Lasioglossum (Dialictus) atwoodi Gibbs, 2010

Gibbs, Jason, 2010, Revision of the metallic species of Lasioglossum (Dialictus) in Canada (Hymenoptera, Halictidae, Halictini) 2591, Zootaxa 2591 (1), pp. 1-382 : 74-76

Lasioglossum (Dialictus) atwoodi Gibbs , new species

( Figure 76A–E )

Holotype. ♀ CANADA, Ontario, Algonquin P.P., Madawaska Lake , 7–19.vi.2007 (E. Proctor); [ PCYU].

Diagnosis. Females of L. atwoodi can be recognised by the diagnostic combination of round head (length/ width ratio = 0.96–0.98), tessellate-imbricate mesoscutum with moderately coarse punctures that are moderately sparse on central disc (i=1–2d), reddish brown tegula, strongly rugose mesepisternum ( Fig. 18A ), metapostnotum rugoso-striate but not reaching the posterior margin, T1 acarinarial fan with dorsal opening, brown metasomal terga with the apical halves obscurely punctate, and T4 with scattered tomentum not obscuring surface. They are most similar to L. viridatum which have the metapostnotal rugae reaching the posterior margin and T4 with sparse tomentum partially obscuring surface.

Male unknown.

Description. FEMALE. Length 5.12–5.67 mm; head length 1.45–1.52 mm; head width 1.51–1.58 mm; forewing length 3.97–4.03 mm.

Colouration. Head and mesosoma blue with greenish reflections. Clypeus with apical half blackish brown and basal half, and supraclypeal area greenish. Antenna dark brown, F8–F10 with ventral surface brownish yellow. Tegula reddish brown. Wing membrane subhyaline, venation and pterostigma yellowish brown. Legs brown, medio- and distitarsi reddish brown. Metasoma dark brown, terga and sterna with apical margins reddish brown to translucent yellowish brown.

Pubescence. Dull white. Sparse. Head and mesosoma with moderately sparse woolly hairs (1–1.5 OD), longest on genal beard, metanotum and mesopleuron (2–2.5 OD). Lower paraocular area and gena with sparse subappressed, plumose hairs, not obscuring surface. Propodeum with moderately dense plumose hairs on lateral and posterior surfaces (2–2.5 OD). Metanotum anteromedial portion with dense tomentum. Metasomal terga with extremely sparse, fine setae. T1 acarinarial fan with wide dorsal opening, equal to width of lateral hair patches. T2–T3 basolaterally and T4 entirely with sparse, scattered tomentum. T2 apicolateral and T3–T4 apical margins with sparse fringes.

Surface sculpture. Face imbricate, punctation moderately strong. Clypeus with apical half polished, punctation sparse (i=1–3d). Supraclypeal area with punctation sparse (i=1–4d). Lower paraocular and antennocular areas punctation moderately dense (i=1–1.5d). Upper paraocular area and frons reticulate-punctate. Ocellocular area obscurely punctate (i≤d). Gena lineolate, punctation obscure. Postgena imbricate. Mesoscutum and mesoscutellum tessellate-imbricate, punctation moderately coarse and deep, moderately sparse between parapsidal lines (i=1–3d), moderately dense laterad of parapsidal line (i=0.5–1.5d), and dense on anterolateral portions (i≤d). Mesoscutellum similar to mesoscutum, submedial punctation sparse (i=2–5d). Metanotum ruguloso-imbricate. Preëpisternum rugose. Hypoepimeral area ruguloso-imbricate. Mesepisternum rugose. Metapostnotum longitudinally rugoso-striate, posterior margin imbricate. Propodeum with dorsolateral slope rugulose to imbricate, lateral surface rugoso-imbricate, posterior surface tessellate. Metasomal terga polished except T1 declivitous surface and apical margins weakly coriarious, punctation on basal halves moderately dense (i=2–3d), obscure on apical halves (i=2–4d).

Structure. Head moderately wide (length/width ratio = 0.96–0.98). Eyes convergent below (UOD/LOD ratio = 1.18–1.28). Clypeus ½ below suborbital tangent, apicolateral margins strongly convergent. Antennal sockets close (IAD/OAD <0.5). Frontal line carinate, ending <2 OD below median ocellus. Gena narrower than eye. Inner metatibial spur pectinate with teeth. Metapostnotum moderately elongate (MMR ratio = 1.13– 1.19), posterior margin weakly angled onto posterior surface. Propodeum with oblique carina weak, lateral carina weak, nearly reaching dorsal margin.

MALE. Unknown.

Range. Nova Scotia west to Wisconsin, south to North Carolina ( Fig. 75 ).

Paratypes. CANADA: NOVA SCOTIA: 1♀ Hants Co., Upper Rawdon , N45.0845 W063.7297, 10.vii.2003 (Sheffield, Rigby & Jansen) ; ONTARIO: 1♀ topotypical, 7–19.vi.2007 (E. Proctor) ; 1♀ York University, near Boyer woodlot, 12.vii.2005 (E. Willis); [ PCYU] ; USA: INDIANA: 1♀ LaPorte Co., Indiana Dunes N.L., Beverly Shores , N41°42´17´´ W086°56´03´´, 14.iv.2004 ( R. Grundel); [ IDNL] ; MARYLAND: 1♀ Pr. George’s Co., N38.8987 W076.6783, 7.vii.2001 (S.W. Droege) ; MICHIGAN: 3♀ Van Buren Co., S. Haven E of Sandbar, 6.v.2001 (L. Packer) ; NEW YORK: 1♀ Hwy 63, N of Genesio, N42.8235 W077.1131, 11.vi.2006 (J. Gibbs); [ PCYU] ; NORTH CAROLINA: 1♀ 11 mi E of Cashiers , 12.vii.1957 (J.G. Chillcott); [ CNC] ; WISCONSIN: 1♀ Brown Co., 3489 Yorkshire Dr. , N44.54414 W087.9071, 25.v.2005 (A. Wolf) ; 1♀ Brown Co., 3489 Yorkshire Dr. , N44.54414 W087.9071, 5.vi.2005 (A. Wolf); [ PCYU] ; 1♀ Kawaunee Co., They’s Ag , N44.53102 W87.70013, 23.v.2006 (J. Watson); [ ARC] .

Etymology. The specific epithet is in honour of the late Canadian entomologist Carl Edmund Atwood. Floral records. PRIMULACEAE : Lysimachia terrestris , ROSACEAE : Rubus .

Comments. Uncommon.

Figures

FIGURE 18. Mesepisternum of female (A) L. atwoodi, (B) L. dreisbachi, arrow indicates sharply delineated change in sculpture.

FIGURE 75. Distribution of Lasioglossum asteris (dark grey) and L. atwoodi (light grey).

FIGURE 76. Lasioglossum atwoodi new species. Female (A) lateral habitus; (B) dorsal habitus; (C) face; (D) mesepisternum; (E) metapostnotum. Scale bars, A–C = 1 mm.