G. Tang & D.-Z. Dong collectors” ; two male and four females ( CAS, IOZ) labeled: “ CASENT 1015868 ” to “ CASENT 1015869 ” and “ CASENT 1015870 ” to “ CASENT 10115874 ”, respectively/ “ CHINA, Yunnan, Gongshan County, Dulongjiang Township, Moqie Wang at Gongshan / Dulongjiang Road Km 91, 1550m, N27.90085º / E098.34721º ” / “ 6 November 2004, Stop #DHK-2004-077, D.H. Kavanaugh & H.-B. Liang collectors” ; 1 male, “ CHINA, Yunnan, Gongshan County, Dulongjiang Township, Dulongjiang at Xianjiudang village , 1580m, N27.94092º / E098.33340º, 4 November 2004 ”/ “Stop #DHK-2004-074, D.H. Kavanaugh, M.A. Dixon, G. Tang & D.-Z. Dong collectors”. All paratypes also bear the following label: “ PARATYPE Broscosoma purpureum Kavanaugh & Liang , sp. nov. designated 2021” [yellow label].

Type locality. China, Yunnan, Gongshan County, Dulongjiang Township, Kongdang area, 1500m.

Derivation of species name. The species epithet, purpureum , is an adjective derived from the Latin word, purpureus, meaning purple. The name refers to the purple or bluish-purple metallic reflection of the dorsum in members of this species.

Diagnosis. Adults of this species ( Fig. 28a ) can be distinguished from those of other species in the region by the following combination of character states: size small, BL = 7.4 to 8. 1 mm; dorsal surface of body bright metallic blue or bluish-purple, head with greenish hue in some specimens, legs (including femora) pale rufous; antennomeres 3 and 4 glabrous except for apical whorl of setae; pronotum with lateral margination absent or present only at or posterior to sub-basal constriction ( Fig. 9d ), basolateral setae absent; elytral silhouette subparallel to subovoid, with humeri distinct, angulate, elytral microsculpture effaced, elytral striae coarsely punctate; metatrochanters asetose in most specimens (a few specimens with one or both metatrochanters unisetose); male protarsi with tarsomeres 1 to 3 with ventral pads of adhesive setae; male genitalia as in Fig. 29 .

Description. Fig. 28a . Size small, BL male = 7. 4–8 mm, female = 7.9– 8.1 mm, ratio EL/PL male = 2.4–2.5, female = 2.6. Body color black or dark piceous, last visible abdominal sternite rufous basally graded to pale yellow apically, antennae with antennomeres 1 and 2 and base of 3 pale rufous, other antennomeres rufous brown, femora, tibiae, and tarsi pale rufous. Dorsum with bright blue or bluish-purple metallic reflection, head with greenish hue on some specimens, venter (except epipleurae) without metallic reflection.

Head. Fig. 6c . Eyes large, convex, their diameter twice the length of the tempora. Frontal furrows moderately impressed, broad or narrow, arcuate, slightly convergent anteriorly and posteriorly, long, extended posteriorly beyond middle of eyes, faintly rugulose, impunctate or sparsely punctate. Vertex with post-temporal transverse sulcus broadly defined, densely and coarsely punctate. Tempora obliquely convex. Genal ridges present, restricted to head region distinctly behind post-temporal constriction ( Fig. 10c ). 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. 6c . Discal region anterior to basal constriction ovoid, slightly narrowed anteriorly with base distinctly pedunculate, widest at middle of discal region, ratio PL/PW = 1.1, disk markedly convex; apical, lateral, and basal margination absent; anterior transverse impression shallow, broad and vaguely delineated, coarsely and sparsely punctate; median longitudinal impression moderately impressed; posterior transverse impression deep, sharply delineated; anterior region sparsely punctate; pronotal base coarsely and densely punctate; one pair of midlateral pronotal setae present at mid-length of discal region; basolateral pronotal setae absent.

Elytra. Elytral silhouette subovoid, slightly narrowed in basal half, widest at middle, or slightly posterior to middle, ratio EL/EW male and female = 1.6–1.7, greatest elevation above lateral margin (in lateral view) posterior to middle; humeri distinctly present, roundly obtuse; lateral margins moderately arcuate and nearly straight in anterior half sub-basally; 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 8 indistinct, obliterated or represented by extremely fine and shallow linear depressions between punctures, successively less evident laterally and apically, stria 8 merged with lateral groove throughout its length or nearly so; stria 1 coarsely and moderately densely punctate, striae 2 to 3, 4, or 5 coarsely and densely 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 effaced. Parascutellar seta present at base of stria 2, discal setae absent, umbilicate series of elytral setae comprised of one post-humeral and two preapical setae.

Hindwings. Full-sized, functional.

Thoracic venter. Metepisternum ratio ML/MW = 2.1–2.4.

Leg. Hind trochanter asetose. Tarsomeres without dorsal pubescence; tarsomere 5 with two or more pairs of setae ventrally; male protarsi with small pads of adhesive setae on tarsomeres 1 to 3 ventrally, male mesotarsi with small 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. 29 .

Comments. Members of this species and B. parvum have the smallest body size of any Broscosoma species in the study area. In the field, they could be mistaken for a species of Ardistomis , a scaritine genus of the New World fauna. They can be distinguished from members of all other species in the region by their very shiny and brilliant purple or blue dorsum (although some individuals have the forebody greenish-blue rather than the purple or blue seen on the elytra), large and convex eyes, pronotum without lateral margination, and elytra with elytral striae (especially striae 1-3) very coarsely punctate, at least at and anterior to midlength, and elytral microsculpture effaced. The only species with which B. purpureum might be confused is B. holomarginatum , members of which are larger, have complete lateral margination on the pronotum, slightly smaller eyes, and elytral microsculpure distinctly impressed.

Among Broscosoma species known from outside the study area, only three have some or all members with distinct blue metallic reflection on the dorsum. As noted above in the Comments section for B. bicoloratum , B. monticola members have the elytra with shiny blue metallic reflection, but the pronotum is black, without metallic reflection, the humeri are obliterated and hindwings reduced (humeri distinct, subangulate and hindwings full-sized and functional in B. purpureum ), and the median lobe of the male genitalia has a large protuberance on the ventral margin. Members of Broscosoma semenovi Belousov and Kataev, 1990 from the Caucasus region also have the dorsum bright metallic blue and are similar in size to B. purpureum members, but they have the apical part of antennomere 4 pubescent (glabrous in B. purpureum ), the pronotum more elongate, the elytra with the humeri obliterated and striae only faintly punctate, and the median lobe of the male genitalia with the apical lamella broader in lateral aspect (see Belousov and Kataev 1990, fig. 2). Some members of the third species, Broscosoma sichuanum Deuve, 1990 also have the dorsum of the body with metallic blue reflection. However, members of that species have the eyes much smaller and less convex, the elytra with humeri indistinct, only stria 1 distinctly impressed (two or more striae impressed in B. purpureum ) and striatal punctures smaller, less coarse, the metatrochanters unisetose (asetose B. purpureum , unisetose unilaterally in very few specimens), and the median lobe of the male genitalia more slender (see Deuve 1990, fig. 11).

Habitat distribution. Members of this species have been found under deeply embedded stones on the upper sandy beaches of rivers ( Fig. 45b ) and along roadcuts with sandy soil during daytime. Adults are active on the surface at night, along roadcuts on moist sandy substrate stabilized by mosses and on open, sandy river beaches, where they congregate near or on boulders surrounded by sand, especially on boulders covered with mosses. Most of these sandy flats have little cover under which these beetles can hide during the day, so it seem likely that many spend daylight hours burrowed in the sand itself. This species is restricted to relatively low elevations, with our records documenting its occurrence in the 1355 to 1880 m range ( Fig. 49 ).

Geographical distribution within the Gaoligong Shan. Fig. 28b . We examined a total of 53 specimens (29 males and 24 females) from the northwestern part of the Gaoligong Shan in Gongshan County. Our records are all from the Dulong Jiang valley at the base of the western slope of the range in Core Area 1 ( Fig. 48 ) (see Type material above for exact collection data) .

Overall geographical distribution. This species has been recorded only from the northwestern part 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 holomarginatum at one or more sites ( Fig. 50 ). Broscosoma ribbei occurs in the same general area but has not been found syntopic with B. purpureum .

Figures

FIGURE 6. Forebody, Broscosoma species, dorsal aspect. a. B. holomarginatum sp. nov. (CASENT1015162; 0.5 km N of Kongdang, Dulongjiang Township, Gongshan County, Yunnan, China); b. B. ribbei Putzeys (CASENT1025337; 0.5 km WSW of Maku village, Dulongjiang Township, Gongshan County, Yunnan, China); c. B. purpureum sp. nov. (CASENT1015338; 0.5 km N of Kongdang, Dulongjiang Township, Gongshan County, Yunnan, China); d. B. resbecqi sp. nov. (Holotype; Siran Wang, Dulongjiang Township, Gongshan County, Yunnan, China); e. B. danzhuense sp. nov. (Holotype; Danzhum He drainage, Cikai Township, Gongshan County, Yunnan, China); f. B. parvum sp. nov. (CASENT1023565; 11.5 km above Shibali, Lishadi Township, Fugong County, Yunnan, China).

FIGURE 9. Prothorax, Broscosoma species, oblique left lateral aspect. a. a. B. holomarginatum sp. nov. (CASENT1016746; 0.5 km N of Kongdang, Dulongjiang Township, Gongshan County, Yunnan, China); b. B. resbecqi sp. nov. (Holotype; Siran Wang, Dulongjiang Township, Gongshan County, Yunnan, China); c. B. ribbei Putzeys (CASENT1025337; 0.5 km WSW of Maku village, Dulongjiang Township, Gongshan County, Yunnan, China); d. B. purpureum sp. nov. (CASENT1015871; Moqie Wang, Dulongjiang Township, Gongshan Yunnan, China). White arrows denote end points of lateral margination.

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 28. Broscosoma purpureum sp. nov. a. Habitus (CASENT1015338; 0.5 km N of Kongdang, Dulongjiang Township, Gongshan 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 km.

FIGURE 29. Male genitalia, Broscosoma purpureum sp. nov. (CASENT1015869; Moqie Wang, Dulongjiang Township, Gongshan Yunnan, China). a. Right paramere, lateral aspect; b. Left paramere, lateral aspect; c. Median lobe, left lateral Maspect; d. Median lobe, ventral aspect; scale line = 1.0 mm.

FIGURE 45. Photographs of habitats for Broscosoma species in the Gaoligong Shan region. a. Snowmelt stream on north-facing slope above North Fork of Yamu He, 8.5 km W of Shibali, 3100-3200 m, 27.18315º/098.71921º, Lumadeng Township, Fugong County, Yunnan (habitat for Broscosoma parvum sp. nov.); b. 0.6 km N of Dizhengdang village on Dulongjiang, 1880 m, 28.084º/098.327º, Dulongjiang Township, Gongshan County, Yunnan (habitat for Broscosoma purpureum 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.