Lasioglossum (Dialictus) sablense 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 : 283-286

Lasioglossum (Dialictus) sablense Gibbs , new species

( Figures 197A–C , 198A–F )

Holotype. 1♀ Canada, Nova Scotia, Sable Island , N43.9319 W059.9985, 8.viii.2008 (P.M. Catling); [ PCYU].

Diagnosis. Females of L. sablense can be recognised by the diagnostic combination of wide head (length/ width ratio = 0.96–0.97), mesoscutum polished due to lack of microsculpture with sparse punctures between parapsidal lines (i=1–3d), ruguloso-imbricate mesepisternum, metapostnotum with rugae not reaching posterior margin, brown metasomal terga that are polished due to weak microsculpture, metasomal terga brown with weak metallic reflections, T1 acarinarial fan strong with dorsal opening, T2–T4 basolaterally with moderately dense tomentum, T3–T4 with moderately strong apical fringes. They are most similar to L. ephialtum which have the mesoscutum imbricate and brown metasomal terga.

Males are similar to females but may be further distinguished by their moderately moderately dense facial tomentum below level of eye emargination, moderately elongate flagellomeres (length/width ratio = 1.57– 1.67), brownish yellow tarsi, metasomal terga impunctate on apical halves, T2–T4 with sparse tomentum basolaterally, moderately dense plumose haris on S3–S5 apicolaterally, and strongly rugose metapostnotum. They are similar to L. laevissimum , L. weemsi and L. ephialtum . Male L. laevissimum lack tomentum on the metasomal terga and have obscure punctures on the ventral portion of the mesepisternum. Male L. weemsi have denser punctures on the metasomal terga that are only absent on the apical impressed areas and the mesoscutum tessellate. Male L. sablense have longer flagellomeres (length/width ratio = 1.80–1.85) and the mesoscutum imbricate and lon due to lack of microsculpture.

Description. FEMALE. Length 5.80–6.10 mm; head length 1.51–1.60 mm; head width 1.56–1.64 mm; forewing length 4.09–4.39 mm.

Colouration. Head and mesosoma pale golden with greenish or bluish reflections. Clypeus with apical half blackish brown. Antenna dark brown, flagellum with ventral surface reddish brown, F8–F10 with ventral surface orange-yellow. Tegula dark reddish brown to translucent brownish yellow. Wing membrane subhyaline, venation and pterostigma pale brownish yellow. Legs brown, medio- and distitarsi reddish brown. Metasomal terga weakly golden green, sterna brown, apical margins 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 tomentum. Propodeum with moderately dense plumose hairs on lateral and posterior surfaces (1.5–2 OD). Metasomal terga with moderately dense, fine setae. T1 acarinarial fan strong with narrow dorsal opening, less than width of lateral hair patches. T2–T3 basolaterally and T4 entirely with tomentum partially obscuring surface. T2 apicolateral and T3–T4 apical margins with moderately strong fringes.

Surface sculpture. Face weakly imbricate, punctation moderately fine. Clypeus with apical half polished, punctation sparse (i=1–3d). Supraclypeal area with punctation sparse (i=1–4d). Lower paraocular area punctation dense (i≤d). Antennocular area punctation moderately dense (i=1–1.5d). Upper paraocular area and frons reticulate-punctate. Ocellocular area obscurely punctate (i≤d). Gena lineolate. Postgena imbricate. Mesoscutum polished, punctation fine, moderately sparse between parapsidal lines (i=1–3d), denser laterad of parapsidal line (i=1–1.5d), contiguous on anterolateral portions. Mesoscutellum similar to mesoscutum, submedial portion punctation moderately dense (i=1–2d). Axilla punctate. Metanotum imbricate. Preëpisternum rugulose. Hypoepimeral area imbricate. Mesepisternum shiny, dorsal portion rugulose, ventral portion imbricate. Metepisternum with dorsal third striate, ventral portion imbricate. Metapostnotum rugoso-striate nearly reaching posterior margin. Propodeum with dorsolateral slope rugulose, lateral surface weakly ruguloso-tessellate, posterior surface tessellate. Metasomal terga polished except faintly coriarious on apical margins, punctation on basal halves moderately dense (i=1–2d), obscure on apical halves (i=2–3d).

Structure. Head moderately wide (length/width ratio = 0.96–0.97). Eyes convergent below (UOD/LOD ratio = 1.21–1.24). Clypeus 2/3 below suborbital tangent, apicolateral margins strongly convergent. Antennal sockets close (IAD/OAD ≤ 0.6). Frontal line carinate, ending 2 OD below median ocellus. IOD less than OOD. Gena narrower than eye. Inner metatibial spur pectinate with 4 teeth. Metapostnotum moderately elongate (MMR ratio = 1.25–1.29), posterior margin weakly angled onto posterior surface. Propodeum with oblique carina very weak, lateral carina weak, not reaching dorsal margin.

MALE. Similar to female except for the usual secondary sexual characters and as follows. Length 5.19– 6.04 mm; head length 1.46–1.58 mm; head width 1.46–1.56 mm; forewing length 3.72–3.90 mm.

Colouration. Flagellum with ventral surface reddish brown to orange. Tibial apices, metatibial base and tarsi brownish yellow. Metasoma dark brown, terga and sterna with apical margins reddish brown.

Pubescence. Face below eye emargination with moderately dense tomentum, partially obscuring surface; less dense on supraclypeal area. Gena with sparse tomentum. T2–T4 basolaterally with sparse tomentum. S3– S5 apicolaterally with moderately dense plumose hairs (1 OD).

Surface sculpture. Clypeus punctation moderately dense (i=1–1.5d). Metanotum rugose. Preëpisternum and hypoepimeral area rugose. Mesepisternum with dorsal portion reticulate-rugose and ventral portion obscurely punctate. Metepisternum with dorsal 2/3 rugoso-striate. Metapostnotum coarsely rugose. Propodeum dorsolateral slope, lateral and posterior surfaces coarsely rugose. Metasomal terga apical impressed areas impunctate.

Structure. Head moderately elongate (length/width ratio = 1.00–1.02). Eyes strongly convergent below (UOD/LOD ratio = 1.52–1.53). Labrum weakly emarginate. Clypeus with apicolateral margins weakly convergent. Antennal sockets distant (IAD/OAD> 1.4). Pedicel shorter than F1. F2 length 1.6–1.7X F1. F2–F10 moderately elongate (length/width ratio = 1.57–1.67). Metapostnotum moderately elongate (MMR ratio = 1.17–1.32), posterior margin sharply angled onto posterior surface.

Terminalia . S7 with median lobe narrowly acuminate, apex narrowly rounded ( Fig. 198F ). S8 with apicomedial margin weakly convex ( Fig. 198F ). Genitalia as in Fig. 198D–E . Gonobase with ventral arms widely separated. Gonostylus small, dorsal setae elongate. Retrorse lobe slender, elongate, weakly attenuated apically.

Range. Sable Island ( Fig. 201 ).

Allotype. CANADA: NOVA SCOTIA: 1♂ topotypical, 8.viii.2008 (P.M. Catling); [ PCYU].

Paratypes. CANADA: NOVA SCOTIA: 2♀ 4♂♂ topotypical, 8.viii.2008 (P.M. Catling); [ PCYU] ; 2♀♀ 2♂♂ Sable Island , 11–15.ix.1967 (W. R. M. Mason); [ CNC] .

Etymology. The specific epithet refers to the type locality.

Floral records. ASTERACEAE : Achillea , ERICACEAE : Vaccinium , ONAGRACEAE : Oenothera , POLYGONACEAE : Polygonum .

Comments. This species is currently only known from Sable Island. This is a member of the L. viridatum species-group.

Figures

FIGURE 197. Lasioglossum sablense new species. Female (A) lateral habitus; (B) dorsal habitus; (C) face. Scale bars, A–C = 1 mm.

FIGURE 198. Lasioglossum sablense 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 201. Distribution of Lasioglossum sablense (star), L. sagax (light grey) and L. sandhousiellum (dark grey).