Exaerete guaykuru Anjos­Silva and Rebêlo, 2006

Anjos-Silva, Evandson José Dos & Rebêlo, José Manuel Macário, 2006, A new species of Exaerete Hoffmannsegg (Hymenoptera: Apidae: Euglossini) from Brazil, Zootaxa 1105, pp. 27-35 : 29-33

Exaerete guaykuru Anjos­Silva and Rebêlo , new species

Figs. 1, 2, 7, 12, 17 , 22, 23

Diagnosis: dorsally, the posterior margin of the mesoscutellum is linear and depressed medially forming an extended median carina. In posterior view, the mesoscutellum with two sub lateral tubercles is unique, most similar to that of E. trochanterica . The hind tibial slit is complete, reaching apex. These features separate E. guaykuru , n. sp. from species in the dentata and frontalis species groups. However, the most distinctive characteristics are the clypeal prominence, the linear posterior margin of the mesoscutellum, the mesoscutellum depressed medially forming an extended median carina, and the hypoepimeron lacking a knob.

Color and vestiture: body mostly uniformly green, with dark blue hues on thorax and legs ( Fig. 1 ); wings evenly blackish; clypeus greenish with black and white setae; scape mostly metallic dark blue; pubescence sparse, predominantly black on thorax and white on abdomen, genal area with whitish setae and sparse and small black pale setae on vertex; almost completely white near antennal sockets, with black and white setae on scape; foretibia and forebasitarsus fringed with long, dense, fulvous black hairs; mesotibia with small, dense black and white hairs; long posterior fringe with sparse fulvous pubescence.

Punctation: head and thorax coarsely punctate; punctures equally crowded on head and clypeus (0.04–0.38 mm), ranging from 0.04 to 0.09 mm on vertex; head with reticulate interspaces and a shiny area in front of the median ocellus; mesoscutal puncture diameters range from 0.04–0.11 mm, a little sparser between the parapsidal lines; mesoscutellar punctures from 0.06 to 0.16 mm, punctures dense on the elevated area on the side of the mesoscutellum; mesepisternum and T2 with punctures crowded.

Head: width range from 5.93 to 6.72 mm, length 4.75 to 4.93 mm; upper interocular distance ca. 0.8x the lower interocular distance and ca. 0.9x the medial interocular distance; interocellar distance slightly less than ocellocular and ca. 2x the diameter of the median ocellus; eye length ca. 2.4x eye width; scape length ca. 3.8x ocellocular distance; flagellum longer than twice the scape length (4.64– 2.23 mm); third flagellar segment slightly shorter than the first, first ca. 1.3x longer than the second; frons not protuberant, lacking a median tubercle ( Figs. 2, 7 a); mandibles bidentate; clypeus ca. 1.3x wider than long, with a carina forming a clypeal prominence ( Figs. 2, 7 b); labrum 0.7x wider than long; malar space short, ca. 0.3x the basal mandibular width; labial palpi four­segmented, with the second segment slightly smaller than the first; tongue long, in repose reaching hind coxa, ranging from 11.5 to 12.3 mm.

Mesosoma: total length ca. 26 mm; forewing length from base to apex ranging from 21.58 to 23.73 mm ( Fig. 1 ); jugal comb present; tegula ca. 1.9x longer than wide; intertegular distance ranging from 4.23 to 4.75 mm; mesoscutellum convex in profile, with a linear posterior margin ( Fig. 12 a), ca. 1.9x longer than wide, with two well­developed sub lateral tubercles ( Fig. 12 a), depressed medially forming an extended median carina ( Fig. 12 b); hypoepimeral area without a well­developed knob ( Fig. 1 ); maximum abdominal width ranging from 6.4 to 7.6 mm.

Legs: foretibia ca. 4x longer than wide; forebasitarsus 3.5x longer than wide; mesotibia expanded, 2,6x longer than wide; hind femur with large tooth in basal half of inner margin; hind tibia 3.8x longer than wide ( Fig. 17 a), with hind tibial slit reaching apex; hind tibia narrow and curved, expanded apically ( Fig. 1 ), with some small denticles and a large sub medial tooth ( Fig. 17 b).

Metasoma: T2 ca. 2.8x longer than T1; T7 slightly depressed medially, with short dense black pubescence apically; S2 ca. 2x longer than S3; S7 bilobed, irregularly rounded and slightly depressed centrally, with long setae covering apical margin and with a sub lateral rows of dense setae medially, and with a slight submedian depression ( Fig. 22 a, 23a); S8 with obtuse apicomedial angle, apex tapering strongly to medial lobes ( Fig. 22 b, 23b); genital capsule: gonostylus laterally subtriangular, with setae along ventral surface and with scattered setae on dorsal surface; gonocoxal lobe with a strong projection; volsella ovoid, well­developed ( Fig. 22 c, 23c).

Material Examined

Holotype male. BRAZIL: Mato Grosso: Planalto dos Guimarães, Chapada dos Guimarães, Chapada dos Guimarães National Park, Véu de Noiva waterfall, Coxipozinho stream, 15º20017”S, 55º50205”W, elevation ca. 600 m and ca. 55 km northeast of Cuiabá Capital, and 10 km west of Chapada dos Guimarães, 29.xi.2004 ( EJAS leg. 959) ( MZUSP).

Paratypes: two males, same data as the holotype ( EJAS leg. 955 and 960).

Etymology: the specific epithet guaykuru is in honor of the extinct Guaykuru Indians, horsemen that lived in the region where the bees were collected.

Attractant chemical baits: all the three males were attracted to methyl salycilate baits, early in the wet season, i.e., November 2004.

Female: unknown.

Comments: a tubercle or convexity in the frons is present in both E. frontalis and E. dentata , but absent in E. smaragdina , E. trochanterica and E. guaykuru . As shown by Engel (1999), the gonocoxal projection is absent in all Exaerete species. To date, only E. guaykuru has a gonocoxal lobe with a strong projection. The holotype of E. guaykuru , n. sp. was deposited in the entomological collection of the Museum of Zoology, Universidade de São Paulo, São Paulo (MZUSP). One paratype was deposited in the Department of Biology ­ FFFCLRP/USP (RPSP), and the other remains in the senior authors collection.

Figures

FIGURES 1 – 17. 1. Lateral view of the body of Exaerete guaykuru, n. sp., holotype. The arrows indicate the hypoepimeron slightly convex, not tuberculate, and hind tibial slit reaching apex. Body length = ca. 26 mm. 2. Lateral view of the head of E. guaykuru, n. sp., paratype, showing the prominence on clypeus (arrow) and the metallic dark blue scape. Eye length = 4, 9 mm. 3 – 7. lateral view of head of male Exaerete spp. showing presence or absence of median tubercle (a) and prominence of clypeus (b); 3. E. smaragdina, 4. E. frontalis, 5. E. dentata, 6. E. trochanterica, 7. E. guaykuru, n. sp. 8 – 12. Mesoscutellum of male Exaerete spp. in dorsal (a) and posterior views (b), showing the shape of mesoscutellum and sub lateral tubercles. 8. E. smaragdina, 9. E. frontalis, 10. E. dentata, Fig. 11. E. trochanterica, Fig. 12. E. guaykuru, n. sp. 13 – 17. External surface of hind leg of male Exaerete spp. showing the hind tibial slit very small or complete (a), and the shape of the hind femur (b). 13. E. smaragdina, 14. E. frontalis, 15. E. dentata, 16. E. trochanterica, 17. E. guaykuru, n. sp.

FIGURES 18 – 23. 18 – 22. Male genitalia of Exaerete spp., showing the shape of S 7 (a), S 8 (b), and the lateral view of the genital capsule (c). 18. E. smaragdina, 19. E. frontalis, 20. E. dentata, 21. E. trochanterica, 22. E. guaykuru, n. sp. 23. Male genitalia of E. guaykuru, n. sp., digital images showing the shape of S 7 (a), S 8 (b), and the lateral view of the genital capsule (c).