THE STUDY OF MORPHOLOGY

Material from the following institutions was examined: American Museum of Natural History (New York), Coleção de Entomologia Pe. Jesus Santiago Moure, Universidade Federal do Paraná (Curitiba, Brazil), and Museo Nacional de Historia Natural del Paraguay (San Lorenzo, Paraguay).

The study of the external morphology was carried out through examination of dry, pinned specimens. Both adult females and males (when available) were examined for character circumscription. Male genitalia were also studied. The genital capsules were detached from the metasoma, heated and cleared in lactophenol, and stored in glycerin. Structures were observed under a stereoscopic microscope ZEISS Stemi SV6. Photographs of relevant structures were obtained with a Leica DFC 500 digital camera attached to the stereoscopic microscope Leica MZ 16. The images were captured with the software IM 50 (Image Manager) and mounted with the software Auto-Montage Pro 5.03.0040.

TABLE 1.

Number of terminals used for each species-group within Monobia and Montezumia following the classification proposed by Willink (1982)

TAXON SAMPLING

In order to test the monophyly of Monobia and Montezumia, species representing all species groups proposed by Willink (1982) were included (table 1). A total of 32 species belonging to either Monobia or Montezumia were used as ingroup taxa. As outgroup taxa, species in the genera Parazumia, Plagiolabra, Pseudodynerus, and Stenonartonia were included. Character polarization was obtained posterior to the analyses by rooting (Nixon and Carpenter, 1993). Trees were rooted between Stenonartonia apicipennis (Fox) and the remaining taxa. Abbreviations for Monobia and Montezumia are Mb. and Mt., respectively, to allow ready distinction between species included in each genus.

CLADISTIC ANALYSES

Characters were treated as nonadditive (Fitch, 1971). The matrix was constructed in Winclada (Nixon 2002), and the searches for most-parsimonious cladograms performed with the software TNT 1.1 (Goloboff et al., 2008a). Characters were treated using equal weights and implied weights (Goloboff, 1993). Under implied weights, values of the constant k between 3 and 10 were tested. The New Technology Search protocols were used for both character weighting schemes, with the algorithms Ratchet (Nixon, 1999; Perturbation Phase adjusted to 25 and 5 for upweighting and downweighting respectively, plus 200 iterations), Drift (Goloboff, 1999; 20 cycles), and Tree Fusing (Goloboff, 1999; 100 rounds) implemented. Each round of analysis comprising the full set of algorithms was performed until minimum tree length was hit at least 100 times. Clade support was investigated through the symmetric resampling method (10,000 replications) (Goloboff et al., 2003) and Bremer support (Bremer, 1994) (suboptimal trees up to 15 steps longer), also performed in TNT 1.1.

CLADISTIC ANALYSES

A total of 49 characters were circumscribed after examination of the specimens (tables 2 and 4). Thirty-nine characters were derived from external morphology, while 10 were limited to male genitalia.

TABLE 2.

Character list for Monobia and Montezumia. Characters were extracted from females except where explicitly indicated

TABLE 3.

Number of trees recovered under different weighting of the characters. Abbreviations used: CI = consistency index; RI = retention index

The analysis of the matrix using equal weights returned 35 trees of 149 steps, with the strict consensus shown in figure 1. The analyses using implied weighting and different constant k values returned different topologies and number of trees compared to equal weights (figs. 2–4; table 3). We base our discussion on the cladograms using equal weighting and implied weighting under the values 3 (strict consensus tree shown in fig. 2), 7 (single tree shown in fig. 3), and 8 (single tree shown in fig. 4) of the constant k, because they differ in terms of the internal relationships among species groups within Monobia and Montezumia.

The higher-level phylogenetic relationships among eumenine genera remain elusive, with only one published effort including Monobia and Montezumia as ingroup taxa (Carpenter and Cumming, 1985). Although their results indicate a sister-group relationship between Parazumia (formerly Paranortonia) and Monobia + Montezumia, related genera such as Plagiolabra and Stenonartonia were not included, rendering any topology obtained within this clade inconclusive with regard to a complete sample of relevant taxa. Therefore, we will defer discussion on the relationships of the outgroup taxa.

Both Monobia and Montezumia were recovered as monophyla, but only if Montezumia arizonensis Bequaert and Montezumia aurata Bertoni are included in Monobia (figs. 1–4). In all analyses, three synapomorphies always supported the clade Monobia + Montezumia: maxillary palpi with five palpomeres (char. 1, state 1), labial palpi with three palpomeres (char. 2, state 1), and epicnemial carina present (char. 22, state 1) (table 4). This palpal formula is clearly synapomorphic for Monobia + Montezumia for the major clade in which these genera are placed (Carpenter and Cumming, 1985), and it is a condition considered diagnostic by Willink (1982). The presence of epicnemial carina, however, is also observed in the species of other related genera such as Pseudodynerus (e.g., P. auratoides Bertoni and P. carpenteri Hermes and Melo; Hermes and Melo, 2008) and Stenonartonia (the species in the species group of S. occipitalis Garcete-Barrett, 2011). One homoplastic transformation also supports Monobia + Montezumia in every analysis, the cephalic foveae placed closer to the occipital carina than to the ocelli (char. 9, state 1), a condition also shared with Plagiolabra. When it comes to the equal-weighting analysis alone, the apex of digitus rounded in the male genitalia (char. 40, state 0) is also synapomorphic for this clade, with several homoplastic changes occurring among lineages within both genera. Thus, it is not surprising that this character would consequently be down-weighted in the implied-weighting analyses.

FIGURE 1.

Strict consensus cladogram of 35 most parsimonious trees using equal weights of the characters. Black circles indicate synapomorphies and white circles homoplastic changes. Mb. = Monobia, Mt. = Montezumia. Bremer support values in boxes below branches. Species group as in figure 2.

FIGURE 2.

Strict consensus cladogram of nine most parsimonious trees using implied weighting of the characters (k = 3). Black circles indicate synapomorphies and white circles homoplastic changes. Mb. = Monobia, Mt. = Montezumia, A = Mb. caridei group, B = Mb. angulosa group, C = Mt. azurescens group, D = Mt. leprieurii group, E = Mt. dimidiata group, F = Mt. nigriceps group.

FIGURE 3.

Single cladogram obtained with implied weighting of the characters (k = 7). Black circles indicate synapomorphies and white circles homoplastic changes.

FIGURE 4.

Single cladogram obtained with implied weighting of the characters (k = 8). Black circles indicate synapomorphies and white circles homoplastic changes.

TABLE 4.

Character matrix for Monobia and Montezumia as constructed from morphological data. Symbols used: unseen (?); inapplicable (-)

FIGURES 5–13.

5–9. Female head in frontal view: 5. Mb. apicalipennis; 6. Mb. schrottkyi; 7. Mt. analis; 8. Mt. dimidiata; 9. Mt. infernalis. 10–13. Female head in dorsal view: 10. Mb. apicalipennis; 11. Mt. dimidiata; 12. Mb. funebris; 13. Mt. analis. Scale bars for 5–9 = 2 mm; 10–11 = 1 mm; 12–13 = 0.5 mm.

As stated above, Monobia is monophyletic provided Montezumia arizonensis and Montezumia aurata are included in this genus. Bequaert (1940a), when describing Mt. arizonensis, commented that this species would be “on the border line of Monobia and Montezumia, the limits between these genera being arbitrary.” Indecision also existed regarding Montezumia aurata, which was originally described in Monobia by Bertoni (1918) and later transferred to Montezumia by Willink (1982). The monophyly of Monobia is supported by different homoplastic transformations when different weighting schemes and values of k were used. Under equal weights the evident notauli (char. 20, state 1; fig. 19), the metasomal sternum I more than three times as wide as long (char. 36, state 1; fig. 31), and the absence of carina on the base of the metasomal sternum I (char. 37, state 1; fig. 32) are supportive of the clade. Of special interest is character 37, which does not conform to the condition, cited above, that supports a large clade within Monobia (char. 37, state 0; fig. 31). Character 36 (state 1) is maintained as supportive of Monobia under implied weighting and k values between 3 and 7 in addition of different homoplastic changes (figs. 2 and 3). With implied weighting under k values between 8 and 10, characters 20 (state 1) and 37 (state 1) were once again recovered as supportive of the clade (fig. 4).

FIGURES 14–22.

14–15. Female pronotum in dorsal-oblique view: 14. Mb. apicalipennis; 15. Mt. analis. 16–18. Female mesosoma in lateral view: 16. Mb. apicalipennis; 17. Mt. dimidiata; 18. Mt. nigriceps. 19–22. Female mesosoma in dorsal view: 19. Mb. apicalipennis; 20. Mt. analis; 21. Mt. dimidiata; 22. Mt. nigriceps. Scale bars for 14–15 = 1 mm; 16–18 and 22 = 1 mm; 19–21 = 2 mm.

FIGURES 23–32.

23–24. Female metanotum in posterior view: 23. Mt. azurescens; 24. Mt. nigriceps. 25–26. Female propodeum in posterior view: 25. Mb. angulosa; 26. Mt. azurescens. 27–28. Female lower propodeum in lateral view: 27. Mt. nigriceps; 28. Mt. coeruleorufa. 29–30. Female tergum I in lateral view: 29. Mb. quadridens; 30. Mt. azurescens. 31–32. Female sternum I in ventral view: 31. Mb. schrottkyi; 32. Mt. azurescens. Scale bars for 23 = 0.3 mm; 24 = 0.5 mm; 25–26, 30–31 = 1 mm; 27–28 = 0.5 mm; 29, 32 = 1 mm.

Within Monobia, Mt. arizonensis was always placed as the sister species to the remaining Monobia, followed by Mt. aurata and Mb. caridei Brèmes. The group of Monobia caridei was recovered as sister to the group of Monobia angulosa de Saussure, which contains the majority of the species within the genus. Species groups proposed for Monobia by Willink (1982) were always recovered as monophyla. The group of Monobia angulosa is supported by one synapomophic condition in all analyses: cephalic foveae margined posteriorly by a carina (char. 8, state 0; fig. 12). The internal relationships of the Monobia angulosa group varied, with greater resolution reached as k values for the implied-weighting scheme were increased (compare figs. 2 and 4), that is, as the weighting function was weakened. Even though topology varied within this group, some relationships were always stable, such as the clade (Mb. goiana + Mb. insueta + Mb. triafasciata), the clade (Mb. apicalipennis + (Mb. funebris + Mb. nigripennis)), and the clade (Mb. angulosa + Mb. cingulata).

FIGURES 33–41.

33–36. Male paramere and volsella (digitus and cuspis) in lateral inner view: 33. Mb. quadridens; 34. Mt. analis; 35. Mt. azurescens; 36. Mt. brethesi. 37–40. Male aedeagus in lateral view: 37. Mb. quadridens; 38. Mt. analis; 39. Mt. azurescens; 40. Mt. brethesi. 41. Sketchy representation of the digitus of Mb. quadridens and Mt. analis: da = basal dorsal angle of digitus; va = basal ventral angle of digitus. Scale bars for 33–35 = 1 mm; figs. 36–39 = 1 mm; 40 = 0.5 mm.

TABLE 5.

Branch support values under different methods

Montezumia is supported by two synapomorphies under equal weights: submarginal carina slightly raised (char. 32, state 1; fig. 27) and preapical longitudinal furrow on metasomal tergum I deep (char. 35, state 1). The raised submarginal carina is present throughout the entire genus, with a different condition (strongly raised: char. 32, state 2; fig. 28) supporting the clade (Mt. azteca + (Mt. azurescens + Mt. coerulorufa)). Despite this character's seeming consistency among species of Montezumia, it was not optimized as a synapomorphy for the genus when implied weighting under k values between 3 and 7 was applied. Under values between 8 and 10, the condition was once again recovered as a synapomorphy for species of Montezumia. This is probably an effect of treating this character as nonadditive multistate.

As observed for the species group of Monobia angulosa, internal relationships within Montezumia varied when different approaches were considered. Again, greater resolution was obtained when implied weights were applied, increasing even more when higher values of k were used (figs. 2 and 3). This trend was maintained to the k value of 7, with some branches collapsing when values between 8 and 10 were tested (fig. 4). Among the species group of Montezumia proposed by Willink (1982), the group of Mt. arizonensis actually belongs to Monobia. The group of Mt. ferruginea de Saussure contains only one species, but its sister group could not be established from the present results. The group of Mt. infernalis (Spinola) was represented in the present study by the species Mt. aurata (now placed in Monobia), Mt. ignobiloides Willink, Mt. infernalis, and Mt. morosa de Saussure. It was the only species group not recovered as monophyletic, with its species recovered in different positions in the different analyses. Although sister-group relationships could not be established for the remaining species groups, all groups were corroborated as monophyletic in every tested weighting scheme: the group of Mt. azurescens (Spinola) with the topology as (Mt. azteca + (Mt. azurescens + Mt. coerulorufa)), the group of Mt. leprieurii (Spinola) with the topology as (Mt. brethesi + Mt. liliacea + Mt. pelagica), the group of Mt. nigriceps (Spinola) with the topology as (Mt. sparsa + (Mt. petiolata + (Mt. bruchii + Mt. nigriceps))), and the group of Mt. dimidiata de Saussure with the topology (Mt. analis + (Mt. cortesia + Mt. dimidiata)).

Although the values for Bremer branch support were relatively low (fig. 1; table 5), most clades were recovered as monophyletic as indicated above, but their relationships were not always stable. The same is true for branch support using the symmetric resampling method (table 5), with higher support values obtained when the implied weighting was performed (as shown by Goloboff et al., 2008b).

TAXONOMY

Monobia and Montezumia, as recognized herein, can be readily separated by the submarginal carina raised above the propodeal orifice in the latter, following the key provided by Carpenter and Garcete-Barrett (2003 [2002]). This condition was also recovered as synapomorphic for the species included in Montezumia in our analysis (see discussion above).

Three new combinations are proposed for species currently placed in Montezumia in congruence with the phylogenetic results: M. aurata, M. arizonensis, and M. oaxaca. The last species cited was not included in the present analyses, but it is morphologically similar to and included in the group of Mt. arizonensis, so its placement follows. Also, a new species of Monobia is described. Abbreviations used in the description are: MOW, median ocellus width; POD, minimum distance between posterior ocelli; OED, minimum distance between compound eye and posterior ocellus; and MPOD, minimum distance between median ocellus and a posterior ocellus. For identification purposes, we recommend the use of the keys provided by Willink (1982), as it is still the most comprehensive work on the taxonomy of both Monobia and Montezumia.

DIAGNOSIS

Monobia goiana is similar to M. insueta Giordani Soika and M. trifasciata Willink, running to couplet 8 in Willink's (1982) key, all these species bearing two slight lateral humps on the base of sternum II (fig. 50). Monobia goiana is more similar to M. insueta, these two differing from M. trifasciata by the lack of long erect and pale hairs on head and mesosoma (present in M. trifasciata; figs. 42–46, 48, 51–53), narrower gena at the level of eye emargination (broader on M. trifasciata; figs. 42, 52), and complete pronotal carina dorsally (interrupted medially on M. trifasciata; figs. 44, 51, 53). Monobia goiana differs from M. insueta by the less evident humeral crest anteriorly (more evident in males of both species), the lack of a differentiated cuticular median area on the mesoscutum (in M. insueta the punctures are separated by somewhat raised cuticle devoid of micropunctures; figs. 44, 48), by the dull and weakly punctured surface of terga I–II (shiny and with coarser punctures on M. insueta; figs. 47, 49), and by the presence of yellow markings on clypeus, pronotum, tegula, and tergum I of female (absent in M. insueta).

FIGURES 42–47.

Monobia goiana. 42–43. Habitus: 42. Female; 43. Male. 44. Female mesosoma in dorsal view. 45–46. Head in frontal view: 45. Female; 46. Male. 47. Female metasoma in dorsal view. Scale bars for 42–43 = 3 mm; 44, 47 = 1 mm; 45–46 = 2 mm.

FIGURES 48–53.

48–50. Mb. insueta, female: 48. Pronotum and mesoscutum in dorsal view; 49. Terga I–II in dorsal view; 50. Sterna I–VI in ventral view. 51–52. Mb. trifasciata, female: 51. Head and pronotum in dorsal view; 52. Head and mesosoma in lateral view. 53. Mb. goiana, female head and pronotum in dorsal view. Scale bars for 48–49 = 1 mm; 50, 52 = 2 mm; 51, 53 = 1 mm.

DESCRIPTION

HOLOTYPE: Female.

COLOR: Integument mostly black with yellow markings as follows: band on base of clypeus, mark on lower inner orbit of compound eye, line on dorsal surface of pronotum interrupted medially, most of tegula, obsolete markings on scutellum, small and thin subapical line on tergum I, broad bands on apex of terga II–V, lateral subapical markings on tergum and sternum VI, lateral apical marks on sterna II–V. Foretibiae yellowish chestnut on inner and anterior surfaces. Wing membrane chestnut, venation chestnut becoming brownish at apex. Body covered by short and erect golden hairs, which are longer on head, lateral surface of propodeum, and sterna I–II.

DIMENSIONS: Body from frons to apex of tergum II = 10.0 mm. Forewing length = 9.5 mm. Width of gena equivalent to 0.89 times the width of eye at emargination. Proportion MOW:POD:OED:MPOD equivalent to 1:1.4:1.4:0.5. Dorsal surface of tergum I 2.2 times wider than long.

STRUCTURE: Clypeus flat on center, somewhat depressed on lateral portions, with coarse striatiform punctures on apical two-thirds; clypeal apex concave, with distance between teeth a little smaller than interantennal distance; frons somewhat swollen, with striatiform punctures intermixed with micropunctures; cuticle around cephalic foveae slightly modified, with foveae delimited posteriorly by an evident and somewhat raised arclike carina; occipital carina strong and sharp, slightly angled on vertex; pronotal carina strong and complete, somewhat lamellar on dorsal surface, interrupted laterally below level of pronotal fovea and then continuous to mesopleural margin; pronotal fovea rounded, broad; dorsal surface of pronotum coarsely striatopunctate; humeral crest sharp especially anteriorly; lateral surface of pronotum depressed with scattered undefined and shallow punctures, reticulate; epicnemial carina strong; mesepisternum coarsely striatopunctate; mesoscutum coarsely striatopunctate, with space between punctures filled with somewhat sparse micropunctation; notauli well marked posteriorly; scutellum strongly punctured, with striatiform punctures restricted to lateral portions, less densely punctured medially where the micropunctures are densely concentrated; lateral crests of metanotum raised; metanotum coarsely striatopunctate, with raised and well-developed transversal crenation along apex of dorsal surface; apex of posterior surface of metanotum devoid of puctures; dorsal surface of propodeum coarsely striatopunctate becoming weaker and scattered on lateral surface; posterolateral angles of propodeum with a strongly pointed projection; posterior surface of propodeum mostly shiny and smooth, with scattered punctures on upper portion and obliquely striate on lower portion, delimited medially by a longitudinal sulcus on upper half and by a sharp carina on lower half; propodeal valvula strongly rounded and continuous with submarginal carina; metasoma with very weak punctures, separated by more than one puncture diameter, reticulate and dull; metasomal sternum II with somewhat stronger punctures than the rest of metasoma; terga I–II broader than long, tergum I with an apical shallow longitudinal furrow; base of sternum II with lateral humps slightly produced.

PARATYPE: Male.

COLOR: As in female, except for extensive yellow markings as follows: clypeus entirely; longitudinal line on scape beneath; broad pronotal band interrupted medially; a spot on upper mesepisternum; broad subapical transversal band on scutellum.

DIMENSIONS: Body from frons to apex of tergum II = 10 mm. Forewing length = 9.1 mm. Width of gena equivalent to 0.9 times the width of eye at emargination. Proportion MOW:POD:OED:MPOD equivalent to 1:1.6:1.6:0.5. Dorsal surface of tergum I 2.5 times wider than long.

STRUCTURE: As in female, except as follows: clypeus with weak and sparse punctation; clypeal apex deeply concave; humeral crest stronger and somewhat lamellar anteriorly; lateral humps on base of sternum II somewhat more developed.

ETYMOLOGY: The specific epithet (feminine) is the demonym applied to the native people of the Brazilian State where the type specimens where collected (Goiás).

SPECIMENS EXAMINED: Holotype: ♀, “Brasil, Goiás, Chapada dos Veadeiros, Fazenda Templo Terra, 14°10′38″S 47°38′33″W, 1220 m, 01.iv.2003, Melo, Aguiar, Marchi e Gonçalves.” Paratype: ♂, same data as holotype, except “02.iv.2003.” The holotype and the paratype are deposited at Coleção de Entomologia Pe. Jesus Santiago Moure, Departamento de Zoologia, Universidade Federal do Paraná (DZUP), Curitiba, Brazil.

ADDITIONAL SPECIMENS EXAMINED: Monobia insueta, 3 ♂ and 2♀, refs. HYM07926, HYM07927, HYM07928, HYM07929 and HYM07930. Monobia trifasciata: 2♂ and 2♀, refs. HYM07996, HYM07999 (Paratype), HYM08003 (Paratype) and HYM08004. These specimens are deposited in the Instituto Miguel Lillo, Tucumán, Argentina.