Lasioglossum ewarti Walker, 2025

Walker, Kenneth L., 2025, The “ weak-veined ” Lasioglossum in Australia, New Zealand and West New Guinea, with descriptions of three new subgenera (Hymenoptera: Apoidea: Halictidae), Zootaxa 5651 (1), pp. 1-94 : 77-82

Lasioglossum . ( Evyloides ). ewarti (Cockerell 1910) new status

( Figures 3, 19, 20, 21A–B, 22A–B, 52A–B, 53A–B, 54A–B)

Halictus ewarti Cockerell 1910a, p. 230 (original description), p. 243 (key); Hacker 1921, p. 137 (catalogue); Cockerell 1933, p. 296 (key), p. 305 (compare), p. 307 (compare), p. 310 (redescription); Rayment 1935, p. 706 (compare).

Lasioglossum (Austrevylaeus) ewarti — Michener 1965, p. 171 (generic and subgeneric status change).

Diagnosis. Females of L. ewarti are unlike any other Australian Lasioglossum and can be recognised by the combination of: Pronotal angle acute and prominent ( Fig. 22B). Body length 5.65 (± 0.50 SD) mm. ITS = 1.22 (± 0.02 SD) mm. Face short (FL/HW ratio 0.73 (± 0.03 SD)). Head and mesosoma dark brown to black, metasoma light testaceous coloured ( Fig. 52A). Mesoscutum sculpture crowded, areolate on anterior one third, in parapsidal areas and inner areas of parapsidal lines and along posterior margin with deep, crowded punctures (IS = 0 PD) with rim of each puncture raised and forms part of adjoining puncture, puncture shape polygonal (mainly 5-sided), medially and posteromedially rugulose-lacunose with dense punctures (IS ≤ 1 PD to moderately dense punctures (IS 1–2 PD) ( Fig. 22B). Metapostnotum areolate rugose ( Fig. 3). Propodeum lateral carina reaching dorsal margin, oblique carina present ( Fig. 3). Inner metatibial spur with eight oblique denticulate-serrate teeth ( Fig. 20).

Males of L. ewarti is unlike any other Australian Lasioglossum and can be recognised by the combination of: Pronotal angle acute and prominent ( Fig. 54A). Body length 5.50 (± 0.12 SD) mm. ITS = 1.19 (± 0.06 SD) mm. Face round (FL/HW ratio 0.85 (± 0.03 SD)). Head and mesosoma dark brown to black, metasoma T1–T3 light testaceous, T4–T6 dark brown to black ( Fig. 52B). Mesoscutum areolate with deep crowded punctures (IS = 0 or>1 PD) ( Fig. 54A). Metapostnotum areolate rugose ( Fig. 54B). Propodeum lateral carina reaching dorsal margin, oblique carina present ( Fig. 54B). Metasoma sterna S2–S4 with moderate cover of plumose hair across apical margin of each sternite and small lateral tufts with density and length of pubescence increasing from S2 to S4 (S4 hair medially - Length of hair:MOW ratio as 1.0 (± 0.03 SD), hair laterally Length of hair:MOW ratio as 2.0 (± 0.04 SD) n = 2), S5 with long, lateral tufts of plumose hair (S5 hair medially: Length of hair:MOW ratio as 1.0 (± 0.03 SD); S5 hair laterally: Length of hair:MOW ratio as 3.6 (± 0.03 SD) n = 2), S6 with inverted V-shaped of simple hair with apical hairs longer than distal hairs. S5 apical margin medially curved basally ( Fig. 53B). Genitalia with retrorse lobe vestigial ( Figs. 22A–B).

Comments. Lasioglossum (Evyloides) ewarti has a highly localised distribution known only from one area just north of Kuranda in North Queensland ( Fig. 19). The female type specimen was collected in January 1902 in Kuranda (NHML) and the second known female specimen was collected in April 1902 in Kuranda (SEMK). The next collection of this species, again near Kuranda, was a female in January 1952 (NMV). The author visited the Kuranda region in January 2001 and October 2005 to search for this rare species. During both visits, the author located and collected 16 specimens (14 ♀, 2 ♂) along Black Mountain Road, approximately 15 km north of Kuranda. The township of Kuranda is located in tropical rainforests whereas the area north of Kuranda, where specimens of L. ewarti were located, would be better described as open forest and not rainforest. This species appears to be monolectic. Specimens were collected on the flowers of Lophostemon grandiflorus ( Myrtaceae ) and only in one general area. Other floral resources were available at the times of these collections (2001 and 2005) but L. ewarti was not collected on them. The distribution map of Lophostemon grandiflorus subsp. riparis on the Australasian Virtual Herbarium ( AVH 2024) shows that it occurs across northern Australia in North Queensland, Northern Territory and Western Australia. However, there are two location records for this plant in the Kuranda region and both plant records are where the author collected specimens of L. ewarti . This species is a “short-range endemic” worthy of significant conservation efforts.

The sex ratio of collected specimens was interesting. During the January 2001 collection date, two females and two males were collected. However, on the October 2005 collection date only females (12) were collected. Packer & Knerer (1985) listed six characteristics used in assessing the sociality levels of Evylaeus . The primary character noted was “a reduction in the proportion of males in the first brood”. Eusocial species usually produce a femalebiased brood during the early provisioning activity period and then switch to a male-biased brood (Packer 1994). It would be worth an examination of female spermathecae to see if there is any sign of primitive sociality in this species.

Etymology. Cockerell did not provide a reason for the name of this species. The name seems to be an honorific for a male with the surname “Ewart”. The only scientist in Australia with the surname “Ewart” in the early 1900s was Alfred Ewart who was Government Botanist for the Victorian Government from February 1906 to February 1921. He collected mainly in Victoria and the Northern Territory but may have accompanied Turner on some collecting trips.

Syntype of “ Halictus ewarti ”. AUSTRALIA. Queensland. ♀: Cairns (“Kur” on label as Cairns Kuranda), 1 Feb. Turner Coll. 1910–7 ( BM Type Hym. 17.a.982. NHMUK014024730 , NHMUK) .

Additional material examined. (18 specimens, 15 ♀, 3 ♂): AUSTRALIA. Queensland. (1 ♀) Kuranda, 4 Feb (presumably Turner as handwriting same as on type label) ( SEMK); (1 ♂) Kuranda , Jan 1952, J.G. Brooks ( AM, genitalia removed but not associated with specimen); (2 ♀, 2 ♂) Kuranda , Black Mountain Forest Road , [16.7852S 145.6186E], Jan 2001, K. Walker, on Lophostemon grandiflorus subsp. riparis (genitalia removed from one male and reattached in microvial attached to pin, NMV); (12 ♀) Kuranda, Black Mountain Forest Road, [16.7852S 145.6186E], 3 Oct 2005, K. Walker, on Lophostemon grandiflorus subsp. riparis (NMV) .

Redescription of female, male described for first time

Female. Body length 5.65 (± 0.50 SD) mm. ITS = 1.22 (± 0.02 SD) mm. Head length 1.58 (± 0.05 SD) mm. Head width 1.77 (± 0.19 SD) mm. Wing length 4.59 (± 0.85 SD) mm. (n=10).

Colouration. Head and mesosoma dark brown to black. Clypeus apically reddish-brown. Labrum reddish-brown. Mandible brown basally, light brown apically with reddish-brown apically. Flagellum brown dorsally, light brown ventrally. Pronotal lobe light brown. Tegula reddish-brown. Wing membrane hyaline, faintly dusky, veins with subcosta brown, otherwise honey coloured. Legs with coxa, trochanter and femur brown, tibia and tarsi light yellow brown. Metasoma light testaceous, T6 dark brown. Wing hairs pale. ( Figs. 22A–B, 52A).

Pubescence. Tomentum dense on pronotal angle and lobe, space between pronotal lobe and tegula, moderately dense on metanotum anterior margin. Head and mesosoma with mostly sparse pilosity, composed of mainly simple setae, a few with branches. Lateral surface of propodeum with moderate cover of weakly branches, erect setae, plumose patch on anterior dorsal area. Metafemoral scopa with dense plumose hairs. T1 glabrous. ( Figs. 22A–B, 52A).

Surface sculpture. Clypeus shining and smooth, with large, irregularly spaced dense punctures (IS <1 PD) on apical half, smaller and slightly less dense on basal margin (IS <1 PD). Supraclypeal area mostly smooth, punctures diveropunctate ranging from dense (IS <1 PD) to moderately dense (IS 1–2 PD). Paraocular area smooth with dense punctures (IS ≤ 1 PD). Frons areolate with deep crowded punctures (IS = 0 PD) with rim of each puncture raised and forms part of adjoining puncture, puncture shape polygonal (mainly 5-sided) ( Fig. 22A). Vertex areolate across entire surface, punctures shape broader polygonal than on frons. Gena porcate, strongly striate with striae parallel to length of eye. Tegula shining, impunctate on apical half, basal half substrigulate and diversopunctate with dense punctures (IS = 0–1 PD). Mesoscutum dull, sculpture crowded, areolate on anterior one third, in parapsidal areas and inner areas of parapsidal lines and along posterior margin with deep crowded punctures (IS = 0 PD) with rim of each puncture raised and forms part of adjoining puncture, puncture shape polygonal (mainly 5-sided), medially and posteromedially rugulose-lacunose, with dense punctures (IS ≤ 1 PD to moderately dense punctures (IS 1–2 PD) ( Fig. 22B). Mesoscutellum dull, anteriorly and laterally areolate, with crowded punctures (IS = 0 or>1 PD) with rim of some punctures raised and forms part of adjoining puncture, puncture shape polygonal (IS = 0 PD), laterally with crowded punctures (IS ≤ 1 PD) interspaces smooth and shining. Metanotum dull, costate, striae running along length of metanotum. Metapostnotum areolate rugose across entire surface, deeply ridged striae reaching dorsal well defined and raised rim, sculpture shining ( Fig. 3). Propodeum lateral face scabrous, lateral and oblique carinae present and separate lateral and posterior surfaces, lateral carina reaching dorsal margin, lateral and oblique carinae strong ( Fig. 3), posterior face weakly puncticulate and shining. Preëpisternum reticulate-rugose to rugose. Upper mesepisternum coarsely striae-scabrous, lower mesepisternum strongly striate with striae running parallel to mesoscutum. Metepisternum dull and striate. T1 dorsal surface shining, appears impunctate, but with minute, moderate to sparse punctures (IS = 1–6 PD). T2 shining with similar punctures to T1.

Structure. Face short (FL/HW ratio 0.73 (± 0.03 SD)). Eyes convergent below [UOD/LOD ratio 1.02 (± 0.02 SD)]. Median ocellus width/ocellocular distance ratio [MOW:OOD ratio 0.48 (± 0.2 SD)]. Clypeus extends ~32% below suborbital tangent, clypeus length/width ratio 0.41 (± 0.07 SD). Clypeus without apicolateral denticles. Gena narrower than eye. Mandible long, reaching beyond opposing clypeal angle. Protibial spur with apical serrations longer than length to width of malus. Inner metatibial spur with eight oblique, apically pointed, denticulate-serrate teeth overlayed on top of each other, basal teeth wider than width of rachis ( Fig. 20). Distance between parapsidal line (at the starting point) 0.90 (± 0.05 SD) mm. Pronotal angle acute and strongly projected ( Fig. 22B). Mesoscutum length/width (widest point) ratio 0.70 (± 0.04 SD). Mesoscutum/mesoscutellum length ratio 2.69 (± 0.16 SD). Mesoscutellum/metanotum length ratio 1.569 (± 0.12 SD). Stigma small, 0.72 mm long, 0.22 mm wide (ratio ~3.27 (± 0.05 SD)), margin in marginal cell convex, marginal cell 1.08 mm long, 0.31 mm wide, free portion about 1.8X that subtended by submarginal cells (0.74 mm: 0.41 mm). 1m-cu distinctly inside the second submarginal cell and separated from 1rs-m. Stigma perpendicular goes towards the basal half of third submarginal cell.

Male. Body length 5.50 (± 0.12 SD) mm. ITS = 1.19 (± 0.06 SD) mm. Head length 1.62 (± 0.06 SD) mm. Head width 1.66 (± 0.02 SD) mm. Wing length 4.45 (± 0.15 SD) mm. (n=3).

Colouration. Head and mesosoma dark brown to black. Clypeus basally brown, apically yellow white. Labrum yellow white. Mandible yellow with brown basomedially and light reddish brown apically. Flagellum brown dorsally, light brown ventrally. Pronotal lobe testaceous to yellow. Metasoma T1–T3 light testaceous, T4–T6 dark brown to black. Legs with coxae and trochanters dark brown, remainder of legs light testaceous. Tegula dark amber to yellow. Wing membrane hyaline, veins with subcosta brown, otherwise light brown to pale amber. Wing hairs pale. ( Figs. 52B, 53A, 54A–B).

Pubescence. Body hair colour white. Tomentum dense on lower paraocular area, near posterior margin of pronotal angle and lobe, dense short hair on lateral margin of propodeum, long hairs on gena, preëpisternum, mesepisternum, and metanotum, mesoscutum with sparse cover of short, erect hairs, a few long hairs on T2–T3 basolaterally, T1–T2 with sparse cover of hair, T3–T6 with moderate cover and slightly longer hairs. Frons with moderate cover of short, erect hair. Metasoma sterna S2–S4 with moderate cover of plumose hair across apical margin of each sternite and small lateral tufts with density and length of pubescence increasing from S2 to S4 (S4 hair medially - Length of hair:MOW ratio as 1.0 (± 0.03 SD), hair laterally Length of hair:MOW ratio as 2.0 (± 0.04 SD) n = 2), S5 with long, lateral tufts of plumose hair (S5 hair medially - Length of hair:MOW ratio as 1.0 (± 0.03 SD), hair laterally Length of hair:MOW ratio as 3.6 (± 0.03 SD) n = 2), S6 with inverted V-shaped of simple hair with apical hairs longer than distal hairs ( Figs. 52B, 53A, 54A–B).

Surface sculpture. Clypeus shining, with sparse to moderately sparse punctures (IS = 2–4 PD), diversopunctate. Supraclypeal area smooth and shining, with dense (IS <1PD) to moderately sparse punctures (IS ≤ 2 PD). Paraocular area smooth and shining with crowded punctures (IS = 0 PD). Frons areolate with deep, crowded punctures (IS = 0 or>1 PD) with rim of some puncture raised and forms part of adjoining puncture, puncture shape polygonal (IS = 0 PD). Vertex areolate across entire surface, punctures shape broader polygonal than on frons. Gena porcate, strongly striate with striae parallel to length of eye. Tegula shining, impunctate across entire surface. Mesoscutum dull, entirely areolate with deep, crowded punctures (IS = 0 PD) with rim of each puncture raised and forms part of adjoining puncture, puncture shape polygonal (IS = 0 PD) ( Fig. 54A). Mesoscutellum dull, medially areolate, with crowded punctures (IS = 0 PD) with rim of each puncture raised and forms part of adjoining puncture, puncture shape polygonal (IS = 0 PD), laterally crowded to dense punctures (IS ≤ 1 PD) interspaces smooth and shining. Metanotum dull, costate, striae running along length of metanotum. Metapostnotum coarsely striae-scabrous across entire surface, deeply ridged striae reaching dorsal well defined and raised rim, sculpture shining ( Fig. 54B). Preëpisternum reticulate-rugose to rugose. Upper mesepisternum coarsely striae-scabrous, lower mesepisternum strongly striate with striae running parallel to mesoscutum. Metepisternum dull and striate. Propodeum lateral face scabrous, posterior face weakly puncticulate and shining ( Fig. 54B). T1 dorsal surface shining, with minute, moderately sparse punctures (IS = 1–3 PD). T2 shining with dense punctures (IS ≤ 1 PD).

Structure. Face round (FL/HW ratio 0.85 (± 0.03 SD)). Clypeus projecting ~40% below suborbital tangent, clypeus length/width ratio 0.75 (± 0.04 SD). Mandible long, reaching beyond opposing clypeal angle. Flagellomeres, except F1, elongate, F2 equal to length of F1 and pedicel combined. F2:F1+pedicel ratio 1.00 (± 0.03 SD). F2:F1 length ratio 2.0 (± 0.03 SD); F2 length/width ratio 1.67 (± 0.05 SD). F9 length/width ratio 1.83 (± 0.08 SD). Eyes strongly convergent below (UOD/LOD ratio 1.57 (± 0.03 SD). Gena narrower than eye. Pronotal angle rounded and not well projected. Mesoscutum length/width ratio 0.75 (± 0.02 SD). Mesoscutum/mesoscutellum length ratio 2.84 (± 0.06 SD). Mesoscutellum/metanotum length ratio 1.86 (± 0.04 SD). Propodeum lateral and oblique carinae present. S5 apical margin medially curved basally.

Genitalia. Gonobase recessed medially at bottom, basally tapered basally, arms ventroapically complete, gonobase:gonocoxite length ratio 0.88, gonostylus:gonocoxite length ratio 0.57, gonostylus apically with short setae, penis valve inner margin with setae, retrorse lobe vestigial with a few short setae ( Figs. 21A–B).

Range. Occurs in open woodland forests north of Kuranda, North Queensland ( Fig. 19).

Flight period. This species has been collected in the months of January and February as well as October.

Floral host. MYRTACEAE : Lophostemon grandifloras subsp. riparis .

Subgenus Hemihalictus Cockerell 1897

Pauly (1986) reviewed and revised the Halictinae fauna from New Guinea and the Bismark Archipelago. Pauly recorded 54 species in the genera Sphecodes Latreille 1804 (two species), Pachyhalictus Cockerell 1929 (three species), Urohalictus Michener 1980 (one species), Lasioglossum (subgenera Parasphecodes , Nesohalictus Crawford 1910 and Ctenonomia [one species in each subgenus]) and Homalictus (45 species of which 21 were described as new species). Pauly (1986) recorded no “weak-veined” Lasioglossum species from New Guinea or the Bismark Archipelago.

Examination of Lasioglossum specimens in the Bishop Museum, revealed a new “weak-veined” species with elongated head diagnostics from West Papua ( Indonesia). The elongated head character and the subgeneric placement of this new species are discussed.