Broscosoma holomarginatum 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 : 128-132

8. Broscosoma holomarginatum Kavanaugh and Liang , sp. nov.

Figures 6a , 9a , 24 , 25 , 44b , 47-50

Type material. Holotype: a male, in IOZ, labeled: “CASENT 1015162”/ “ CHINA, Yunnan, Gongshan County, Dulongjiang Township, Kongdang , 1525 m, N27.87696° / E098.33587°,”/ “ 5 November 2004, Stop # LHB-2004-047, H.-B. Liang collector”/ “ HOLOTYPE Broscosoma holomarginatum Kavanaugh & Liang sp. nov. designated 2021” [red label] . Paratypes (a total of 19): two females ( CAS, IOZ), labeled: same as holotype except first label: “CASENT 1015163” and “CASENT 1015164”, respectively ; one female ( IOZ) labeled: “CASENT 1016688”/ “ CHINA, Yunnan, Gongshan County, Dulongjiang Township , 0.5km N of Kongdang, 1500m, N27.88111º / E098.34063º, 25 October 2004 ”/ “Stop #DHK-2004-057B, D.H. Kavanaugh, H.-B. Liang, & D.-Z. Dong collectors” ; two males ( CAS, IOZ) labeled: “CASENT 1014588” and “CASENT 1014589”, 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” ; one male and four females ( CAS, IOZ) labeled: “CASENT 1016748” and “CASENT 1016744” to “CASENT 1016747”, respectively/ “ CHINA, Yunnan, Gongshan County, Dulongjiang Township , 0.5km N of Kongdang, 1500m, N27.88111º / E098.34063º, 25 October 2004 ”/ “Stop #DHK-2004-057D, D.H. Kavanaugh, Q.B. Hou, H.B. Liang collectors” ; one male ( CAS) labeled: “CASENT 1025538”/ “ CHINA, Yunnan, Gongshan County, Dulongjiang Township, Maku village along old road through village, N27.68804º / E098.30758º ”/ “ 1615m, 3 September 2006, Stop DHK-2006-120, D.H. Kavanaugh, Y. Liu, S.Z Ma & P. Hu collectors” ; four males and three females ( CAS, IOZ) labeled: “CASENT 1000600” to “CASENT 1000603” and “CASENT 1000604” to “CASENT 1000606”, respectively/ “ CHINA, Yunnan Province, Gaoligongshan Mountains, Nujiang Prefecture, Gangfang Sancha Lukou , 26º073´N/98º34.5´E”/ “ 1500m, 14-15 October 1998, Stop #98-117C, D.H. Kavanaugh, C.E. Griswold, C. Ferraris & C.-L. Long collectors” ; one male ( IOZ) labeled: “ China, Tibet, Medog, 81.5km on Medog road, N29.65650, E95.49348 ”/ “ 2023m, 2020.9.17 N, Liang H.B, Xu Y. coll., Inst. Zool., Chinese Acad. Sci.”. All paratypes also bear the following label: “ PARATYPE Broscosoma holomarginatum Kavanaugh & Liang , sp. nov. designated 2021” [yellow label] .

Type locality. CHINA, Yunnan, Gongshan County, Dulongjiang Township, Kongdang .

Derivation of species name. The species epithet, holomarginatum , is an adjective derived from the Greek word, holos, meaning whole or entire, and the Latin word, marginatus, meaning bordered or enclosed with a border. The name refers the complete lateral margination (or lateral bead) of the pronotum found in members of this species.

Diagnosis. Adults of this species ( Fig. 24a ) can be distinguished from those of other species in the region by the following combination of character states: size moderate, BL = 8.1 to 9. 5 mm; dorsal surface with distinct blue or blue-green luster, legs pale rufous; antennomeres 3 and 4 glabrous except for apical whorl of setae; pronotum with lateral margination (lateral bead) complete between apical and basal margins ( Fig. 9a ), basolateral setae absent; elytral silhouette subparallel to subovoid, with humeri distinct, elytral microsculpture distinct, comprised of isodiametric to slightly longitudinally stretched sculpticells; male protarsi with tarsomeres 1 to 3 with ventral pads of adhesive setae; male genitalia as in Fig. 25 .

Description. Fig. 24a . Size small to medium, BL male = 8.5–9. 3 mm, female = 8.1–9. 5 mm, ratio EL/PL male = 2.1–2.3, female =2.1–2.3. Body color black or dark piceous, last visible abdominal sternite rufous brown, or rufous basally graded to pale yellow apically, antennae with all antennomeres pale rufous, femora, tibiae and tarsi pale rufous. Head with green, pronotum with blue or bluish-green, and elytra with marked blue metallic reflection, venter with metallic reflection absent or only faintly present.

Head. Fig. 6a . Eyes large, convex, their diameter slightly greater than length of tempora. Frontal furrows deeply impressed, narrow, arcuate, slightly convergent anteriorly and posteriorly, medium length, extended posteriorly to middle of eyes, rugulose and sparsely and coarsely punctate. Vertex with post-temporal transverse sulcus shallow, densely and coarsely punctate. Tempora straight, not convex. Genal ridges present, restricted to head region distinctly behind post-temporal constriction. 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. Glossal 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 = 1.2–1.3.

Pronotum. Fig. 6a . Globose anterior to sub-basal constriction with base distinctly pedunculate, widest at middle of discal region, PL/PW = 1.1, disk markedly convex; apical margination absent; lateral margination present, narrow, distinctly delineated throughout pronotal length (Fig. FX09a); 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 moderately to densely and coarsely punctate; 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 subovoid, slightly narrowed in basal half, widest at or slightly posterior to middle, ratio EL/EW in males = 1.5, in female = EL/EW 1.6, 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 elytral striae present; stria 1 deeply and sharply impressed, striae 2 to 8 indistinct, obliterated or represented by extremely fine and shallow linear depressions, successively less evident laterally and apically, 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 densely and moderately punctate, but with punctures increasingly shallower and sparser laterally and apically. Elytral microsculpture comprised of distinct, deeply to shallowly impressed isodiameteric sculpticells. Parascutellar seta present at base of stria 2, discal setae absent, umbilicate series comprised of one post-humeral and two preapical setae.

Hindwings. Full-sized, functional.

Thoracic venter. Metepisternum ratio ML/MW = 2.2–2.3.

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 both male and female with one pair of apicoparamedial setae.

Male genitalia. As in Fig. 25 .

Comments. This is apparently the only species in genus Broscosoma in which members have the pronotum with complete and well-defined lateral margination (Fig, 9a). Lateral margination is also present B. resbecqi , in which it is nearly complete but interrupted in the basal one-third of the discal region (Fig, 9b), and in most specimens of B. ribbei , in which it is present in the area of insertion of the midlateral seta and extended slightly anteriorly and posteriorly in a some specimens (Fig, 9b). Members of both of these species have the dorsum with vivid green metallic reflection, whereas B. holomarginatum members are distinctly blue or greenish-blue dorsally. The left paramere of the male genitalia ( Fig. 25b ) is unusual for a Broscosoma species and similar only to that of B. resbecqi males among species of the region.

Habitat distribution. Within the study area, members of this species have been found under stones on the upper sandy beaches of rivers ( Fig. 44b ) 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. Within the Gaoligong Shan region, this species occurs at relatively low elevations, with our records documenting its occurrence in the 1500 to 1615 m range ( Fig. 49 ). The record from Medog (Tibet) is from a slightly higher elevation of 2023 m.

Geographical distribution within the Gaoligong Shan. Fig. 24b . We examined a total of 20 specimens (ten males and ten females) from the northern and southcentral parts of the Gaoligong Shan in Gongshan and Lushui Counties. Our records from both areas are on the western side of the range (in Core Areas 1 and 4, respectively ( Fig. 48 ) (see Type material above for exact collection data).

Overall geographical distribution. Fig. 47 . This species has been recorded only from Gongshan and Lushui Counties in Yunnan and Medog County in Xizhang (Tibet). Its occurrence in the study area represents the southern part its geographical range.

Geographical relationships with other Broscosoma species. Within the study area, members of this species have been found together with those of Broscosoma purpureum (described below) and B. ribbei at one or more sites ( Fig. 50 ). In Medog County, Xizang (Tibet), they have been found syntopic with members of B. ribbei and another (undescribed) Broscosoma species.

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 24. Broscosoma holomarginatum sp. nov. a. Habitus (CASENT1015162; 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 25. Male genitalia, Broscosoma holomarginatum sp. nov. (CASENT1016743; 0.5 km N of Kongdang, Dulongjiang Township, Gongshan 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 44. Photographs of habitats for Broscosoma species in the Gaoligong Shan region. a. 0.5 km E of Fengxue Yakou, 3150 m, 25.972º/098.683 º, Luzhang Township, Lushui County, Yunnan (habitat for Broscosoma gaoligongense sp. nov.); b. Xiao Jiang at Gangfang Sancha Lukou, 1500 m, 26.122º/98.573º, Lushui County, Yunnan (habitat for Broscosoma holomarginatum sp. nov.). Photos by David H. Kavanaugh.

FIGURE 47. Map showing approximate known overall geographical distributions of broscine species occurring in the Gaoligong Shan region as well as outside the study area. a. Broscus punctatus (Dejean); b. Eobroscus bhutanensis Morvan; c. Broscosoma ribbei Putzeys; d. Broscosoma holomarginatum 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 k

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.