Bradynobaenus diminutus Torréns & Fidalgo, 2017

Torréns, Javier & Fidalgo, Patricio, 2017, Two new species of Bradynobaenus Spinola, 1851 (Hymenoptera: Bradynobaenidae) in the semiarid area of Argentina, Zootaxa 4232 (2), pp. 293-300 : 294-297

Bradynobaenus diminutus Torréns & Fidalgo , sp. nov.

( Figs 1, 2, 6–8 )

Diagnosis. Body length 3.2 mm; general body color light brown to yellowish; mesonotum with oblique line of few punctures from anterolateral angle towards center, not reaching the middle of the sclerite; MLS interrupted, Description. Female. Body length 3.2 mm; maximum width 0.8 mm. General body color light brown to yellowish; head slightly darker; distal half of mandible orange ( Fig. 1 ). Head 1.3 × wider than long in dorsal view ( Fig. 2 ). Scape 1.5 × its width, as long as flagellomeres 1–4 combined; pedicel 1.2 × its maximum width, 1.4 × flagellomere 1; flagellomeres cylindrical. Mandible 0.8 × length of head; with three distal teeth in row, proximal tooth subquadrate ( Fig. 2 ). Head almost completely glabrous, with setae distributed as follows: dense group of long, whitish setae on upper surface of scape and with few scattered setae on lower surface of scape; long and whitish setae on external surface of pedicel; row of whitish and long setae bordering dorsally antennal insertion; row of whitish and long setae from base of mandible running between eye and antennal insertion; row of whitish and scattered setae over vertex and surrounding postoccipital suture ( Figs 1, 2 ).

Mesosoma . Depressed, in dorsal view 1.0 × longer than maximum width ( Figs 6 , 8 ). Pronotum 2.4 × wider than long; anterior margin of dorsal surface with irregular band of strong and separated punctures bearing long and white seta; this band continued laterally but punctures are distributed throughout surface; space between punctures and rest of pronotum smooth. Mesonotum 1.8 × wider than long ( Fig. 8 ); surface mostly smooth, with few strong punctures towards sides of dorsal surface and forming oblique line not very marked from anterolateral angle towards center, not reaching middle of mesonotum ( Fig. 8 ); meso-metathoracic suture with strong punctures bearing long and whitish setae. Fused metanotum and propodeum vertical, surface mostly smooth, with few strong punctures and with long and whitish setae near insertion of metasoma. MLS interrupted, forming a curved line; surface of mesopleuron smooth, with few long and whitish setae ( Fig. 6 ). Meso-metapleural suture distinct; separation of metapleuron and propodeum indicated only by feeble depression. Coxae smooth with long, whitish setae on anterior surface; femur and tibia with long dispersed setae, especially on posterior surface. Foreleg: tarsomere 1 widened and flattened apically, posterior margin sharp and with three pits at apex; tarsomeres 2–3 slightly flattened towards apex. Mid leg: apex of tibia with short spiniform setae towards posterior margin and with small pits surrounding insertion of tarsomere; tarsomeres 1–2 widened towards apex and with 1–2 short spininiform setae. Hind leg: apex of tibia with two thick and long setae in posterior margin and with small pits surrounding insertion of tarsomere; tarsomere 1 widened towards apex and with short spiniform setae.

Metasoma. 2.0 × longer than maximum width in dorsal view ( Fig. 7 ). First tergum 1.1 × wider than long and 0.6 × width of tergum 2, with anterior vertical surface covered with setae; rest of tergum 1 and terga 2–5 without setae or with few scattered setae in posterior margin. Tergum 6 with four longitudinal carinae, internal carinae curved towards apex of sclerite; posterior margin of tergum slightly curved ( Fig. 7 ). Sterna 1–2 with few and dispersed setae throughout surface; rest of sterna with few setae only restricted to posterior margin.

Male. Unknown.

Etymology. The specific name originates from Latin diminutus referring to the small size of the species.

Material examined. Holotype ♀: ARGENTINA: La Rioja, Santa Teresita (dunes), 28°35'57''S 66°33'44''W, 21-22/XII/2009, YPT, J. Torréns & P. Fidalgo ( MACN).

Remarks. A female of new species differs from that of similar B. cordobensis Genise by body mostly glabrous, with a few setae; head and general body color paler ( Figs 1–4 ) (in B. cordobensis testaceous to orange); MLS interrupted and with a few setae (in B. cordobensis MLS continuous, sigmoid, with many setae) ( Figs 5, 6 ); oblique line of mesonotum homogeneously distributed (in B. cordobensis irregular line) ( Figs 8, 10 ); protarsomere without spiniform setae (in B. cordobensis with 3–4 spiniform setae); shape of metasomal terga 1–2 dorsally ( Figs 7, 9 ).

Figures

FIGURES 1 – 6. Bradynobaenus spp. (♀). 1, 2. B. diminutus sp. nov.: 1. Habitus, lateral view; 2. Head and antenna, frontal view, mandible magnified. 3 – 5. B. cordobensis: 3. Habitus, lateral view; 4. Head, frontal view; 5. Mesosoma, lateral view. 6. B. diminutus, mesosoma, lateral view. MLS shaded.

FIGURES 7 – 10. Bradynobaenus spp. (♀). 7, 8. B. diminutus sp. nov.: 7. Metasoma, dorsal view, tergum 6 magnified; 8. Mesosoma, dorsal view, line of punctures marked. 9, 10. B. cordobensis: 9. Metasoma, dorsal view, tergum 6 magnified; 10. Mesosoma, dorsal view, line of punctures marked.