Axima nordestina (Hymenoptera, Eurytomidae), a new stalk-eyed wasp from Brazilian savannah

Abstract

A new stalk-eyed wasp Axima nordestina sp. n. is described from the Northeastern Brazilian savannah. Axima nordestina is the fourth species of stalk-eyed wasps (A. noyesi species group) and the second one known from Brazil. The head morphology of A. nordestina appears less derived than in the other known species. An updated key of the A. noyesi species group is provided.

Axima noyesi species group; Chalcidoidea; Maranhão; New species

Introduction

Stalk-eyed wasps are morphologically bizarre chalcidoid parasitoids, which are only known from the Neotropics. So far, three species have been described within the recently revised Axima noyesi species group, one from Brazil, and four other non noyesi species group (spinifrons species group) were also described from Brazil ( Arias-Penna et al., 2014). During a research stay at the Coleção Zoológica do Maranhão (CZMA) at Maranhão, Brazil, we recently discovered an additional species, which is described and diagnosed below.

Material and methods

The material examined was provided by Francisco Limeira-de-Oliveira, curator of the Coleção Zoológica do Maranhão (CZMA), Universidade Estadual do Maranhão, Caxias, Maranhão, Brazil. Morphological terminology follows the Hymenoptera Anatomy Ontology (Hymenoptera Anatomy Consortium, 2014). The nomenclature of integument sculpture follows Harris (1979). The key for species follows Arias-Penna et al. (2014). The new species has been prospectively registered with Zoobank (Polaszek et al., 2005). The following abbreviations are used in the text: cl = clava, F = flagellomere, Mt = metasomal tergite, ped = pedicel.

The specimen was examined with a Leica MZ80 Stereo Microscope. Images were taken with a Leica DFC 495 camera attached to a Leica Z16 APO Stereo Microscope. Figures were produced from stacks of images that vertically transected the specimen using Leica LAS (Leica Application Suite V4.3.0) Microsystems by Leica (Switzerland) Limited. These were combined automatically into a single image using Helicon Focus (version 6.0.18), based on Method C (Pyramid) and focus autoadjustments 1% (horizontally).

Results

Taxonomy

Key to females ofAxima noyesispecies group (modified from Arias-Penna et al., 2014)

1. Mesoscutum without median carina (Figs. 4 and 8)...2

-. Mesoscutum with median carina at least slightly indicated....3

2. Head strongly transverse in dorsal view, 2.0 times as broad as mesosoma. Mesoscutellar process more posteriorly pointed (shark-fin shaped). Mt5 entirely covered with sparse white setae ... A. diabolus (Yoshimoto & Gibson, 1979)

- Head less transverse in dorsal view, 1.7 times as broad as mesosoma (Fig. 8), Mesoscutellar process dorsally pointed (cone shaped) (Fig. 5). Mt5 with lateral patch of white setae (Fig. 7)... A. nordestina sp. nov.

3. Median mesoscutal carina slightly indicated, laterally flanked by rows of piliferous punctures (rounded depressions). Mt5 and Mt6 with distinct setation ... A. noyesi Subba Rao, 1978

- Median mesoscutal carina more distinctly raised, laterally flanked by rows of piliferous foveae (subrectangular depres-sions). Mt5 bare, Mt6 with few scattered setae ... A. sidi Arias-Penna, Pape & Krogmann, 2014

Axima nordestina Barbosa, Krogmann & Azevedo sp. n. ( Figs. 1-4 and Figs. 5-8)

Type material. Holotype female: Brasil, Maranhão, Mirador, Parque Est[adual] Mirador, Povoado Pindaíba (Mel), 06°39'44" S 45°01'37" W, Armadilha Malaise, 01-05.vi.2011, F. Limeira-de-Oliveira, M.M. Abreu & J.S. Pinto Junior (CZMA). The holotype is deposited in Coleção Zoológica do Maranhão (CZMA), Caxias, Maranhão, Brazil.

Figs. 1-4. Axima nordestina Barbosa, Krogmann & Azevedo sp. nov. 1. Habitus, lateral view. 2. Head, lateral view. 3. Head, frontal view. 4. Mesosoma and petiole, dorsal view.

Figs. 5-8. Axima nordestina Barbosa, Krogmann & Azevedo sp. nov., 5. Head and mesosoma, lateral view. 6. Wings, dorsal view. 7. Metasoma, lateral view. 8. Head and mesosoma, dorsal view.

Diagnosis. Eye stalks relatively short, head in dorsal view 1.7 times as broad as mesosoma. Mesoscutellar process dorsally pointed and cone-shaped. Mt5 with lateral patch of white setae.

Description. Body color ( Figs. 1-4 and Figs. 5-8). Body generally dark brown with ventral and lateral portions of head ( Figs. 2 and 3) and mesosoma ( Figs. 1-4 and Figs. 5-8) brown. Legs dark brown ( Fig. 5). Fore and hind wings hyaline. Body length: 7.15 mm, head plus mesosoma: 3.07 mm.

Head ( Figs. 1-4 and Figs. 5-8). Head punctuate, densely covered with white setae ( Figs 2 and 3), though less distinct, shorter and thinner, dorsally ( Fig. 3). Antenna 10-segmented. Length of antennal segments (in mm): scape: 0.92, pedicel: 0.08, F1 (anellus): 0.04, F2: 0.31, F3: 0.23, F4: 0.23, F5: 0.19, F6: 0.19, F7: 0.15, clava: 0.30. F2-F6 densely covered with long and depressed setae. Longitudinal sensilla arranged in multiple irregular rows (number of rows depending on length of flagellomere). Clava ( Figs. 2 and 3) one-segmented, but limits of fused antennomeres still slightly indicated, densely covered with long setae. Frons densely setose and entirely foveate, with basal portion wide, at least more than half width of head in frontal view. Gena short, shorter than eye length in lateral profile; with expansion around posterior margin.

Mesosoma ( Figs. 1-4 and Figs. 5-8). Pronotum ( Fig. 8) 0.34 as long as wide; with piliferous punctures, more dense at lateral panel of pronotum. Mesoscutum with complete and broadly foveolate notauli ( Figs. 1-4 and Figs. 5-8); without median mesoscutal carina ( Fig. 8), remaining mesoscutum with piliferous punctures. Dorsal surface of axillae with piliferous punctures, posterior portion of axillae smooth with distinct patch of white setae. Axillula smooth, dorsally defined by distinct carinae. Mesoscutellum expanded dorsally into cone-shaped process, antero-medially with keel-like carina ( Figs. 5 and 8). Mesepisternum with distinct but shallow mesofemoral depression ( Figs. 1-4 and Figs. 5-8), the depression anteriorly without carina; Mesepisternum anteriorly with distinct white setae. Mesepimeron ( Figs. 1-4 and Figs. 5-8) glabrous, upper mesepimeron marked by deep impression, with well-marked fovea. Ventral mesopleuron with piliferous foveae; mesofurcal pit large, situated anterior to mesocoxal depression; mesodiscriminal line absent. Metanotum with metascutellar arms carinate; lateral panel of metanotum consisting of row of large fovea; metascutellum carinate, reaching anterior margin but separated from posterior margin of metanotum. Lateral panel of metapleuron with densely foveolate punctures and distinct long white setation. Ventral metepisternum anteriorly smooth, posterior portion irregularly foveolate and greatly expanded between hind coxae. Propodeum with median foveolate sulcus, and most piliferous punctures foveolate and much larger than on pro- and mesonotum.

Legs ( Fig. 5). Forecoxa with large piliferous punctures. Meso and hind coxae setose and polished.

Wings ( Fig. 6). Length of submarginal vein: 1.08 mm, marginal vein: 0.69 mm, postmarginal vein: 0.15 mm, stigmal vein: 0.15 mm.

Metasoma ( Fig. 7). Length of metasomal tergites in dorsal view (in mm): Mt1 (petiole): 1.08, Mt2: 0.23, Mt3: 0.23, Mt4: 0.23, Mt5: 0.46, Mt6: 0.77, Mt7: 0.69, Mt8/9: 0.23. Petiole with indistinct, shallow reticulation; subrectangular in cross section, with four strong carinae delineating each of the dorso- and ventrolateral margins; dorsal surface with median carina along anterior 3/4; lateral surface with additional complete length carina. Post-petiolar metasoma without microreticulation; tergites bare except Mt4-6 with distinct patches of white setae, Mt7-9 setose ( Fig. 7). Length of exposed part of ovipositor in dorsal view: 0.08 mm.

Male. Unknown.

Distribution. Maranhão, Brazil.

Etymology. The specific epithet nordestina refers to its Northeastern Brazil origin.

Host. Unknown.

Discussion

Axima nordestina is the fourth species in the noyesi species group. Arias-Penna et al. (2014) suggested that the stalked eyes, characteristic for the noyesi species group, serve as a "head-butting device" for leaving the host through soft plant tissue. They further hypothesized that the pronotal invaginations might further support this function ( Arias-Penna et al., 2014, Fig. 7). Interestingly, in A. nordestina the stalks are shorter than in the other known stalk-eyed wasp species and the pronotal invaginations are not well developed. These morphological features seem to constitute a less derived character state, which needs confirmation from future cladistic analysis of Axima.

As for the three previously described species, A. nordestina is only known from the female holotype. Therefore, it still needs to be shown whether the extreme head modification is present in both sexes.

More records are needed to assess the distribution of stalk-eyed wasps, which are currently only known from Central and Northeastern Brazil, Colombia and Trinidad. The fact that these extremely distinct insects have only been found on four occasions shows that the Neotropical parasitoid fauna is still insufficiently sampled. Increased collecting efforts with a strong focus on microhymenopterans would be needed to better assess the terrestrial biodiversity of South America.

Acknowledgments

We thank Francisco Limeira-de-Oliveira for his kind reception at Coleção Zoológica do Maranhão in Caxias; to FAPES grant #2012/20 and CNPq grant #301669/2010-4 for providing scholarship to first and third authors respectively. The two trips to Caxias were supported by CNPq/FAPES grant #52263010/2011 (Pronex) and CNPq grant #562224/2010-6 (Programa de Taxonomia).

References

• Arias-Penna, D.C., Pape, T., Krogmann, L., 2014. Stalk-eyed wasps - review of a largely unnoticed group of morphologically bizarre chalcidoid wasps (Hymenoptera: Eurytomidae: Axima). Zootaxa 3866, 583-590.
• Harris, R.A., 1979. A glossary of surface sculpturing. Occas. Pap. Entomol. 28, 1-31.
• Hymenoptera Anatomy Consortium, 2014. The Hymenoptera Glossary, Available from: http://glossary.hymao.org (accessed 17.03.14).
  » http://glossary.hymao.org
• Polaszek, A., Agosti, D., Alonso-Zarazaga, M., Beccaloni, G., de Place Bjørn, P., Bouchet, P., Brothers, D.J., Earl of Cranbrook, Evenhuis, N.L., Godfray, H.C.J., Johnson, N.F., Krell, F.T., Lipscomb, D., Lyal, C.H.C., Mace, G.M., Mawatari, S.F., Miller, S.E., Minelli, A., Morris, S., Ng, P.K.L., Patterson, D.J., Pyle, R.L., Robinson, N., Rogo, L., Taverne, J., Thompson, F.C., van Tol, J., Wheeler, Q.D., Wilson, E.O., 2005. A universal register for animal names. Nature 437, 477.

Publication Dates

• Publication in this collection
  Apr-Jun 2015

History

• Received
  18 Dec 2014
• Reviewed
  02 Feb 2015
• Accepted
  09 Apr 2015