Lasioglossum (Dialictus) stictaspis
Creators: name: Gardner, Joel
name: Gibbs, Jason
Publisher: name: Zenodo
Year: 2023
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Hymenoptera
Halictidae
Lasioglossum
Lasioglossum stictaspis

description: Lasioglossum (Dialictus) stictaspis (Sandhouse, 1923)
Figs 60– 66, 76O, 81C, 89B, 91A, 100B, 111B, 112B, 114B
Dialictus stictaspis Sandhouse, 1923: 195 (holotype, ♂, deposited in USNM, examined).
Halictus (Chloralictus) albuquerquensis Michener, 1937: 316 (holotype, ♀, deposited in CAS, examined).
Lasioglossum (Dialictus) stictaspis – Michener 1951: 1119 (catalogue).
Lasioglossum (Chloralictus) albuquerquense – Michener 1951: 1112 (catalogue).
Dialictus stictaspis – Hurd 1979: 1971 (catalogue). — Moure & Hurd 1987: 131 (catalogue).
Dialictus albuquerquensis – Hurd 1979: 1964 (catalogue). — Moure & Hurd 1987: 89 (catalogue).
Diagnosis
See the diagnosis for the L. stictaspis species complex and the diagnosis for L. paululum. Females of L. stictaspis s. str., described from New Mexico, have the tegula relatively large (reaching and sometimes slightly exceeding posterior margin of mesoscutum in dorsal view), with inner posterior margin weakly concave, and densely punctate (IS ≤ 1 PD); metapostnotum dull, tessellate to finely reticulate, and usually with fine subparallel rugae; mesepisternum shiny (sometimes with weak microsculpture) and densely punctate (IS <1 PD); mesoscutum dull and coarsely punctate (2–3 punctures between posterior end of parapsidal line and/or lateral edge of mesoscutum and some IS = 1–2 PD between parapsidal lines); T1–T2 discs finely and moderately sparsely punctate (IS = 1–3 PD) and apical rims impunctate; T3 with dense subapical band of tomentum (often medially interrupted); face short (length/width ratio ≤0.83) and gena narrower than eye in lateral view.
Females of L. stictaspis s. str. are most similar to those of L. angelicum sp. nov., L. diabolicum sp. nov., L. ellisiae, L. gaudiale, and L. pseudotegulare. Females of L. angelicum and L. pseudotegulare have the T1–T2 discs more deeply and densely punctate (IS = 1–2 PD) with some punctures often extending onto apical rims. In addition, females of L. angelicum have the metapostnotum shiny with strong anastomosing rugae, and females of L. pseudotegulare have the face slightly longer (length/width ratio usually>0.83). Females of L. ellisiae have the tegula slightly smaller (not exceeding posterior margin of mesoscutum in dorsal view) and usually more sparsely punctate (up to IS = 1–3 PD), metapostnotum with strong, coarse rugae and basal half shiny, and T3 usually without subapical tomentum (rarely with a sparse, broadly interrupted band). Females of L. gaudiale have the metapostnotum with strong, coarse rugae and basal half shiny, gena about as wide as eye in lateral view, and T3 without subapical tomentum.
Males of L. stictaspis s. str. have the tegula densely punctate (IS ≤ 1 PD), relatively large (slightly exceeding posterior margin of mesoscutum in dorsal view), and inner posterior margin concave, with a small rounded posterior projection about 0.5 lateral OD in size; metapostnotum tessellate to finely reticulate with shallow subparallel rugae; mesepisternum densely punctate (IS <1 PD); mesoscutum coarsely and moderately densely punctate (IS = 1–2 PD); disc of T2 with punctures deep, distinct, and usually dense (IS ≤ 1 PD); and T1–T2 apical rims impunctate.
Males of L. stictaspis s. str. are most similar to those of L. angelicum sp. nov., L. diabolicum sp. nov., L. ellisiae, and L. pseudotegulare. Males of L. angelicum and L. pseudotegulare have the T1–T2 apical rims punctate; in addition, males of L. pseudotegulare have the T2 disc even more densely punctate medially(IS <1 PD). Males of L. diabolicum and L. ellisiae have the tegula slightly smaller (not exceeding posterior margin of mesoscutum in dorsal view) with inner posterior margin straight or sinuous and a blunt posterior angle or point narrower than 0.5 lateral OD, and usually more sparsely punctate in part (IS ≥1 PD); in addition, males of L. ellisiae have the mesoscutum more uniformly and densely punctate (IS ≤1 PD).
Lasioglossum stictaspis s. lat. is highly variable and a large number of specimens, especially those from south or west of New Mexico, may lack one or more of the above diagnostic characters, making them very difficult to separate from similar species.
Etymology
Sandhouse (1923) formed the specific epithet ʻ stictaspis ʼ from the Greek adjective ʻ stiktos ʼ (punctured, spotted) and the noun ʻ aspis ʼ (shield). It likely refers to the punctured tegula of this species.
Range
Western Great Plains and Rio Grande River valley (L. stictaspis s. str.) and west to California, south throughout Mexico (L. stictaspis s. lat.).
DNA barcodes
Twenty-four confirmed sequences available, three haplotypes (BOLD process IDs: DLIII224-20, DLIII225-20, DLIII227-20 (haplotype 1); DLIII231-20, NCBEE336-21, NCBEE339-21, NCBEE343-21, NCBEE347-21, NCBEE349-21, NCBEE357-21, NCBEE369-21, NCBEE404-21, NCBEE407-21, NCBEE412-21 (haplotype 2); DLIII124-18, DLIII128-19, DLIII129-19, DLIII130-19, DLIII131-19, DLIII132-19, DLIII135-19, DLIII136-19, NCBEE403-21, SMTPP733-15 (haplotype 3)). Haplotypes 2 and 3 are shared with L. diabolicum sp. nov. Haplotype 3 has some relatively deep divergence and may be possible to split into additional haplotypes. No fixed nucleotide substitutions distinguish all L. stictaspis from all other Nearctic species of the L. gemmatum complex, but one fixed substitution distinguishes haplotype 2: 402(G) (Supp. file 2).
Comments
The species treated by Gardner & Gibbs (2022) as L. stictaspis may include two species, the other one being L. paululum, described from Colorado. See that work for specimen records and range map. Specimens with a duller mesoscutum and ocellocular area, yellowish pubescence, and a slightly weaker T3 subapical band of tomentum match the holotype of L. albuquerquense and are here considered L. stictaspis s. str .. Lasioglossum stictaspis s. lat. ranges south throughout Mexico and west to California. It can have almost any combination of punctation and surface sculpture in any location.
It is likely that L. stictaspis s. lat. comprises multiple species, but correlates between morphological, genetic, and geographic variation cannot be found to support a species hypothesis. One of these may be L. paululum, but additional species from Mexico, Arizona, or California are likely undescribed. More data is needed to clarify limits and relationships between these species.
description: Published as part of Gardner, Joel & Gibbs, Jason, 2023, Revision of the Nearctic species of the Lasioglossum (Dialictus) gemmatum species complex (Hymenoptera: Halictidae), pp. 1-222 in European Journal of Taxonomy 858 (1) on pages 161-170, DOI: 10.5852/ejt.2023.858.2041, http://zenodo.org/record/7629347