Lasioglossum (Dialictus) sandhousiellum 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 : 291-294

Lasioglossum (Dialictus) sandhousiellum Gibbs , new species

( Figures 202A–D , 203A–F )

Holotype. ♀ Canada, British Columbia, Elk Falls Provincial Park, ~ 6 km W Campbell River, N50°02´34.9´´ W125°19´32´´, 25.vi.2005 (E. Elle); [ PCYU].

Diagnosis. Females of L. sandhousiellum can be recognised by the diagnostic combination of a moderately elongate head (length/width ratio = 1.00–1.02), weakly lineolate gena, dense mesoscutal punctures except submedially (i=1–1.5d), minute mesepisternal punctures densely spaced, metapostnotum rugoso-striate except posterior margin smooth, T1 declivitous surface polished on ventral portion ( Figs. 32A , 202D ), and distinctly green metasomal terga. They are very similar to L. prasinogaster , L. sedi and the American species L. veganum (Cockerell) . Female L. prasinogaster have very distinct and relatively strong mesepisternal punctures. Female L. sedi have the T1 declivitous surface coriarious on the ventral portion due to lack of microsculpture. Female L. veganum have the gena lineolate.

Males of L. sandhousiellum can be recognised by the elongate head (length/width ratio = 1.11), facial tomentum limited to lower paraocular area, flagellomeres moderately long (length/width ratio = 1.38–1.77) with the ventral surface brownish yellow, deep mesoscutal punctures moderately sparse on central disc (i=1– 4d), hypoepimeral area and mesepisternum polished due to lack of microsculpture with deep punctures (i≤d), subhyaline wings with reddish brown pterostigma, tarsi brownish yellow, and metasomal terga distinctly punctate except apical impressed areas impunctate. They are similar to L. sedi and L. prasinogaster . Male L. sedi have pale brown tarsi and sparse punctures on posterior half of central disc (i=1–2d). Male L. prasinogaster have more abundant pubescence on the face and mesosoma, hyaline wings with pale pterostigma and very dense mesepisternal punctures (i<d).

Redescription. FEMALE. Length 5.98–6.16 mm; head length 1.42–1.49 mm; head width 1.42–1.49 mm; forewing length 3.66–3.72 mm.

Colouration. Head and mesosoma green with bluish reflections. Labrum reddish brown. Clypeus apical half blackish brown. Antenna dark brown, F2–F10 with ventral surface yellow-orange. Tegula reddish brown. Wing membrane subhyaline, venation and pterostigma brownish yellow. Legs brown, medio- and distitarsi reddish brown. Metasomal terga golden green, sterna brown, apical margins pale translucent brownish yellow.

Pubescence. Dull white. Moderately sparse. 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 sparse subappressed pubescence. Propodeum with moderately dense plumose hairs on lateral and posterior surfaces (1.5–2 OD). Metasomal terga moderately sparse, fine setae. T1 acarinarial fan complete dorsally. T2–T3 basolaterally and T4–T5 entirely with sparse tomentum. T3–T4 with very weak fringes.

Surface sculpture. Face weakly imbricate. Clypeus with apical half polished, punctation strong (i=1–3d). Supraclypeal area with punctation sparse (i=1–3d). Lower paraocular area punctation dense (i≤1d). Antennocular area punctation dense (i≤1d). Upper paraocular area and frons reticulate. Ocellocular area reticulatepunctate. Gena polished due to weak microsculpture, weakly lineolate-punctate. Postgena polished. Mesoscutum imbricate medially, polished or weakly imbricate laterally, punctation between parapsidal lines dense (i≤d), more widely spaced submedially (i=1–1.5d), dense laterad of parapsidal line (i≤d), and reticulate on anterolateral portion. Mesoscutellum polished, submedial punctation sparse (i=1–5d). Axilla punctate. Metanotum imbricate. Preëpisternum weakly ruguloso-imbricate. Hypoepimeral area weakly imbricate-punctate (i=1–1.5d). Mesepisternum dorsal portion ruguloso-imbricate, ventral portion polished, punctation (i=1– 1.5d). Metepisternum with dorsal third rugoso-striate, ventral portion ruguloso-imbricate. Metapostnotum rugoso-striate, reaching 2/3 of the distance to the posterior margin. Propodeum with dorsolateral slope ruguloso-imbricate, lateral surface ruguloso-tessellate, posterior surface tessellate. Metasomal terga polished due to weak microsculpture, weakly coriarious, punctation on basal halves dense (i=1–1.5d), sparse on apical halves, more obscure (i=2–4d). T1 densely punctate on dorsal surface.

Structure. Head moderately elongate (length/width ratio = 1.00–1.02). Eyes convergent below (UOD/ LOD ratio = 1.11). Clypeus 2/3 below suborbital line, apicolateral margins of clypeus convergent. Antennal sockets close (IAD/OAD ratio <0.5). IOD subequal to OOD. Gena narrower than eye. Inner metatibial spur pectinate with 3 teeth. Metapostnotum elongate (MMR ratio = 1.11–1.13), posterior margin narrowly rounded onto posterior surface. Propodeum with oblique carina weak, virtually absent, lateral carina weak not reaching dorsal margin.

MALE. Similar to female except for the usual secondary sexual characters and as follows. Length 4.39 mm; head length 1.37 mm; head width 1.24 mm; forewing length 3.42 mm.

Colouration. Flagellum with ventral surface bright yellow-orange. Tarsi pale brownish yellow.

Pubescence. Lower paraocular area with moderately dense tomentum. Gena with very sparse tomentum. S2–S3 apical portions and S4–S5 lateral portions with erect woolly hairs (1–1.5 OD).

Surface sculpture. Mesoscutum polished, punctation widely spaced on submedial area of disc (i=2–5d). Hypoepimeral area polished with strong punctation (i=1–1.5d). Mesepisternum polished with punctation distinct (i≤d). Metapostnotum polished on posterior margin. Metasomal terga polished with deep punctation basal to premarginal line (i=1–2d), apical impressed areas impunctate.

Structure. Head elongate (length/width ratio = 1.11). Eyes convergent below (UOD/LOD ratio = 1.36). Antennal sockets distant (IAD/OAD ratio> 1.0). Pedicel longer than F1. F2 length 1.5X F1. F2–F10 moderately elongate (length/width ratio = 1.38–1.77). Metapostnotum truncate (MMR ratio = 1.25), posterior margin rounded onto posterior surface.

Terminalia . S7 with median lobe narrowly clavate, apex rounded ( Fig. 203F ). S8 with apicomedial margin weakly convex ( Fig. 203F ). Genitalia as in Fig. 203D–E . Gonobase with ventral arms narrowly separated. Gonostylus small, dorsal setae elongate. Retrorse lobe elongate, weakly attenuated apically.

Range. British Columbia south to Utah ( Fig. 201 ).

Allotype. CANADA: BRITISH COLUMBIA: ♂ Okanagan-Similkameen Reg. Dist., Oliver, McKinney Camp Rd. , “sandy hill”, N49.1138 W119.342, 1195 m, 26.vii.2008 (L. R. Best); [ PCYU]

Paratypes. CANADA: BRITISH COLUMBIA: 1♀ topotypical, 26.v.2005 (E. Elle) ; 1♀ Okanagan- Similkameen Reg. Dist., Osoyoos, Strawberry Crk. Rd. , N49.28548 W119.4931, 440 m, 1–3.v.2009. (L. R. Best) ; 1♀ Okanagan-Similkameen Reg. Dist., Oliver, McKinney Camp Rd. , “sandy cut”, N49.1135 W119.3406, 1190 m, 26.iv–3.v.2009. (L. R. Best); [ PCYU] ; 1♀ Squamish, Diamond Head Trail , 2400 ft., 13.viii.1953 (W. R. M. Mason); [ CNC] ; USA: UTAH: 1♀ Iron Co., 1–4 mi S of Cedar Breaks N.M., 9900 ft., 21.vi.1999 (L. Packer); [ PCYU] .

Etymology. The specific epithet is a dedication to Grace Adelbert Sandhouse in recognition of her studies of Dialictus .

Figures

FIGURE 32. T1 declivitous surface of female (A) L. sandhousiellum, arrows indicated polished surface, (B) L. sedi, arrows indicated coriarious surface.

FIGURE 201. Distribution of Lasioglossum sablense (star), L. sagax (light grey) and L. sandhousiellum (dark grey).

FIGURE 202. Lasioglossum sandhousiellum new species. Female (A) lateral habitus; (B) dorsal habitus; (C) face; (D) T1. Scale bars, A–C = 1 mm.

FIGURE 203. Lasioglossum sandhousiellum new species. Male (A) lateral habitus; (B) dorsal habitus; (C) face; (D) ventral view of genital capsule; (E) dorsal view of genital capsule; (F) S7, S8. Scale bars, A–C = 1 mm, F = 0.5 mm.