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

description: Lasioglossum gemmatum species complex
Species included
Lasioglossum angelicum sp. nov., L. busckiellum (Cockerell, 1915), L. carlinvillense Gibbs, 2009, L. coactus (Cresson, 1872), L. cupreicollis (Friese, 1917), L. deludens sp. nov., L. diabolicum sp. nov., L. ellisiae (Sandhouse, 1924), L. enatum Gibbs, 2018, L. eremum sp. nov., L. fernandezis Engel, 2000, L. gaudiale (Sandhouse, 1924), L. gemmatum (Smith, 1853), L. gloriosum sp. nov., L. helianthi (Cockerell, 1916), L. holzenthali sp. nov., L. indagator sp. nov., L. lepidii (Graenicher, 1927), L. magnitegula sp. nov., L. monense Gibbs, 2018, L. parvum (Cresson, 1865), L. paululum (Sandhouse, 1924), L. perparvum (Ellis, 1914), L. profundum sp. nov., L. pseudotegulare (Cockerell, 1896), L. puteulanum Gibbs, 2009, L. rufodeludens sp. nov., L. stictaspis (Sandhouse, 1923), L. surianae (Mitchell, 1960), L. tegulare (Robertson, 1890), and L. tegulariforme (Crawford, 1907).
Diagnosis
Both sexes in the L. gemmatum complex have the tegula enlarged (reaching the posterior margin of the mesoscutum in dorsal view or nearly so), usually strongly punctate, and with the inner posterior margin straight or concave; about 50% of clypeus projecting below suborbital tangent; and T1 without tomentum. Additionally, females have the propodeum with a distinct oblique carina, and males have the mesepisternum and often propodeum lateral face shiny with large, distinct punctures, and metasomal sterna with moderately sparse plumose pubescence 1–2 OD long.
Some members of the L. perdifficile complex (defined in Gardner & Gibbs 2022) have a similar tegula, but these have more than 50% of the clypeus projecting below the suborbital tangent, females with propodeum oblique carina absent, and T1 with lateral tomentum. Some atypical specimens of L. knereri Gibbs, 2010 from California (possibly representing a cryptic species) also have a similar tegula, but have the propodeum without a distinct oblique carina, the metasomal terga all without appressed tomentum, and males have the metasomal sterna with very long and dense scopa-like pubescence (> 2 OD).
Lasioglossum comulum Michener, 1951, L. dispersum Gibbs, 2018, L. immigrans Gardner & Gibbs, 2022, L. strigosigena Michener, 1954, and several undescribed species have the tegula small, ovoid, and impunctate, which is standard for most L. (Dialictus), but resemble the L. gemmatum complex in most other characters. Additionally, DNA barcodes of these two species groups are very similar and suggest a close relationship. These species are informally defined as the L. comulum group. The L. comulum group appears to be an evolutionary grade from which the L. gemmatum complex is derived (Fig. 2), but additional taxon sampling and more molecular data are needed to resolve their relationship with more certainty.
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 page 10, DOI: 10.5852/ejt.2023.858.2041, http://zenodo.org/record/7629347