Lasioglossum (Dialictus) yukonae 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 : 358-362

Lasioglossum (Dialictus) yukonae Gibbs , new species

( Figures 240A–E , 241A–D )

Holotype. ♀ CANADA, British Columbia, Pitt Meadows , N49°13´25´´ W122°45´12´´, comm. cranberry field “Banns” WPT 25.vi.2005 (C. Ratti); [ PCYU]

Diagnosis. Females of L. yukonae can be recognised by the diagnostic combination of moderately wide to round head (length/width ratio = 0.96–1.00), tessellate mesoscutum with dense punctures dense including the medial portion, mesepisternum dull without evident irregular punctures, metapostnotum with strongly anastomosing rugae ( Fig. 240E ), T1 acarinarial fan complete dorsally, metasomal terga polished with faint metallic reflections and T3–T4 with moderately dense tomentum. They are most similar to L. sheffieldi and L. perpunctatum . Female L. sheffieldi have a longer head (length/width ratio = 1.00–1.01), sparse mesoscutal punctures medially and shiny mesepisternum with evident punctures. Female L. perpunctatum have a wide head (length/width ratio = 0.95–0.96) and primarily longitudinal rugae on the metapostnotum.

Males of L. yukonae can be recognised by the diagnostic combination of head moderately long (length/ width ratio = 1.02), face below eye emarginaton obscured by dense white tomentum, flagellomeres moderately short (length/width ratio = 1.55–1.61), mesepisternum reticulate-punctate, tegula moderately elongate with weak posterior angle, and metabasitarsus pale brown. They are most similar to L. albipenne , L. perpunctatum and L. sheffieldi . Male L. albipenne have metabasitarsus yellow. Male L. perpunctatum have facial tomentum limited to lower paraocular area. Male L. sheffieldi have a longer head (length/width ratio = 1.06– 1.08) with less extensive facial tomentum.

Description. FEMALE. Length 5.86–6.80 mm; head length 1.61–1.66 mm; head width 1.61–1.70 mm; forewing length 4.15–4.58 mm.

Colouration. Head and mesosoma pale green with bluish and golden reflections. Clypeus with apical half blackish brown and basal half, and supraclypeal area bronze. Antenna dark brown, flagellum with ventral surface reddish brown. Tegula translucent reddish amber. Wing membrane subhyaline, venation and pterostigma pale amber. Legs brown, medio- and distitarsi reddish. Metasomal blackish brown, terga and sterna with apical margins amber to pale translucent yellow.

Pubescence. Dull 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 sparse, subappressed tomentum, not obscuring surface. Propodeum with dense plumose hairs on lateral and posterior surfaces (2–2.5 OD). Metasomal terga with moderately dense, fine setae. T1 acarinarial fan dense, complete dorsally. T1 dorsolateral portion with small patch of appressed tomentum. T2 basolaterally and T3–T5 entirely with tomentum partially obscuring surface. T2 apicolateral and T3–T4 apical margins with weak fringes.

Surface sculpture. Face imbricate, punctation moderately fine. Clypeus with apical half polished, basal punctation dense (i≤d). Supraclypeal area with punctation sparse (i=1–3d). Lower paraocular and antennocular areas with punctation dense (i≤d). Upper paraocular area and frons punctate-reticulate. Ocellocular area minutely punctate (i≤d). Gena lineolate. Postgena polished, weakly lineolate. Mesoscutum imbricate-tessellate, punctation fine, dense between parapsidal lines (i≤d), except on anteromedial and submedial areas (i=1– 1.5d), and dense laterad of parapsidal line (i≤d), contiguous on anterolateral portion of disc. Mesoscutellum polished, submedial punctation moderately dense (i=1–2d). Axilla punctate. Metanotum imbricate. Preëpisternum rugulose. Hypoepimeral area imbricate, obscurely punctate. Mesepisternum ruguloso-imbricate, obscurely punctate. Metepisternum with dorsal half rugoso-striate, ventral half imbricate. Metapostnotum with strong anastomosing rugae. Propodeum with dorsolateral slope rugose, lateral surface ruguloso-imbricate, posterior surface rugulose. Metasomal terga polished except T1 declivitous surface weakly coriarious, punctation fine, on basal halves dense (i=1–1.5d), on apical half moderately sparse (i=2–3d).

Structure. Head moderately wide to round (length/width ratio = 0.96–1.00). Eyes weakly convergent below (UOD/LOD = 1.07–1.16). Clypeus 2/3 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. Hypostomal carina parallel. Tegula ovoid, somewhat elongate with slight posterior angle ( Fig. 241D ). Inner metatibial spur pectinate with 3–4 teeth. Metapostnotum crescentic. Metapostnotum moderately elongate (MMR ratio = 1.23–1.27), posterior margin weakly angled onto posterior surface. Propodeum with oblique carina weak, lateral carina not reaching dorsal margin.

MALE. Similar to female except for the usual secondary sexual characters and as follows. Length 4.96 mm; head length 1.51 mm; head width 1.49 mm; forewing length 3.87 mm.

Colouration. Head and mesosoma blue. Flagellum with ventral surface reddish brown. Wings hyaline. Tibial bases and medio- and distitarsi reddish brown. Metasoma dark brown; apical margins pale translucent yellow

Pubescence. Face below eye emargination with moderately dense tomentum obscuring surface, densest on lower paraocular area, sparse on distal half of clypeus. Gena with sparse tomentum. T2–T4 basolaterally with very sparse tomentum. S2–S5 apicolaterally with very sparse plumose hairs (1 OD).

Surface sculpture. Mesocutum polished, punctation between parapsidal lines sparse (i=1–2.5). Mesepisternum polished, reticulate-punctate. Metapostnotum posterior margin smooth, polished. Propodeum with dorsolateral slope rugulose.

Structure. Head moderately elongate (length/width ratio = 1.02). Eyes convergent below (UOD/LOD ratio = 1.22). Antennal sockets distant (IAD/OAD> 1.0). Pedicel length subequal to F1. F2 length 1.7X F1. F2– F10 moderately short (length/width ratio = 1.55–1.61). Metapostnotum moderately elongate (MMR ratio = 1.27), posterior margin rounded onto posterior surface.

Terminalia . S7 with median lobe elongate, columnar, apex rounded (as in Fig. 210F ). S8 with apicomedial margin weakly convex (as in Fig. 210F ). Genitalia similar to Fig. 210D–E . Gonobase with ventral arms narrowly separated. Gonostylus small, dorsal setae elongate. Retrorse lobe elongate, weakly attenuated apically.

Range. Southwestern British Columbia north to the Yukon Territory ( Fig. 239 ).

Allotype. CANADA: YUKON TERRITORY: ♂ 14 mi E. Dawson, 1300ʹ, 3.viii.1962 ( R. E. Leech); [ CNC].

Paratypes. CANADA: BRITISH COLUMBIA: 1♀ 9.v.2001; [ PCYU] ; 2♀ Saanich, Island View Beach, N48°33´59´´ W123°22´02´´, 19.vi.1994 (Nadel & Hannah); [ RBCM] ; YUKON TERRITORY: 1♀ Kluane N.P., 10.vii.2006 (L. Packer); Carcross Dunes, vii.2006 (L. Packer); [ PCYU] .

Etymology. The specific epithet has a dual meaning. It refers to the location of the first recognised specimens from the Yukon Territory and is also dedicated to Yuko Nozoe for putting up with my infatuation with bees.

Floral records. ROSACEAE : Prunus serrulata .

Comments. Rare. This species is only known from a small number of individuals from sandy areas (beaches or dunes). The same is true for its possible sister species L. sheffieldi .

Figures

FIGURE 210. Lasioglossum sheffieldi 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.

FIGURE 239. Distribution of Lasioglossum weemsi (light grey) and L. yukonae (dark grey).

FIGURE 240. Lasioglossum yukonae new species. Female (A) lateral habitus; (B) dorsal habitus; (C) face; (D) mesepisternum; (E) metapostnotum. Scale bars, A–C = 1 mm.

FIGURE 241. Lasioglossum yukonae new species. Male (A) lateral habitus; (B) dorsal habitus; (C) face; (D) tegula. Scale bars, A–C = 1 mm.