Lasioglossum (Dialictus) foveolatum (Robertson)

Gibbs, Jason, 2010, Revision of the metallic species of Lasioglossum (Dialictus) in Canada (Hymenoptera, Halictidae, Halictini) 2591, Zootaxa 2591 (1), pp. 1-382 : 132-136

Lasioglossum (Dialictus) foveolatum (Robertson)

( Figures 111A–E , 112A–F )

Chloralictus foveolatus Robertson, 1902: 250 . ♂.

Lectotype. ♂ USA, Illinois, Carlinville , (C. Robertson); [ INHS 179,560 ] by W.E. LaBerge. Examined.

Dialictus supraclypeatus Mitchell, 1960: 420 . ♀. [new synonymy]

Holotype. ♀ USA, Virginia, Dunn Loring , 26.vi.1948, (K. V. Krombein); [ NMNH: 66071]. Examined.

Taxonomy. Michener, 1951: Lasioglossum (Chloralictus) foveolatum , p. 1113 (catalogue); Mitchell, 1960: Dialictus foveolatus ♂, p. 394 (redescription); Krombein, 1967: Lasioglossum (Dialictus) foveolatum , p. 463, L. (D.) supraclypeatum , p. 466 (catalogue); Hurd, 1979: Dialictus foveolatus , p. 1966, D. supraclypeatus , p. 1972 (catalogue); Moure & Hurd, 1987: Dialictus foveolatus , p. 101, D. supraclypeatus , p. 132 (catalogue).

Diagnosis. Females of L. foveolatum can be differentiated from all other Canadian Dialictus by the strongly convex and purple supraclypeal area ( Fig. 111D ) and deep and conspicuous parapsidal lines ( Fig. 111E ). Female L. subversans and the Eastern USA species L. ceanothi are similar to this species but each lack the distinguishing characters above. Lasioglossum foveolatum can be further distinguished from L. ceanothi by its sparse punctation of the lower paraocular area.

Males of L. foveolatum can be recognised by the deep and conspicuous parapsidal lines and distinct mesepisternal punctation. Male L. pictum are similar but have thin and inconspicuous parapsidal lines and reddish brown metasoma.

Redescription. FEMALE. Length 4.39–5.43 mm; head length 1.36–1.49 mm; head width 1.42–1.51 mm; forewing length 3.66–3.78 mm.

Colouration. Head and mesosoma bluish green with golden reflections. Mandible orange. Clypeus with apical half blackish brown, basal half, and supraclypeal area brassy, centre purple. Antenna dark brown, flagellum with ventral surface reddish brown. Mesoscutum and mesoscutellum golden green with brassy reflections. Tegula reddish brown-amber. Wing membrane subhyaline, venation and pterostigma amber. Legs brown, medio- and distitarsi and metabasitarsus reddish brown. Metasoma golden brown, terga and sterna with apical margins translucent yellow.

Pubescence. Dull white. Sparse. 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 without appressed tomentum. Propodeum with moderately dense plumose hairs on lateral and posterior surfaces (2–2.5 OD). Metasomal terga with moderately sparse, fine setae. T1 acarinarial fan sparse, complete. T1 apicolateral portion with sparse tomentum. T2 basolaterally and T3–T4 entirely with tomentum partially obscuring surface. T2–T3 apicolateral and T4 apical margins with very sparse fringes.

Surface sculpture. Face imbricate. Clypeus polished, punctation moderately dense (i=1–1.5d). Supraclypeal area with punctation on lateral margins moderately dense (i=1–1.5d), centre impunctate. Lower paraocular and antennocular areas with tessellate, punctation moderately sparse (i=1–2d). Upper paraocular area and frons punctate-reticulate. Ocellocular area punctate (i≤d). Gena and postgena lineolate. Mesoscutum tessellate, punctation moderately dense between parapsidal lines (i=1–1.5d), closer laterad of parapsidal lines (i≤d), contiguous on anterolateral portions. Mesoscutellum without large impunctate area. Axilla reticulate. Metanotum ruguloso-imbricate. Preëpisternum and hypoepimeral area rugulose. Mesepisternum rugulose above, imbricate below. Mesepisternum obscurely punctate (i≤d). Metepisternum with dorsal third rugoso-striate, ventral portion imbricate. Metapostnotum with incomplete longitudinal striae. Propodeum with dorsolateral slope ruguloso-imbricate, lateral surface imbricate, posterior surface tessellate. Metasomal terga polished, punctation obscure throughout (i=1–2d).

Structure. Head moderately wide (length/width ratio = 0.96–0.97). Eyes convergent below (UOD/LOD ratio = 1.19–1.26). Clypeus projecting 1/2 below suborbital line, apicolateral margins convergent. Supraclypeal area distinctly convex, protruding well above face in lateral view. Antennal sockets close (IAD/OAD ratio <0.5). Frontal line carinate, ending 2 OD below median ocellus. OOD subequal to IOD. Gena narrower than eye. Medial and parapsidal lines deep and conspicuously wide. Mesoscutellum flat. Inner metatibial spur pectinate with 3 teeth. Metapostnotum truncate to moderately elongate (MMR ratio = 1.18–1.50), posterior margin weakly angled onto posterior surface. Propodeum with oblique carina weak, lateral carina weak, not reaching dorsal margin.

MALE. Similar to female except for the usual secondary sexual characters and as follows. Length 4.45– 5.43 mm; head length 1.32–1.34 mm; head width 1.30–1.37 mm; forewing length 3.23–3.42 mm.

Colouration. Head and mesosoma bluish green to golden green. Supraclypeal area blue or brassy. Flagellum with ventral surface orange to brownish yellow. Protibia inner surface and tarsi brownish yellow.

Pubescence. Sparse. Paraocular area and gena with sparse tomentum, not obscuring surface. S2–S3 apical portions with moderately dense plumose hairs (1–1.5 OD). S4–S5 apical portions with dense plumose hairs (1–1.5 OD).

Surface sculpture. Lower paraocular area punctation contiguous. Supraclypeal area with punctation sparse (i=1–4d). Upper paraocular area and frons reticulate. Ocellocular area punctate (i=1–2d). Mesoscutum weakly imbricate, polished, punctation sparse between parapsidal lines (i=1–3d), denser laterad of parapsidal lines (i=1–1.5d), dense on anterolateral portions (i≤d). Mesoscutellum coarsely punctate. Mesepisternum polished and coarsely punctate (i=1–2d). Propodeum with lateral surface coarsely ruguloso-punctate. Metasomal terga with punctation distinct (i=d), apical impressed areas impunctate except on basomedial portion (i=1–2d).

Structure. Head moderately wide to moderately elongate (length/width ratio = 0.98–1.02). Eyes convergent below (UOD/LOD ratio = 1.50–1.52). Supraclypeal area weakly convex. Antennal sockets distant (IAD/ OAD ratio> 1.2). Frontal line carinate, ending 1.5 OD below median ocellus. OOD subequal to IOD. Pedicel subequal to F1. F2 length 1.8X F1. F2–F10 moderately short (length/width ratio = 1.17–1.63). Parapsidal lines in deep furrow. Metapostnotum moderately elongate (MMR ratio = 1.18–1.20), posterior margin sharply angled onto posterior surface.

Terminalia . S7 with median lobe weakly clavate, apex rounded ( Fig. 112F ). S8 with apicomedial margin weakly convex ( Fig. 112F ). Genitalia as in Fig. 112D–E . Gonobase with ventral arms widely separated. Gonostylus small, dorsal setae elongate. Retrorse lobe wide, weakly attenuated apically.

Range. Southern Ontario and Connecticut, west to Missouri ( Fig. 113 ).

Additional material examined. CANADA: ONTARIO: 15♀ 9♂♂ Manestar Tract, St. Williams , N42°43´W080°26´, 2–8.vi.1994 (P.J. Carson) ; 1♂ Manestar Tract , St. Williams Co., N42°43´W080°26´, 2– 31.vi.1994 (P.J. Carson) ; 2♂♂ Manestar Tract, St. Williams , N42°43´W080°26´, 23.vii.1994 (P.J. Carson) ; USA: ILLINOIS: 1♀ Kankakee Co., Hooper Br. , 2.vii.2003 ( R. P. Jean) ; INDIANA: 2♀ Jasper Co., Nipsco , 22.v.2003 ( R. P. Jean) ; 1♀ Jasper Co., Nipsco , 9.vi.2001 ( R. P. Jean) ; 1♀ Jasper Co., Prairie Border , 22.vi.2003 ( R. P. Jean) ; 1♀ Jasper Co., Stoutsburg , 11.vi.2003 ( R. P. Jean) ; 1♀ Newton Co., Conrad , 1.viii.2001 ( R. P. Jean) ; 1♂ Porter Co., Indiana Dunes NL, Ogden Dunes , N41°36´55´´ W087°12´12´´, 9.viii.2004 ( R. Grundel) ; MARYLAND: 2♀ Calvert Co., v.2007 (M. Gates) ; 1♀ PG Co., Laurel , PWRC, 6.vi.2001 (Russell & Droege); [ PCYU] ; WISCONSIN: 1♀ Dane Co., Hawkhill , 11.vi.1996 [ IRCW] .

Floral records. ANACARDIACEAE : Rhus aromatica , ASTERACEAE : Symphyotrichum pilosum , COMMELINACEAE : Tradescantia ohiensis , FABACEAE : Chamaecrista fasciculata , FAGACEAE : Castanea , SCROPHULARIACEAE : Scrophularia lanceolata .

Comments. Uncommon. Mitchell (1960) suggested that L. foveolatum might be the male of L. disparile (as D. brassicae ). The synonymy with L. supraclypeatum is supported by DNA barcoding results, the shared diagnostic character of the parapsidal line, and the presence of both males and females at the same locality. The correct male of L. disparile has been identified (see above and Gibbs 2010).

Figures

FIGURE 111. Lasioglossum foveolatum (Robertson). Female (A) lateral habitus; (B) dorsal habitus; (C) face; (D) lateral view of head; (E) mesoscutum, tegula. Scale bars, A–C = 1 mm.

FIGURE 112. Lasioglossum foveolatum (Robertson). Male (A) lateral habitus; (B) dorsal habitus; (C) face; (D) ventral view of genital capsule; (E) dorsal view of genital capsule; (F) S7, S8. Scale bars, A–C = 1 mm, F = 0.5 mm.

FIGURE 113. Distribution of Lasioglossum foveolatum (dark grey), L. heterognathum (light grey), and L. hudsoniellum (medium grey).