Lasioglossum (Dialictus) obnubilum (Sandhouse, 1924)

Gardner, Joel & Gibbs, Jason, 2022, New and little-known Canadian LasIOGLOssum (DIaLICTus) (Hymenoptera: Halictidae) and an emended key to species, The Canadian Entomologist (e 3) 154 (1), pp. 1-37 : 14-15

Lasioglossum (Dialictus) obnubilum (Sandhouse, 1924)

Figure 6

Halictus (Chloralictus) obnubilus Sandhouse 1924: 28 (holotype, ♂, deposited in USNM; examined)

Lasioglossum (Dialictus) lilliputense Gibbs 2010: 178 (holotype, ♀, deposited in PCYU; examined) new synonymy

Lasioglossum (Chloralictus) obnubilum – Michener 1951: 1115 (catalogue)

Dialictus obnubilus – Hurd 1979: 1969 (catalogue) – Moure and Hurd 1987: 117 (catalogue)

Diagnosis. Males of L. obnubilum can be recognised by the combination of their small size (body length 4–4.5 mm; ITD ∼ 0.7 mm), face relatively long (length/width ratio ∼ 0.93), mesepisternum and central mesoscutum finely and moderately densely punctate (IS = 1–2 PD), propodeum relatively smooth with weak rugae, metasomal sterna with very short, sparse, thin hair, face with dense tomentum limited to paraocular area and upper clypeus, clypeus apical margin, flagellum, legs, tegula, and wings all dark brown, and head and mesosoma blue–green to olive green. They are most similar to an undescribed species that occurs at lower elevations in the southern United States of America. This species has the mesepisternum and mesoscutum more coarsely and densely punctate (IS <1 PD), face covered in dense tomentum below eye emargination, and head and mesosoma blue to blue–green. They are also somewhat similar to L. brunneiventre and L. macroprosopum . Both of these species have very long, dense, plumose hair on the metasomal sterna, the flagellum ventral surface and tarsi orange, and a more western distribution not including the Rocky Mountains.

Comments. Lasioglossum obnubilum was described from the male only (Sandhouse 1924). There have been no published records of this species outside of Colorado, United States of America. Lasioglossum lilliputense was described based on morphology and DNA barcode data from female specimens collected in British Columbia, Canada and Idaho and Montana, United States of America ( Gibbs 2010). It was suggested at the time of its description that L. lilliputense could be the female of L. obnubilum . Examination of additional material, including males and females of L. obnubilum from the same locality, confirms this interpretation.

Figures

Fig. 6. Lasioglossum obnubilum (Sandhouse, 1924) (♂): A, dorsal habitus; B, lateral habitus; C, propodeum and metasoma; and D, face. Scale bars: 1 mm.