Lasioglossum (Dialictus) longifrons ( Baker )

Gibbs, Jason, 2011, Revision of the metallic Lasioglossum (Dialictus) of eastern North America (Hymenoptera: Halictidae: Halictini), Zootaxa 3073, pp. 1-216 : 137-139

Lasioglossum (Dialictus) longifrons ( Baker)

( Figures 150–154 )

Halictus longiceps Robertson, 1892: 272 . Ƥ. (junior primary homonym of Halictus longiceps Saunders, 1879 ) Lectotype. Ƥ USA, Florida, Inverness, 12.ii.1891 (C. Robertson); [INHS: 9993] by W. E. LaBerge in Webb 1980). Examined.

Halictus longifrons Baker. 1906: 269 . Ƥ. [new synonymy]

Holotype. Unknown.

Lasioglossum (Chloralictus) robertsonellum Michener, 1951: 1117 . (catalogue, replacement name for H. longiceps Robertson )

Taxonomy. Graenicher, 1927: Halictus (Chloralictus) longiceps 206. 3. (description).

Diagnosis. Both sexes of L. longifrons can be recognised by the following diagnostic combination: head very long (length/width ratio = 1.18–1.21) ( Figs. 150 B, 152B); mesoscutum strongly tessellate, punctures sparse (i=1–2.5d) ( Figs. 151 , 153 ), except closer laterad of parapsidal line; and females have T1 acarinarial fan sparse dorsally or with dorsal opening ( Fig. 151 ). They are most similar to L. coreopsis , which has a shorter head (length/width ratio = 1.09–1.13) ( Figs. 79 B, 81B) and T1 acarinarial fan dense dorsally.

Redescription. FEMALE. Length 3.75–4.42 mm; head length 1.22–1.44 mm; head width 1.01–1.20 mm; forewing length 2.60–3.27 mm.

Colouration. Head and mesosoma golden green to bluish green. Clypeus with apical half blackish brown to yellowish brown. Antenna dark brown, flagellum with ventral surface brownish orange to orange-yellow. Tegula brownish yellow. Wings subhyaline, venation and pterostigma pale brownish yellow. Legs brown, except medio- and distitarsi reddish brown to brownish yellow, metabasitarsus infused with reddish brown. Metasomal terga and sterna golden brown, apical margins pale, translucent yellow.

Pubescence. Dull white. Head and mesosoma with moderately dense woolly hairs (1–1.5 OD), longest on genal beard, metanotum, and mesopleuron (2–2.5 OD). Paraocular area and gena with sparse subappressed tomentum. Propodeum with moderately dense plumose hairs on lateral and posterior surfaces (2–2.5 OD). Metasomal terga with moderately sparse, fine hairs. T1 acarinarial fan complete, sparse dorsally or with dorsal opening. T2 basolaterally with sparse tomentum. T3–T5 with sparse tomentum not obscuring surface. T2–T4 apical margins with moderately dense fringes.

Surface sculpture. Face imbricate, punctation fine. Clypeus punctation (i=1–2.5d). Supraclypeal area with punctation moderately dense (i=1–3d). Lower paraocular and antennocular areas with punctation dense (i≤d). Upper paraocular area and frons punctate-reticulate. Ocellocular area obscurely punctate (i≤d). Gena and postgena lineolate. Mesoscutum coarsely tessellate-granulose, punctation sparse on disc (i=1–2.5d), denser laterad of parapsidal line and on anterolateral portion (i=1–1.5d). Mesoscutellum tessellate, submedial punctation sparse (i=1–4d). Axilla punctate. Metanotum imbricate. Preëpisternum rugulose-imbricate. Hypoepimeral area tessellate-imbricate. Mesepisternum rugulose-imbricate. Metepisternum with dorsal half rugoso-carinulate, ventral half imbricate. Metapostnotum weakly rugoso-carinulate, posterior margin imbricate. Propodeum with dorsolateral slope imbricate, lateral surface tessellate-imbricate, posterior surface tessellate. Metasomal terga weakly coriarious, punctation moderately dense basally (i=1–1.5d), apical impressed areas obscurely, sparsely punctate.

Structure. Head elongate (length/width ratio = 1.20–1.21). Eyes convergent below (UOD/LOD ratio = 1.39–1.48). Clypeus ½ below suborbital tangent, apicolateral margins weakly convergent. Antennal sockets close (IAD/OAD <0.5). Frontal line carinate, ending 2.5–3 OD below median ocellus. Gena narrower than eye. Inner metatibial spur pectinate with 3–4 branches. Metapostnotum truncate (MMR ratio = 1.22–1.38), posterior margin rounded onto posterior surface. Propodeum with oblique carina very fine or absent, lateral carina fine, reaching less than halfway to dorsal margin.

MALE. Similar to female except for the usual secondary sexual characters and as follows. Length 5.26 mm; head length 1.61 mm; head width 1.37 mm; forewing length 3.39 mm.

Colouration. Labrum and mandible yellow. Legs brown, except tarsi brownish yellow.

Pubescence. Face below eye emargination obscured by dense tomentum. Metasomal terga with sparse tomentum. S3–S5 with lateral patches of posteriorly directed hairs (1–1.5 OD).

Surface sculpture. Mesepisternum finely punctate. Metasomal terga punctation moderately dense (i=1–1.5d), apical impressed areas impunctate.

Structure. Head very elongate (length/width ratio = 1.18). Eyes strongly convergent below (UOD/LOD ratio = 1.42). Clypeus 2/3 below suborbital tangent, apicolateral margins weakly convergent. Antennal sockets distant (IAD/OAD> 0.8). Frontal line carinate, ending 2 OD below median ocellus. Pedicel shorter than F1. F2 length 1.5X F1. F2–F10 moderately short (length/width ratio = 1.27–1.60). Metapostnotum truncate (MMR ratio = 1.40), posterior margin rounded onto posterior surface.

Terminalia . S7 with median lobe clavate, apex rounded ( Fig. 154 ). S8 with apicomedial margin weakly convex ( Fig. 154 ). Genital capsule as in Fig. 154 . Gonobase with ventral arms widely separated. Volsella roughly ovoid. Gonostylus elongate, dorsal setae elongate. Retrorse lobe elongate, apex reflexed, strongly attenuated apically.

Range. Florida north to South Carolina, west to Texas ( Fig. 149 ). CUBA. JAMAICA. USA: FL, GA, MS, NC, SC, TX.

Additional specimens examined. CUBA: 1Ƥ13 Havana ( Baker); [ AMNH]; JAMAICA: 4ƤƤ St. Ann Parish, Claremont, 12.viii.1985 (G.C. Eickwort); [ CUIC]; USA: FLORIDA: 1Ƥ Hardee Co., 4.v.1930 (J.M. Kelly); [ CUIC]; 1Ƥ Coral Gables, 11.xii.1934 (?J. Pearson); [ INHS];1Ƥ Alachua Co., N29.6425 W082.5639, 18–19.x.2007 (C. Puckett); 1Ƥ Homestead, Miami, 30.viii.2006 (J. Genaro); [ PCYU]; GEORGIA: 1Ƥ Pavo, N30.941 W083.708, 21.vi.2005 (A. Zayed); [ PCYU]; 1Ƥ Bryan Co., Richmond Hill St. Pk., 2.v.1974 (G.C. Eickwort); [ CUIC]; MISSISSIPPI: 1Ƥ Jackson Co., N30.3657 W088.7325, 4–5.vi.2005 (S.W. Droege); 2ƤƤ Jackson Co., N30.3957 W088.7552, 4–5.vi.2005 (S.W. Droege); [ PCYU]; NORTH CAROLINA: 1Ƥ Southern Pines,? 9.xii.19? (A.H. Manee); [ UCMC]; SOUTH CAROLINA: 1Ƥ Chesterfield Co., N34.5789 W080.23341, 18.v.2006 (S.W. Droege); [ PCYU]; TEXAS: 13 Galveston, 19.v; [ PCYU].

Floral Records. Mainland populations of this species were formerly treated as a junior synonym of L. coreopsis . Some of the floral records for that species may be applicable to L. longifrons .

DNA Barcode. Available. Multiple sequences.

Comments. Common.

Eickwort (1988) first recognised the synonymy of L. longifrons with L. robertsonellum (see also Deyrup et al. 2002) but at that time the latter name was considered a junior synonym of L. coreopsis (see Mitchell 1960), which has priority over L. longifrons . The head sizes of L. longifrons and L. coreopsis are quite different and DNA barcodes of the two species differ substantially (J. Gibbs unpublished data). Morphological comparison of West Indian and Floridian material failed to find any differences between the two populations. Other halictine bees, such as L. eleutherense , L. halophitum , and Halictus poeyi (Lepeletier) , also have distributions that include both the West Indies and the continental United States. It is certainly possible that additional study will prove that the West Indian and Floridian populations constitute separate species, in which case the name L. robertsonellum should be used for the mainland population.

Figures

FIGURE 79. Lasioglossum coreopsis (Robertson) female, (A) lateral habitus, (B) face. Scale bars = 1 mm.

FIGURE 149. Distribution map of Lasioglossum leviense (circles) and L. longifrons (stars).

FIGURE 150. Lasioglossum longifrons (Baker) female, (A) lateral habitus, (B) face. Scale bars = 1 mm.

FIGURE 151. Lasioglossum longifrons (Baker) female, dorsal view of mesosoma.

FIGURE 152. Lasioglossum longifrons (Baker) male, (A) lateral habitus, (B) face. Scale bars = 1 mm.

FIGURE 153. Lasioglossum longifrons (Baker). Maale dorsal view of mesosoma.

FIGURE 154. Lasioglossum longifrons (Baker) male terminalia, (A) ventral view, (B) dorsal view, (C) lateral view, (D) S 7 and S 8. Scale bar = 0.5 mm.