Lasioglossum (Dialictus) testaceum ( Robertson, 1897 )

Gardner, Joel & Gibbs, Jason, 2020, The ‘ red-tailed’ Lasioglossum (Dialictus) (Hymenoptera: Halictidae) of the western Nearctic, European Journal of Taxonomy 725, pp. 1-242 : 192-195

Lasioglossum (Dialictus) testaceum ( Robertson, 1897)

Figs 84 , 90O , 96A , 98A

Halictus testaceus Robertson, 1897: 323 (lectotype designated by W.E. LaBerge in Webb 1980, ♀, deposited in INHS, examined).

Halictus (Chloralictus) scrophulariae Cockerell, 1906: 428 (holotype, ♀, deposited in USNM, examined; synonymy by Gibbs 2011).

Halictus (Chloralictus) occultus Sandhouse, 1924: 27 (holotype, ♂, deposited in USNM, examined; name preoccupied due to primary homonymy with Halictus occultus Vachal, 1904 ).

Lasioglossum (Chloralictus) sandhouseae Michener, 1951: 1117 (catalog, replacement name for H. (C.) occultus Sandhouse, 1924 ; synonymy by Gibbs 2011).

Chloralictus testaceus – Robertson 1902 b: 249 (key).

Halictus (Chloralictus) scrophulariae – Sandhouse 1924: 4 (key).

Lasioglossum (Chloralictus) scrophulariae – Michener 1951: 1117 (catalog).

Lasioglossum (Chloralictus) testaceum – Michener 1951: 1118 (catalog).

Dialictus sandhouseae – Mitchell 1960: 418, fig. 102 (key, redescription). — Hurd 1979: 1971 (catalog). — Moure & Hurd 1987: 129 (catalog).

Dialictus testaceus – Mitchell 1960: 424 (key, redescription). — Hurd 1979: 1972 (catalog). — Moure & Hurd 1987: 135 (catalog).

Dialictus scrophulariae – Hurd 1979: 1971 (catalog). — Moure & Hurd 1987: 129 (catalog).

Lasioglossum (Dialictus) sandhouseae – Krombein 1967: 466 (catalogue).

Lasioglossum testaceum – Donovall & van Engeldorp 2010: 18 (checklist).

Lasioglossum (Evylaeus) testaceum – Gibbs 2010: 42, fig. 9b (key). — Scott et al. 2011: 32 (checklist).

Lasioglossum (Dialictus) testaceum – Wolf & Ascher 2009: 144 (checklist). — Gibbs 2011: 197 , figs 213–217 (key, redescription).

Diagnosis

Females of Lasioglossum testaceum are readily identified by the propodeum with strong dorsoventral and oblique carinae, and T1 with sparse erect hairs and no acarinarial fan. This combination is unique among Nearctic L. ( Dialictus ) except for L. rufulipes (Cockerell, 1938) , which has a dark metasoma, T4 with sparser tomentum, and a boreal distribution, and L. aquilae , which has the metasoma dark metallic green.

Males of L. testaceum can be recognized by the face short (length/width ratio ~0.81), clypeus apical half pale yellow, propodeum dorsolateral slope and posterior face rugose, propodeum lateral face smooth and tessellate, and retrorse lobe very narrow. They are most similar to L. zephyrus and L. pictum . Both of these species have the clypeus apical margin dark or much more narrowly yellow, retrorse lobes much broader, and face slightly longer. In addition, males of L. pictum have the scutum and mesepisternum with larger and denser punctures (i=1–2 pd) and propodeum lateral face rugulose.

Etymology

Robertson (1897) named this species with the Latin adjective ‘ testaceus ’ (brick-like).

Material examined

Lectotype

UNITED STATES – Illinois • ♀; Macoupin Co., Carlinville ; [39.28° N, 89.88° W]; 11 Apr. 1896; C. Robertson leg.; INHS.

Other material

CANADA – Alberta • 1 ♀; Writing-On-Stone Prov. Pk.; [49.09° N, 111.62° W]; 26 May–6 Jun. 1990; D. McCorquodale leg.; WRME. – British Columbia • 1 ♂; 5 mi. S of Hedley; [49.29° N, 120.04° W]; 24 Jul. 1985; Finnamore and Thormin leg.; PMAE .

UNITED STATES – Colorado • 2 ♀♀; Alamosa Co., 4 mi. SW of Alamosa (intersection 370 and S106); 37.42738° N, 105.92846° W; 2301 m a.s.l.; 25 May 2001; Va. Scott leg.; ex Salix (staminate); UCMC • 1 ♀; El Paso Co., Ramah ; [39.12° N, 104.17° W]; 15 Jun. 1971; Michener and Schorr leg.; ex Salix sp.; SEMC • 1 ♀; same location as for preceding; 15 Jun. 1971; C. Michener and R. Schorr leg.; ex Salix ; SEMC • 2 ♀♀; Fremont Co., 5 mi. SW of Coaldale ; [38.31° N, 105.82° W]; 10 Jun. 1971; C. Michener and R. Schorr leg.; ex Salix ; SEMC • 1 ♀; same location as for preceding; 10 Jun. 1971; C. Michener and R. Schorr leg.; ex Rhus trilobata ; SEMC • 2 ♀♀; Fremont Co., Coaldale ; [38.37° N, 105.76° W]; 11 Jun. 1971; C. Michener and R. Schorr leg.; ex Salix ; SEMC • 1 ♀; Jackson Co., Lake John ; 40.7862° N, 106.4692° W; 2461 m a.s.l.; 27 Jun. 2014; T. McIntyre and F.D. Parker leg.; BBSL • 1 ♀; Park Co., N. Fk. S. Platte R., 0.2 mi. E of Bailey; [39.404° N, 105.47° W]; 11 Jun. 1988; E. Bergey leg.; CSUC • 1 ♂; Routt Co., 4 mi. E of Clark; [40.71° N, 106.84° W]; 29 Aug. 1979; U.N. Lanham leg.; ex Solidago ; UCMC • 1 ♀; Teller Co., S base of Blue Mtn., nr Florissant ; [38.923° N, 105.327° W]; 2568 m a.s.l.; 1 Aug. 1966; T. Emmel and M. Fosdick leg.; LACM • 1 ♀; Weld Co., 2–4 mi. W of Orchard; [40.33° N, 104.18° W]; 14 May 1992; M.G. Galindo and R.S. Beal leg.; ex Salix ; CSUC • 3 ♂♂; 8 mi. NW of Steamboat Spgs.; [40.57° N, 106.94° W]; 28 Aug. 1979; U.N. Lanham leg.; ex Solidago ; UCMC • 3 ♀♀; 9 mi. N of Arboles; [37.15° N, 107.36° W]; 27 May 1977; U. Lanham and P. Byron leg.; ex Salix ; UCMC • 1 ♂; Florissant ; [38.95° N, 105.29° W]; 23 Jul. year unknown; Cockerell leg.; ex Potentilla ; USNM • 1 ♀; same location as for preceding; 25 Jul. year unknown; Cockerell leg.; ex Scrophularia ; USNM . – Minnesota • 1 ♀; 43.7509° N, 91.6541° W; 20 Jun. 2014; S. Leddy leg.; ex Rudbeckia triloba ; WRME . – Utah • 1 ♀; Uintah Co., Bonanza ; [40.02° N, 109.18° W]; Jul. 1977; G. Bohart leg.; BBSL . – Wyoming • 1 ♀; Lincoln Co., Salt Creek ; 42.4667° N, 110.9678° W; 2027 m a.s.l.; 14 Aug. 2014; J.B. Runyon leg.; MTEC .

Description

See Gibbs (2010) for a complete redescription and figures.

Range

Rocky Mountains from British Columbia southeast to New Mexico, east through the Great Plains to Illinois ( Fig. 84 ).

Floral records

ANACARDIACEAE R.Br. Rhus L. R. trilobata Nutt. • APOCYNACEAE Juss. Asclepias L. A. speciosa Torr. (G11) • ASTERACEAE Giseke : Anaphalis (G11) • Nothocalais : N. cuspidata (Pursh) Greene (G11) • Rudbeckia : R. triloba L. • Solidago • Taraxacum (G11) • FABACEAE Juss. Amorpha : A. canescens Pursh (G11) • GROSSULARIACEAE DC. Ribes L. R. valicola Greene (G11) • ONAGRACEAE Juss. Epilobium L. (G11) • POLYGONACEAE Juss. Eriogonum Michx. E. annuum Nutt. (G11) • ROSACEAE Juss. Dasiphora Raf. D. fruticosa (L.) Rydb. (G11) • Potentilla L. • Prunus L. (G11) • Spiraea L. (G11) • SALICACEAE Mirb. Salix L. S. brachycarpa Nutt. (G11) • S. eriocephala Michx. (G11) • SCROPHULARIACEAE Juss. Scrophularia L.

DNA barcodes

Not available. Lasioglosusm testaceum is morphologically similar to L. rufulipes , for which 3 sequences are available (BOLD process IDs: DLII1138-08, DLII1140-08, DLII1142-08). Barcodes of L. testaceum are expected to be similar to those of L. rufulipes , as these are very likely sister species. Phylogenetic analysis of COI barcodes and other genes of L. rufulipes suggest it is a distinct lineage relatively distantly related from the major clade of New World L. ( Dialictus ) ( Gibbs et al. 2012b; Fig. 7 ).

Figures

Fig. 84. Georeferenced collection records of Lasioglossum (D.) testaceum (Robertson, 1897) (black squares) and predicted distribution by maximum entropy ecological niche modeling in Maxent (colour shading). Warmer colours indicate higher cloglog probability of occurrence.

Fig. 90. Male genitalia. A. Lasioglossum (D.) arenisaltans sp. nov. B. L. (D.) clastipedion sp. nov. C. L. (D.) clematisellum (Cockerell, 1904). D. L. (D.) hudsoniellum (Cockerell, 1919). E. L. (D.) julipile sp. nov. F. L. (D.) lilianae sp. nov. G. L. (D.) mesillense (Cockerell, 1898). H. L. (D.) meteorum sp. nov. I. L. (D.) miltolepoides sp. nov. J. L. (D.) minckleyi sp. nov. K. L. (D.) pallidellum (Ellis, 1914). L. L. (D.) pictum (Crawford, 1902). M. L. (D.) rufornatum sp. nov. N. L. (D.) spivakae sp. nov. O. L. (D.) testaceum (Robertson, 1897).P. L. (D.) vierecki (Crawford, 1904). Q. L. (D.) zephyrus (Smith, 1853). Genitalia are illustrated in dorsal view and positioned such that the gonostylus is parallel to the plane of vision. Retrorse lobes are also illustrated separately to the bottom left of each figure in lateral view, positioned parallel to the plane of vision.

Fig. 96. T1 anterior face. A. Lasioglossum (D.) testaceum (Robertson, 1897), ♀, acarinarial fan absent with erect hairs throughout. B. L. (D.) clastipedion sp. nov., ♀, acarinarial fan present but weak, with erect hairs restricted to lateral margins. Scale bars: 0.5 mm.

Fig. 98. Propodeum. A. Lasioglossum (D.) testaceum (Robertson, 1897), ♀, with strong oblique carina (arrow). B. L. (D.) minckleyi sp. nov., ♀, without oblique carina. Scale bars: 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.