Lasioglossum stictaspis (Sandhouse, 1923)

Landaverde-González, Patricia, Gardner, Joel, Moo-Valle, Humberto, Quezada-Euán, José Javier G., Ayala, Ricardo & Husemann, Martin, 2023, Seven new species of Lasioglossum (Dialictus) Robertson, 1902 (Hymenoptera: Halictidae: Halictini) from the Yucatán Peninsula, Mexico, European Journal of Taxonomy 862 (1), pp. 1-65 : 24-26

Lasioglossum stictaspis species complex

Figs 6C , 11–12 , 22C , 31A

Ten specimens and six DNA barcode sequences were examined from the Yucatán Peninsula which belong to a complex of species related to L. stictaspis (Sandhouse, 1923) . Morphological variation suggests that this complex may include up to 5–6 cryptic species, but overlapping geographic ranges and COI haplotypes preclude delimitation of these species. Further revision, including more robust genetic data beyond DNA barcodes and across a large geographic area, is needed. The Yucatán specimens appear to be distinct from the nominal L. stictaspis , but separating them from L. cupreicollis (Friese, 1917) and other undescribed morphospecies is difficult and beyond the scope of this study. Here we diagnose briefly the Yucatán morphospecies in the L. stictaspis species complex from other species on the Yucatán Peninsula.

Diagnosis

Females of the L. stictaspis species complex in the Yucatán Peninsula can be recognised by the diagnostic combination of tegula greatly enlarged (reaching posterior margin of mesoscutum in dorsal view and

tegula width/ITS> 0.23) and densely, distinctly punctate (i <1 pd), sometimes becoming more sparsely punctate medially (i ≤ 1.5 pd); mesepisternum usually imbricate and moderately densely punctate (i ≤ 1.5 pd) with distinct interspaces; mesoscutum with dense plumose setae 1 OD long or slightly more (all setae separated by less than half their length in lateral view); T2–T3 with extensive basolateral fine tomentum covering about half length of segment laterally and apical impressed areas minutely punctate with fine setae associated with punctation.

Males have the tegula large and densely punctate (as in the female, but punctures not becoming sparser medially); mesepisternum shiny and moderatly sparsely punctate at least in ventral half (i = 1–2 pd); and mesoscutum with dense plumose setae about 1 OD long (as in the female).

Differential diagnosis

Both sexes of the L. stictaspis species complex are most similar to L. yucatanense sp. nov., L. paralepidii sp. nov., and L. aureoviride sp. nov. Both sexes of L. yucatanense have the mesoscutum with sparser, shorter setae (most setae separated by half or more their length in lateral view); females of L. yucatanense also have the mesepisternum strongly imbricate to finely rugulose with indistinct punctures at least in dorsal portion and T2–T3 apical impressed areas largely glabrous; males of L. yucatanense have the mesepisternum shiny and densely and distinctly punctate (i <1 pd). Both sexes of L. paralepidii and L. aureoviride have the mesepisternum much more densely punctate (i <1 pd).

DNA barcodes

Six sequences available (BOLD process IDs: LDSPS034-15 to LDSPS039-15). These sequences are distinct from those of other Yucatán species (maximum intraspecific p-distance 0.6%; minimum interspecific distance (to L. aureoviride sp. nov.) 3.77%) but poorly distinguished from other members of the L. stictaspis species complex (minimum p-distance 0.15%).

Remarks

Common. The L. stictaspis species complex is a subset of the L. gemmatum species complex. The Yucatán morphospecies corresponds to mOTU 3 in Landaverde-González et al. (2017a).

Figures

Fig. 6. Images of tegula form and punctation in species of Lasioglossum (Dialictus) Robertson, 1902. A. L. (Dialictus) yucatanense Landaverde-González sp. nov. B. L. (Dialictus) paxtoni Landaverde- González sp. nov. C. Specimen of the Lasioglossum stictaspis species complex. D. L. (Dialictus) ameshoferi Landaverde-González sp. nov. E. L. (Dialictus) aureoviride Landaverde-González & Husemann sp. nov. F. L. (Dialictus) paralepidii Gardner sp. nov. G. L. (Dialictus) milpa Landaverde- González sp. nov. H. L. (Dialictus) nanotegula Landaverde-González & Husemann sp. nov.

Fig. 11. Female of L. stictaspis species complex (ZMH 81030). A. Lateral habitus. B. Dorsal habitus. C. Face.

Fig. 12. Male of L. stictaspis species complex (ZMH 839507). A. Lateral habitus. B. Dorsal habitus. C. Face.

Fig. 22. Propodeum.A. Lasioglossum (Dialictus) exiguum (Smith, 1879), ♀, smooth with metapostnotum rugae covering less than half its length and oblique carina absent. B. L. (D.) meteorum Gardner & Gibbs, 2020, ♀, smooth with metapostnotum rugae covering about half its length and oblique carina absent. C. L. (D.) stictaspis species complex female, roughened by strong anastomosing rugae reaching posterior margin and oblique carina present (arrow).

Fig. 31. Mesepisternum.A. Lasioglossum (Dialictus) stictaspis species complex, ♀, moderately sparsely punctate (i = 1–2 pd). B. L. (D.) paralepidii Gardner sp. nov., ♀, very densely puncate (i <0.5 pd).