Lasioglossum (Evylaeus) canaliculatum Murao

Murao, Ryuki, Tadauchi, Osamu, Goubara, Masashi & Maeta, Yasuo, 2010, Taxonomy of the carinaless group of Lasioglossum (Evylaeus) (Hymenoptera, Halictidae) from the Ryukyu Islands, Japan, with description of seven new species, Zootaxa 2669, pp. 1-33 : 9-13

Lasioglossum (Evylaeus) canaliculatum Murao sp. nov.

( Figs. 5 , 6 , 17 E–H)

Description. Female. Body length 5.9–6.8 mm, wing length 5.3–5.7 mm (n= 5).

Color. Tegula brown or blackish brown translucent. Posterior margins of metasomal terga narrowly blackish or yellowish brown translucent.

Pilosity. T1 ( Fig. 6 C) medially with moderately dense simple and short hairs. Metasomal terga with neither basal hair bands nor apical fimbriae.

Structure. Head wider than or as wide as long; head length/width ratio 0.93–1.01 (n= 10). Interocellar distance subequal to ocellocular distance. Frons and paraocular area reticulate-punctate, frons dull, and lower paraocular area shiny. Supraclypeal area ( Fig. 5 B) shiny, with moderately dense PP; IS with weak tessellation. Clypeal length 1.4x distance between lower rim of antennal socket and upper margin of clypeus, with moderately dense shallow PP on the entire surface; IS smooth. Basal area of labrum 2.5x as wide as long; distal process without lateral projection; keel of distal process moderately broad, apically bluntly pointed in frontal view. Scape length approximately 0.8 mm (n= 5). Mesoscutum ( Fig. 5 C, D) dull, with dense PP and IS with distinct tessellation on the entire surface. Mesoscutellum ( Fig. 5 E) shiny, with dense PP and IS smooth on the entire surface. Mesepisternum ( Fig. 5 F) shiny, with dense PP and IS smooth on upper area, and with rugulae on lower area. Propodeal dorsum ( Fig. 5 N) 0.8x mesoscutellum, and 1.2x as long as metanotum, with longitudinal ridges on the entire surface; dorsomedial ridges present on basal half or basal 2/3, dorsomedially with weak tessellation on apical 1/3; propodeal side weakly rugulose, with distinct tessellation; shield weakly tessellate. Inner hind tibial spur ( Fig. 5 O) pectinate, with 3–6 teeth (n= 21). T1–T4 with very weak lineolation on the entire surface; T1 ( Fig. 6 C) medially with moderately dense fine PP.

Male. As in female except as follows. Body length 4.3–6.5 mm, wing length 4.2–5.6 mm (n= 5).

Color. Lower half of clypeus yellow; mandible yellow excluding apical area; labrum yellowish brown or yellow.

Pilosity. S4–S5 ( Fig. 6 B) posterolaterally with fine branched hairs, moderately dense and long.

Structure. Head length/width ratio 0.87–0.97 (n= 13). Interocellar distance 0.9x ocellocular distance. Clypeal length 1.2x distance between lower rim of antennal socket and upper margin of clypeus. Basal area of labrum 3.2x as wide as long; basal elevation distinctly concaved in frontal view; distal process absent. Scape length approximately 0.5–0.6 mm (n= 12), F2 1.4x F1. Mesoscutal IS anteriorly with weak tessellation, medially and posteriorly smooth. Mesepisternum with dense PP on lower area. Propodeal dorsum ( Fig. 5 Q) 1.5x as long as metanotum; dorsomedial area nearly smooth apically. Basitibial plate of hind legs without carina marginally. T1( Fig. 6 D) both basally and apically or only apically with very weak lineolation. S7–S8 ( Fig. 6 H): S7 with moderately long, apically truncate median process; S8 without median process. Genitalia as in Fig. 6 E–G. Gonobasal ventral arm ring-shaped, and not connected to each other at apical ends; bottom nearly flat. Gonocoxite with distinct tessellation and sparse short hairs apically, and with longitudinal lineolation on medial area in dorsal view. Gonostylus triangle-shaped, and rounded apically in lateral view, with moderately dense and long hairs on apical margin. Retrorse lobe ( Fig. 6 G) long and narrow, and with moderately dense short hairs on its surface.

Variation. The cephalic polymorphism occurs in male as shown in Fig. 17 E–H. However, the head lacks the genal process as stated above in Lasioglossum (Evylaeus) amamiense Ebmer & Sakagami. The larger males are accompanied with the gigantic head ( Fig. 17 F, H). In the sexstrigatum -group, the male polymorphism without the genal process has been known only in Lasioglossum (Evylaeus) japonicum (Dalla Torre) .

Remarks. The species code sp. O–1 reported by Maeta et al. (2004) corresponds to this new species. Within the sexstrigatum -group, this species is similar to Lasioglossum (Evylaeus) japonicum (Dalla Torre) from Japan proper and L. (E.) urumaense sp. nov. from the central Ryukyus. But it is separated from the former by the following morphological characters: female labrum without lateral projection, femaleT1 with weak lineolation, basal elevation of male labrum depressed, male F2 longer than F1, gonostylus triangleshaped in lateral view, and retrorse lobe elongate. In contrast, in L. (E.) japonicum , female labrum with small lateral projections, femaleT1 without lineolation, basal elevation of male labrum not depressed, male F2 as long as F1, gonostylus truncate apically, and retrorse lobe tongue-like shaped. For the differences between this species and the latter one see the key. So far as the first author surveyed in Amami-Ôshima, this species was found in various environments from the seaside to mountain areas.

Etymology. The specific name is derived from the male labrum with concave basal elevation.

Distribution. Japan (central Ryukyus: Amami-Ôshima, Tokuno-shima, Okinoerabu-jima, Okinawa-jima).

Flight records. Female: March to October. Male: May to October.

Flower records. The flowering plants visited by this species were 11 species in six families listed as follows. Anacardiaceae : Rhus javanica var. chinensis . Asteraceae : Asteraceae gen. sp.; Bidens pilosa var. minor ; Crepidiastrum denticulatum ; Eupatorium variabile ; Vernonia cinerea . Hydrangeaceae : Deutzia sp. Liliaceae : Liriope muscari . Oxalidaceae : Oxalidaceae gen. sp. Polygonaceae : Fallopia japonica ; Persicaria longiseta .

Type material. Holotype (Type No. ELKU 3303): female, Santarou-touge, Sumiyou-son, Amami- Ôshima, Kagoshima Pref., Ryukyus, JAPAN, 15. x. 2004 (R. Murao leg., RMPC). Paratypes: [Ryukyus: JAPAN] Amami-Ôshima, Kagoshima Pref.: 1 female, 29. ix. 1971 (H. Fukuda, SCMH); 1 female, Asato, 14. iv. 1970 (S. F. Sakagami & H. Fukuda, SCMH); 1 female, Kasarizaki, Kasari-cho, 22. ix. 2006 (R. Murao, RMPC); 3 females, Materiya-no-taki, Yamato-son, 19. ix. 2006 (R. Murao, RMPC); 2 females, Mt. Yuwandake, 3. v. 1953 (T. Shiraki, ELKU), 28. iv. 1970 (K. Kanmiya, ELKU); 9 females and 6 males, Mt. Yuwandake, Uken-son, 14. x. 2004 (R. Murao, RMPC), 19. ix. 2006 (K. Matsuo, RMPC); 1 female, Naze, 4. iv. 1964 (T. Shirôzu, ELKU); 1 female and 1 male, near Mt. Yuwan-dake, Yamato-son, 19. ix. 2006 (R. Murao, RMPC); 1 female, Nishinakama, 25. v. 1973 (H. Makihara, ELKU); 1 female, Nishinakama, Sumiyou-son, 8. iv. 2005 (K. Mitai, RMPC); 1 female, Nishinakama-Shinmura, 3. x. 1971 (H. Fukuda, SCMH); 6 females and 2 males, same locality as the holotype, 15. x. 2004 (R. Murao, RMPC), 21. ix. 2006 (R. Murao, RMPC); 1 female, Yadori-hama, Setouchi-cho, 19. ix. 2006 (R. Murao, RMPC). Tokuno-shima, Kagoshima Pref.: 1 female, Mikyo, 26. vii. 1963 (M. Yoshimoto, ELKU). Okinoerabu-jima, Kagoshima Pref.: 1 female, Oyama, alt. 254m, 29. vii. 1963 (M. Yoshimoto, ELKU). Okinawa-jima, Okinawa Pref.: 5 females, Hedona, Kunigami-son, 17–18. x. 2002 (Y. Maeta, MCDS); 1 female, Hentona, 19. vi. 1953 (T. Shiraki, ELKU); 1 female, Makiyaôkawa, 11. viii. 1987 (T. Murota, RMPC); 1 female, Misato, 21. iv. 1953 (T. Shiraki, ELKU); 1 female, Ôkayou, Motobu-cho, Kunigami-gun, 3. iv. 2005 (K. Mitai, RMPC); 1 female, Shoshi, 23. iii. 1964 (M. Yoshimoto & J. Harrell, ELKU); 1 female and 3 males, Yona, Kunigami-son, 11. vi. 1972 ( ELKU), 12. viii. 1988 (T. Murota), 15. v. 2004 (T. Mita, RMPC); 2 males, Mt. Nago-dake, 23. v. 2004 (T. Mita, RMPC).

Type depository. The holotype and 54 paratypes are deposited in ELKU, five paratypes in MCDS, and three paratypes in SCMH.

Figures

FIGURE 5. Lasioglossum (Evylaeus) canaliculatum Murao, sp. nov. A – F: holotype, female. M – O: paratype, female. G – L, P, Q: male, paratype. A, G: lateral habitus. B, H: lower face. C, I: mesoscutum. D, J: sculpture on mesoscutum. E, K: mesoscutellum. F, L: mesepisternum. M, P: labrum. N, Q: propodeal dorsum. O: inner hind tibial spur. Scale bars: N, 0.5 mm; P, Q, 0.25 mm; M, O, 0.2 mm.

FIGURE 6. Lasioglossum (Evylaeus) canaliculatum Murao, sp. nov. A, C: holotype, female. B, D, E – H: paratype, male. A: head in frontal view. B: metasomal sterna. C, D: first metasomal tergum (left half, sculpture; right half, hair pattern). E – G: male genitalia (E: left, ventral view; right, dorsal view. F: lateral view. G: retrorse lobe). H: seventh and eighth metasomal sterna. Scale bars: A, B, C, D, 1 mm; E, F, H, 0.2 mm; G, 0.1 mm.

FIGURE 17. A – D: Lasioglossum (Evylaeus) amamiense Ebmer & Sakagami, male. E – H: Lasioglossum (Evylaeus) canaliculatum Murao, sp. nov., male. A, B, E, F: head in frontal view (stippled area: yellow coloration). C, D, G, H: head in lateral view. A, C, E, G: normal head. B, D, F, H: gigantic head. Scale bar: 1 mm.