Broscosoma parvum 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 : 132-136

publication ID	https://doi.org/ 10.5281/zenodo.11067355
persistent identifier	https://treatment.plazi.org/id/03AF0B0C-FFF0-FF86-FF9F-FEA1A586FD97
treatment provided by	Felipe
scientific name	Broscosoma parvum Kavanaugh and Liang
status	sp. nov.

Treatment

9. Broscosoma parvum Kavanaugh and Liang , sp. nov.

Figures 6f View FIGURE , 26 View FIGURE , 27 View FIGURE , 45a View FIGURE , 48-50 View FIGURE View FIGURE View FIGURE

Type material. Holotype, a male, in IOZ, labeled: “CASENT 1022788”/ “ CHINA, Yunnan, Fugong County, Lumadeng Township, 8.5 km above Shibali on Shibali road, North Fork of Yamu He ” / “ N27.18326º / E098.72002º, 3100m, 9 May 2004, Stop #DHK2004-042, D.H. Kavanaugh & H.B. Liang collectors”/ HOLOTYPE Broscosoma furvum Kavanaugh & Liang sp. nov. designated 2021” [red label] GoogleMaps . Paratypes (a total of 6): one female ( IOZ) labeled: same as holotype except first label “CASENT 1022789” ; one male ( CAS) labeled: “CASENT 1023771”/ “ CHINA, Yunnan, Fugong County, Lumadeng Township, 8.5 km above Shibali on Shibali road, North Fork of Yamu He ” / “ N27.18326º / E098.72002º, 3100m, 7 May 2004, Stop #DHK2004-038B, D.H. Kavanaugh collectors” GoogleMaps ; one male and one female ( CAS, IOZ) labeled: “CASENT 1019759” and “CASENT 1019754”, respectively “ CHINA, Yunnan, Fugong County, Lumadeng Township, 8.5 km W of Shibali on Shibali road, south bank of North Fork Yamu He ” / “ N27.18315º / E098.71921º, 3100- 3200m, 16 August 2005, Stop #DHK2005-090, D.H. Kavanaugh & H.B. Liang collectors” GoogleMaps ; one female ( CAS), “ CHINA, Yunnan, Fugong County, Lumadeng Township, 8.5 km W of Shibali on Shibali road, south bank of North Fork Yamu He , N27.18326º / E098.72002º ” / “ 3100m, 8 August 2005, Stop #DHK2005-067B, D.H. Kavanaugh & H.B. Liang, D.Z. Dong & J.F. Zhang collectors” GoogleMaps ; one male ( CAS) labeled: “CASENT1023565”/ “ CHINA, Yunnan, Fugong County, Lishadi Township , 11.5 km above Shibali on Shibali road, N27.20676º / E098.71763º ”/ “ 3290m, 6 May 2004, Stop #DHK-2004-036, D.H. Kavanaugh, C. E. Griswold, Liang H.-B., Li X.-Y. & Zhu B.-X. collectors”. All paratypes also bear the following label: “ PARATYPE Broscosoma parvum Kavanaugh & Liang , sp. nov. designated 2021” [yellow label] GoogleMaps .

Type locality. China, Yunnan, Fugong County, Lumadeng Township, 8.5 km W of Shibali on Shibali road, North Fork of Yamu He , 27.18326º/98.72002º, 3100m .

Derivation of species name. The species epithet, parvum , is an adjective derived from the Latin word, parvus, meaning small. The name refers to the relatively small body size of members of this species.

Diagnosis. Adults of this species ( Fig. 26a View FIGURE ) can be distinguished from those of other species in the region by the following combination of character states: size small, BL = 7.5 to 8. 5 mm; dorsum with distinct metallic reflection, green on head, green or blue-green on pronotum, blue-green on elytra; antennomeres 3 and 4 glabrous except for apical whorl of setae; eyes ( Fig. 6f View FIGURE ) less convex, slightly flattened in some specimens; pronotum with basolateral setae absent; elytral silhouette ovoid, with greatest width at or near midlength, with humeri rounded yet slightly evident, two or more elytral striae impressed, all striae punctate with punctures diminishing in size and depth laterally and posteriorly, medial two or more elytral intervals very slightly to moderately convex; male protarsi with tarsomeres 1 to 3 with ventral pads of adhesive setae; male genitalia as in Fig. 27 View FIGURE .

Description. Fig. 26a View FIGURE . Size small, BL male = 7.5-7. 7 mm, female = 7.9- 8.5 mm, ratio EL/PL male 2.2-2.4, female 2.3. Body color black or piceous, last visible addominal sternite dark brown or rufous brown, antennae with all antennomeres rufous brown, femora black or dark piceous, tibiae and tarsi rufous brown. Dorsum with distinct metallic reflection, green on head, green or blue-green on pronotum, and blue-green on elytra, venter without metallic reflection.

Head. Fig. 6f. View FIGURE Eyes only slightly convex, slightly flattened, small, their diameter slightly less than length of tempora. Frontal furrows deeply impressed, narrow, linear, slightly divergent posteriorly, medium length, extended posteriorly to middle of eyes, smooth or faintly rugulose, impunctate. Vertex with post-temporal transverse sulcus deep, sharply defined, moderately punctate. Tempora straight, oblique. Genal ridges absent or restricted to head region distinctly posterior to 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 deeply foveate, one pair of mental setae present. Glosal sclerite (ligula) with one pair of setae. Submentum with two or three pairs of setae. Gula without transverse grooves. Antennomeres 3 and 4 without pubescence, ratio A3/A5 = 1.2.

Pronotum. Fig. 6f. View FIGURE Disc anterior to sub-basal constriction slightly narrow, 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, lateral, and basal margination absent; anterior transverse impression shallow, broad and vaguely delineated, impunctate or sparsely and coarsely punctate; median longitudinal impression moderately impressed; posterior transverse impression deep, sharply delineated; anterior region smooth; pronotal base coarsely and sparsely to densely punctate; one pair of midlateral pronotal setae inserted slightly anterior to mid-length of discal region; basolateral pronotal setae absent.

Elytra. Elytral silhouette subovoid, slightly narrowed in basal half, widest at or near middle, ratio EL/EW male and female = 1.6, greatest elevation above lateral margin (in lateral view) posterior to middle; humeri faintly 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 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 or obliterated laterally and apically, striae 8 merged with lateral groove throughout its length or nearly so; stria 1 coarsely and moderately densely 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 comprised of very faintly impressed, nearly effaced isodiametric sculpticells. Parascutellar seta present at base of stria 2, 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 = 1.8–2.2.

Legs. Hind trochanters 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. 27 View FIGURE .

Comments. Only four species in the study area have the full dorsum of the body with green metallic reflection. Members of B. danzhuens e are larger in size, have eyes that are more convex ( Fig. 6e View FIGURE ), the elytral silhouette slightly broader across the humeri and their greatest width distinctly posterior to midlength (at or very near midlength in B. parvum ), elytra striae that are more finely punctate, and elytral intervals that are flat (at least some intervals slightly convex in B. parvum ). The holotype of B. resbecqi is larger and has the pronotum with the discal portion relatively short- er and more globose ( Fig. 6d View FIGURE ) and lateral margination present and nearly complete ( Fig. 9b View FIGURE ) (absent from B. parvum ), the femora pale rufous (darker in B. parvum ), and the median lobe of the male genitalia much thicker ( Fig. 31c View FIGURE ) and with the apical lamella short and tapered to a narrowly round- ed tip in lateral aspect (median lobe much thinner and the apical lamella slightly hooked dorsally in B. parvum ). Members of B. ribbei are generally much larger and have the eyes distinctly more convex, the pronotum with the discal portion relatively shorter and more globose ( Fig. 6b View FIGURE ) and lateral margination incomplete but present in most specimens, at least in the vicinity of the midlateral setae and more extensively in some specimens, elytral microsculpture distinct, deeply to moderately impressed (very faintly impressed or effaced in B. parvum ), the metatrochanters unisetose (unilaterally asetose in a few specimens) (asetose in B. parvum ), and the median lobe of the male genitalia much longer, thinner, and with the apical lamella more symmetrically rounded in lateral aspect.

As noted in the Comments section for B. danzhuense , only two Broscosoma species known from outside the study area have members in which the elytral humeri are at least faintly evident (although in both they are less evident than in B. parvum ) and the entire dorsum exhibits metallic green or bluish-green reflection. In members of B. montreuili , the forebody is a darker, less vivid metallic green than the elytra (both parts equally vivid or forebody lighter and more vivid in B. parvum ), and in both B. montreuili and B. tiani body size is larger, the discal portion of the pronotum is more globose (narrower and more elongate in B. parvum ), the elytra have striae 2 to 8 more faintly defined and finely punctate, and the median lobe of the male genitalia is longer, less arcuate and with the apical lamella either rounded apically or hooked ventrally (hooked dorsally in B. parvum ).

Habitat distribution. Members of this species have been found under stones along small to medium-sized streams on moist organic substrate. Half of the specimens collected were found along a small snowmelt stream on a steep, north-facing slope ( Fig. 45a View FIGURE ). This species is found at moderately high elevations, with our records documenting its occurrence in the 3100 to 3290 m range ( Fig. 49 View FIGURE ).

Geographical distribution within the Gaoligong Shan. Fig. 26b View FIGURE . We examined a total of seven specimens (four males and three 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 View FIGURE ) (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 together (syntopic) only with those of B. viridicollare at one or more sites ( Fig. 50 View FIGURE ).