Lasioglossum (Dialictus) cyaneum (Ashmead 1900)

Gibbs, Jason, Bass, Amber & Morgan, Katherine, 2022, Habralictus and Lasioglossum of Saint Lucia and Saint Vincent and the Grenadines, Lesser Antilles (Hymenoptera, Apoidea, Halictidae), ZooKeys 1089, pp. 125-167 : 125

Lasioglossum (Dialictus) cyaneum (Ashmead 1900)

Figs 10, 11 , 12 , 13

Halictus cyaneus Ashmead (1900: 218-220). Saint Vincent. Syntype males (2) and females (3) (NHMUK, USNM; Figs 10, 11 ).

Dufourea subcyanea Ashmead (1900: 215). Saint Vincent. Holotype male (NHMUK). Syn. nov.

Trigona nigrocyanea Ashmead (1900: 208). Saint Vincent - Leeward side. Holotype male (NHMUK; Fig. 12 ). Syn. nov.

Dufourea subcyanea : Ashmead (1900: 303) checklist; Friese (1909: 38) catalogue.

Halictus cyaneus : Ashmead (1900: 304) checklist; Friese (1909: 37) catalogue.

Dialictus cyaneus : Cockerell (1904: 235) taxonomic placement; Moure and Hurd (1987: 98) catalogue; Moure (2007: 848, 849) catalogue.

Dialictus nigrocyaneus : Moure (2007: 852) catalogue.

Dialictus subcyaneus ; Cockerell (1922: 268) taxonomic notes; Sandhouse (1923: 194) checklist; Moure (2007: 855) catalogue; Moure and Hurd (1987: 132) catalogue.

Lasioglossum cyaneum : Gibbs (2016: 6) taxonomic characters.

Trigona nigrocyanea : Ashmead (1900: 299) checklist; Friese (1909: 39) catalogue; Lutz and Cockerell (1920: 499) checklist, type locality.

Material examined.

SVG • Saint Vincent • Saint Vincent ( Halictus cyaneus syntypes 1 ♀ 1 ♂ USNM); Saint Vincent ( Dufourea subcyanea holotype ♂ NHMUK); Saint Vincent , leeward side ( Trigona nigrocyanea holotype ♂ NHMUK; from photos) • St. George Parish • Majorca Mts. , Riley Rd. , 13.180694 -61.193556, 366 m, 13.V.2016, leg. Miklasevskaja and Ferrari (1 ♂ WRME) • St. Patrick Parish • Cumberland Valley , 17.VI.1977, leg., E.E. Grissell (6 ♂ FSCA) .

Taxonomic notes.

Lasioglossum cyaneum is structurally similar to L. plumbeum and L. sanctivincenti but is easily recognisable by the entirely blue body and dark wing venation. The male T1-T6 are blue on the disc and dark reddish brown on the lateral and apical margins. The head is distinctly shorter (female and male face length/head width = 0.82-0.85) than L. plumbeum (male face length/head width = 0.87-0.90). Both Dufourea subcyanea and Trigona nigrocyanea were described from single males in the same publication with Halictus cyaneus . The former differs from L. cyaneum only in the absence of vein 1rs-m, leading to two submarginal cells rather than three. Loss of this vein is relatively common in L. (Dialictus) ( Gibbs 2010b; Scarpulla 2018; see also L. gemmeum below), which led to the synonymy of the genus-group names Dialictus and Chloralictus ( Mitchell 1960). The holotype of Trigona nigrocyanea is glued to the side of a card and has most of the metasoma missing. It is very evidently a Lasioglossum (Dialictus) . The first tergum is intact and shows distinct metallic reflections consistent with L. cyaneum . Ashmead (1900) describes the abdomen as 'rufous, black at base only’, but cannot be verified with most of the metasoma missing. In other respects, the holotype matches well with L. cyaneum , including the relatively smooth metapostnotum between carinulae.

Figures

Figure 11. Lasioglossum (Dialictus) cyaneum (Ashmead), syntype male of Halictus cyaneus Ashmead A dorsal habitus B head, frontal view C lateral habitus. Images courtesy of the National Museum of Natural History, Smithsonian Institution. https: // collections. nmnh. si. edu / search / ento /

Figure 12. Lasioglossum (Dialictus) cyaneum (Ashmead), syntype male of Trigona nigrocyanea Ashmead A dorsal habitus B head, frontal view C lateral habitus. Images courtesy of the Trustees of the Natural History Museum, London (https: // creativecommons. org / licenses / by / 4.0 /). Photographs by David Notton.

Figure 13. Lasioglossum (Dialictus) cyaneum (Ashmead), male A dorsal habitus B head, frontal view C lateral habitus.