Herein we propose the pulchra species group as a distinct lineage within Centris s.str., comprising for the moment two species: Centris pulchra and Centris byrsonimae sp. n. This species group is characterized by the clypeus largely yellow with two longitudinal dark brown streaks located in the upper half; a narrow band of whitish and dense bristles bordering the posterior border of T2–T4, extended to the sides and narrowed in the middle, but not interrupted; by the maxillary palpus reduced to four palpomeres; the mandibles with five teeth, the most basal substantially smaller and located in the lower inner edge of the mandible; and the secondary basitibial plate yellow, but only slightly elevated (merely inflated), not projecting over the basal plate.

Comments. In the identification keys of Ayala (in Michener 2007) and Silveira et al. (2002), the species of the pulchra group do not fit well into Centris s.str. based on four characters: (1) the maxillary palpus is 5- or 6-segmented, (2) the mandible 3- or 4-toothed, (3) the basitibial plate with a defined secondary plate with sharp projecting margins, and (4) the clypeus with yellow or white markings in the form of an inverted T or Y. Although the pulchra group differs in these four characters and indicated in the key as diagnostic for the subgenus Centris, Centris pulchra and Centris byrsonimae sp. n. can be retained there based on the unique character of the subgenus: the long, slender, apical projection of the male gonocoxite, extending parallel to the gonostylus (Michener 2007); this gonocoxal projection bearing giant branched setae. In regard to parasitism by Mesonychium asteria (Smith, 1854) (Apinae: Ericrocidini) in nests of Centris pulchra reported by M.C. Ramos (pers. comm. in Rocha-Filho et al. 2009), this was probably a mistake. According to Marina C. Ramos (pers. comm. 2012) the parasitism observed was of an unidentified species of Mesoplia Lepeletier de Saint Fargeau (Apinae: Ericrocidini) in nests of Centris byrsonimae sp. n. She observed adults of Mesoplia sp. emerging from brood cells of Centris byrsonimae sp. n. nesting in the ground.

♀, São Luís, MA, Brasil, 15.ix.1984, Albuquerque Leg. // Coletada na flor, Byrsonima crassifolia: Malpighiaceae // Holótipo // Centris byrsonimae Moure, 1985, Holotype // Centris birsonimae Moure, 1986 // Hr 15:00–16:00 // Holotype ♀ Centris byrsonimae Mahlmann & Oliveira, 2012. The specimen is in excellent condition and is deposited in DZUP.

♂, Alótipo // Barreirinhas, MA, Brasil, 09.viii.1991, Brito & Mendonça // Pl. N.017, 10–11h // Centris sp.2, C. byrsoni. Mou. // Allotype ♂ Centris byrsonimae Mahlmann & Oliveira, 2012. The specimen is deposited in MZUFBA.

(13♀♀, 3♂♂): Parátipo // Barreirinhas, MA, Brasil, 19.xi.1991, Brito & Mendonça // Pl. N.006, 9–10h // Centris byrsonimae // Coletada em Banisteriopsis sp.: Malpighiaceae (1♀, LEACOL); Parátipo // São Luis, MA, Brasil, 21.x.1984, Albuquerque Leg. // Hr. 10:00–11:00 // Moure, 1985, Paratype // Coletada em Byrsonima crassifolia (L.) Kunth: Malpighiaceae (1♀, LEACOL); Parátipo // São Luis, MA, Brasil, 21.x.1984, Albuquerque Leg. // Hr. 7:00–8:00 // Paratype // Coletada em Byrsonima crassifolia (L.) Kunth: Malpighiaceae (1♀, LEACOL); Parátipo // São Luis, MA, Brasil, 19.viii.1984, Albuquerque Leg. // Hr. 10:00–11:00 // Centris byrsonimae // Moure, 1985, Paratype // Coletada em Byrsonima crassifolia (L.) Kunth: Malpighiaceae (1♀, MZUFBA); Parátipo // Ilha de Curupu, MA, Br., 14.viii.1999, Sousa & Martins Leg. // Pl.N.006, Hr. 13:14, 62 (1♀, LEACOL); Parátipo // Urbano Santos, MA, Brasil, 03°12'28"S, 43°24'12"W, 27.viii.2005, 6:00–7:00, Mendes FN, Leg. // 795 // Coletada em Byrsonima umbellata Mart. ex A.Juss.: Malpighiaceae (1♀, LEACOL); Parátipo // Urbano Santos, MA, Brasil, 03°12'28"S, 43°24'12"W, 27.viii.2005, 7:00–8:00, Mendes FN, Leg. // 800 // Coletada em Byrsonima umbellata Mart. ex A.Juss.: Malpighiaceae (1♀, LEACOL); Parátipo // Urbano Santos, MA, Brasil, 03°12'28"S, 43°24'12"W, 10.ix.2005, 9:00–10:00, Mendes FN, Leg. // 849 // Coletada em Byrsonima umbellata Mart. ex A.Juss.: Malpighiaceae (1♀, MZUFBA); Parátipo // Barreirinhas, MA, Brasil, 09.viii.1991, Brito & Mendonça // Pl. N.017, 10–11h // Centris sp.2 // Centris byrsonimae Moure, MS, Det. Camargo, 1992 (1♂, LEACOL); Parátipo // Barreirinhas, MA, Brasil, 22.viii.1992, Brito & Mendonça // Pl. N.064, 11–12h (1♂, LEACOL); Parátipo // Barreirinhas, MA, Brasil, 21.viii.1992, Brito & Mendonça // Pl. N.064, 12–13h (1♂, MZUFBA); Parátipo // Brasil, Ceará, Horizonte, 10.ix.2011, Rede Entomológica, 9h, P. Andrade Leg. // Coletada na flor, Anacardium occidentale L.: Anacardiaceae // 544 (1♀, MZUFBA); idem // 546 (1♀, MZUFBA); Parátipo // Brasil, Ceará, São Gonçalo do Amarante, Praia do Pecém, xi.2008, T. Mahlmann & Y. Antonini Leg. // Favízia 001153 (1♀, Snow Entomological Collections, University of Kansas Natural History Museum-SEMC, Lawrence, Kansas, USA); Parátipo // Brasil, Bahia, Camaçari, 04.xi.2008, J.F. Rosa e equipe leg.//987, Litoral Norte, Ponto 1, 04.xi.2008, 9:20–10:20, Byrsonima sericea, Rosa, JF; Monteiro, D; Silva, MD; Oliveira JFL leg. // sp.11 (1♀, MZUFBA); Parátipo // Brasil, Bahia, Salvador, Abaeté, 05.xi.1996, 11:15hs, B.F. Viana Leg. // Coletada na flor: Byrsonima teopteridifolia Juss [Byrsonima microphylla A.Juss.], Planta Nº1 // Abaeté, SSa, Ba, 5.xi.1996, N, pl:01, 11:15 // 21 // 2330 // Paratype ♀, Centris pulchra Moure, Oliveira & Viana, 2003 (1♀, MZUFBA). All specimens with the same Paratype yellow labels: Paratype Centris byrsonimae Mahlmann & Oliveira, 2012.

This species is quite similar to Centris (Centris) pulchra but differs by its smaller body size (ca. 10.6); the largely honey-brown integument (Figs. 2, 7); metallic blue iridescence almost imperceptible on metasomal terga; T1–T5 interlay covered by pale pubescence including the yellowish pubescence, largely golden on apical margin of T5 (Fig. 7); inner surface of probasitarsus with the combs for collecting floral oil, on distal half of posterior margin with three distinct strongly spatulate setae, curved on the inner surface and wider on its apex (Fig. 6); and the gonocoxal projection covered by dense, giant branched setae on the inner surface, forming a distinct fringe of plumose hairs longer than the gonocoxal projection itself (Figs. 19–21).

♀: Structure: Total body length 10.6; forewing length 7.1; head length 2.9, width 4.4; clypeus length 1.3, width 1.8; labrum length 0.7, width 1.2; scape length 0.6; F1 length 0.7; F2 length 0.2; F3 length 0.3; diameter of the anterior ocellus 0.3; ocellocular distance 0.4 (1.1x lateral ocellar diameter); upper interocular distance 2.1; lower interocular distance 2.0; metasomal width 4.2 (measured on T2). Clypeus convex with a smooth bottleneck in upper third from tentorial foveae; labrum semicircular. Maxillary palpus with four palpomeres (Fig. 4), 1st palpomere bulged and 0.5× shorter than subsequent two palpomeres, 4th palpomere much shorter than others (0.3× smaller than 2nd and 3rd). Mandibles with four normal teeth and one internal basal denticle separated from 3rd by a distance equivalent to 2× its length (Fig. 1). Posterior margin of procoxae with a broad process (Fig. 5), projected ventrally over mesepisternum and covered with long plumose pubescence. Basitibial plate with distinct secondary plate, primary plate concave and oval, secondary plate only slightly elevated but not projecting over primary plate; upper pygidial plate relatively long and narrow with its apex away from apex of lower plate by approximately 0.8× SL; inferior plate gently depressed from sides to middle and flat on apical third, ending in a point (Fig. 8).

Coloration: Integument predominantly honey brown with metallic blue highlights almost imperceptible on metasoma (Fig. 7); head and mesosoma dark brown, mesoscutellum brownish. Yellow marks: clypeus, except two divergent wide dark brown stripes, located on upper half of clypeus and above separated from each other by distance equivalent to lateral ocellar diameter; labrum; basal 2/3 of mandibles; malar area; very short narrow triangle on supraclypeal area; paraocular stripe ventrally wider, widest at level of tentorial fovea, narrowing upward and gradually ending at median level of compound eyes; wide stripe on lateroposterior surface of scape; small yellow marks on base of tibiae, most developed on secondary basitibial plate on metatibia; on protibia yellow marks followed by long dorsolateral stripe. Tegulae translucent honey colored; wing membrane slightly yellowish, with little brownish streak in basal third of marginal cell, with very thin arched transverse vein on apical third of first submarginal cell; brown venation slightly yellowish at pterostigma and base of wings; primary basitibial plate honey translucent; metallic blue reflections almost imperceptible on T2–T5.

Pubescence: In general pale and yellowish, with mostly whitish hairs as follows: lower surface of face and gena, ventral portion of mesepisterna, metepisterna, propodeum, base of metasoma and sterna; reddish bristles only on inner surface of tarsi, mostly visible on basitarsi; mesepisterna with plumose hairs restricted to upper half, dorsoventral surface covered by simple setae more widely spaced; lower 2/3 of ventral surface of procoxae covered by extremely thick, curved, yellow-whitish setae, decreasing in length toward posterior border, upper portion of procoxae covered by plumose hairs; outer surface of mesocoxae covered by simple bristles, upper margins with plumose hairs 0.5x smaller; probasitarsus with long line of bristles (2× SL) on outer dorsolateral surface, shortening toward apex and interspersed by a dense band of short plumose hairs, inner surface with few short bristles sparsely distributed; inner surface of probasitarsus, on distal half of posterior margin, with combs for collecting floral oils with three distinct and strongly spatulate setae, curved toward inner surface and wider at apex (Fig. 6); outer surface of mesobasitarsus with dense, short, plumose pubescence interspersed with simple bristles longer and sparser; metatibiae and metabasitarsus with thicker, milky white bristles; T2–T4 entirely covered by pale yellow, short and sparse setae, longer and denser on sides of terga and near posterior border, contrasting with hairiness of discal terga but not forming distinct band of yellowish bristles (Fig. 7); apical margin of T5 with long fringe of golden branched bristles (0.5× SL); S2–S5 with dense apical fringe, with hairs of central stripe slightly longer; fringe of S5 curved and with rachis relatively longer.

Sculpturing: Dense but of moderate size: on vertex spacing 1/2 of puncture width, with cariniform spaces between punctures, slightly smoother on supraclypeal area; midline of clypeus with integument smooth and polished, interspersed by very few punctures; punctures most evident on the side slopes of clypeus and labrum. Punctures obscured by pilosity on mesosoma and metasoma, mostly fine and spaced on sides of propodeum, and finer and piligerous on terga.

♂: Structure: Total body length 10.8; forewing length 7.7; head length 2.7, width 4.1; clypeus length 1.2, width 1.7; labrum length 0.8, width 1.2; scape length 0.6; F1 length 0.7; F2 length 0.2; F3 length 0.3; diameter of the anterior ocellus 0.3; ocellocular distance 0.3 (1.3× lateral ocellar diameter); upper interocular distance 2.0; lower interocular distance 2.3; metasoma width 4.2 (measured on T2). Similar to female except as follows: mandibles with three normal teeth and one basal denticle on inner margin; basitibial and pygidial plates absent. S7 and S8 as in figure 22: S7 about as long as wide as measured at base, approximately 2/3 of S8 length and covered by setae on its lateral areas and apex; apical margin of S7 indented; median projection of S8 slightly uniformly tapering to apex; dorsal surface and apical 1/3 of S8 covered by long branched setae, apex covered by simple, shorter erect setae. Genitalia as in figures 19–21: dorsal surface of gonocoxite with small basal edge, internal surface covered by long, dense pilosity; gonocoxal projection covered by dense, long branched setae on inside surface forming distinct fringe of plumose hairs longer than gonocoxal projection itself; gonostylus covered by short setae.

Coloration: Metallic blue–greenish reflections more visible than in female at T2–T5 (Fig. 12); clypeus without two divergent dark brown stripes on upper half (Fig. 9).

Pubescence: Similar to female but mesepisterna fully covered by dense plumose hairs; ventral surface of pro- and mesocoxae covered by plumose hairs only, procoxae with plumose hairs markedly longer, denser and recurved; probasitarsus without long line of long bristles; inner surface of probasitarsus without combs for collecting floral oils; outer surface of mesobasitarsus without velvet, dense, short plumose pubescence; external surface of metabasitarsus covered by dark-brown setae; base of metapretarsal claws with pair of thin, simple setae almost as long as pretarsal claws; pilosity of T1 denser and longer than remaining terga; T2–T5 with band of yellowish setae more distinctive and wider than in female (Fig. 12); margin of T5 without long fringe of golden branched bristles.

Sculpturing: Midline of clypeus with integument mostly smooth and polished, interspersed by very few punctures.

The specific epithet was originally given by Dr. Jesus S. Moure in 1985 when he identified the material collected by Dra. Patrícia Maia C. de Albuquerque for her dissertation, using the generic name of the most common host plant for this bee species (Byrsonima crassifolia L. Rich: Malpighiaceae). Unfortunately, while Moure placed the name on labels of specimens he never published a description of the species or put into writing those characters from which he based his conclusions. In 2003, after the publication of Centris pulchra, Moure invited the second author of the present paper to describe with him this new species after a restudy of all paratypes of Centris pulchra and other specimens from Maranhão deposited in LEACOL, including the male specimens, are re-examined. However, Moure died in June 2010 before the paper was completed. Thus, despite the fact that he recognized the novelty of the species, his name is not included as a coauthor given that he did not review or approve any version of this manuscript. Nonetheless, we retained the name he intended as well as the specimen he selected as the holotype. Such an epithet also seems to be a good choice given that it has been used before in the literature.

Although Centris byrsonimae sp. n.is quite similar to Centris pulchra, it can be differentiated from that species by the integument predominantly honey-brown (mostly dark brown in Centris pulchra); Centris byrsonimae with metallic blue highlights almost imperceptible on metasomal terga, marked in Centris pulchra. The pubescence in general is yellowish, especially on the disc of the terga and the apex of T5, with an apical fringe of golden bristles at the apex of T5; in Centris byrsonimae sp. n. T2–T4 are entirely covered by pale, short yellow and sparse setae on the disk of the terga but not forming a distinct band of bristles on the posterior border, while in Centris pulchra the discs of T2–T4 are covered by dark-brown setae contrasting with the narrow and dense bands of whitish bristles bordering the posterior edge of the terga extending to the sides and narrowed in the middle, but not interrupted, and contrasting also with the hairiness of the disc of the terga. On the mesepisterna of Centris byrsonimae sp. n.the plumose hairs are restricted to the upper half, while in Centris pulchra they are distributed on the dorsoventral surface; the lower 2/3 of the ventral surface of the procoxae are covered by extremely thick, curved yellow-whitish setae (the upper portion covered by plumose hairs) in Centris byrsonimae sp. n.while in Centris pulchra this structure has only plumose hairs; the inner surface of the probasitarsus with secondary combs for collecting floral oils is modified, with three distinct, strongly spatulate setae in Centris byrsonimae sp. n.while in Centris pulchra these setae are thick but not modified (Figs. 6, 16); the pygidial plate of both species is doubled but in Centris byrsonimae sp. n.the upper plate is relatively longer (Fig. 8); the lower plate of the pygidial plate is slightly depressed from the sides to the middle and flat on the apical third contrasting with Centris pulchra in which this depression is notably more pronounced and convex in the apical third (Fig. 18). The male of both species are quite similar but in Centris byrsonimae sp. n.the pubescence is markedly yellowish while in Centris pulchra it is whitish; the metallic highlights are most visible and bluish in Centris pulchra and almost imperceptible and greenish in Centris byrsonimae sp. n.; the base of the metapretarsal claws have a pair of thin simple setae in Centris byrsonimae sp. n.while in Centris pulchra there is a tuft of long dense plumose hairs. In addition, the male terminalia is quite different as shown in Figures 19–26.

Table 2

One female specimen originally designated by Moure et al. (2003) as paratype of Centris pulchra is actually an individual of the species described above as Centris byrsonimae sp. n.and is selected as a paratype of that species (Parátipo ♀ // Brasil, Bahia, Salvador, Abaeté, 05.xi.1996, 11:15hs, B.F. Viana Leg. // Coletada na flor: Byrsonima teopteridifolia Juss, Planta Nº1 // Abaeté, SSa, Ba, 5.xi.1996, N, pl:01, 11:15 // 21 // 2330 // Paratype ♀, Centris pulchra Moure, Oliveira & Viana, 2003). For this female paratype a mistake was made in reporting the identification of the host plant in the original description. The plant identification was subsequently corrected by the specialist who first identified the botanical species considered presently as Byrsonima microphylla A.Juss. (F.O. da Silva and B.F Viana 2012, pers. comm.). Moure et al. (2003) listed six male paratypes, probably a typographic mistake due the fact that one specimen with the label (Parátipo // Brasil, Bahia, Salvador, Abaeté, 11.ix.1996, 13:35hs, B.F. Viana Leg. // Coletada na flor: Waltheria cinerescens St. Hil, Planta Nº22 // Abaeté, SSa, Ba, 11.ix.1996, N, pl:22, 13:35 // 21, ♂ // 2319 // Paratype ♂, Centris pulchra Moure, Oliveira & Viana, 2003) is a male, giving a total of 22♀♀ and 7♂♂ paratypes for Centris pulchra in MZUFBA. Two other typographic mistakes were observed about the labels as recorded in the original description of Centris pulchra. The data for these two paratypes are corrected here: (Parátipo // Brasil, Bahia, Salvador, Abaeté, 01.ix.1996, 12:20hs, B.F. Viana Leg. // Coletada na flor: Eriope blanchetii (Benth) Harley, Planta Nº10 // Abaeté, SSa, Ba, 01.ix.1996, N, pl:10, 12:20 // 21 // 2328 // Paratype ♀, Centris pulchra Moure, Oliveira & Viana, 2003) and (Parátipo // Brasil, Bahia, Salvador, Abaeté, 13.iv.1996, 14:20hs, B.F. Viana Leg. // Coletada na flor: Cuphea branchiata Koehne, Planta Nº3 // Abaeté, SSa, Ba, 13.iv.1996, N, pl:03, 14:20 // 21, ♂ // 2317 // Paratype ♂, Centris pulchra Moure, Oliveira & Viana, 2003).

Total body length 13.9. Integument brown-blackish, except legs and metasoma ferruginous; metallic blue highlights on T2 – T5, mostly marked on T5 (Fig. 17); distal edge of terga with a band of whitish setae; most part of basal area of T2–T4 with black bristles. Inner surface of probasitarsus with combs for collecting floral oil, on distal half of posterior margin, with setae unmodified (Fig. 16). Male genitalia with pubescence relatively spaced, apical projection of gonocoxite with a fringe of short, unbranched bristles, about 1/2 length of projection itself (23–25).

Male S7, S8 and genitalia as in figures 23–26: S7 notably wider than long, approximately 1/5 of length of S8; edge of S7 strongly angular, forming two distinct lobes, these covered with erect bristles; median projection of S8 with a strong median strangulation, apical 1/3 enlarged; dorsal surface of S8 covered by erect bristles, apical 1/3 covered by longer branched bristles curved laterally, apex with shorter simple erect bristles. Dorsal surface of gonocoxite with a large basal edge strongly keeled, internal border covered by short dense pilosity; apical projection of gonocoxite relatively short, its apex distant from gonostylus apex and covered internally by a fringe of simple setae shorter than projection; gonostylus covered by short bristles sparsely distributed (Figures 23–25).

Table 2