Olixon pantanensis Bulbol, Bartholomay & Somavilla, 2023

Bulbol, Mayara Medeiros, Bartholomay, Pedro Reck, Oliveira, Márcio Luiz De & Somavilla, Alexandre, 2023, A new species of Olixon Cameron, 1887 (Hymenoptera: Rhopalosomatidae) and new records for the genus in Brazil, Zootaxa 5277 (3), pp. 573-580 : 574-576

Olixon pantanensis Bulbol, Bartholomay & Somavilla sp. nov.

( Figs 1 ; 2 a, b, c, d ; 3 a, b, c and 4 )

Diagnosis. Within the New World Olixon , the new species can be separated by the following character combination: malar space with sulcus from eye to mandible ( Fig. 2a ); temple length 0.06 mm and malar space 0.2 times as long as eye length; fore wing with two remnant veins ( Fig. 2c ); propodeum with posterolateral and two posteromedian propodeal processes ( Fig. 2b ); metasomal tergum I without median sulcus posterior to transverse carina ( Fig. 2d ).

Description.

Male. Body length 5.61 mm. Head and mesosoma combined length 2.592 mm.

Colour (as in Fig. 1 ). Predominantly brownish-black or dark brown with the following brown to pale brown: antennae, clypeus, malar space, mandibles (except apical third), maxillar and labial palpi, legs (except mid and hind femora), metasomal terga 5–7. Certain areas might appear darker or lighter depending on the incidence of light.

Head. Vertex with short pubescence, setae arising from small punctures, interspaces between setae smooth. Ocelli absent. Eye 1.6 × as long as wide, temple length 0.06 mm and malar space 0.2 × as long as eye length. Malar sulcus present, complete ( Fig. 2a ). Clypeus 2.28 × as wide as high. FI 4.41 × as long as wide, 1.5 × as long as pedicel and 0.9 × as long as FII.

Mesosoma. Pronotal index: 0.87. Tegula broad, dorsally separated by 2.6 × its own width. Propodeal index: 1; each posterolateral propodeal process long, inner margin ecarinate; two posteromedian propodeal process short ( Fig. 2b ). Propodeal surface densely pubescent, setae arising from tiny punctures.

Legs. Hind femur 5.5 × as long as wide. Outer hind tibial spur present, inner hind tibial spur 0.4 × as long as basitarsus.

Wings. Fore wing membrane expanded and with two remnant veins ( Fig. 2c ), posteriorly reaching to posterior half of TI. Hind wing absent.

Metasoma.TI with evenly arched transverse carina, without median sulcus posterior to transverse carina ( Fig. 2d ).

Genitalia. Paramere ( Fig. 3a ): 1.1 × longer than wide; spine of paramere elongated and acute apically, slightly upcurved medially (sickle-shaped). Cuspis and Digitus ( Fig. 3b ): linked by the membrane that joins them to the paramere; membrane with pilosity; both with a cylindrical apex, strongly sclerotized and converging at the tip (similar to tweezers); digitus with punctuation and cuspis with light dentation, both apically. Penis valve ( Fig. 3c ): elongated and with cylindrical apex; ventral margin with strong notch medially; preapical process sharp and sclerotized.

Female. Unknown.

Etymology. In reference to the Brazilian Pantanal ecosystem, the world’s largest flooded grasslands, where the holotype was collected. Treat as a singular adjective in the nominative case.

Distribution. Brazil.

Material examined. Holotype, male. BRAZIL, MATO GROSSO, Poconé, Fazenda S „o Sebasti„o da Borba, Pantanal , antes do fogo, área L12 transecto 9, X.2015, pitfall 60m, L. Pavão leg [1♁, CMT] ( Fig. 4 ) . Holotype deposited in: Entomology sector of the UFMT zoological collection ( CMT) . Holotype condition: The sternum VII was cut for the male genital study, the right antenna is broken in F2 (fixed to the specimen) and no left forewing.

Remarks. It resembles O. bicolor in dark brown to black coloration and malar sulcus complete but differs in head color and the presence of a transverse carina on the first metasomal tergum: O. bicolor the head and metasoma (except its first segment) black, mesosoma and metasomal segment I reddish brown; O. pantanensis sp. nov. is entire dark brown to black and metasomal tergum I with a transverse carina. Separated from the O. atlanticum and O. banksii by the sulcus in malar space, absent in both species and present from eye to mandible in O. pantanensis sp. nov. Can be easily separated from the O. testaceum by color, while O. pantanensis is mostly dark brown, O. testaceum varies from bright stramineous to brown.

Figures

FIGURE 1. Olixon pantanensis Bulbol, Bartholomay & Somavilla sp. nov. in a) lateral and b) dorsal view.

FIGURE 2. Olixon pantanensis Bulbol, Bartholomay & Somavilla sp. nov. a) malar sulcus; b) propodeum; c) fore wing; d) metasomal tergite I. Abbreviations. mps—posteromedian propodeal process; lps—posterolateral propodeal process.

FIGURE 3. Male genitalia. a, b, c. Olixon pantanensis Bulbol, Bartholomay & Somavilla sp. nov., a) paramere; b) digitus and cuspis; c) penis valve. d, e, f. Olixon testaceum Cameron, 1887, d) paramere; e) digitus and cuspis; f) penis valve.Abbreviations. cus—cuspis; dig—digitus; hpv—head of penis valve; pap—preapical process.

FIGURE 4. Geographic distribution of Olixon testaceum Cameron, 1887 and Olixon pantanensis Bulbol, Bartholomay & Somavilla sp. nov. in Brazil.