Lasioglossum (Dialictus) brunneiventre (Crawford)

Gibbs, Jason, 2010, Revision of the metallic species of Lasioglossum (Dialictus) in Canada (Hymenoptera, Halictidae, Halictini) 2591, Zootaxa 2591 (1), pp. 1-382 : 80-84

Lasioglossum (Dialictus) brunneiventre (Crawford)

( Figures 80A–D , 81A–E )

Halictus brunneiventris Crawford, 1907: 194 . ♀.

Holotype. ♀ USA, Nevada, Ormsby Co., vii (Baker); [ NMNH: 12079]. Examined.

Halictus (Chloralictus) pilosicaudus Cockerell, 1937b: 155 . ♀. [new synonymy]

Holotype. ♀ USA, California , San Miguel Island , end of vii, (Cockerell); [ CAS: 4659].Examined.

Taxonomy. Michener, 1951: Lasioglossum (Chloralictus) brunneiventre , p. 1112, L. (C.) pilosicaudum , p. 1116 (catalogue); Hurd, 1979: Dialictus brunneiventris , p. 1964, D. pilosicaudus , p. 1970 (catalogue); Moure & Hurd, 1987: Dialictus brunneiventris , p. 93, D. pilosicaudus , p. 123 (catalogue).

Diagnosis. Females of L. brunneiventre are recognisable by the diagnostic combination of a small size (3.7–4.0 mm), elongate head (length/width ratio = 1.07–1.10), dense mesoscutal and mesepisternal punctures, complete T1 acarinarial fan and a lack of dense tomentum on the brown metasomal terga. They are most similar to L. macroprosopum (see below) which are larger (5.98–6.34 mm) with a slightly shorter head (length/ width ratio = 1.05–1.07). A similar undescribed species of intermediate size (approx. 4.2–5.2 mm) with a very elongate head (length/width ratio = 1.10–1.17) occurs in the Western USA as far north as southeastern Washington but has abundant tomentum on the metasomal terga.

Males of L. brunneiventre are similar to females but may be further distinguished by their weakly convergent eyes (UOD/ LOD ratio = 1.28), relatively short flagellomeres (length/width ratio = 1.44–1.50), and less dense mesoscutal punctures.

Redescription. FEMALE. Length 3.72–4.03 mm; head length 1.22–1.32 mm; head width 1.13–1.22 mm; forewing length 2.75–2.87 mm.

Colouration. Head and mesosoma pale green to golden green, sometimes with blue reflections. Labrum reddish brown to yellow. Mandible orange to yellow. Clypeus with apical half brown, distal margin reddish brown to yellow, basal half, and supraclypeal area with brassy reflections. Antenna dark brown, flagellum with ventral surface reddish brown to bright orange-yellow. Tegula pale yellow. Wing membrane subhyaline, venation and pterostigma pale yellowish brown. Legs brown, tibial bases and apices, and tarsi reddish brown to bright yellow, metabasitarsus infused with brown. Metasoma reddish brown, terga and sterna with apical margins pale translucent brownish yellow.

Pubescence. White. Moderately dense. Head and mesosoma with moderately dense woolly hairs (1–1.5 OD), longest on genal beard, metanotum and mesopleuron (2–2.5 OD). Lower paraocular area and gena with abundant tomentum partially obscuring surface. Propodeum with moderately dense plumose hairs on lateral and posterior surfaces (2–2.5 OD). Metasomal terga with very dense, fine setae. T1 acarinarial fan complete, mingling with erect hairs on lateral margins. T2–T3 basolateral areas with tomentum. T4 disc with tomentum partially obscuring surface. T2 apicolateral and T3–T4 apical margins with weak, indistinct fringes.

Surface sculpture. Face imbricate, punctation fine and deep. Clypeus polished, basal margin imbricate, punctation moderately sparse (i=1–3d). Supraclypeal area with punctation moderately sparse (i=1–2.5d). Lower paraocular and antennocular areas with punctation dense (i≤d). Upper paraocular area, frons and ocellocular area punctate-reticulate. Gena lineolate. Postgena polished. Mesoscutum polished, punctation fine and deep, uniformly dense (i<d) ( Fig. 80D ). Mesoscutellum similar to mesoscutum, submedial punctation moderately sparse (i=1–2d). Axilla punctate. Metanotum imbricate. Preëpisternum reticulate. Hypoepimeral area and mesepisternum polished, densely punctate (i<d). Metepisternum with dorsal fifth striate and ventral portion weakly reticulate. Metapostnotum anastomosingly rugose. Propodeum with dorsolateral slope and lateral surface imbricate, posterior surface tessellate. Metasomal terga polished except T1 declivitous surface and apical impressed areas distinctly coriarious, punctation dense throughout (i≤d).

Structure. Head elongate (length/width ratio = 1.07–1.10). Eyes convergent below (UOD/ LOD ratio = 1.10–1.20). Clypeus 1/2 below suborbital line, apicolateral margins convergent. Antennal sockets close (IAD/ OAD <0.5). Frontal line carinate, ending 2.5 OD below median ocellus. Gena narrower than eye. Inner metatibial spur with 3 teeth. Metapostnotum moderately elongate (MMR ratio = 1.24–1.38). Propodeum with oblique carina weak, lateral carina not reaching dorsal surface.

MALE. Similar to female except for the usual secondary sexual characters and as follows. Length. 3.90 mm; head length 1.32 mm; head width 1.20 mm; forewing length 2.87 mm.

Colouration. Flagellum with ventral surface yellow. Tibial bases and apices, and tarsi reddish brown.

Pubescence. Face below level of eye emargination with dense tomentum obscuring surface except clypeus with moderately sparse tomentum, not obscuring surface

Surface sculpture. Mesoscutum punctation moderately sparse between parapsidal lines (i=1–2d). Propodeum with dorsolateral slope and lateral and posterior surfaces reticulate-punctate.

Structure. Head elongate (length/width ratio = 1.10). Eyes convergent below (UOD/ LOD ratio = 1.28). Antennal sockets distant (IAD/OAD> 1.0). Pedicel shorter than F1. F2 length 1.3X F1. F2–F10 moderately short (length/width ratio = 1.44–1.50). Metapostnotum moderately elongate (MMR ratio = 1.28), posterior margin weakly angled onto posterior surface.

Terminalia . S7 with median lobe narrowly clavate, sides subparallel, apex rounded ( Fig. 81D ). S8 with apicomedial margin weakly convex ( Fig. 81D ). Genitalia as in Fig. 81D–E . Gonobase with ventral arms narrowly separated. Gonostylus small, dorsal setae elongate. Retrorse lobes narrow, weakly attenuated apically.

Range. Southern British Columbia south to Southern California , east to Utah ( Fig. 79 ).

Additional material examined. CANADA: BRITISH COLUMBIA: 1♂ Okanagan-Similkameen Reg. Dist., Osoyoos, Mt. Kruger , Strawberry Crk. Rd. , N49.029 W119.4915, 415 m, 15.viii.2008 (L. R. Best) ; 1♀ Okanagan-Similkameen Reg. Dist., Osoyoos, Mt. Kruger , Strawberry Crk. Rd. , N49.0296 W119.4925, 440 m, 29.vii.2008 (L. R. Best) ; 1♀ Okanagan-Similkameen Reg. Dist., Osoyoos, Mt. Kruger , Strawberry Crk. Rd. , N49.03 W119.4929, 415 m, 28.vii.2008 (L. R. Best) ; USA: CALIFORNIA : 2♀ Los Angeles Co., N34.1116 W118.7773, 30.v.2008 (S.W. Droege); [ PCYU] ; 1♀ Mariposa Co., El Portal, 1.1 mi S Eagle Pk. , 11S N4173196 E 253773, 586 m, 8.v.2005 (H.W. Ikerd) ; 3♀ Mariposa Co., El Portal , 1.1 mi S Eagle Pk., 11S N4173196 E 253773, 586 m, 15.vii.2005 (L. Fuerst & H. Briggs) ; 1♀ Mariposa Co., Yosem Vly. , 0.9 mi W Sentinel Pk, 11S N4179077 E269998, 1204 m, 11.v.2005 (H. Briggs & E. Stephens) ; 1♀ Mariposa Co., Yosem Vly. , 0.9 mi W Sentinel Pk, 11S N4179077 E269998, 1204 m, 1.vi.2005 (H. Briggs & E. Stephens); UTAH : 1♀ Tooele Co., Dugway P.G., 2.5 km N of Ditto HQ N40°12´05´´ W112°55´12´´, 11.v.1998 ( T. Toler) ; 1♀ Washington Co. , 0.5 mi NNW Stave Spr. m., 12S N4126314 E330668, 26.v.2006 (B. Hayes & F. Nicklen) ; 1♀ Washington Co. , 0.72 mi E Firepit Kn. 12S N4135688 E314780, 5.vii.2006 (F. Nicklen & B. Hays); [ BBSL] .

Floral records. AIZOACEAE : Mesembryanthemum crystallinum , ASTERACEAE : Heterotheca villosa , Chrysothamnus , Ericameria linearifolia , Gutierrezia californica , Lasthenia californica chrysostoma , Lessingia germanorum , Malacothrix saxatilis , Solidago canadensis salebrosa ,, Stephanomeria exigua , BORAG- INACEAE: Cryptantha , EUPHORBIACEAE : Euphorbia albomarginata , HYDROPHYLLACEAE : Nemophila menziesii , Phacelia davidsonii , ONAGRACEAE : Camissonia campestris , PAPAVERACEAE : Eschscholzia californica , POLEMONIACEAE : Gilia ochroleuca exilis , G. multicaulis , Leptosiphon aureus , POLYGONACEAE : Eriogonum gracile , E. nudum , PORTULACACEAE : Calandrinia menziesii .

Comments. New record for Canada. First description of male. The new synonymy is based on comparison of type material which differ only in colour of integument. DNA barcoded specimens from near the type locality of H. pilosicaudus with colour matching the type do not differ from other L. brunneiventre barcode sequences.

Figures

FIGURE 79. Distribution of Lasioglossum bruneri (light grey), and L. brunneiventre (dark grey).

FIGURE 80. Lasioglossum brunneiventre (Crawford). Female (A) lateral habitus; (B) dorsal habitus; (C) face; (D) mesoscutum. Scale bars, A–C = 1 mm.

FIGURE 81. Lasioglossum brunneiventre (Crawford). Male (A) lateral habitus; (B) dorsal habitus; (C) face; (D) ventral view of genital capsule; (E) dorsal view of genital capsule. Scale bars, A–C = 1 mm, E = 0.5 mm.