Mimesa rhyssocephalica Ma, Li and Chen

Ma, Li, Li, Qiang & Chen, Xue-Xin, 2008, The genus Mimesa in China with descriptions of two new species (Hymenoptera: Apoidea: Crabronidae), Zootaxa 1745, pp. 19-29 : 24-25

2. Mimesa rhyssocephalica Ma, Li and Chen , sp. nov.

( Figs. 6–13 )

Diagnosis: This species can be distinguished from the similar M. equestris (Fabricius, 1804) and other species of the genus by the following combination of characters: upper frons, vertex, and gena with slender, longitudinal or transverse ridges; antennal segments IV–XII beneath with linear carinae in male; in female, free margin of clypeus with four denticular prominences medially, near apex with a transverse elongate oval tubercle medially; head and thorax with very dense, fine punctures; and interantennal tooth conspicuous.

Description: Female. Body length 7.0– 7.5 mm. Black; mandible apically, gastral tergum I posteriorly, segment II, and pygidial area apically reddish brown; tibial spurs fulvous; tegula, and wing veins dark brown. Clypeus with sparse, silvery setae intermixed with some long brown setae; setae on frons, vertex, and thorax dense, brown, long, on propodeum, leg and petiole dense, silvery, long.

Clypeus with dense, fine punctures that are slightly more than one diameter apart; free margin with four denticular prominences medially; near apex with transversely elongate oval tubercle medially, tubercle shiny, impunctate, longer than half length of clypeal apical prominences ( Fig. 6 ); basal half of clypeal disk slightly elevated. Mandible bidentate apically. Interantennal tooth conspicuous ( Fig. 6 ). Antenna slightly dull, segments III and IV slender, long, segments III–XII gradually thicker and shorter toward apex; segment III about 3 ×, segment IV about 1.6 ×, and segment XI about 0.6 × as long as wide apically, respectively. Upper frons with fine, contiguous punctures, and with dense, slender, longitudinal ridges; ocellar area and vertex with fine, contiguous punctures; vertex flat, vertex and gena with very dense, slender, transverse ridges; ocellar area slightly elevated. HW: HLD: HLF = 74: 30: 57; POD: OOD: OCD = 10: 15: 11.

Anterior and middle portions of mesoscutum with fine, sparse punctures that are 1.5–2 × diameters apart; posterior portion of mesoscutum with fine, dense punctures that are less than one diameter apart. Scutellum with fine, sparse punctures. Metanotum with dense micro-punctures. Mesopleuron shiny, impunctate; lower portion with slender, dense, long, longitudinally oblique ridges posteriorly; upper mesopleuron with slender, longitudinal, contiguous rugae. Propodeal enclosure delimited by triangular, slender carina, with shallow depression, and slightly sturdy, sparse, longitudinal rugae, some rugae extending to posterior surface; posterior surface of propodeum with dense, slender, longitudinal, regular rugae; lateral surface of propodeum alutaceous, slightly shiny, without punctures or ridges. Both first and second recurrent veins of forewing ending in second submarginal cell. Legs normal, hind tibia with one or two rows of dark brown spines on outer surface, spines short, blunt on basal area, slightly longer and more acute on posterior surface.

Dorsal surface of petiole moderately convex, with broad longitudinal carina medially; in dorsal view, basal width of petiole nearly equal to its apical width ( Fig. 7 ); petiole with several slender, longitudinal carinae on its apical half laterally; ventral surface of petiole flat, without keel. PL: PW: LTI: WTI: HFL: HTL = 30: 7: 33: 35: 40: 48. Hind trochanter reaching end of petiole. Gastral segments shiny, impunctate; pygidial area elongate triangle, apex round, with dense, coarse punctures and setae ( Fig. 8 ).

Male: Body length 6.5–7.2 mm. Free margin of clypeus with two semicircular prominences medially, without tubercle near apex ( Fig.9 ). Antenna slenderer than in female; length of antennal segments IV–XII nearly equal to each other; segments IV–XII beneath with long, linear carinae ( Fig. 10 ); segment III about 2 ×, segment IV about 1.6 ×, and segment XII about 1.4 × as long as wide apically, respectively. HW: HLD: HLF = 64: 25: 46; POD: OOD: OCD = 7: 13: 8. Mesopleuron with sparse micro-punctures. Rugae on propodeum sturdier than in female. Hind tibia with one row of yellowish, slender, short spines on outer surface. PL: PW: LTI: WTI: HFL: HTL = 32: 7: 30: 27: 40: 45. Hind trochanter not reaching end of petiole. Male genitalia ( Figs. 11–13 ).

Specimen examined: Holotype: Ψ, China: Yunnan, Weixi, Lidiping, 3200m, 27°6'N 99°12'E, 3.viii.1984, coll. Jianguo Fan.

Paratypes: 1 Ψ, China: Yunnan, Weixi, Lidiping, 3200m, 27°6'N 99°12'E, 3.viii.1984, coll. Jianguo Fan; 1 Ψ, China: Yunnan, Xiaozhongdian, 3200m, 27°35'N 99°48'E, 3.viii.1984, coll. Jianguo Fan; 1 Ψ, China: Yunnan, Zhongdian, Tuying village, 2900m, 27°47'N 99°43'E, 7.vii.1984, coll. Jianguo Fan; 2 ɗ, China: Yunnan, Weixi, Lidiping, 3200m, 27°6'N 99°12'E, 15.viii.1984, coll. Jianguo Fan.

All specimens are deposited in the Institute of Zoology Chinese Academy of Sciences, Beijing, P. R. China.

Distribution: China: Yunnan Provinces.

Etymology: The name rhyssocephalica is derived from the Greek: rhyss- (= rugose) and cephalos (= head), referring to longitudinal or transverse slender ridges on the upper frons, vertex, and gena, one of the main recognition characters of this species.

Figures

FIGURES 6 – 13. Mimesa rhyssocephalica Ma, Li and Chen, sp. nov. (6 – 8 Female; 9 – 13 Male). 6, 9 Frontal view of head; 7 Dorsal view of gastral tergum I; 8 Dorsal view of pygidial plate; 10 Lateral view of antennal segments III – XIII; 11, 12 Lateral view of male genitalia; 13 Ventral view of male genitalia (scale line for figures 7 and 10: 1 mm; for 6 and 9: 1.18 mm; for 8: 1.52 mm; for 11, 12 and 13: 1.82 mm).