Lasioglossum (Dialictus) decorum, 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 : 69-73

Lasioglossum (Dialictus) decorum sp. nov.

urn:lsid:zoobank.org:act:6516BD4E-BBFE-48CB-82D0-6420F8C2748A

Figs 31–33 , 100B

Diagnosis

Females of Lasioglossum decorum sp. nov. can be recognized by the head and mesosoma with strong tessellate microsculpture, acarinarial fan dense but incomplete with a wide central gap, T1 anterior surface coriarious, T2–3 with small but distinct basolateral patches of tomentum and T4 with sparse tomentum, pronotal angle obtuse, ocelli somewhat enlarged (separated by ~0.5 OD), and T2 lacking dark spiracular spots. They are most similar to L. austerum sp. nov., L. torrens sp. nov., and L. meteorum sp. nov. All of these species have a weak acarinarial fan and normal ocelli. In addition, females of L. austerum sp. nov. have the metasomal terga without tomentum and T2 with dark spiracular spots. Females of L. torrens sp. nov. have the postgena and T1 anterior surface shiny, pronotal angle nearly 90 degrees, and T2 with dark spiracular spots. Females of L. meteorum sp. nov. have the scutum duller and more sparsely punctate (i= 1–4 pd) and metasoma with less extensive tomentum.

Males of L. decorum sp. nov. can be recognized by the frons dull with crowded punctures (i=0 pd) becoming reticulate above antenna sockets, rims of T1–3 impunctate, tomentum largely absent except on paraocular area and pronotum, mesepisternum shiny and sparsely punctate (i=1–2 pd), propodeum smooth with metapostnotal rugae not reaching the posterior margin, and clypeus distinctly projecting below the eyes. They are most similar to L. austerum sp. nov. and L. arenisaltans sp. nov. Males of L. austerum sp. nov. have the frons punctures distinctly separated, clypeus not strongly projecting below the eyes, and rims of T1–3 sparsely punctate medially (i =1–4 pd). Males of L. arenisaltans sp. nov. have the flagellomeres relatively longer (F2 about 1.75 times as long as F1), metapostnotum with strong rugae reaching the posterior margin, mesepisternum densely punctate (i ≤ 1 pd) and rims of T1–3 moderately densely punctate (i=1–3 pd).

Etymology

The specific epithet decorum is formed from the Latin adjective ‘ decorus ’ (‘decorated’, ‘beautiful’, ‘proper’). It refers to the similarity of this species with L. austerum sp. nov., except adorned with more hair and inhabiting the tropical regions of southern Mexico. An appropriate translation would be the decorated sweat bee.

Material examined

Holotype

MEXICO – Jalisco • ♀; Puerto Vallarta ; 20.6214° N, 105.226° W; 8 Dec. 1984; G.E. Bohart leg.; BBSL.

[Verbatim label: Mexico: Jalisco Puerto Vallarta N20.6214 W105.2260 8 Dec 1984 G.E. Bohart / BBSL1100700 // MEXICO Jalisco / Puerto Vallarta / 8 Dec 1984 / G. E. Bohart // HOLOTYPE / Lasioglossum (Dialictus) decorum Gardner and Gibbs ]

Paratypes

MEXICO – Jalisco • 1 ♀; Careyes ; 19.4289° N, 105.0274° W; 12 Feb.–19 Mar. 1997; F.D. Parker leg.; BBSL • 2 ♂♂; Guadalajara; [20.65° N, 103.35° W]; Crawford leg.; USNM . – Morelos • 1 ♀; 8 mi. S. of Yautepec; [18.76° N, 99.06° W]; 16 Aug. 1962; Roberts and Marston leg.; SEMC .

Description

Female

COLOURATION. Head and mesosoma blue-green to olive green; clypeus apical colour orange; labrum reddish brown to orange; mandible orange with black basal spot and red tip; flagellum reddish brown; pronotal lobe orange; metasoma orange to reddish brown with dark spiracular spots on T3–4; legs reddish brown with femur-tibia joints, base and apex of tibiae, inner surface of fore tibia, and tarsi orange; tegula orange; wing membrane infuscated, veins dark brown.

PUBESCENCE. Body hair colour white to pale yellow. Tomentum dense on pronotal collar and lobe, space between pronotal lobe and tegula, and T2–3 basolaterally; sparse on paraocular area, gena, and T4 throughout. Scutum hair thin. Wing hairs dark, long and dense. Acarinarial fan incomplete, dense. T2 fringes sparse, T3 fringes sparse.

SURFACE SCULPTURE. Clypeus punctures sparse (i =1–3 pd), sculpture shiny, becoming weakly imbricate basally; supraclypeal area punctures sparse (i=1–3 pd), sculpture tessellate, becoming shiny medially; paraocular area punctures dense to moderately sparse (i ≤ 2 pd), sculpture tessellate to imbricate around antenna socket, otherwise shiny; frons punctures dense (i <1 pd) to crowded (i= 0 pd), sculpture finely reticulate to rugulose, becoming smooth and shiny to imbricate dorsally; vertex punctures moderately dense laterally (i=1–2 pd), sparse medially (i=1–3 pd), sculpture shiny, sometimes weakly rugulose laterally; gena punctures fine, moderately dense (i =1–2 pd), sculpture shiny, becoming lineolate posteriorly and ventrally; postgena sculpture lineolate to tessellate; tegula punctures absent; scutum punctures dense (i ≤ 1 pd), becoming moderately sparse submedially and anteromedially (i =1–3 pd), sculpture shiny to weakly tessellate, becoming more strongly tessellate anteromedially; scutellum punctures moderately sparse marginally and on median line (i=1–2 pd), sparse submedially (i =1–4 pd), diversopunctate, sculpture shiny, becoming weakly tessellate marginally; metanotum sculpture imbricate, sometimes finely and densely punctate medially (i <1 pd); metapostnotum rugae strong, subparallel or anastomosing, not reaching margin, sculpture tessellate to finely reticulate; preëpisternum sculpture imbricate and weakly rugulose; hypoepimeron punctures moderately sparse (i= 1–2 pd), obscure, sculpture tessellate to finely reticulate; mesepisternum punctures moderately sparse (i= 1–2 pd), sculpture tessellate to finely reticulate; metepisternum sculpture lineate dorsally, imbricate ventrally; propodeum lateral face sculpture tessellate; propodeum posterior face sculpture tessellate; T1 anterior face sculpture coriarious; T1 dorsal surface punctures fine, sparse (i= 1–4 pd), absent in narrow median line, large apicolateral patches, and on rim, sculpture shiny; T2 disc punctures fine, sparse (i=1–3 pd), disc sculpture shiny, rim punctures minute, sparse (i=2–4 pd), hardly visible, rim sculpture weakly coriarious.

STRUCTURE. Face length/width ratio 0.87 (± 0.02 SD). Clypeus projecting ~67% below suborbital tangent; clypeal area length/width ratio 0.48 (± 0.06 SD); apicolateral denticles rounded knobs; supraclypeal area length/width ratio 0.79 (± 0.02 SD). Ocelli separated by about 0.5 OD. Forewing with 3 submarginal cells; pronotal angle obtuse; tegula shape normal. Intertegular distance 0.9 (± 0.03 SD) mm. Scutum length/ width ratio 0.77 (± 0.01 SD); scutum/scutellum length ratio 2.67 (± 0.01 SD); scutellum/metanotum length ratio 1.62 (± 0.12 SD); metanotum/metapostnotum length ratio 0.71 (± 0.1 SD). Propodeum lateral carinae not reaching dorsal margin; oblique carina absent. T2 depressed apical rim length less than 50% of segment. (n=3)

Male

COLOURATION. Head and mesosoma blue-green to golden-green; clypeus apical colour orange; labrum orange; mandible orange with black basal spot and red tip; flagellum black to reddish brown, F2–5 becoming light brown ventrally; pronotal lobe orange; metasoma black to reddish brown with rims of terga and sterna and downcurved lateral areas of terga broadly translucent brown; legs reddish brown with femur-tibia joints, tarsi, and sometimes tibiae orange; tegula orange; wing membrane infuscated, veins dark brown.

PUBESCENCE. Body hair colour pale yellow to white. Tomentum dense on pronotal angle and lobe, and space between pronotal lobe and tegula; sparse on paraocular area. Scutum hair thin. Sterna hair moderately long (1–2 OD), densely plumose, dense and erect. Wing hairs dark, long and dense.

SURFACE SCULPTURE. Clypeus punctures sparse (i= 1–3 pd), sculpture shiny; supraclypeal area punctures sparse (i= 1–3 pd), sculpture shiny, becoming tessellate dorsally; paraocular area punctures moderately dense (i=1–2 pd), sculpture shiny; frons punctures crowded (i=0 pd), sculpture shiny to imbricate, becoming reticulate above antenna; vertex punctures moderately dense laterally (i=1–2 pd), sparse medially (i=1–3 pd), sculpture shiny to weakly imbricate; gena punctures moderately dense (i=1–2 pd), sculpture shiny, becoming imbricate posteriorly and ventrally; postgena sculpture shiny, becoming imbricate laterad of hypostomal carina; tegula punctures absent; scutum punctures moderately dense (i =1–2 pd), becoming sparse submedially (i =1–3 pd), sculpture shiny, becoming tessellate anteromedially; scutellum punctures sparse (i=1–5 pd), sculpture shiny; metanotum sculpture shiny and moderately densely punctate (i =1–2 pd), becoming imbricate laterally; metapostnotum rugae strong or weak, anastomosing, not reaching margin, sculpture imbricate; preëpisternum sculpture shiny and densely punctate (i <1 pd); hypoepimeron punctures dense (i ≤ 1 pd), sculpture shiny to weakly imbricate; mesepisternum punctures moderately sparse (i=1–2 pd), sculpture shiny; metepisternum sculpture lineate dorsally, imbricate ventrally; propodeum lateral face punctures obscure, sculpture tessellate to weakly rugulose; propodeum posterior face sculpture tessellate; T1 anterior face sculpture coriarious; T1 dorsal surface punctures sparse (i=1–4 pd), absent in large apicolateral oval patches, rim, and sometimes median line, sculpture shiny; T2 disc punctures sparse (i =1–4 pd), disc sculpture shiny, rim punctures absent, rim sculpture shiny.

STRUCTURE. Face length/width ratio 0.86 (± 0.02 SD). F1:pedicel length ratio 0.81 (± 0.07 SD); F2:F1 length ratio 1.52 (± 0.09 SD); F2 length/width ratio 1.52 (± 0.09 SD); F9 length/width ratio 1.26 (± 0.01 SD). Forewing with 3 submarginal cells; pronotal angle obtuse; tegula shape normal. Intertegular distance 0.71 (± 0.06 SD) mm. Scutum length/width ratio 0.91 (± 0.05 SD); scutum/scutellum length ratio 2.43 (± 0.33 SD); scutellum/metanotum length ratio 1.78 (± 0 SD); metanotum/metapostnotum length ratio 0.64 (± 0.08 SD). Propodeum lateral carinae not reaching dorsal margin; oblique carina absent. (n =2)

GENITALIA. Not examined.

Range

Jalisco and Morelos ( Fig. 33 ).

DNA barcodes

Not available.

Remarks

Rare. Only known from five specimens from four locations. The enlarged ocelli (similar to those of L. eophilus ) suggest that L. decorum sp. nov. may have low-light activity.

Figures

Fig. 31. Lasioglossum (D.) decorum sp. nov., ♀. A. Lateral habitus. B. Dorsal habitus. C. Face. D. Propodeum and metasoma. Scale bars: 1 mm.

Fig. 32. Lasioglossum (D.) decorum sp. nov., ♂. A. Dorsal habitus. B. Lateral habitus. C. Face. D. Propodeum and metasoma. Scale bars: 1 mm.

Fig. 33. Georeferenced collection records of Lasioglossum (D.) decorum 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. Due to the very small number of records, this distribution should be interpreted with caution.

Fig. 100. Forewings. A. Lasioglossum (D.) pallidellum (Ellis, 1914), ♂, with white hair, pale veins, and hyaline membrane. B. L. (D.) decorum sp. nov., ♀, with dark hair, dark veins, and lightly infuscated membrane. Scale bars: 1 mm.