Lasioglossum (Dialictus) carlinvillense Gibbs

Gibbs, Jason, 2009, Integrative taxonomy identifies new (and old) species in the Lasioglossum (Dialictus) tegulare (Robertson) species group (Hymenoptera, Halictidae), Zootaxa 2032, pp. 1-38 : 28-29

Lasioglossum (Dialictus) carlinvillense Gibbs , sp. n.

( Figures 11 A–D)

Diagnosis. This species is smaller in body size than other species. The inner hind tibial spur of the female is unique in having only two subapical teeth as opposed to the three or four teeth in the other species. The male is unknown.

Description. Female. Length: 4.3 (4.3–4.5) mm, fore wing length: 2.7 (2.7) mm, head width: 1.2 (1.2–1.3) mm, head length: 1.2 (1.2) mm, n=3

Colouration. Head and mesosoma dull metallic bluish-green except the following: labrum brown-piceous, mandible base brown, apex red; clypeus brown, golden above; supraclypeal area bronzed above; antennae brown-piceous except ventral surface of flagellomeres brown, F8–F10 testaceous ventrally; gena blue; mesoscutum green to golden green; tegula piceous with central area ferruginous; legs brown-piceous, medio- and distitarsi ferruginous; wing venation and pterostigma testaceous; wings faintly dusky; propodeum darker with blue reflections; metasoma piceous-brown; apical portions of terga and sterna light brown.

Pubescence. Lower paraocular area with sparse, subappressed, plumose hairs; head and mesosoma with sparse, erect, plumose hairs (1–1.5OD), longer on metanotum and ventral pleura (2OD); posterolateral margin of pronotum and pronotal lobe with dense, appressed tomentum; dense scopa on hind femur; propodeal lateral surface hairs (2OD) with long branches; acarinarial appressed fan complete; terga with sparse, erect hairs (1–2OD), more abundant on ventrolaterally reflexed portions; T3–T5 ventrolaterally reflexed areas with few erect hairs (2.5–3OD); T2–T3 basolateral portions and T4 dorsal surface with sparse appressed, plumose hairs; sterna with long, posteriorly oriented hairs emerging from apical half of disc (2–3OD); S1–S4 hairs with long branches.

Surface sculpture. Clypeus glabrate except upper margin imbricate, punctures moderately coarse (i=1–2d), fine above (i=d); supraclypeal area smooth and shining below, imbricate above, punctures fine (i=1–1.5d); lower paraocular area imbricate, glabrate below, punctures moderately coarse and deep (i<d); upper paraocular area and frons punctures fine and shallow becoming reticulate; gena lineolate, punctures fine and obscure; mesoscutum and mesoscutellum tessellate between fine punctures; mesoscutum punctures well spaced but not sparse in anteromedial and submedial areas (i=1–1.5d), dense on remainder of disc (i<d); mesoscutellum densely punctate medially and along margins with sublateral area less densely punctate (i=1–1.5d); pre-episternum rugulose; mesepisternum scabriculous, closely and coarsely punctate (i<d), punctures finer and more obscure below, hypoepimeral area reticulate; tegula finely punctate (i=1–1.5d), central area more sparsely punctate; metapostnotum with irregular striations, median striation reaching margin, lateral striations extending onto anterior half of lateral slope; posterior half of lateral slope dull due to microsculpture; lateral surface of propodeum tessellate with sparse punctures (i>2d); metasoma coriarious with fine but deep punctures, evenly spaced over T1–T4 (i=1.5d) except less dense on apically impressed area; anteriorly directed surface of T1 and dorsolateral portions anterior to premarginal line impunctate.

Structure. Face broader than long to subequal; eyes convergent below (UOD:LOD = 1.2:1); clypeus protruding almost one half below lower ocular tangent; distance from antennal sockets to clypeus, shorter than clypeus; antennal sockets distinctly nearer to each other than to inner eye margin; frontal line carinate ending 2OD from median ocellus; OOC less than IOC (1.0:1.7); eye wider than gena from lateral view; hypostomal carinae parallel; mesoscutum length to width (1.0:1.3); ratio of lengths of mesoscutellum: metanotum: dorsal surface of propodeum (1.8:1.0:1.4); tegula elongate with posterior margin angled posteromedially; inner hind tibial spur pectinate with two subapical teeth; oblique propodeal carina weakly evident, not contiguous with lateral carina.

Range. South-central Illinois

Specimens examined. USA, ILLINOIS: HOLOTYPE Ƥ, Macoupin Co., E of Carlinville, N39.2787 W89.7961, 25.vi.2006, (J Gibbs & C Sheffield) [Barcoded]; 1 Ƥ, Carlinville, N39.2787, W89.8898, 24.vi.2006, (J Gibbs) [Barcoded]; 1 Ƥ, Litchfield, N39.1484 W89.667, 25.vi.2006, (C Sheffield) [Barcoded] (PCYU); 1 Ƥ, Dubois, 8.viii.1917 (INHS)

Type depository. PCYU

Etymology. The specific epithet refers to the type locality and the famous collection site of Charles Robertson.

Comments. The male of this species is unknown. The known range of this species is very small. It is possible that this is a prairie species found at the eastern edge of its range.

Figures

FIGURE 11. Lasioglossum carlinvillense A) face of female holotype; B) lateral habitus of female holotype.