Lasioglossum (Dialictus) paululum ( Sandhouse, 1924 )

Gardner, Joel & Gibbs, Jason, 2023, Revision of the Nearctic species of the Lasioglossum (Dialictus) gemmatum species complex (Hymenoptera: Halictidae), European Journal of Taxonomy 858 (1), pp. 1-222 : 127

Lasioglossum (Dialictus) paululum ( Sandhouse, 1924)

Halictus (Chloralictus) paululus Sandhouse, 1924: 23 (holotype, ♂, deposited in USNM, type no. 26419, USNMENT01570300, examined).

Lasioglossum (Chloralictus) paululum – Michener 1951: 1116 (catalogue).

Dialictus paululus – Hurd 1979: 1969 (catalogue). — Moure & Hurd 1987: 120 (catalogue).

Lasioglossum (Dialictus) paululum – Scott et al. 2011: 30 (checklist).

Diagnosis

See the diagnosis for the L. stictaspis species complex. Lasioglossum paululum is a member of this group and reliable, unique diagnostic characters are not yet known. Female specimens determined as L. stictaspis from Colorado, which may correspond to L. paululum , frequently have the mesoscutum and mesepisternum shiny, T3 with very dense and complete subapical band of tomentum, ocellocular area shiny with distinctly separated punctures (IS ≤1 PD), and all pubescence bright white, in contrast with specimens from New Mexico which usually have the mesoscutum and mesepisternum dull, T3 with subapical band of tomentum slightly sparser and narrowly interrupted medially, ocellocular area dull with crowded punctures (IS = 0 PD), and pubescence yellowish dorsally. However, the dull New Mexico forms can occur as far north as Alberta, and the shiny Colorado forms can occur west to Arizona, with any combination of these characters possible in between. The males are even more difficult to separate, but male L. paululum may have a slightly longer face. Sandhouse (1924) described the face as relatively long, although the holotype length/width ratio is only 0.84.

Comments

Lasioglossum paululum may be a junior synonym of L. stictaspis , but a more detailed revision of the L. stictaspis species complex is needed. If L. paululum proves to be distinct, then at least some of the L. stictaspis specimens recorded from Canada in Gardner & Gibbs (2022) are probably this species.