Lasioglossum (Hemihalictus) ikudomei, Murao, 2021

Murao, Ryuki, 2021, Redefinition of the sexstrigatus group of Lasioglossum (Hemihalictus) Cockerell, 1897 (Hymenoptera, Apoidea, Halictidae), with a revision of Japanese species, European Journal of Taxonomy 763, pp. 1-74 : 14-18

Lasioglossum (Hemihalictus) ikudomei sp. nov.

urn:lsid:zoobank.org:act:2F66A01B-2176-4764-8DB7-59D53A335FB5

Figs 5 , 15B , 18D , 20B

Diagnosis

Females are similar to Lasioglossum (Hemihalictus) smilodon Ebmer & Sakagami, 1994 from Japan but are separated from them by the supraclypeal area shinier (IS weakly tessellate), the PP on the mesoscutum sparser (IS=3 d in maximum) ( Fig. 5E ), and T1 with very weak lineolation. In contrast, in L. (H.) smilodon , the supraclypeal area is dimly shiny (IS distinctly tessellate), the PP on the mesoscutum denser (IS = 2 d at maximum) ( Fig. 9E ), and the lineolation of T1 clearer.

Etymology

The specific name is dedicated to Dr Shuichi Ikudome (KWC), who contributed greatly to clarify the bee fauna of Ryukyus Islands, southwestern Japan.

Material examined

Holotype JAPAN – Ryukyus • ♀; Okinawa Pref., Miyako-jima, Henna-zaki ; 3 Jul. 1992; S. Ikudome leg.; ELKU. [Verbatim label:MIYAKO-JIMA/ Henna-zaki/Okinawa Pref./ 3.VII.1992 /S.Ikudome leg.//HOLOTYPE // Lasiioglossum (Hemihalictus) ikudomei Murao ]

Paratypes JAPAN – Ryukyus • 1 ♀; Yoron Is ., Maeno-hama ; 4 Jun. 1989; KWC • 1 ♀; Okinawa Pref., Kunigami, Hedo ; 5 Apr. 1979; K. Kusigemati leg.; ELKU • 2 ♀♀; Okinawa Pref., Hedo ; 5 Apr. 1979; K. Ohara leg.; ELKU • 2 ♀♀; Okinawa Pref., Kunigami-gun, Kunigami-son, Cape Hedo ; 26°52′ N, 128°15′ E; 2 Apr. 2017; K. Otsui leg.; cMur • 1 ♀; Okinawa Pref., Okinawa-jima, Kunigami-gun, Kunigami-son , Ada ; 22 Aug. 2007; Y. Nishimura leg.; cMur • 1 ♀; Miyako Is ., Nishi-heana ; 27 Mar. 1995; T. Matsumura leg.; ELKU • 1 ♂; Okinawa Pref., Miyako-jima, Henna-zaki ; 3 Jul. 1992; S. Ikudome leg.; ELKU • 1 ♀; Okinawa Pref., Iriomote Is. ; 16–17 Mar. 2005; Y. Maeta leg.; SULE .

Description

Female

MEASUREMENTS (n=5, unit mm). BL =5.13–5.63 (5.43± 0.23), WL= 4.25–4.88 (4.65 ± 0.26), HL=1.55– 1.65 (1.61 ±0.04), HW= 1.48–1.65 (1.57± 0.06), IOD =0.26–0.29 (0.28 ± 0.02), OOD=0.24–0.31 (0.26 ± 0.02), OCD =0.18–0.19 (0.19± 0.01, n=4), UOD =0.94–1.03 (0.98 ±0.04), MOD =1.10– 1.23 (1.15± 0.05), LOD =0.84–0.94 (0.88± 0.04), IAD =0.15–0.16 (0.16 ± 0.01), AOD=0.26–0.31 (0.28 ± 0.02), CAL =0.29–0.32 (0.31± 0.01), CPL=0.34–0.37 (0.35 ±0.01), EL=1.75–1.85 (1.80± 0.04), EW =0.39–0.45 (0.41± 0.04), GW=0.29–0.39 (0.35 ± 0.04), SPL=0.61–0.66 (0.64 ± 0.02), F1L=0.10 (0.10 ± 0.00), F2L =0.08 (0.08± 0.00), F3L= 0.08 (0.08± 0.00), F2W=0.13–0.15 (0.14 ± 0.01), MsW = 1.80–2.05 (1.93 ±0.09), SCL= 0.38–0.45 (0.43 ± 0.03), MNL=0.25–0.30 (0.27± 0.02), MPL =0.25–0.33 (0.28 ±0.03), MtW=1.75–2.10 (1.97 ± 0.13).

COLORATION. Body black except for the following parts: mandible reddish brown apically; flagellum brown or blackish brown ventrally; tegula yellowish brown translucent; tibial spur yellow; metasomal terga narrowly yellowish brown translucent apically. Wings transparent, veins and stigma brown.

PUBESCENCE. Body hairs whitish, and covered with erect and sparse straight or fine branched hairs except for the following parts: pronotum moderately densely tomentose dorsally and around lobe; hind trochanter, femur, and tibia mixed with plumose hairs, forming scopa. Disc of T1 without distinct short hairs on medial area.

STRUCTURE AND SCULPTURE HEAD. Slightly longer than wide or nearly as long as wide; HW:HL=1:1.03. Vertex rounded in frontal view. MOD:UOD:LOD=1:0.85:0.76. IOD:OOD:OCD =1:0.95:0.69. IAD:AOD = 1:1.86. Ocellocular area with moderately dense PP, IS smooth (IS =0.5–3 d). Paraocular area and frons weakly shiny, with shallow reticulate PP. Supraclypeal area slightly convex, weakly shiny, with sparse PP, IS weakly tessellate (IS =1–4 d). CPL:CAL= 1:0.87. Clypeus nearly flat, with sparse PP over entire surface, IS very weakly tessellate on upper half or ⅓ and smooth on lower half or ⅔ (IS =1–5 d). EW:GW =1:0.86. Genal area to postgena with distinct straight ridges. Malar space linear. Occiput not carinate. Hypostomal carinae nearly parallel. Mandible bidentate. Labrum ( Fig. 5D ): basal area approximately 1.9 × as wide as long; distal process approximately 0.6× as long as basal area, tongue-like, and without lateral projection; distal keel rounded, pointed apically. Antenna short, not reaching metasoma. F2L:F2W=1:1.72; flagellum nearly flattened ventrally.

THORAX. Dorsolateral angle of pronotum obtuse; lateral surface without ridges; lateral lobe rounded. Tegula ovoid, nearly smooth. Mesoscutum ( Fig. 5E ) with moderately dense PP over entire surface; IS weakly tessellate over entire surface (particularly very weak on posterior area) (IS =0.5–3 d); parapsidal line a narrow groove. Mesoscutellum with 2–4 PP on submedian area and denser PP on marginal area; IS nearly smooth on submedian area and very weakly tessellate on marginal area (IS =2–5 d on submedian area, =0.5–2 d on marginal area). Metanotum weakly rugulose. Mesepisternum weakly shiny, with dense shallow PP on upper area and reticulate PP on lower area; IS nearly smooth on upper area (IS=0.5–1 d on upper area). SCL:MNL:MPL=1:0.62:0.66. Propodeum: metapostnotum ( Fig. 5F ) gently inclined, with irregular sinuate ridges on anterior half in holotype and two paratypes (remaining five paratypes with short longitudinal ridges), with weak tessellation on posterior half, and nearly smooth among ridges; junction between metapostnotum and posterior surface not carinate, with weak tessellation; lateral surface weakly rugulose; posterior surface with lateral carina on lower half, without oblique carina. Coxae usual shape, without tubercle. Fore trochanter narrow, longer than wide. Basitibial plate of hind leg carinate marginally. Inner hind tibial spur with slender 2–4 teeth as in Fig. 20B (n= 7). Fore wing with three submarginal cells.

ABDOMEN. Disc of T1 without distinct PP on medial area, and with very weak lineolation interrupted on medial area ( Fig. 15B ). Disc of T2 nearly smooth on anterior to medial area in holotype and two paratypes, and with weak lineolation on posterior area (anterior and posterior area with weak lineolation in four paratypes). Discs of T3–T4 with weak lineolation over entire surface.

Male

MEASUREMENTS (n=1, unit mm). BL=4.23, WL=3.92, HL=1.56, HW=1.51, IOD =0.29, OOD =0.29, OCD =0.16, UOD=0.98, MOD =1.04, LOD =0.84, IAD =0.20, AOD= 0.24, CAL =0.31, CPL=0.33, EL = 1.07, EW= 0.40, GW=0.44, SPL=0.44, F1L=0.11, F2L=0.18, F3L= 0.16, F2W=0.13, MsW = 1.55, SCL=0.36, MNL=0.22, MPL=0.27, MtW=1.35.

COLORATION. Body black except for the following parts: mandible yellowish brown except for apically reddish brown; labrum dark yellow; pronotal lobe yellowish brown; tegula yellowish brown translucent; legs brown, without distinct yellow marks; tibial spur yellow; metasomal terga broadly yellowish brown translucent apically. Wings transparent, veins and stigma pale brown.

PUBESCENCE. Body hairs whitish, and covered with erect and sparse straight or fine branched hairs except for the following parts: lower paraocular area and pronotal dorsum to lobe sparsely tomentose. Disc of T1 with sparse hairs only on marginal area. Disc of T2–T4 with sparse short hairs over entire surface. T2–T3 with thin apical fimbriae, less distinct than in the female.

STRUCTURE AND SCULPTURE HEAD. Nearly as long as wide; HW:HL=1:1.03. Vertex rounded in frontal view. MOD:UOD:LOD =1:0.94:0.81. IOD:OOD:OCD =1:1:0.54. IAD:AOD =1:1.22. Ocellocular area with moderately dense PP, IS smooth (IS =1–4 d). Paraocular area and frons weakly shiny, with shallow reticulate PP. Supraclypeal area slightly convex, weakly shiny, with moderately dense PP, IS weakly tessellate (IS= 1–3 d). CPL:CAL= 1:0.93. Clypeus nearly flat, with sparse shallow PP over entire sutface; IS smooth (IS =1–6 d). EW:GW=1:1.11. Genal area on lower margin and postgena with straight ridges. Malar space linear. Hypostomal carinae nearly parallel. Mandible edentate. Labrum with basal elevation, but not examined in detail. Antenna short, not reaching metasoma. F2L:F2W =1:0.75; flagellum nearly flattened ventrally.

THORAX. Dorsolateral angle of pronotum obtuse; lateral surface without ridges; lateral lobe rounded. Tegula ovoid, nearly smooth. Mesoscutum with moderately dense PP over entire surface; IS weakly tessellate on anterior margin, nearly smooth on rest parts (IS =1.5–3 d); parapsidal line a narrow groove. Mesoscutellum with sparse PP over entire surface; IS smooth (IS=2.5–6 d). Metanotum weakly rugulose. Mesepisternum with moderately dense PP over entire surface; IS smooth (IS=1–3 d). SCL:MNL:MPL=1:0.63:0.75. Propodeum: metapostnotum weakly shiny and gently inclined, with short straight ridges occupying anterior ⅔; junction between metapostnotum and posterior surface not carinate, nearly smooth; lateral surface weakly reticulate; posterior surface nearly smooth, with lateral carina on lower ⅓, and without oblique carina. Coxae usual shape, without tubercle. Fore trochanter narrow, longer than wide. Basitibial plate of hind leg carinate marginally. Inner hind tibial spur serrate. Fore wing with three submarginal cells.

ABDOMEN. Disc of T1 nearly smooth. Disc of T2–T3 with sparse fine PP; T2 weakly lineolate on apical margin; T3 weakly lioneolate on apical half. Disc of T4 weakly lineolate over entire surface. S7 with moderately long, apically rounded median process.

GENITALIA. Gonobase flat at bottom; gonocoxite smooth; ventral retrorse lobe tongue-like, moderately long but not reaching gonobase, with sparse short hairs ventrally.

Distribution

Japan (central to southern Ryukyus: Yoron-jima Is., Okinawa-jima Is., Miyako-jima Is., Iriomote-jima Is.).

Flight period

Female: middle March to late August.

Male: July.

Flower records

Ixeris japonica (Burm.f.) Nakai ( Asteraceae ).

Figures

Fig. 5. Lasioglossum (Hemihalictus) ikudomei sp. nov. A. ♀, lateral habitus. B. ♀, head in frontal view. C. ♂, head in frontal view. D. ♀, labrum. E. ♀, mesoscutum. F. ♀, metapostnotum. Scale bars: A = 2 mm; B–C, E = 1 mm; D = 0.2 mm; F = 0.5 mm.

Fig. 15. 1st metasomal tergum, ♀. A. Lasioglossum (Hemihalictus) frigidum Sakagami & Ebmer, 1996. B. L. (H.) ikudomei sp. nov. C. L. (H.) kiautschouense (Strand, 1910). D. L. (H.) ohei Hirashima & Sakagami, 1966. E. L. (H.) simplicior (Cockerell, 1931). F. L. (H.) smilodon Ebmer & Sakagami, 1994. Scale bars: 1 mm.

Fig. 18. Distribution maps. A. Lasioglossum (Hemihalictus) sphecodicolor Sakagami & Tadauchi, 1995. B. L. (H.) subsimplicior sp. nov. C. L. (H.) taeniolellum (Vachal, 1903). D. L. (H.) amamiense Ebmer & Sakagami, 1994 (red circle), L. (H.) ikudomei sp. nov. (purple circle), L. (H.) smilodon Ebmer & Sakagami, 1994 (light blue circle) and L. (H.) tadauchii Murao, 2012 (yellow circle).

Fig. 20. Female inner hind tibial spur. A. Lasioglossum (Hemihalictus) frigidum Sakagami & Ebmer, 1996. B. L. (H.) ikudomei sp. nov. C. L. (H.) kiautschouense (Strand, 1910). D. L. (H.) ohei Hirashima & Sakagami, 1966. E. L. (H.) smilodon Ebmer & Sakagami, 1994. F. L. (H.) spectrum sp. nov. G. L. (H.) speculinum (Cockerell, 1925). H. L. (H.) sphecodicolor Sakagami & Tadauchi, 1995. I. L. (H.) taeniolellum (Vachal, 1903). Scale bars: 0.2 mm.

Fig. 9. Lasioglossum (Hemihalictus) smilodon Ebmer & Sakagami, 1994. A. ♀, lateral habitus. B. ♀, head in frontal view. C. ♂, head in frontal view. D. ♀, labrum. E. ♀, mesoscutum. F. ♀, metapostnotum. Scale bars: A = 2 mm; B = 1 mm; C, E–F = 0.5 mm; D = 0.2 mm.