Lasioglossum (Dialictus) argammon, 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 : 23-27

Lasioglossum (Dialictus) argammon sp. nov.

urn:lsid:zoobank.org:act:AE9F3361-270B-4D1A-BA1C-83074AC69F50

Figs 11–12 , 95B

Diagnosis

Females of Lasioglossum argammon sp. nov. can be recognized by the face relatively long (length/width ratio ~0.91), episterna and metasomal terga mostly covered in dense tomentum, T1 anterior surface and scutum anterior portion with dull microsculpture, frons shiny with dense but distinctly separated punctures, mesosoma mostly densely punctate (i ≤ 1 pd) with sparser punctures (i =1–3 pd) limited to submedial areas of the scutum and scutellum, metasomal terga finely and moderately sparsely punctate (i =1–3 pd), pronotal angle obtuse, T2–4 with dark spiracular spots, ocelli normal (separated by more than two thirds of one OD), and relatively small size (ITD usually <1 mm). They are most similar to L. lilianae sp. nov. and are somewhat similar to L. hudsoniellum . Females of L. lilianae sp. nov. have the scutum and T1 anterior surface almost entirely shiny, scutum more sparsely punctate (i = 1–4 pd), ocelli slightly enlarged (separated by less than two thirds of one OD), and are larger (ITD usually> 1 mm). Females of L. hudsoniellum have T1 anterior surface shiny, metasomal terga usually with moderately large and dense punctures (i=1–2 pd), T2 lacking dark spiracular spots, and pronotal angle nearly 90 degrees.

The male of Lasioglossum argammon sp. nov. is unknown, but it is probably similar to that of L. lilianae sp. nov.

Etymology

The specific epithet argammon is formed from the Greek adjective ‘ argos ’ (‘bright’, ‘white’) and the genitive plural noun ‘ ammon ’ (‘of sands’). It refers to this species’ restricted distribution in and around the White Sands National Monument. An appropriate translation would be the White Sands sweat bee.

Material examined

Holotype

UNITED STATES – New Mexico • ♀; Otero Co., White Sands National Monument; [32.7° N, 106.3° W]; 16 Jul. 1991; B. Alexander leg.; ex Lepidium ; SEMC.

[ Verbatim label: NEW MEXICO:Otero Co. / White Sands Nat’l Mon. / 16 July 1991, B. Alexander / ex: Lepidium // HOLOTYPE / Lasioglossum (Dialictus) argammon Gardner and Gibbs ]

Paratypes

UNITED STATES – New Mexico • 2 ♀♀; 25 mi. W of Tularosa; [33.07° N, 106.45° W]; 1 Jul. 1940; D.E. Hardy leg.; SEMC • 2 ♀♀; Dona Ana Co.; 32.4435° N, 106.3992° W; 17 Nov. 2004 – 26 Feb. 2005; S.L. Buchmann and A.J. Donovan leg.; RLM . – Texas • 1 ♀; Hudspeth Co., Salt Flats , N of Hwy 62/180; 31.7563° N, 104.9909° W; 1105 m a.s.l.; 26 Jun. 2010; J. D. Herndon leg.; BBSL .

Description

Female

COLOURATION. Head and mesosoma blue-green to olive green; clypeus apical colour reddish brown to orange; labrum reddish brown to orange; mandible orange with black basal spot and red tip; flagellum reddish brown dorsally, orange ventrally; pronotal lobe reddish brown to orange; metasoma reddish brown to orange with dark spiracular spots on T2–4; legs reddish brown with femur-tibia joints, base and apex of tibiae, and tarsi mostly orange; tegula pale amber to orange; wing membrane hyaline, veins with subcosta dark brown, otherwise pale amber to brown.

PUBESCENCE. Body hair colour white. Tomentum dense on paraocular area, frons, gena, pronotal collar and lobe, space between pronotal lobe and tegula, margins of scutum, metanotum, episterna, T1 laterally, T2 basolaterally, and T3–4 throughout; sparse on clypeus and supraclypeal area. Scutum hair moderately plumose. Wing hairs light, long or short, and dense. Acarinarial fan complete, sparse. T2 fringes sparse, T3 fringes sparse.

SURFACE SCULPTURE. Clypeus punctures dense to sparse (i=1–4 pd), large and irregularly spaced apically (i <2 pd), sculpture shiny; supraclypeal area punctures dense (i ≤ 1 pd), sculpture shiny; paraocular area punctures dense (i <1 pd), sometimes crowded around antenna socket (i= 0 pd), sculpture shiny, sometimes weakly imbricate around antenna socket; frons punctures dense (i <1 pd), sculpture shiny; vertex punctures dense (i ≤ 1 pd), sometimes fine and sparse medially (i= 1–3 pd), sculpture shiny; gena punctures fine, moderately dense (i=1–2 pd), sculpture shiny; postgena sculpture shiny, becoming tessellate posteriorly; tegula punctures absent; scutum punctures dense (i ≤ 1 pd), becoming moderately dense to sparse submedially and anteromedially (i =1–3 pd), sculpture shiny to weakly tessellate, becoming more strongly tessellate anteromedially; scutellum punctures dense marginally and on median line (i <1 pd), sometimes finer and sparser anteriorly (i=1–2 pd), sparse submedially (i= 1–3 pd), diversopunctate, sculpture shiny, becoming weakly tessellate marginally; metanotum sculpture shiny and finely, densely punctate (i <1 pd), becoming weakly rugulose laterally; metapostnotum rugae strong, anastomosing, not reaching margin, sculpture tessellate; preëpisternum sculpture areolaterugulose; hypoepimeron punctures crowded (i= 0 pd), sculpture shiny; mesepisternum punctures crowded (i= 0 pd), sculpture shiny; metepisternum sculpture ruguloso-lineate dorsally, imbricate ventrally; propodeum lateral face sculpture tessellate; propodeum posterior face sculpture tessellate; T1 anterior face sculpture coriarious; T1 dorsal surface punctures moderately sparse (i=1–3 pd), absent or very sparse in large apicolateral oval patches, sculpture shiny; T2 disc punctures moderately sparse (i=1–3 pd), disc sculpture shiny, rim punctures minute, sparse (i= 2–6 pd), rim sculpture shiny.

STRUCTURE. Face length/width ratio 0.91 (± 0.01 SD). Clypeus projecting ~67% below suborbital tangent; clypeal area length/width ratio 0.42 (± 0.05 SD); apicolateral denticles rounded knobs; supraclypeal area length/width ratio 0.81 (± 0.07 SD). Forewing with 3 submarginal cells; pronotal angle obtuse; tegula shape normal. Intertegular distance 0.86 (± 0.05 SD) mm. Scutum length/width ratio 0.83 (± 0.05 SD); scutum/scutellum length ratio 3.14 (± 0.29 SD); scutellum/metanotum length ratio 1.65 (± 0.1 SD); metanotum/metapostnotum length ratio 0.58 (± 0.06 SD). Propodeum lateral carinae not reaching dorsal margin; oblique carina absent. T2 depressed apical rim length less than 50% of segment. (n =6)

Male

Unknown.

Range

Gypsum dunes of the White Sands Desert of New Mexico, southeast to Hudspeth County, Texas ( Fig. 12 ).

Floral records

BRASSICACEAE Burnett : Lepidium L.

DNA barcodes

One sequence available (BOLD process ID: DLIII160-19; BIN: BOLD:AEA0446). This sequence has greater than expected divergence from L. lilianae sp. nov. (4.7% p-distance), which appears to be closely related based on overall morphology. Phylogenetic analysis of DNA barcodes ( Fig. 7 ) suggests that L. argammon sp. nov. may be more closely related to L. mesillense . Lasioglossum argammon sp. nov. has no unique fixed substitutions among all western red-tailed L. ( Dialictus ).

Remarks

Rare. Only six specimens are known, all from gypsum dunes in southern New Mexico and western Texas.

Figures

Fig. 11. Lasioglossum (D.) argammon sp. nov., holotype, ♀. A. Dorsal habitus. B. Lateral habitus. C. Propodeum. D. Face. E. Metasoma. Scale bars: 1 mm.

Fig. 12. Georeferenced collection records of Lasioglossum (D.) argammon 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. 95. T1 anterior face. A. Lasioglossum (D.) kunzei (Cockerell, 1898), ♀, shiny with weak and worn acarinarial fan. B. L. (D.) argammon sp. nov., ♀, weakly coriarious with sparse acarinarial fan. C. L. (D.) rufornatum sp. nov., ♀, strongly coriarious with dense and well-developed acarinarial fan. Arrows point to areas where microsculpture is most easily visible. Scale bar is 0.5 mm.

Fig. 7. 50% majority-rule consensus tree of red-tailed Lasioglossum (Dialictus) and representatives of other major lineages of L. (D.) based on a Bayesian phylogenetic analysis of 654-bp CO1 barcode sequences downloaded from BOLD. MCMC tree search was run in MrBayes ver. 3.2.7 for 30000000 generations, using a GTR+I+Γ model of evolution, with L. (Austrevylaeus) sordidum (Smith, 1853) set as the outgroup. Node labels are posterior probabilities. Names in vermilion text are red-tailed species; BOLD process IDs are given before species names. In addition to the labeled red-tailed species, L. (D.) rufulipes (Cockerell, 1938) is hypothesized to be an additional lineage containing the red-tailed species L. (D.) testaceum (Robertson, 1897), for which CO1 barcodes were not available. As this phylogeny is based on very limited data, some relationships are likely misleading or incorrect (particularly those with low posterior probability); however, it serves to illustrate the point that the redtailed L. (Dialictus) are an unnatural grouping.