Lasioglossum (Dialictus) clavicorne, Gardner & Gibbs, 2020

Gardner, Joel & Gibbs, Jason, 2020, The ‘ red-tailed’ Lasioglossum (Dialictus) (Hymenoptera: Halictidae) of the western Nearctic, European Journal of Taxonomy 725, pp. 1-242 : 53-58

Lasioglossum (Dialictus) clavicorne sp. nov.

urn:lsid:zoobank.org:act:4E418EEB-5C3D-4985-9546-AFB1E1B903AA

Figs 25–27 , 106A

Diagnosis

Females of Lasioglossum clavicorne sp. nov. can be recognized by the characters for the L. clematisellum species complex (below), in addition to the head and mesosoma shiny with moderately sparse (i=1–3 pd), diversopunctate punctation, scutum with numerous thin, simple hairs, metasomal terga with dense tomentum, and larger overall size than other members of the L. clematisellum group (~ 5 mm). They are most similar to L. julipile sp. nov. Females of L. julipile sp. nov. have the head and mesosoma with finer, uniformly sized punctures, scutum with all hairs densely plumose, and smaller size (~ 4 mm).

Males of L. clavicorne sp. nov. are unique among known Lasioglossum (Dialictus) in the clavate antennae (F7–11 about 1.3 times as broad as basal segments). They can also be recognized by the head and mesosoma mostly shiny, postgena lineate, propodeum shiny with strong subparallel rugae extending nearly to the apical margin and onto the dorsolateral slope, rims of T1–3 sparsely and evenly punctate (i=1–5 pd), T2–5 with abundant tomentum (especially T4–5 which have sparse tomentum throughout), mesosoma with sparse tomentum, head and mesosoma with most hairs densely plumose, and relatively large size (~ 5 mm). They are most similar to L. pallidellum and L. julipile sp. nov., both of which have the antennae normal. Males of L. pallidellum have the propodeum posterior margin and dorsolateral slope smooth and rounded, and mesosoma with dense tomentum. Males of L. julipile sp. nov. have the rims of T1–3 unevenly punctate, becoming impunctate laterally, T2–5 with less extensive tomentum, and smaller size (~ 4 mm).

Etymology

The specific epithet clavicorne is formed from the Latin genitive singular noun ‘ clavae ’ (‘club’) and the adjective ‘ cornis ‘ (‘horned’). It refers to the clubbed antennae of the male. An appropriate translation would be the club-horned sweat bee.

Material examined

Holotype

UNITED STATES – Texas • ♂; Culberson Co., 10 mi. W of Kent; [31.07° N, 104.39° W]; 14 Sep. 1965; Timberlake leg.; ex Pyrrhopappus ; UCRC.

[Verbatim label: 10 mi. W of Kent, Tex // Culberson Co. Sept-14 65 // Sitilias // Timberlake Coll. // HOLOTYPE / Lasioglossum (Dialictus) clavicorne Gardner and Gibbs ]

Paratypes

UNITED STATES – Arizona • 1 ♀; 2.5 mi. S of Portal; [31.88° N, 109.14° W]; 12 May 1940; Timberlake leg.; ex Argemone ; UCRC . – New Mexico • 5 ♀♀; Carrizozo ; [33.64° N, 105.88° W]; 10 Jun. 1950; L.D. Beamer leg.; ex Helenium laciniatum ; SEMC . – Texas • 1 ♀; Brewster Co., 1 mi. E. of Marathon; [30.2° N, 103.23° W]; 12 Apr. 1965; Timberlake leg.; ex Physaria ; UCRC • 1 ♀; same location as for holotype; 14 Sep. 1965; D. Smith leg.; ex Pyrrhopappus ; UCRC • 1 ♀; same location as for holotype; 14 Sep. 1965; Timberlake leg.; UCRC

Description

Female

COLOURATION. Head and mesosoma blue-green; clypeus apical colour black to reddish brown; labrum reddish brown to orange; mandible orange with black basal spot or band and red tip; flagellum reddish brown dorsally, light brown ventrally; pronotal lobe reddish brown; metasoma red to orange with dark spiracular spots on T3–4; legs reddish brown with femur-tibia joints, tibia apices, and tarsi light brown to orange; tegula orange; wing membrane hyaline, veins with subcosta brown, otherwise pale amber.

PUBESCENCE. Body hair colour white. Tomentum dense on paraocular area, gena, pronotal collar and lobe, space between pronotal lobe and tegula, metanotum medially, metepisternum, T2–3 basolaterally, and T4 throughout; sparse on face below eye emargination, preëpisternum, mesepisternum, and T3 apical rim. Scutum hair densely plumose. Wing hairs light, very short and sparse. Acarinarial fan incomplete, sparse. T2 fringes sparse, T3 fringes sparse.

SURFACE SCULPTURE. Clypeus punctures large and irregularly sparse (i <4 pd), becoming fine and moderately dense in basal third (i=1–2 pd), sculpture shiny; supraclypeal area punctures sparse (i =1–4 pd), sculpture shiny; paraocular area punctures dense (i ≤ 1 pd), sometimes crowded around antenna socket, sculpture shiny; frons punctures dense (i ≤ 1 pd), sculpture shiny; vertex punctures fine, sparse (i=1–4 pd), sculpture shiny; gena punctures dense (i <1 pd), sculpture shiny, becoming tessellate and lineate posteriorly; postgena sculpture lineate, sometimes becoming smooth and tessellate to shiny anteriorly; tegula punctures absent; scutum punctures moderately sparse (i =1–4 pd), becoming dense posteromedially (i <1 pd), diversopunctate, sculpture shiny, becoming tessellate anteromedially; scutellum punctures dense marginally and on median line (i ≤ 1 pd), sparse submedially (i= 1–4 pd), diversopunctate, sculpture shiny; metanotum sculpture shiny and finely, densely punctate (i <1 pd), becoming rugulose laterally; metapostnotum rugae strong, highly anastomosing, reaching margin, sculpture shiny to weakly imbricate; preëpisternum sculpture areolate; hypoepimeron punctures dense (i ≤ 1 pd), diversopunctate, sculpture shiny; mesepisternum punctures dense (i ≤ 1 pd), diversopunctate, sculpture shiny; metepisternum sculpture lineate dorsally, finely ruguloso-punctate medially, imbricate ventrally; propodeum lateral face sculpture tessellate; propodeum posterior face sculpture tessellate; T1 anterior face sculpture shiny; T1 dorsal surface punctures fine, sparse (i =1–4 pd), absent in broad median line and large apicolateral oval patches, sculpture shiny; T2 disc punctures fine, moderately sparse (i=1–4 pd), disc sculpture shiny, rim punctures fine, sparse (i =1–5 pd), rim sculpture shiny.

SCULPTURE. Face length/width ratio 0.82 (± 0.01 SD). Clypeus projecting ~67% below suborbital tangent; clypeal area length/width ratio 0.39 (± 0.02 SD); apicolateral denticles low rounded knobs; supraclypeal area length/width ratio 0.74 (± 0.08 SD). Forewing with 3 submarginal cells; pronotal angle rightangled; tegula shape normal. Intertegular distance 1.05 (± 0.05 SD) mm. Scutum length/width ratio 0.79 (± 0.01 SD); scutum/scutellum length ratio 3.22 (± 0.09 SD); scutellum/metanotum length ratio 1.53 (± 0.08 SD); metanotum/metapostnotum length ratio 0.66 (± 0.07 SD). Propodeum lateral carinae not reaching dorsal margin; oblique carina weak, straight. T2 depressed apical rim length less than 50% of segment. (n=8)

Male

COLOURATION. Head and mesosoma blue to blue-green; clypeus apical colour reddish brown; labrum reddish brown; mandible orange with black basal spot and red tip; flagellum reddish brown dorsally, orange ventrally; pronotal lobe reddish brown; metasoma reddish brown with rims of terga broadly orange to translucent yellow; legs reddish brown with femur-tibia joints, base and apex of tibiae, and tarsi orange; tegula pale amber; wing membrane hyaline, veins with subcosta dark brown, otherwise pale amber to light brown.

PUBESCENCE. Body hair colour white. Tomentum dense on face below ocelli, gena, pronotal angle and lobe, space between pronotal lobe and tegula, and T2–3 basolaterally; sparse on episterna and T4–5 throughout. Scutum hair densely plumose. Sterna hair short (1–1.5 OD), densely plumose, dense and erect. Wing hairs light, short and sparse.

SURFACE SCULPTURE. Clypeus punctures moderately dense (i=1–2 pd), sculpture shiny; supraclypeal area punctures moderately dense (i =1–2 pd), sculpture shiny; paraocular area punctures crowded (i=0 pd), sculpture shiny; frons punctures dense (i <1 pd), sculpture shiny; vertex punctures moderately dense (i=1–2 pd), sculpture shiny; gena punctures moderately dense (i=1–2 pd), sculpture shiny; postgena sculpture weakly lineate; tegula punctures absent; scutum punctures sparse (i=1–3 pd), becoming dense medially (i ≤ 1 pd), diversopunctate, sculpture shiny; scutellum punctures sparse (i=1–3 pd), becoming dense marginally (i <1 pd), diversopunctate, sculpture shiny; metanotum sculpture shiny and moderately densely punctate (i =1–2 pd), becoming rugulose laterally; metapostnotum rugae strong, anastomosing, reaching margin, sculpture shiny; preëpisternum sculpture areolate; hypoepimeron punctures dense (i ≤ 1 pd), sculpture shiny; mesepisternum punctures dense (i ≤ 1 pd), sculpture shiny; metepisternum sculpture lineate dorsally, areolate ventrally; propodeum lateral face punctures obscure, sculpture imbricate, becoming rugulose posteriorly; propodeum posterior face sculpture not visible; T1 anterior face sculpture shiny; T1 dorsal surface punctures moderately dense (i= 1–2 pd), sparse in small apicolateral oval patches (i =1–4 pd), sculpture shiny; T2 disc punctures moderately dense (i=1–2 pd), disc sculpture shiny, rim punctures moderately sparse (i=1–3 pd), rim sculpture shiny.

STRUCTURE. Face length/width ratio 0.8. F1:pedicel length ratio 0.93; F2:F1 length ratio 1.43; F2 length/ width ratio 1.18; F9 length/width ratio 0.91. F9:F2 width ratio 1.31. Forewing with 3 submarginal cells; pronotal angle obtuse; tegula shape normal. Intertegular distance 0.93 mm. Scutum length/width ratio 0.9; scutum:scutellum length ratio 2.91; scutellum:metanotum length ratio 1.56; metanotum:metapostnotum length ratio 0.71. Propodeum lateral carinae not reaching dorsal margin; oblique carina absent. (n =1)

GENITALIA. Not examined.

Range

Chihuahuan Desert of southern Arizona, New Mexico, and Texas ( Fig. 27 ).

Floral records

ASTERACEAE Giseke : Helenium : H. laciniatum A.Gray • Pyrrhopappus • BRASSICACEAE Burnett : Physaria (Nutt. ex Torr. & A.Gray) A.Gray • PAPAVERACEAE Juss. Argemone L.

DNA barcodes

Not available.

Remarks

Rare. Only 10 specimens are known.

Figures

Fig. 25. Lasioglossum (D.) clavicorne sp. nov., ♀. A. Dorsal habitus. B. Lateral habitus. C. Face. D. Propodeum. E. Metasoma. Scale bars: 1 mm.

Fig. 26. Lasioglossum (D.) clavicorne sp. nov., holotype, ♂. A. Dorsal habitus. B. Lateral habitus. C. Face. Scale bars: 1 mm.

Fig. 27. Georeferenced collection records of Lasioglossum (D.) clavicorne sp. nov. (black squares) and predicted distribution by maximum entropy ecological niche modeling in Maxent (colour shading). Warmer colours indicate higher cloglog probability of occurrence. The predicted distribution was generated with a regularization multiplier of 0.5 to obtain a more conservative prediction. Due to the very small number of records, this distribution should be interpreted with caution.

Fig. 106. Ocellocular area. A. Lasioglossum (D.) clavicorne sp. nov., ♀, sparsely and distinctly punctate. B. L. (D.) clematisellum (Cockerell, 1904), ♀, densely punctate with punctures somewhat obscured by microsculpture. Scale bar: 0.25 mm.