Stigmus denticorneus Bashir & Ma

Bashir, Nawaz Haider, Li, Qiang & Ma, Li, 2019, Review of the genus Stigmus Panzer (Hymenoptera, Crabronidae) in China, with description of five new species from the Oriental and Palearctic Regions, ZooKeys 843, pp. 51-69 : 56-60

Stigmus denticorneus Bashir & Ma sp. n. Figs 2, 6b, c

Type material.

Holotype: ♀, China: Gansu: Dangxian: Daheba, 35°32'N, 105°17'E, 30.VII.2004, 2530m, No. 200707781, coll. Qiong Wu (ZJU); Paratypes: 1♀7♂, China: Gansu: Dangxian: Daheba, 35°32'N, 105°17'E, 30.VII.2004, 2530m, ♀, No. 200707788, 7♂, No. 200707785, 200707812, 200707771, 200707795, 200707816, 200707814, 200707829, coll. Qiong Wu, Min Shi (ZJU).

Diagnosis.

Distinguished from S. japonicus by combination of characters: in female, free margin of clypeus slightly produced and with two distinct cornuted teeth medially, deeply emarginated in the middle; scrobal suture inconspicuous, just with several longitudinal rugae; lateral surface of petiole with two strong longitudinal carinae; admedian and parapsidal line weakly impressed; posterior surface of propodeum with a shallow narrow median groove, shiny, remaining with contiguous punctures and sparse irregular oblique longitudinal rugae. Closely related to S. quadriceps except antenna dark brown; forewing veins brown; gena with sparse midsize to large punctures dorsally; in male, frontal furrow distinctly impressed on upper frons; free margin of clypeus slightly produced and nearly truncate medially; anterior area of pronotal collar narrowly emarginated in middle, antero-lateral corner lacking; petiole subquadrate (non-cylindrical), slightly convex, not longer than 1st abdominal tergite.

Description.

Female (Figs 2 a–g, 6b):

Measurements. ♀ BL: 5 mm; HW: HLD: HLF = 68: 42: 52; HW: EWd: EW: TW: EL = 68: 15: 20: 21: 42; length of scape: length of pedicel: length of flagellomere I: width of flagellomere I: length of flagellomere II: width of flagellomere II = 20: 8: 6: 4: 6: 4; PL: PW: LTI: WTI = 37: 9: 32: 38. ♂, BL: 3.8-4.2 mm; HW: HLD: HLF = 62: 36: 48; HW: EWd: EW: TW: EL = 62: 16: 21: 14: 38; length of scape: length of pedicel: length of flagellomere I: width of flagellomere I: length of flagellomere II: width of flagellomere II = 15: 7: 6: 3: 7: 3.5; PL: PW: LTI: WTI = 34: 10: 28: 28.

Colour pattern. Clypeus with reddish brown to dark brown band subapically; mandible yellowish except reddish brown apically; labrum dark brown; palpi fulvous; antenna beneath fulvous and dark brown; pronotal lobe ivory; tegula fulvous; forewing veins brown; fore and mid legs: base and apex of femur, tibia, tarsi fulvous, trochanter and remaining femur dark brown; hind leg basal one fourth of tibia and tarsus fulvous, remaining tibia dark brown; petiole black; gaster dark brown; setae on clypeus and mandible yellow.

Head. Mandible tridentate apically, median tooth larger (Fig. 2a). Labrum pentagonal, apex deeply emarginated (Fig. 2a). Clypeus shiny, slightly convex, with sparse midsize punctures, setae on clypeus sparse, long; free margin of clypeus slightly produced and with two distinct cornuted teeth medially, slightly reflected (Fig. 2a). Scapal hollow half mat, coriaceous, somewhat shallow, provided with a vestigial minute tubercle medianly, not spined. Frontal furrow very fine and weakly impressed, inconspicuous. Median and upper frons shiny, with fine sparse punctures, gently convex. Ocellar triangle area flat, shiny, impunctate, near eyes area with dense, short, impressed lines, opaque area smaller than hind ocellus. Vertex behind ocelli half mat, with slender mi crosculpture, and fine sparse punctures. Gena shiny, with sparse midsize to large punctures dorsally (Fig. 2b), ventral gena shiny, smooth. Head from above with temples rarely convergent posteriorly, subquadrate. Occipital carina incomplete, not ending in hypostomal carina, suddenly ended at the posterior ridge of stomal hollow, not tooth, much narrowed, no crenulate; inner and outer orbital furrows lacking.

Mesosoma. Anterior area of pronotal collar with sturdy carinae (incomplete), narrowly emarginated in middle, lateral carina lacking, antero-lateral corner lacking (Fig. 2c). Mesoscutum half mat, anterior area with large dense punctures and slender coriaceous, remaining with sparse, midsize to large punctures. Admedian line weakly impressed, extending to half of scutum. Prescutal sutures deeply grooved, reaching one third of scutum. Parapsidal line weakly impressed. Scutellum shiny, with fine sparse, punctures; metanotum slenderly coriaceous. Mesopleuron shiny, with sparse, midsize punctures, episcrobal area with dense longitudinal rugae, omaulus and hypersternaulus broadened, distinctly crenate, scrobal suture inconspicuous, just with several longitudinal rugae. Propodeal enclosure elongate, U-shaped medially, and with a sturdy longitudinal median rugae and sparse transvers rugae, lateral area with contiguous, irregular rugae and punctures mixed with several, sturdy, oblique longitudinal rugae laterally (Fig. 2d). Posterior surface of propodeum with a shallow narrow median groove, shiny, remaining with contiguous punctures and sparse, irregular, oblique longitudinal rugae (Fig. 2d). Lateral surface of propodeum with slender, contiguous mixed with several sturdy, oblique longitudinal rugae.

Legs. Normal, outer surface of hind tibia with three long, slender, fulvous to dark brown, spines.

Wings. Forewing venation typical for genus Stigmus , hindwing media diverging beyond cu-a.

Metasoma. Dorsal surface of petiole subquadrate (cross section), slightly convex and widened toward apex slightly, with two strong longitudinal carinae, and irregular, strong rugae anteriorly and medially, lateral area with 2 strong longitudinal carinae posteriorly on each side (Fig. 2e). Lateral surface of petiole with a few strong longitudinal carinae (Fig. 2f). Ventral surface of petiole with a few strong, longitudinal carinae medially and posteriorly. Gastral segments shiny, nearly impunctate, gastral sternum VI with fine, coarse punctures, half mat. Pygidial area shiny, broadly U-shaped, apex rounded, with 2 lines, large punctures and setae medially (Fig. 2g).

Male (Figs 2 h–l, 6c). Almost same to female except mandible ivory with reddish brown apically; palpi ivory; flagellomere reddish brown to dark brown; pronotal lobe white; fore and mid legs: trochanter, base and apex of femur, tibia, tarsi yellowish to fulvous, remaining dark brown; setae on clypeus dense, silvery, short. Mandible bidentate apically (Fig. 2h); clypeus near flat, with dense tiny punctures; free margin of clypeus slightly produced and nearly truncate medially, moderately reflected apically (Fig. 2h); frontal furrow distinctly impressed on upper frons; median and upper frons shiny, with several midsize to large punctures, strongly convex; ocellar triangle area slightly convex, shiny, impunctate, near eyes area with dense, short, impressed lines, opaque area large (Fig. 2i); vertex behind ocelli half mat, slenderly coriaceous, with several shallow, midsize punctures; gena shiny, inconspicuous coriaceous, with several fine to midsize punctures dorsally; head from above with temples somewhat roundly convergent posteriorly (Fig. 2i); occipital carina incomplete, distinctly crenulate; flagellomeres without tyloids, normal. Male genitalia (Fig. 2 j–l).

Distribution.

China (Gansu).

Etymology.

The specific epithetic, is derived from the Latin dent- (= tooth) and the Latin word corneus (= cornuted), referring to the free margin of clypeus with two distinct cornuted teeth medially.