Lasioglossum (Dialictus) tegulariforme ( Crawford, 1907 )

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 : 28-30

Lasioglossum (Dialictus) tegulariforme ( Crawford, 1907)

Figures 15, 16, 17B

Halictus (Chloralictus) tegulariformis Crawford 1907: 194 (holotype, ♀, deposited in USNM, examined)

Lasioglossum (Chloralictus) tegulariforme – Michener 1951: 1118 (catalogue)

Dialictus tegulariformis – Hurd 1979: 1972 (catalogue) – Moure and Hurd 1987: 133 (catalogue)

Specimens examined

Holotype: UNITED STATES – Nevada ♀; Ormsby Co.; [39.2° N, 119.8° W]; 6.vii; Baker leg.; USNM 12068 .

Other material. (See Supplementary material, Table S1 for complete data including coordinates and collection codes.) CANADA – British Columbia 1♀; PCYU . UNITED STATES – California 2♀; CAS 25♀; UCDC 1♀, 2♂; WRME – Idaho 3♀; CUIC 6♀; FWSE – Nevada 1♂; SEMC – Oregon 23♀; FWSE – Washington 4♀; FWSE .

Diagnosis. Females of L. tegulariforme can be recognised by the combination of T1 with at least a narrow impunctate median line (often broader) (T1 evenly punctate throughout in all other known species), paraocular area punctures similar in size and density to frons punctures (paraocular area punctures larger and coarser in other Canadian species), T3 densely clothed in short, simple, yellow hairs in addition to basolateral tomentum (T3 with sparser, whiter hairs in other Canadian species, except tomentose in L. helianthi ), tegula very large (clearly exceeding posterior margin of mesoscutum in dorsal view) and densely punctate with few or no interspaces up to 1 PD (tegula not exceeding posterior margin of mesoscutum in dorsal view and with many interspaces 1 PD or more in other Canadian species except L. stictaspis ), and T1 anterior slope usually with weak microsculpture (T1 shiny in L. gaudiale and strongly coriarious in other Canadian species).

Males of L. tegulariforme can be recognised by the combination of T1 at least slightly more sparsely punctate medially (IS = 2–6 PD) than laterally (IS = 1–3 PD) (T1 evenly punctate throughout in all other known species), metasomal terga with basolateral tomentum very sparse or absent (T2–T3 with distinct basolateral tomentum in L. gaudiale ), face with tomentum dense below eye emargination and absent above (face with dense tomentum below median ocellus in L. gaudiale and some other species), tegula very densely punctate with few or no distinct interspaces (surface appearing dull) and inner margin strongly concave with broadly rounded projection directed towards axilla posteriorly (tegula more sparsely punctate with inner posterior margin more weakly concave in other Canadian species except L. stictaspis ), and propodeum lateral face with punctures shallow and indistinct (shiny and distinctly punctate in L. gaudiale ).

Both sexes of L. tegulariforme are most similar to L. gaudiale and an undescribed species from southern California, United States of America, but the characters of T1 will readily separate them.

Range. California Central Valley, United States of America north to southern British

Columbia, Canada and east through Idaho, United States of America ( Fig. 17B).

Floral hosts. Broadly polylectic (Supplementary material, Table S2).

DNA barcodes. Three sequences available (BOLD process IDs: BCLRB752-10, DLIII111-18, DLIII112-18). These sequences are highly divergent from L. gaudiale and L. helianthi (maximum intraspecific P -distance 0.31%; minimum interspecific P -distance to L. gaudiale 3.37%; to L. helianthi 2.83%).

Comments. Lasioglossum gaudiale is herein resurrected from synonymy with L. tegulariforme . Lasioglossum gaudiale and L. helianthi were synonymised with L. tegulariforme in Michener (1951). The holotype of L. tegulariforme is a female, that of L. gaudiale a male, so it has seemed plausible that these are different sexes of the same species. Series of associated females and males and DNA barcodes now indicate that the true male of L. tegulariforme is morphologically, genetically, and geographically distinct from L. gaudiale . Lasioglossum gaudiale is primarily a desert species common in the Sonoran and Mojave deserts and the Los Angeles basin, United States of America. The true L. tegulariforme is here considered to have a much more restricted range than previously recorded. It occurs sympatrically with L. helianthi throughout this range.

The holotype of L. helianthi is a female but is in poor condition, making morphological comparison difficult. However, certain diagnostic characters, including the face, tegula, and dorsal surface of T1, are visible and clearly match L. imbrex more closely than L. tegulariforme . Specimens determined by P.H. Timberlake as L. helianthi before he synonymised it in Michener (1951) are also clearly L. imbrex .

The name Lasioglossum tegulariforme has been widely over-applied to specimens from the western Nearctic region. This was first noted by Cockerell (1937) and corroborated by Gibbs (2010), who suggested that many old records of L. tegulariforme actually pertain to L. imbrex (= L. helianthi ). In this work, we suggest that old L. tegulariforme records (especially any from far outside the range in Fig. 17B) may also pertain to L. gaudiale , L. stictaspis , L. paululum (Sandhouse, 1924) , L. pseudotegulare (Cockerell, 1896) , or an undescribed species. References to L. tegulariforme in Sandhouse (1924) probably pertain to L. stictaspis , and references in Sandhouse and Cockerell (1924) probably pertain to L. gaudiale and/or an undescribed species. Specimen records and floral hosts in Moure and Hurd (1987) are likely from several species. Only records from specimens personally examined by J. Gardner or Joe Engler (FWSE) and known to be correctly identified are presented here.