Lasioglossum (Dialictus) atroglaucum ( Strand, 1913 )

Murao, Ryuki, Tadauchi, Osamu & Lee, Heung-Sik, 2015, Synopsis of Lasioglossum (Dialictus) Robertson, 1902 (Hymenoptera, Apoidea, Halictidae) in Japan, the Korean Peninsula and Taiwan, European Journal of Taxonomy 137, pp. 1-50 : 13-18

Lasioglossum (Dialictus) atroglaucum ( Strand, 1913)

Figs 4A , 5 A–C, 6, 7, 12A

Halictus atroglaucus Strand, 1913: 170 (holotype: SDEI, ♂; type locality: Suisharyo, Formosa).

Halictus atroglaucus – Hirashima 1957: 5.

Lasioglossum (Evylaeus) atroglaucum – Ebmer 2002: 860–861.

Diagnosis

This species is easily separated from other members of the atroglaucum subgroup by the male S4 having dense and curly plumose hairs ( Fig. 4A ) and by the shape of the gonostylus ( Fig. 7C ).

Material examined

Holotype

TAIWAN: ♂ (Code No. DEIGISHym10517), Suisharyo, 11 Oct. (Sauter leg., SDEI).

Additional material

TAIWAN: 1 ♂, Ya Kou, alt. 2800 m, Kao Hsiung Hsien, S-Taiwan, 1 Aug. 1986 (K. Baba, ELKU); 3 ♂♂, Yu Shih, (alt. 1900 m), Nao Tow Hsien, M-Taiwan, 4 Jul. 1986 (K. Baba, ELKU); 1 ♂, Hehuanxi, 23 Jun. 1976 (H. Makihara, ELKU).

Measurements (n= 5, unit mm)

BL = 5.57–7.29 (6.17 ±0.66), WL = 4.86–5.29 (5.06 ±0.22), HL = 1.29–1.42 (1.37 ±0.05), HW = 1.35– 1.39 (1.38 ±0.01), IOD = 0.24–0.29 (0.26 ±0.02), OOD = 0.23–0.26 (0.24 ±0.01), OCD = 0.16–0.19 (0.18 ±0.01, n= 4), UOD = 0.84–0.87 (0.85 ±0.02), MOD = 0.97–1.00 (0.99 ±0.02), LOD = 0.50–0.58 (0.55 ±0.03), IAD = 0.19–0.23 (0.21 ±0.01), AOD = 0.16–0.18 (0.16 ±0.01), CAL = 0.23–0.27 (0.25 ±0.02), CPL = 0.34–0.37 (0.35 ±0.01), EL = 1.00–1.10 (1.06 ±0.04), EW = 0.45–0.50 (0.49 ±0.02), GW = 0.25–0.35 (0.30 ±0.04), SPL = 0.31–0.34 (0.32 ±0.01), F1L = 0.13–0.16 (0.14 ±0.01), F2L = 0.27– 0.29 (0.28 ±0.01), F3L = 0.27–0.32 (0.31 ±0.02), F2W = 0.13–0.16 (0.15 ±0.01), MsW = 1.50–1.60 (1.55 ±0.06, n= 4), SCL = 0.34–0.38 (0.36 ±0.02), MNL = 0.18–0.23 (0.20 ±0.02), MPL = 0.30–0.34 (0.33 ±0.02), MtW = 1.00–1.15 (1.07 ±0.07).

Redescription

Male

COLORATION. Body black except for the following parts: head dark green and mesosoma metallic green; clypeus yellow on lower half; mandible reddish brown apically; flagellum blackish brown ventrally; tegula blackish brown translucent; tibial spur yellow; metasomal terga narrowly brown translucent apically. Wings transparent, veins and stigma brown.

PUBESCENCE. Body hairs whitish, and covered with erect and sparse fine, branched hairs except for the following parts: lower paraocular area with sparse tomentose; lower clypeus with sparse simple hairs; tibial and tarsal hairs nearly simple; disc of metasomal terga with sparse and simple short hairs; disc of S2–S3 apically with moderately dense fine, branched hairs; disc of S4 apically with dense and curly plumose hairs ( Fig. 4A ); disc of S5 with sparse short and simple hairs, mixed with sparse fine, branched hairs laterally; disc of S6 with sparse short and simple hairs.

HEAD. As long as wide; HW:HL = 1:0.99. Vertex rounded in frontal view. MOD:UOD:LOD = 1:0.86:0.56. IOD:OOD:OCD = 1:0.90:0.67. IAD:AOD = 1:0.76. Ocellocular and paraocular areas and frons dull,

with reticulate PP. Supraclypeal area weakly convex, dull, with sparse PP, IS distinctly tessellate (IS = 1–4). CPL:CAL = 1:0.72. Clypeus nearly flat, with sparse PP, IS weakly tessellate (IS = 1–4.5). EW:GW = 1:0.61. Genal area with straight ridges and distinct tessellation. Malar space linear. Occiput not carinate. Postgena weakly tessellate. Mandible edentate. Labrum ( Fig. 6C ) without basal elevation and distal process. Antenna long, reaching metasoma. F2L:F2W = 1:0.54; flagellum nearly flattened ventrally.

THORAX. Dorsolateral angle of pronotum obtuse; lateral surface without ridges; lateral lobe rounded. Tegula ovoid, nearly smooth. Mesoscutum ( Fig. 6D ) with moderately dense PP on marginal area,

gradually sparse toward anterior to medial areas; IS weakly tessellate anteriorly, but nearly smooth medially and posteriorly (IS = 0.5–2 in marginal area, 1.5–4.5 in anterior to medial areas); parapsidal line a narrow groove. Mesoscutellum with dense PP over entire surface, IS smooth (IS = 1–2). Metanotum weakly rugulose. Mesepisternum ( Fig. 6E ) shiny, with sparse PP over entire surface, IS smooth (IS = 1.5–6). SCL:MNL:MPL = 1:0.55:0.91. Propodeum: metapostnotum ( Fig. 6F ) gently inclined, with longitudinal ridges not reaching posterior margin; junction between metapostnotum and posterior surface smooth, not carinate; lateral surface weakly rugulose; posterior surface with lateral carina on lower half, without oblique carina. Fore trochanter narrow, longer than wide. Hind tibia without basitibial plate. Hind basitarsus slender, approximately 4.6 × as long as wide. Inner hind tibial spur finely serrate. Fore wing with three submarginal cells.

ABDOMEN. Discs of T1–T3 with sparse fine PP. T1 without lineolation. Lineolation on T2 basally, on T3–T5 over entire surface. Apical margin of S4–S6 nearly straight ( Fig. 5 A–C). S5 with shallow apical depression ( Fig. 5B ). S7–S8 ( Fig. 7E ): median process of S7 triangular, apex not exceeding S8; S8 without median process.

GENITALIA ( Fig. 7 A–D). Gonobase flat at bottom, ventral arms not connected with each other at upper ends; gonocoxite smooth, gently sloped in lateral view, inner dorsal margin angulate at the approximately basal half; gonostylus small and thin, bud-like in lateral view, located on top of gonocoxite, and with

sparse short and a few relatively long hairs; ventral retrorse lobe tongue-like, moderately long but not reaching gonobase, with dense short setae; penis valve higher than gonocoxite, with low cleft on top.

Female

Unknown.

Distribution

Taiwan.

Flight period

Male: late June to early August.

Flower records

Not recorded.

Figures

Fig. 4. Hairs on metasomal sterna in species of the atroglaucum subgroup, ♂. A. Lasioglossum (Dialictus) atroglaucum (Strand, 1913). B. Lasioglossum (Dialictus) virideglaucum Ebmer & Sakagami, 1994. C. Lasioglossum (Dialictus) yamanei Murao et al., 2006. D. Lasioglossum (Dialictus) negoroi Murao & Tadauchi, 2008, holotype. E. Lasioglossum (Dialictus) taiwanense Murao sp. nov., holotype.

Fig. 5. S4–S6 in species of the atroglaucum subgroup, ♂. — A–C. Lasioglossum (Dialictus) atroglaucum (Strand, 1913). — D–F. Lasioglossum (Dialictus) virideglaucum Ebmer & Sakagami, 1994. — G–I. Lasioglossum (Dialictus) yamanei Murao et al., 2006 — J–L. Lasioglossum (Dialictus) negoroi Murao & Tadauchi, 2008, paratype. — M–O. Lasioglossum (Dialictus) taiwanense Murao sp. nov., paratype. A, D, G, J, M: S4. B, E, H, K, N: S5. C, F, I, L, O: S6. Dotted area on S5 shows the apical depression. Scale bars: 0.2 mm.

Fig. 7. Lasioglossum (Dialictus) atroglaucum (Strand, 1913), ♂. A. Genitalia in ventral view. B. Genitalia in dorsal view. C. Genitalia in lateral view. D. Ventral retrorse lobe of genitalia. E. S7–S8. Scale bars: A–C, E = 0.2 mm, D = 0.1 mm.

Fig. 6. Lasioglossum (Dialictus) atroglaucum (Strand, 1913), ♂. A. General habitus. B. Head in frontal view. C. Labrum. D. Mesoscutum. E. Mesepisternum. F. Metapostnotum.