Euglossa (Euglossella) bigibba Dressler

Hinojosa-Díaz, Ismael A. & Engel, Michael S., 2014, Revision of the orchid bee subgenus Euglossella (Hymenoptera: Apidae), Part II: The viridis and mandibularis species groups, Journal of Melittology 2014 (36), pp. 1-108 : 90-93

Euglossa (Euglossella) bigibba Dressler

( Figs. 133–138, 154, 163, 167–169, 170)

Euglossa (Euglossella) bigibba Dressler 1982b: 129 [♂]. Holotype ♂ (HNHM, visum).

DIAGNOSIS: Labiomaxillary complex in repose reaching tip of metasoma; lower interorbital distance about 1.20 times as wide as upper interorbital distance ( Fig. 135); malar area long (over 0.45 mm, twice as long as diameter of mid-flagellar articles) ( Figs. 135); pronotal dorsolateral angle acute; mesotibial tufts as follows: anterior tuft rhomboid, long (maximum length exceeding mid-width of velvety area) and moderately wide (mid-width slightly exceeding width of contiguous section of velvety area), posterior tuft oval ( Figs. 136, 154); mesobasitarsus with posterior keel projected in an obtuse angle ( Fig. 137); second metasomal sternum with two, simple meso-lateral tufts; metasoma noticeably wider than head (by about 1.15 times) ( Fig. 133); head mainly green ( Fig. 135); paraocular marks trapezoidal, lower width about two thirds of length of lower lateral part of clypeus ( Figs. 134–135); scape with yellow-ivory spot covering almost entire outer-lateral surface ( Fig. 135); mesosoma green with noticeable blue-green iridescence dorsally ( Figs. 133–134); metasomal terga green with noticeable blue-green iridescence ( Fig. 133); mesoscutellum rather sparse (punctures separated by two puncture diameters) ( Fig. 133); central area of mesepisternum moderately-densely punctate (punctures separated by one to one and a half puncture diameters); metasomal terga with dense to moderately-dense, big punctures (about half size of mid-ocellus) ( Figs. 133–134); mesosomal vestiture dominated by a mix of soft, fulvous and reddish-brown, sturdy setae ( Figs 133–134); eighth metasomal sternum posterior section conical in dorsal or ventral views, lateral width equivalent to width of lateral section of sternum (this is the only species in Euglossella with this condition) ( Figs. 168–169); gonocoxite dorsal process longer than wide (slender) ( Fig. 163); gonostylar lateral section with well-developed “secondary” lobe (convexity of posterior margin of basal sector), large, and with tightly dense and long setae ( Fig. 167).

DESCRIPTION: ♂: Structure. Total body length 13.96 mm (13.70–14.22; n=2); labiomaxillary complex in repose reaching metasomal apex ( Fig. 134). Head length 2.96 mm (2.81–3.11; n=2), width 5.19 mm (5.12–5.26; n=2); upper interorbital distance 2.23 mm (2.22–2.24; n=2); lower interorbital distance 2.59 mm (n=2); upper clypeal width 1.39 mm (1.37–1.41; n=2); lower clypeal width 2.19 mm (2.15–2.22; n=2); clypeal protuberance 1.11 mm (n=2); medial clypeal ridge sharp, paramedial clypeal ridges as sharp or slightly sharper than medial, paramedial ridges oblique (clypeal disk trapezoidal); labrum wider than long, length 1.19 mm (n=2), width 1.33 mm (n=2) ( Fig. 135); labral ridges sharp, paramedial ones oblique, present along entire labral length; labral windows ovoid, occupying proximal half of labrum ( Fig. 135); interocellar distance 0.34 mm (0.30–0.37; n=2); ocellocular distance 0.58 mm (0.57–0.59; n=2); first flagellar article longer [0.62 mm (0.60–0.64; n=2)] than second and third flagellar articles combined [0.54 mm (0.52–0.56; n=4)]; length of malar area 0.48 mm (0.47–0.48; n=2). Mandible tridentate. Pronotal dorsolateral angle acute; intertegular distance 4.09 mm (3.96–4.22; n=2); mesoscutal length 3.37 mm (3.33–3.41; n=2); mesoscutellar length 1.55 mm (1.52– 1.57; n=2); posterior margin of mesoscutellum convex, mesially rather truncate or very slightly concave, mesoscutellar disc with a central concavity, creating two mid-lateral cusps ( Fig. 133); mesotibial length 2.74 mm (n=2); mesobasitarsal length 2.52 mm (n=2), width 0.89 mm (n=2), posterior keel projected in an obtuse angle with proximal margin (between tibia-basitarsus joint and apex of keel) noticeably convex ( Fig. 137); metatibia triangular (scalene triangular) ( Fig. 138), maximum thickness 1.21 mm (1.19–1.22; n=2); metatibial anterior margin length 4.37 mm (n=2), ventral margin length 2.81 mm (n=2), postero-dorsal margin length 5.26 mm (n=2); metatibial organ slit as described for E. viridis , dorsal section length 0.56 mm (0.53–0.59; n=2); metabasitarsal length 2.52 mm (2.44–2.59; n=2), mid-width 1.07 mm (n=2); metabasitarsal ventral margin truncate. Forewing length 10.78 mm (10.67–10.89; n=2); jugal comb with 13–15 (n=2) blades; hind wing with 20–23 (n=2) hamuli. Maximum metasomal width 5.96 mm (5.85–6.07; n=2); second metasomal sternum with two meso-lateral tufts separated by twice width of an individual tuft.

Coloration. Head uniformly green with noticeable golden-bronzy iridescence throughout; noticeable amber brown matte coloration on clypeal ridges ( Fig. 135); paraocular mark yellowish, triangular, lower width half of length of lateral part of clypeus ( Figs. 134–135); scape lateral surface covered with yellow spot; malar area and mandible (except margins and teeth) yellow ( Fig. 135). Mesosoma (including legs) green with noticeable golden-bronzy iridescence throughout, and blue-green iridescence, especially strong on mesoscutum and mesoscutellum; preomaular area largely amber ( Figs. 133–134). Metasoma uniformely green; first tergum with noticeable blue-green iridescence, remaining terga with noticeable golden-bronzy iridescence, becoming strong on fourth to seventh terga as well as all sterna ( Figs. 133–134).

Sculpturing. Head as described for males of E. mandibularis ( Fig. 135). Mesoscutum and mesoscutellum comparable to E. mandibularis , slightly sparser ( Fig. 133); mesepisternum punctures denser than those on E. mandibularis (punctures on central areas separated only by one to one and a half puncture diameters). Metasomal terga densely to moderately-densely punctate, all terga with large, elongate punctures, length of those on second metasomal tergum (and mainly on all following terga) about 0.50x mid-ocellar diameters ( Fig. 133).

Vestiture. As described for male of E. mandibularis except as follows: setae in general lighter, those brown, sturdy setae as described in E. mandibularis instead light brown-amber on dorsal areas of body, while fuscous setae as described in E. mandibularis instead rather fulvous throughout ( Figs. 133–135); mesotibial tufts with fulvous-amber setae, posterior tuft longitudinally oval, almost touching anterior tuft, dimensions of anterior tuft and contiguous velvety area as described for E. mandibularis ( Figs. 136, 154).

Terminalia. Seventh metasomal sternum as described for E. viridis and E. mandibularis . Eighth metasomal sternum as described for E. mandibularis except noticeably wider (as wide as anterior section of sternum) in lateral view, and with sparser and very short simple setae present only on shaft of posterior projection ( Figs. 168–169). Gonocoxite as described for E. mandibularis ( Fig. 163). Gonostylus as described for E. mandibularis but with denser setae ( Fig. 167). Spatha as described for E. viridis ( Fig. 163).

♀: Unknown.

HOLOTYPE: ♀, Peru : “ Euglossa ; bigibba ; Dressler; HT [handwritten in red ink] // 685.; 80. [handwritten] // PERU; Pebas [handwritten] // Holotypus; Euglossa ; bigibba ; R. L. Dressler [label with red margin, first row in red ink, species name and author handwritten] // HOLOTYPE; Euglossa ; bigibba Dressler ; R. L. Dressler, 1982 [red colored label]” ( HNHM).

ADDITIONAL MATERIAL EXAMINED (2♂♂): Brazil: 1♂, “TABATINGA; Amazonas BRASIL; Novembro 1958; F.M. Oliveira // Euglossella [handwritten] // E. ( Euglossella ); bigibba (DZUP) . Peru: 1♂, “Peru // 685; 80 [handwritten] // Euglossa ; bigibba // PARATYPE; Euglossa ; bigibba Dressler ; R.L. Dressler, 1982 [label with red margin]” ( FSCA).

COMMENTS: The particular morphology of E. bigibba was noted by Dressler (1982b) when describing the species. The species has a pronouncedly biconvex mesoscutellum (hence the specific epithet), as well as a markedly protuberant clypeus ( Figs. 133–134). Features of the eighth metasomal sternum ( Figs. 168–169) and the gonostylus ( Fig. 167), although comparable to those observed in E. mandibularis , are a bit more deviant compared to other species of Euglossella species. Specifically, the lateral width of the posterior section of the eighth sternum is noticeably wide ( Fig. 169), whereas in all other taxa with males known, including E. mandibularis , this section is comparatively narrow (Figs. 12, 129). Females are not yet known for E. bigibba nor could we confidently associate such specimens as definitively conspecific with the males. However, the numerous characters shared with E. perfulgens , for which only females are known and from the same region (vide Comments for E. perfulgens , infra), does raise the suspicion that these taxa might be synonymous. Despite this strong possibility, we could not confidently assert this with conclusive evidence and they are retained here as distinct, pending future work (refer to more extensive discussion of the matter under Comments for E. perfulgens , infra). This is another area where the application of DNA barcoding techniques might aid a final determination of the validity of E. bigibba relative to E. perfulgens . The species is known from a small sample of specimens, all of which come from the western section of the Amazon Basin in Peru and Brazil ( Fig. 170).