Lasioglossum (Dialictus) perditum, 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 : 161-166

Lasioglossum (Dialictus) perditum sp. nov.

urn:lsid:zoobank.org:act:71D0A259-8327-4C5B-8615-A7DF4C2F373B

Figs 6B , 70–72 , 94D

Diagnosis

Females of Lasioglossum perditum sp. nov. can be recognized by the characters for the Lasioglossum clematisellum species complex (below), in addition to their very small size (3.5 mm), forewing almost always with only two submarginal cells (a single specimen has three submarginal cells in one wing), and head and mesosoma very shiny and sparsely punctate (up to i=6 pd). They are most similar to L. julipile sp. nov. and L. spivakae sp. nov. Both of these species have the head and mesosoma more densely punctate (up to i= 3 pd) and forewing rarely with two submarginal cells. In addition, females of L. julipile sp. nov. are larger (4–4.5 mm) and L. spivakae sp. nov. have the face slightly longer (length/ width ratio ~0.87).

Males of L. perditum sp. nov. can be recognized by the same characters as for females. In addition, the propodeum lateral face is usually smooth and tessellate. They are most similar to L. julipile sp. nov., L. clematisellum , L. clastipedion sp. nov., and L. spivakae sp. nov. All of these species have the frons and vertex more densely punctate (up to i =2 pd) and propodeum lateral face usually rugulose. In addition, males of L. spivakae sp. nov. have T1–3 rims completely punctate to the apex with no change in sculpture across the premarginal line.

Etymology

The specific epithet ‘ perditum ’ is a Latin perfect participle meaning ‘lost’. It refers to this species’ extremely small size and two submarginal cells, which is reminiscent of the bee genus Perdita Smith, 1853 . An appropriate translation would be the lost sweat bee.

Material examined

Holotype

UNITED STATES – Texas • ♀; Big Bend N.P., Santa Elena Can.; [29.165° N, 103.612° W]; 640 m a.s.l.; 5 May 1959; W.R.M. Mason leg.; CNC.

[Verbatim label: Big Bend N.P.TEX. / Santa Elena Can. / 2100 ft. May 5 / W.R.M. Mason 1959 // HOLOTYPE / Lasioglossum (Dialictus) perditum Gardner and Gibbs ]

Paratypes

UNITED STATES – New Mexico • 1 ♂; Eddy Co.; 32.1095° N, 104.4716° W; 1115 m a.s.l.; 2 Aug. 2010; J.D. Herndon and A. Druk leg.; ex Asclepias subverticillata ; BBSL . – Texas • 1 ♂; same collection data as for holotype; BBSL • 1 ♀, 1 ♂; same location as for holotype; 9 May 1959; W.R.M. Mason leg.; BBSL • 7 ♀♀, 14 ♂♂; same collection data as for holotype; CNC • 4 ♀♀, 2 ♂♂; same location as for holotype; 9 May 1959; W.R.M. Mason leg.; CNC .

Description

Female

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

PUBESCENCE. Body hair colour white. Tomentum dense on paraocular area, gena, pronotal collar and lobe, space between pronotal lobe and tegula, metanotum medially, metepisternum, narrow basal band on T2–3, 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 complete, very sparse. T2 fringes sparse, T3 fringes sparse.

SURFACE SCULPTURE. Clypeus punctures irregularly sparse (i ≤ 2 pd), sometimes becoming dense in basal half (i <1 pd), sculpture shiny, sometimes weakly imbricate basally; supraclypeal area punctures sparse (i =1–6 pd), sometimes becoming dense laterally (i ≤ 1 pd), diversopunctate, sculpture shiny; paraocular area punctures large and moderately sparse (i=1–2 pd) to extremely minute and sparse (i= 2–4 pd), sculpture shiny; frons punctures fine and moderately sparse (i=1–2 pd) to extremely minute and sparse (i =2–6 pd), sculpture shiny; vertex punctures minute, sparse (i=2–6 pd), sculpture shiny; gena punctures minute, sparse (i = 2–4 pd), sculpture shiny; postgena sculpture tessellate to weakly so; tegula punctures absent; scutum punctures moderately dense (i =1–2 pd), becoming sparse (i =1–5 pd) and sometimes minute laterally and anteromedially, sculpture shiny, becoming tessellate anteromedially; scutellum punctures sparse (i =1–5 pd), sometimes becoming dense posteriorly (i <1 pd), diversopunctate, sculpture shiny to tessellate; metanotum sculpture shiny and minutely, sparsely punctate (i=1–4 pd), sometimes weakly rugulose; metapostnotum rugae weak, highly anastomosing, reaching margin, or sometimes absent, sculpture tessellate; preëpisternum sculpture shiny with crowded punctures (i=0 pd), sometimes slightly sparser (i ≤ 1 pd); hypoepimeron punctures large and crowded (i= 0 pd) to minute and sparse (i=2–6 pd), sculpture shiny; mesepisternum punctures large and crowded (i=0 pd) to minute and sparse (i =2–6 pd), sculpture shiny; metepisternum sculpture ruguloso-lineate dorsally, weakly rugulose ventrally; propodeum lateral face sculpture tessellate; propodeum posterior face sculpture tessellate; T1 anterior face sculpture shiny; T1 dorsal surface punctures sparse (i= 1–5 pd), becoming finer or obscure on rim and absent in large apicolateral oval patches, sculpture shiny; T2 disc punctures sparse (i =1–4 pd), disc sculpture shiny, rim punctures sparse (i= 1–4 pd), sometimes minute and obscure, rim sculpture shiny to weakly coriarious.

STRUCTURE. Face length/width ratio 0.82 (± 0.03 SD). Clypeus projecting ~50% below suborbital tangent; clypeal area length/width ratio 0.38 (± 0.03 SD); apicolateral denticles very low rounded knobs; supraclypeal area length/width ratio 0.76 (± 0.12 SD). Forewing with 2 submarginal cells; pronotal angle obtuse; tegula shape normal. Intertegular distance 0.67 (± 0.03 SD) mm. Scutum length/width ratio 0.82 (± 0.05 SD); scutum/scutellum length ratio 3.31 (± 0.19 SD); scutellum/metanotum length ratio 1.39 (± 0.11 SD); metanotum/metapostnotum length ratio 0.65 (± 0.07 SD). Propodeum lateral carinae not reaching dorsal margin; oblique carina absent. T2 depressed apical rim length less than 50% of segment. (n =10)

Male

COLOURATION. Head and mesosoma blue to olive green; clypeus apical colour black to reddish brown; labrum reddish brown to orange; mandible orange with black basal spot and red tip; flagellum reddish brown dorsally, orange to brown ventrally; pronotal lobe reddish brown; metasoma black to dark reddish brown with rims of terga and sterna broadly translucent reddish brown and downcurved lateral areas of terga becoming translucent orange; legs black to reddish brown with femur-tibia joints, base and apex of tibiae, and tarsi orange to yellow; tegula orange to pale amber; wing membrane hyaline, veins with subcosta dark brown, otherwise brown 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, metepisternum, and mesosterna; sparse on preëpisternum, mesepisternum, and T2–3 basolaterally. Scutum hair densely plumose. Sterna hair short (0.75–1.25 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 moderately dense (i=1–2 pd), sculpture shiny; frons punctures sparse (i =1–3 pd), sculpture shiny; vertex punctures fine, sparse (i =1–4 pd), sometimes larger and denser laterally (i=1–2 pd), sculpture shiny; gena punctures moderately dense (i=1–2 pd), sculpture shiny; postgena sculpture shiny to imbricate, sometimes lineolate; tegula punctures absent; scutum punctures sparse (i= 1–5 pd), becoming moderately dense posteriorly and on median line (i=1–2 pd), sculpture shiny, sometimes becoming weakly tessellate anteromedially; scutellum punctures sparse (i =1–5 pd), sometimes becoming moderately dense posteriorly (i=1–2 pd), sculpture shiny; metanotum sculpture shiny and moderately densely punctate (i=1–2 pd), becoming rugulose laterally; metapostnotum rugae strong or weak, anastomosing, nearly reaching margin, sculpture shiny to imbricate; preëpisternum sculpture areolate; hypoepimeron punctures moderately dense (i =1–2 pd), sculpture shiny; mesepisternum punctures moderately dense (i=1–2 pd), sculpture shiny; metepisternum sculpture lineate dorsally, areolate ventrally; propodeum lateral face punctures dense (i ≤ 1 pd), often obscure, sculpture tessellate to rugulose; propodeum posterior face sculpture shiny and sparsely punctate (i=1–3 pd); T1 anterior face sculpture shiny; T1 dorsal surface punctures moderately dense (i=1–2 pd), becoming sparse laterally and in small apicolateral oval patches (i =1–4 pd), sculpture shiny; T2 disc punctures moderately dense (i= 1–2 pd), becoming sparse laterally and in small apicolateral oval patches (i= 1–4 pd), disc sculpture shiny, rim punctures sparse medially (i=1–4 pd), absent laterally, rim sculpture shiny.

STRUCTURE. Face length/width ratio 0.84 (± 0.04 SD). F1:pedicel length ratio 0.9 (± 0.14 SD); F2:F1 length ratio 1.75 (± 0.17 SD); F2 length/width ratio 1.39 (± 0.23 SD); F9 length/width ratio 1.26 (± 0.14 SD). Forewing with 2 or 3 submarginal cells; pronotal angle obtuse; tegula shape normal. Intertegular distance 0.65 (± 0.06 SD) mm. Scutum length/width ratio 0.84 (± 0.04 SD); scutum/scutellum length ratio 3.13 (± 0.31 SD); scutellum/metanotum length ratio 1.55 (± 0.19 SD); metanotum/metapostnotum length ratio 0.64 (± 0.06 SD). Propodeum lateral carinae not reaching dorsal margin; oblique carina absent. (n =10)

GENITALIA. Not examined.

Range

Chihuahuan Desert of southeastern New Mexico and western Texas ( Fig. 72 ).

Floral records

APOCYNACEAE Juss. Asclepias L. A. subverticillata (A.Gray) Vail.

DNA barcodes

Not available.

Remarks

Rare, but may be locally common in some areas. Lasioglossum perditum sp. nov. is only known from a single specimen from Carlsbad Caverns National Park and a relatively long series from Big Bend National Park.

Figures

Fig. 6. Two-dimensional representation of clusters created by PAM. A. ♀♀. B. ♂♂. Actual species identifications are indicated by the colour of filled centre points, and cluster assignments by PAM are indicated by borders around each point. Black borders in B indicate a second cluster corresponding to L. (D.) perditum sp. nov.

Fig. 70. Lasioglossum (D.) perditum sp. nov., ♀. A. Dorsal habitus. B. Lateral habitus. C. Face. D. Propodeum and metasoma. Scale bars: 1 mm.

Fig. 71. Lasioglossum (D.) perditum sp. nov., ♂. A. Dorsal habitus. B. Lateral habitus. C. Face. D. Propodeum and metasoma. Scale bars: 1 mm.

Fig. 72. Georeferenced collection records of Lasioglossum (D.) perditum 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. 94. Variation in frons punctation. A. Lasioglossum (D.) tessellatosum sp. nov., ♀, reticulatepunctate to ruguloso-punctate with crowded punctures. B. L. (D.) meteorum sp. nov., ♀, fine and dense but distinctly separated punctures. C. L. (D.) julipile sp. nov., ♀, moderately sparsely punctate. D. L. (D.) perditum sp. nov., ♀, very sparsely punctate. Scale bars: 0.5 mm.