Lasioglossum (Dialictus) exiguum ( Smith, 1879 )

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 : 51

Lasioglossum (Dialictus) exiguum ( Smith, 1879)

Figs 22A , 23A , 24A , 34A

Halictus exiguus Smith, 1879: 37 (holotype, ♀, NHMUK 010265368).

Dialictus exiguus – Moure & Hurd 1987: 100 (catalogue).

Type material

Holotype MEXICO – ♀; on/around Orizaba volcano; [19° N, 97.3° W]; “8.M.1856”; M. Salle leg.; NHMUK 010265368 .

Other material examined

MEXICO – Quintana Roo • 1 ♀; 12 km NW of Reforma ; [18.89° N, 88.65° W]; 14 Oct. 1986; Charles D. Michener leg.; SEMC SM0753053 • 2 ♂♂; same collection data as for preceding; 14 Oct. 1986; Charles D. Michener leg.; SEMC SM0730146 , SM0753052 • 1 ♀; Reforma ; [18.81° N, 88.57° W]; 14 Oct. 1986; Charles D. Michener leg.; SEMC .

Remarks

Uncommon on the Yucatán Peninsula (four specimens examined in the region); more common in Veracruz. The very large head and rectangular, strongly toothed clypeus apical margin are unmistakable diagnostic characters for this species. We consider the identifications highly reliable despite the distance between Orizaba and Quintana Roo.

Figures

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. 23. Mesoscutum sculpture and metanotum pubescence. A. Lasioglossum (Dialictus) exiguum (Smith, 1879), ♀, mesoscutum shiny and metanotum with abundant short plumose setae (arrow). B. L. (D.) meteorum Gardner & Gibbs, 2020, ♀, mesoscutum dull and metanotum with very sparse short plumose setae.

Fig. 24. Face and clypeus. A. Lasioglossum (Dialictus) exiguum (Smith, 1879), ♀, with clypeus apicolateral margins parallel and forming acute teeth (arrow). B. L. (D.) tropicior (Ellis, 1914), ♀, with clypeus apicolateral margins convergent and forming low rounded knobs (arrow).

Fig. 34. Propodeum. A. Lasioglossum (Dialictus) exiguum (Smith, 1879), ♂, with metapostnotum rugae not reaching posterior margin and dorsolateral slope smooth (arrow). B. L. (D.) nanotegula Landaverde- González & Husemann sp. nov., ♂, with metapostnotum rugae reaching posterior margin and extending onto dorsolateral slope at base (arrow). C. L. (D.) ameshoferi Landaverde-González sp. nov., ♂, with metapostnotum rugae reaching posterior margin and covering dorsolateral slope (arrow).