Lasioglossum exoneuroides 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 : 67-72

Lasioglossum . ( Enigmalictus ). exoneuroides ( Rayment 1953) new status

( Figures 1A–B, 16, 18A–B, 25A–B, 32B, 48A–B, 49A–B)

Halictus exoneuroides Rayment 1953, p. 17 (original description).

Halictus portlandensis Rayment 1953, p. 23 (original description); Michener 1965, p. 162 (unplaced status) new synonymy. Lasioglossum (Austrevylaeus) exoneuroides — Michener, 1965, p. 171 (generic and subgeneric status change).

Diagnosis. Females of L. exoneuroides can be recognised by the combination of: Body length 5.12 (± 0.46 SD) mm ( Fig. 48A). ITS = 1.20 (± 0.04 SD) mm. Face round (FL/HW ratio 0.83 (± 0.03 SD)). Head and mesosoma black ( Fig. 25A). Metasoma T1–T4 light brown, T5–T6 dark brown ( Fig. 48A). Mesoscutum diversopunctate (i.e. medially with different sized punctures), medially with moderately sparse punctures (IS = 2–6 PD), inner margins of parapsidal lines with sparse punctures (IS = 3–6 PD), in parapsidal areas with sparse punctures (IS = 3–6 PD), in posterolateral corners with moderately sparse punctures (IS = 2–3 PD) and along posterior margin with moderately sparse punctures (IS = 2–3 PD) ( Fig. 25B). Metapostnotum striate. Inner metatibial spur pectinate and oblique with several, sharply pointed teeth less than one third width of rachis.

Males of L. exoneuroides can be recognised by the combination of: Body length 5.52 (± 0.14 SD) mm ( Fig. 48B). ITS = 1.32 (± 0.03 SD) mm. Face short (FL/HW ratio 0.79 (± 0.03 SD)). Mesoscutum with dense punctures (IS ≤ 1 PD) medially and laterally. Head and mesosoma black. Metasoma T1–T3 light red brown, T4–T6 dark brown ( Fig. 48B). Metasoma sterna S4 with weak lateral, plumose tufts either side of midline (Length of hair:MOW ratio as 0.5 (± 0.03 SD)), S5 with greater density of lateral, plumose tufts than S4 either side of midline (Length of hair: MOW ratio as 0.75 (± 0.03 SD)). S5 apical margin medially almost straight ( Fig. 32B). Genitalia with gonostylus: gonocoxite length ratio 1.00 (± 0.03 SD), retrorse lobe present ( Figs. 49A–B).

Comments. Michener (1965 p. 162) did not place Halictus portlandensis into his revised classification. The species was later labelled as “ Incertae Sedis ” ( ABRS 2024). This was due to Rayment’s (1953, p. 23) description of Halictus portlandensis in which he nominated a type specimen but did not provide a depository for the type and did not provide the type specimen’s label data. The reason for these omissions may have been due the title of the publication, in which Halictus portlandensis was described, as “Bees of the Portland District”. Rayment’s description did provide this information about the type specimen of Halictus portlandensis “Taken on flowers of Aster sp. , 22 April 1952 ”. During this revision, a specimen collected by Clifford Beauglehole (recognised by his handwriting and who also collected the type of Halictus exoneuroides at Gorae West, Victoria) was found in the ANIC collection where other Rayment types are deposited. This specimen has three labels which say: “Gorae, W.V., 22 April 1952 ” in Clifford Beauglehole handwriting; a red “ TYPE ” label, and an identification label of “ Halictus portlandensis ” both in Rayment’s handwriting. The author considers this to be the type specimen of Halictus portlandensis and therefore considers the name to be valid. Rayment (1953) erected both Halictus exoneuroides (p. 17) and Halictus portlandensis (p. 23) in the same publication. As “First Reviser”, Halictus exoneuroides is nominated as first published and Halictus portlandensis is made a junior subjective synonym of Halictus exoneuroides (ICZN Article 24.2). The types of Halictus exoneuroides and H. portlandensis were collected at the same location.

A specimen labelled as “ PARATYPE ” and “ Halictus exoneuroides ” in Rayment’s handwriting was in ANIC. This specimen has the same label data as the type specimen. However, this specimen was not mentioned in Rayment’s (1953, p. 17) description and therefore has no type status.

See diagnosis for L. disclusum to distinguish between L. disclusum , L. exoneuroides and L. excelsum .

Etymology. The species name “exoneuroides ” is a combination of three parts: “exo” is Greek for “without”, “neuro” is Greek for “nerve, sinew or tendon”, and “oides” is Greek for “resembling”. Rayment’s (1953, p. 17) description of Halictus exoneuroides commented on the wing venation saying “the outer recurrent and intercubitus weakened” which refers to veins 1rs-m and 2rs-m for submarginal cross veins. The species name “portlandensis ” refers to the town nearest the type locality for this species and Portland appears in the title of the publication in which this species was first described.

Syntype of “ Halictus exoneuroides ”. AUSTRALIA. Victoria. ♀: Gorae West, 10 November 1950, leg. Clifford Beauglehole (Right metatibia and tarsal segments glued to the specimen pith. ANIC) .

Syntype of “ Halictus portlandensis ”. AUSTRALIA. Victoria. ♀: Gorae, W. V., 22 April 1952 ( ANIC) .

Additional material examined. (21 specimens, 16 ♀, 5 ♂): AUSTRALIA. New South Wales and Canberra: (1 ♀) Mt Tomah, Blue Mountains , 11 Nov 1992, N.W. Rodd ( AM); (1 ♂) Mt Tomah, Blue Mountains , 22 April 1978, N.W. Rodd ( AM); (1 ♀) Clyde Mountain , 13 Oct 1986, I.D. Naumann ( ANIC); (1 ♀) Mt Victoria , 21 Oct 1930, A.N. Burns ( NMV); (1 ♀) Fitzroy Falls , 22 March 1961, E.F. Riek ( ANIC); (1 ♀) Black Mtn , Oct 1982, I.D. Naumann & J.C. Cardale, malaise trap /ethanol ( ANIC) .

Victoria: (1 ♂) Dingo Ck, Lind Nat Pk , 26 Feb 1980, I.D. Naumann & J.C. Cardale ( ANIC); (1 ♂) 7 km S Mt Richmond , 7 Feb 1990, K. Walker, on Scaevola calendulacea (NMV) ; (1 ♂) 6 km S Warburton , 27 Feb 1976, A. Neboiss ( NMV); (1 ♀) 12 mls (19 kms) of Neerim , 6 Jan 1965, A. Neboiss ( NMV); (1 ♀) Cape Otway , 29 Nov 1966, A. Neboiss ( NMV); (1 ♀) 6 mls (9 kms) E Marysville , 18 Dec 1968, E.M. Exley, on Prostanthera melissifolia (QM) ; (1 ♀, 1 ♂) Erica , 19–20 April 1983, P. Bernhardt, on Acacia terminalis (NMV) ; (1 ♀) Frankston , 26 Oct 1984, P. Bernhardt, on Hibbertia scandens (NMV) ; (1 ♀) Lorne , 19 Dec 1930, L.F. Graham ( NMV); (2 ♀) Gorae , 10 Nov 1950, 22 April 1952, Clifford Beauglehole ( ANIC); (1 ♀) Emerald , Jan 1936 ( ANIC) (1 ♀) Ringwood , 24 Oct 1951, A. Burns ( NMV) .

South Australia. (1 ♀) 6kmn N Rendelsham, 8 Feb 1990, K. Walker, on Melaleuca lanceolata (NMV) ; (1 ♀) 3 km W Rocky River Hmst, Kangaroo Island, 11 Oct 1994, L. Janson, on Leucopogon parviflorus (NMV) .

Redescription of female, male described for first time

Female. Body length 5.12 (± 0.46 SD) mm. ITS = 1.20 (± 0.04 SD) mm. Head length 1.38 (± 0.05 SD) mm. Head width 1.75 (± 0.18 SD) mm. Wing length 4.33 (± 0.67 SD) mm. (n=10).

Colouration. Head and mesosoma black. Clypeus with apical one third light red brown, remainder black. Labrum light red brown. Mandible light red brown basally and medially with reddish-brown apically. Flagellum dark brown dorsally and ventrally. Pronotal lobe dark brown. Tegula reddish-brown. Wing membrane hyaline, faintly dusky, veins with subcosta brown, otherwise honey coloured. Legs with coxa, trochanter and femur brown, fore and mid legs with both tibiae and all tarsi light red brown, hind leg with tibia and metatarsi brown. Metasoma T1–T4 light brown, T5–T6 dark brown. Body setae white. Wing hairs pale. ( Figs. 1A–B, 25A–B, 48A, 49A).

Pubescence. Head with frons, vertex and gena with sparse cover of erect hair, paraocular area with a light cover of appressed hair ( Fig. 25A). Pronotal lobe almost bare, posterior margin of spiracle cover with dense layer of short, appressed hair. Mesoscutum with sparse cover of short, erect hair, a few more hairs along posterior margin ( Fig. 25B). Mesepisternum with weak cover of erect hair. Lateral surface of propodeum with moderate cover of elongated, branched, erect hair, posterior surface with spare cover of erect hair. Metafemoral scopa with dense plumose hairs. T1–T4 dorsally almost bare, some hairs laterally, T5–T6 with sparse cover of short setae ( Fig. 48A).

Surface sculpture. Clypeus shining and smooth on anterior half, dull with imbricate pattern on basal half, apical half punctures large, deeply impressed, irregularly spaced with moderately sparse punctures (IS = 2–3 PD), basal half with smaller moderately sparse punctures (IS = 2–3 PD). Supraclypeal area dull, with imbricate pattern, medially impunctate, laterally with moderately sparse punctures (IS = 2–3 PD. Paraocular area smooth and impunctate. Frons dull, with minute, crowded punctures (IS = 0 PD) with rim of each puncture raised and forms part of adjoining puncture ( Fig. 25A). Vertex impunctate with imbricate pattern. Gena strigulate with parallel lines. Tegula shining, impunctate on apical half, basal half substrigulate, with minute, dense punctures (IS = 0– 1 PD). Mesoscutum with a dull sheen, entirely covered with imbricate pattern, diversopunctate, medially with moderately sparse punctures (IS = 2–6 PD), inner margins of parapsidal lines with sparse punctures (IS = 3–6 PD), in parapsidal areas with sparse punctures (IS = 3–6 PD), in posterolateral corners with moderate punctures (IS = 2–3 PD) and along posterior margin with moderately sparse punctures (IS = 2–3 PD) ( Fig. 25B). Mesoscutellum dull, imbricate, with dense punctures (IS = 1 PD), laterally with moderate punctures (IS = 1–2 PD). Metanotum dull, impunctate, imbricate. Metapostnotum striate across entire surface, medially striae reaching halfway to but not reaching posterior margin, laterally striae reaching dorsolateral slope, posterior margin rounded, sculpture shining but imbricate ( Fig. 49A). Propodeum lateral face dull, imbricate and impunctate, posterior face dull, imbricate and impunctate, lateral and oblique carinae absent ( Fig. 49A). Preëpisternum weakly scabrous. Mesepisternum coarsely imbricate and impunctate. Metepisternum dull, imbricate and impunctate. Hypoepimeron inflated, dull, glabrous, weakly imbricate and impunctate. T1 dorsal surface shining, with minute, moderately sparse punctures (IS = 2–3 PD). T2 shining with similar punctures to T1.

Structure. Face round (FL/HW ratio 0.83 (± 0.03 SD)). Eyes convergent below [UOD/LOD ratio 1.11 (± 0.02 SD)]. Median ocellus width/ocellocular distance ratio [MOW:OOD ratio 0.50 (± 0.3 SD)]. Clypeus extends ~50% below suborbital tangent, clypeus length/width ratio 0.50 (± 0.07 SD). Clypeus with apicolateral denticles ( Fig. 25A). Gena narrower than eye. Mandible short, not reaching opposing clypeal angle. Protibial spur with apical serrations longer than length to width of malus. Inner metatibial spur pectinate and oblique with several, sharply pointed teeth less than one third width of rachis. Distance between parapsidal line (at the starting point) 0.86 (± 0.03 SD) mm. Pronotal angle rounded and weakly projected. Mesoscutum length/width (widest point) ratio 0.76 (± 0.05 SD). Mesoscutum/mesoscutellum length ratio 2.80 (± 0.15 SD). Mesoscutellum/metanotum length ratio 1.36 (± 0.12 SD). Stigma medium, 0.76 mm long, 0.26 mm wide (ratio ~2.93 (± 0.05 SD)), margin in marginal cell convex, marginal cell 1.20 mm long, 0.36 mm wide, free portion about 2X that subtended by submarginal cells (0.77 mm: 0.38 mm). 1m-cu distinctly inside the second submarginal cell and separated from 1rs-m. Stigma perpendicular goes about middle of third submarginal cell.

Male. Body length 5.52 (± 0.14 SD) mm. ITS = 1.32 (± 0.03 SD) mm. Head length 1.46 (± 0.04 SD) mm. Head width 1.58 (± 0.04 SD) mm. Wing length 4.87 (± 0.12 SD) mm. (n=5).

Colouration. Head and mesosoma black ( Fig. 48B). Clypeus almost entirely yellow-white, dark brown patches on basal half lateral margins ( Fig. 49B). Labrum yellow white. Mandible with dark brown basal patch, remainder yellow white except tip dark reddish-brown. Flagellum dark brown to black dorsally, brown ventrally. Pronotal lobe dark brown. Metasoma T1–T3 light red brown, T4–T6 dark brown. Legs almost entirely light red brown except coxae and trochanters dark brown. Tegula red brown. Wing membrane hyaline, veins with subcosta brown, otherwise light brown to pale amber. Wing hairs pale ( Fig. 1B).

Pubescence. Body hair colour brownish white ( Fig. 48B). Frons with sparse cover of erect setae, dense setae between antennal bases, moderate cover of appressed hair in paraocularareas. Clypeus dorsal surface almost glabrous, with sparse erect hairs, laterally with denser long setae ( Fig. 50B). Gena with sparse cover of erect setae. Pronotal lobe almost glabrous, some denser hair around posterior margin of spiracle cover. Sparse cover of hair on preëpisternum and mesepisternum. Metanotum, mesoscutum with sparse cover of short, erect hairs. T1–T6 with sparse cover of short, erect hair, a few long hairs on margins of tergites. Metasoma sterna S4 with weak lateral, plumose tufts either side of midline (Length of hair:MOW ratio as 0.5 (± 0.03 SD)), S5 with greater density of lateral, plumose tufts than S4 either side of midline (Length of hair:MOW ratio as 0.75 (± 0.03 SD)) ( Fig. 32B).

Surface sculpture. Clypeus with a dull sheen, apical half with moderately dense punctures (IS = 1–2 PD), basal half with large and deep punctures, moderately dense punctures (IS = 1–3 PD) with imbricate sculpture, diversopunctate between apical and basal halves. Supraclypeal area with imbricate sculpture, with minute, moderately dense punctures (IS = 1–2 PD). Paraocular area smooth and shining, impunctate. Frons with minute, crowded to dense punctures (IS = 0 PD). Vertex weakly rugulose across vertex surface. Gena weakly rugulose. Tegula shining, impunctate across apical half, on basal half with dense (IS ≤ 1 PD) to moderate punctures (IS = 1–2 PD). Mesoscutum dull with dense punctures (IS ≤ 1 PD) medially and laterally. Mesoscutellum dull with crowded punctures medially, dense punctures laterally (IS ≤ 1 PD). Metanotum dull, scabriculous. Metapostnotum rugulose with striae reaching about halfway to posterior margin, sculpture shining. Propodeum lateral face scabriculous, posterior face imbricate-scabriculous. Preëpisternum and mesepisternum imbricate and with sparse punctures (IS = 2–3 PD). Metepisternum dull and striate. T1 dorsal surface shining, medially with dense punctures medially (IS ≤ 1 PD), laterally with moderately sparse punctures (IS = 1–3 PD). T2 shining, with moderately sparse punctures (IS = 2–4 PD).

Structure. Face short (FL/HW ratio 0.79 (± 0.03 SD)). Clypeus projecting ~40% below suborbital tangent, clypeus length/width ratio 0.49 (± 0.04 SD). Flagellomeres, except F1, elongate, F2 equal to F1 and pedicel combined. F2:F1+pedicel length ratio 1.00 (± 0.03 SD). F2:F1 length ratio 2.14 (± 0.02 SD). F2 length/width ratio 1.50 (± 0.04 SD). F9 length/width ratio 1.38 (± 0.09 SD). Eyes strongly convergent below (UOD/LOD ratio 1.48 (± 0.03 SD). Gena narrower than eye. Mandible short, not reaching opposing clypeal angle. Pronotal angle rounded and not well projected. Mesoscutum length/width ratio 0.77 (± 0.02 SD). Mesoscutum/mesoscutellum length ratio 2.50 (± 0.04 SD). Mesoscutellum/metanotum length ratio 1.67 (± 0.03 SD). Propodeum lateral and oblique carinae absent. S5 apical margin medially almost straight.

Genitalia. Gonobase flat at bottom, tapered basally, arms ventroapically complete, gonobase:gonocoxite length ratio 0.93 (± 0.03 SD), gonostylus:gonocoxite length ratio 1.00 (± 0.03 SD), gonostylus apically with elongated setae, inner margin setae curved at tip and setae from each gonostylus extends beyond midway between gonostyli, penis valve inner margin with setae, retrorse lobe present, long and narrow (length 3 times width), not reaching gonobase, densely setose medially with short setae, apical and inner margin with elongated setae, length of setae equal to or greater than width of retrorse lobe, setae radiating out from margins of retrorse lobe, setae straight at tip ( Figs. 18A–B).

Range. Occurs in New South Wales, Victoria and South Australia ( Fig. 16).

Flight period. This species has been collected in the months of March and April and again between October and December ( Table 1).

Floral hosts. DILLENIACEAE : Hibbertia scandens . ERICACEAE : Leucopogon parviflorus . FABACEAE : Acacia terminalis . GOODENIACEAE : Scaevola calendulacea . LAMIACEAE : Prostanthera melissifolia . MRYTACEAE: Melaleuca lanceolata .