Megalopta Smith 1853
Creators: name: Santos, L. M.
name: Melo, G. A. R.
Publisher: name: Zenodo
Year: 2014
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Hymenoptera
Halictidae
Megalopta

description: Megalopta Smith, 1853
Megalopta Smith, 1853: 83. Type species: Megalopta idalia Smith, 1853.
Megalopta (Megaloptella) Schrottky, 1906: 312. Type species: Halictus ochrias Vachal, 1904.
Tmetocoelia Moure, 1943: 481. Type species: Megalopta sulciventris Friese, 1926.
Megalopta (Noctoraptor) Engel et al. 1997: 12. Type species: Megalopta byroni Engel et al. 1997.
Diagnosis
Megalopta differs from other augochlorines, including Xenochlora, by the large ocelli and the closely packed series of hamuli in the hind wing (Engel 2000; Michener 2007), as well as in the morphology of the male S3–S5 (Santos and Melo 2013). Megalopta and Xenochlora differ from most augochlorines for their non-metallic, pale brown metasoma. A pale metasoma is present in Megaloptidia Cockerell, Megommation Moure, and some species of Megaloptina Eickwort, but these genera have a very slender proboscis, with the prementum 10 to over 20× as long as broad, and except for Megaloptina, also a serrate inner metatibial spur, while in Megalopta and Xenochlora the proboscis is not so slender, with the prementum about 4–8× as long as broad, and the inner metatibial spur is pectinate.
Three main lineages are recognized in the genus, the first one formed by the cleptoparasitic species, corresponding to the subgenus Noctoraptor, and treated here as the byrony group, the second one formed by the species in which the males have a conspicuous large process covered with velvety pilosity in the posterior upper margin of the metepisternum, and the last lineage comprises those species lacking a welldeveloped metepisternal process (Santos and Melo, unpublished data). The species of the second and third lineages can be further subdivided in four species groups: aegis, amoena, yanomami and sodalis. A subgeneric classification is not adopted here because the available name Megaloptella applies only to the amoena species group and Tmetocoelia has been shown to form a paraphyletic assemblage (Santos and Melo, unpublished data).
Identification key to the species of Megalopta from Brazil
This key includes species that occur in other South American countries (Bolivia, Ecuador, French Guiana, Guyana, Nicaragua, Peru, Suriname, Trinidad and Tobago, and Venezuela) and in Central America.
Females
1. Posterior upper margin of metepisternum modified into a conspicuously large process covered with velvety pilosity (Figure 1A, B) ......................... 2
– Posterior upper margin of metepisternum unmodified, lacking a velvety process (Figure 1C) .................................................................................... 8
2 (1). Posterior margin of basal area of metapostnotum arcuate, gradually curved toward the metanotum laterally, the longitudinal rugulosities sometimes numerous and present laterally (Figure 1D); upper frons conspicuously convex, strongly declivous toward sulcus around median ocellus (Figure 1E)… aegis group .................................................................................................. 3
– Posterior margin of basal area of metapostnotum straight, abruptly bending laterally toward the metanotum, the longitudinal rugulosities restricted to mid portion, absent laterally (Figure 1F); upper frons flat, not strongly declivous toward sulcus around median ocellus (Figure 2A)... amoena group (in part) ............................................................................................. 6
3 (2). Basal area of metapostnotum with longitudinal rugulosities weakly impressed medially and more developed laterally, the integument often reddish brown on basal half and metallic green on apical half (Figure 2B) .............................................................................. M. nitidicollis
– Basal area of metapostnotum with weak longitudinal rugulosities along its entire surface (Figures 1D, 2C, D) ............................................................. 4
4 (3). Basal area of metapostnotum orangish, without metallic reflections, surface entirely finely rugulose, stronger rugulosities rectilinear and long along entire surface (Figure 2C) ................................................................. M. aeneicollis
– Basal area of metapostnotum reddish brown or metallic green, the longitudinal rugulosities imbricated laterally (Figures 1D, 2D) ........................ 5
5 (4). Metanotum with dense short plumose pilosity, present on entire surface and obscuring the integument in oblique view (Figure 2D); basal area of metapostnotum with the integument entirely reddish brown, sometimes with green highlights laterally (Figure 2D) .............................................. M. aegis
– Metanotum sometimes with pilosity short and plumose, present only in two-thirds of disc, not obscuring the integument in oblique view (Figure 1D); basal area of metapostnotum with the integument metallic green with strongly imbricated longitudinal rugulosities (Figure 1D) ...... ............................................................................................ M. sulciventris
6 (2). Basal area of metapostnotum very short, about one-third as long as metanotum (Figure 2E) ........................................................................ M. chaperi
– Basal area of metapostnotum longer, about as long as or only slightly shorter than metanotum (Figures 1F, 3A) ............................................................. 7
7 (6). Basal area of metapostnotum uniformly metallic green (Figure 1F); mesoscutum, adjacent to parapsidial line, densely punctured (<1 pd), punctation sparser in direction to mesoscutal lip (≥ 1 pd) (Figure 3B); scutellum with posterior margin levelled to anterior margin of metanotum (Figure 3C) ...... ................................................................................................ M. guimaraesi
– Basal area of metapostnotum often reddish brown medially and metallic green laterally (Figure 3A); mesoscutum, adjacent to parapsidial line, with very dense contiguous punctation, in direction to mesoscutal lip punctures separated by <1 pd (Figure 3D); scutellum with posterior margin raised in relation to anterior margin of metanotum (Figure 3E) .... ............................................................................................... M. mura sp. n.
8 (1). Basal area of metapostnotum smooth laterally (Figures 2F, 3F, 4A ‒ C) ... 9
– Basal area of metapostnotum microreticulated laterally (Figure 4D, E)... sodalis group ............................................................................................. 13
9 (8). Mandible simple and lacking supplementary teeth; ocellocular distance longer than F1 length (Figure 4F); scopa absent; basitibial plate with undefined margins (Figure 5A) ......................................... M. xavante sp. n.
– Mandible bidentate and with supplementary teeth; ocellocular distance shorter than F1 length (Figure 5B); scopa present; basitibial plate with defined margin (Figure 5C) ...................................................................... 10
10 (9). Basal area of metapostnotum without longitudinal rugulae (Figure 2F); metepisternum usually with dense pilosity obscuring at the least upper half of sclerite (Figure 5D) ................................................................. M. amoena
– Basal area of metapostnotum with longitudinal rugulae (Figure 4A ‒ C); metepisternum with sparse pilosity, integument not obscured by pubescence (Figure 1C)… yanomami group ................................................................ 11
11 (10). Basal area of metapostnotum with longitudinal rugulosities restricted to mid portion, external rugulosities strongly impressed and forming semicircles, integument often dark green (Figure 4A); metanotum with contiguous punctation (Figure 5E); T1 densely punctured (<1 pd) ....... M. yanomami sp. n.
– Basal area of metapostnotum without defined external sulcus delimiting the longitudinal rugulosities, integument light green (Figure 4B); metanotum often densely punctured (<1 pd) (Figure 5F); T1 with sparse punctation (≥ 1 pd) ................................................................................. M. piraha sp. n.
12 (8). Basal area of metapostnotum with mid depression restricted to anterior half, not extending to posterior margin (Figure 4C) ............ M. munduruku sp. n.
– Basal area of metapostnotum with mid depression extending to posterior margin ...................................................................................................... 13
13 (12). Head and thorax mostly dark brown, lacking metallic reflections (Figure 4D) ............................................................................... M. cuprea
– Head and thorax metallic green (Figure 4E) ................................. M. sodalis
Males
1. Posterior upper margin of metepisternum modified into a conspicuously large process covered with velvety pilosity (Figure 6A) ............................. 2
– Posterior upper margin of metepisternum unmodified, lacking a velvety process (Figure 6B) ..................................................................................... 9
2 (1). Posterior margin of basal area of metapostnotum arcuate, gradually curved toward the metanotum laterally, longitudinal rugulosities sometimes numerous and present laterally (Figure 6C ‒ F); pilosity of metepisternum sparse, not obscuring the integument; diameter of velvety metepisternal process about 0.5× the tegula length (Figure 6A); 1st and 2nd tarsomere of foreleg with longest simple setae longer than summed length of the three apical tarsomeres; longitudinal sulcus of S3 strongly impressed (Figure 7A)... aegis group .................................................................................................. 3
– Posterior margin of basal area of metapostnotum straight, abruptly bending laterally toward the metanotum, the longitudinal rugulosities restricted to mid portion, absent laterally (Figure 7B, E); pilosity of metepisternum dense, obscuring the integument; diameter of velvety metepisternal process about 0.75× tegula length (Figure 7F); 1st and 2nd tarsomere of foreleg with longest simple setae smaller than summed length of the three apical tarsomeres; S3 lacking a longitudinal sulcus or sulcus only weakly indicated (Figure 8A ‒ C)… amoena group .................................................................. 6
3 (2). Glabrous basal portion of F6–F11 raised in relation to remainder of flagellomere surface (Figure 8D); pilosity of metanotum restricted to two-thirds of disc, not obscuring the integument in oblique view (Figure 6C); basal area of metapostnotum entirely metallic green or sometimes reddish brown medially (Figure 6C) ............................................................................. M. sulciventris
– Glabrous basal portion of F6–F11 levelled to remainder of flagellomere surface (Figure 8E); metanotum often with very dense pilosity covering entire disc and obscuring the integument in oblique view (Figure 6D, F); basal area of metapostnotum reddish brown, orangish or reddish brown with metallic green, never entirely metallic green (Figure 6D, F) ................................... 4
4 (3). Surface of basal area of metapostnotum entirely finely rugulose, its posterior margin slightly raised but not forming a carina (Figure 6D) ......... ............................................................................................. M. aeneicollis
– Surface of basal area of metapostnotum variable, its posterior margin forming a carina (Figure 6E, F) ........................................................................ 5
5 (4). Basal area of metapostnotum with strongly impressed longitudinal rugulosities along its entire surface, lateral portions with only short rugulosities (Figure 6E) ...................................................................................... M. aegis
– Basal area of metapostnotum lacking longitudinal rugulosities or only with a few weak rugulosities in its mid portion (Figure 6F) ............. M. nitidicollis
6 (2). Metanotum with dense pilosity; mid portion of basal area of metapostnotum very short, about one-third as long as metanotum (Figure 7B) ........... ...................................................................................................... M. chaperi
– Metanotum with sparse pilosity; mid portion of basal area of metapostnotum short, about one half as long as metanotum (Figure 7D, E) ..................... 7
7 (6). F6–F11 about as wide as remaining flagellomeres (Figure 8F); basal area of metapostnotum often lacking longitudinal rugulosities, only rarely with a few weak rugulosities in its mid portion (Figure 7C); S3 mostly flat, lacking a mid longitudinal sulcus (Figure 8B); S4 with pilosity basally, its apical margin slightly notched laterally (Figure 9B) ............................. M. amoena
– F6–F11 wider than remaining flagellomeres (Figure 9A); basal area of metapostnotum with longitudinal rugulosities in mid portion (Figure 7D, E); S3 with a weakly impressed longitudinal sulcus (Figure 8C); S4 lacking pilosity basally, its apical margin strongly notched laterally (Figure 8C) .. 8
8 (7). Mesoscutum, adjacent to parapsidial line, sparsely punctured (≥ 1 pd) ........ ................................................................................................ M. guimaraesi
– Mesoscutum, adjacent to parapsidial line, densely punctured (<1 pd) ........ ............................................................................................... M. mura sp. n.
9 (1). Inner orbit of eye only slightly angled; ocellocular distance longer than F1 length (Figures 9C ‒ F, 10A); F2 about two-thirds of F 3 in length; dorsal surface of flagellomeres flat (Figure 10B)… byroni group ........................ 10
– Inner orbit of eye strongly angled (Figure 10C); ocellocular distance shorter than F1 length; F2 about as long as F3; dorsal surface of flagellomeres strongly depressed (Figure 10D) ............................................................... 15
10 (9). Protruding process of S4 short, triangular shaped in lateral view (Figure 10E); basal area of metapostnotum without longitudinal rugulosities ................................................................................................ 11
– Protruding process of S4 digitiform (Figure 11B); basal area of metapostnotum with longitudinal rugulosities, or if rugulosities absent then the integument mostly dark brown to black (Figures 11C ‒ F) .................................................................................... 12
11 (10). Head and mesosoma metallic green with coppery tints, metasoma reddish brown (Figures 9C, 10F) M. guarani sp. n.
– Head and mesosoma dark brown with metallic green reflections, metasoma dark brown with purple tints (Figure 11A) ..................... M. karitiana sp. n.
12 (10). Mesosoma homogeneously metallic green (Figure 11C) ........................... ................................................................................. M. mapinguari sp. n.
– Mesosoma dark brown to black with metallic green tints on mesoscutum, scutellum, metanotum and basal area of metapostnotum (Figure 12A ‒ C) ................................................................................... 13
13 (12). Integument mostly brown with metallic green tints (Figure 12A) ................. ........................................................................................... M. xavante sp. n.
– Integument mostly dark brown to black (Figure 12B, C) ........................ 14
14 (13). Basal area of metapostnotum with longitudinal rugulosities longer on mid portion, becoming shorter laterally (Figure 11E) ...................... M. atlantica
– Basal area of metapostnotum smooth, without longitudinal rugulosities (Figure 11F) ............................................................................. M. purpurata
15 (9). Mid portion of basal area of metapostnotum flattened, longitudinal rugulosities absent or only a few present (Figure 12D, E) ............................... 16
– Mid portion of basal area of metapostnotum weakly concave, numerous longitudinal rugulosities present (Figures 12F, 13A, B) ........................... 17
16 (15). Scape uniformly enlarged (Figure 13C); flagellomeres with depressed and glabrous area (Figure 13D); basal area of metapostnotum dark green, longitudinal rugulosities strongly impressed and enclosed laterally by two sulci (Figure 12D) ................................................................. M. yanomami sp. n.
– Scape gradually enlarging toward the apex (Figure 13E); flagellomeres without depressed and glabrous area (Figure 10D); basal area of metapostnotum light green, longitudinal rugulosities not enclosed by two lateral sulci (Figure 12E) ......................................................................... M. piraha sp. n.
17 (15). Basal area of metapostnotum with shorter and weakly impressed longitudinal rugulosities (Figure 12F) ........................................ M. munduruku sp. n.
– Basal area of metapostnotum with longer and strongly impressed longitudinal rugulosities .......................................................................................... 18
18 (17). Integument mostly dark brown to black (Figure 13A, F) ............. M. cuprea – Integument mostly metallic green (Figure 13B) ............................ M. sodalis
The aegis species group
Diagnosis
The aegis species group includes M. aegis, M. aeneicollis, M. nitidicollis and M. sulciventris. Its species can be identified by the following characters: posterior margin of basal area of metapostnotum arcuate, gradually curved toward the metanotum laterally, the longitudinal rugulosities sometimes numerous and present laterally (Figure 1D); upper frons conspicuously convex, strongly declivous toward sulcus around median ocellus (Figure 1E); male with glabrous basal portion of F6–F11 expanded (Figure 8D, E); posterior upper margin of metepisternum modified into a conspicuously large process covered with velvety pilosity in both sexes, its diameter at least 0.5× the tegula length (Figure 1A); basal area of metapostnotum laterally with rugulose surface, the posterior margin arcuate, gradually curved towards the anterior margin laterally (Figure 1D, 2B ‒ D, 6C ‒ 6F); 1st and 2nd tarsomere of foreleg with longest simple setae longer than summed length of the three apical tarsomeres and T1 with contiguous punctation.
Megalopta aeneicollis, M. nitidicollis and M. sulciventris inhabit the Amazon Basin (Figure 14A ‒ C), while M. aegis occurs in the savannahs of central Brazil (cerrado) and in the Atlantic Forest of eastern Brazil (Figure 14A).
description: Published as part of Santos, L. M. & Melo, G. A. R., 2014, Updating the taxonomy of the bee genus Megalopta (Hymenoptera: Apidae, Augochlorini) including revision of the Brazilian species, pp. 575-674 in Journal of Natural History 49 (11) on pages 578-597, DOI: 10.1080/00222933.2014.946106, http://zenodo.org/record/4004455