Gilbertnixonius Fernandez-Triana, 2018

Fernandez-Triana, Jose L & Boudreault, Caroline, 2018, Seventeen new genera of microgastrine parasitoid wasps (Hymenoptera, Braconidae) from tropical areas of the world, Journal of Hymenoptera Research 64, pp. 25-140 : 52-53

Gilbertnixonius Fernandez-Triana gen. n.

Type species.

Gilbertnixonius biem Fernandez-Triana & Boudreault, here designated.

Diagnostic description.

Head with relatively large tentorial pits, and very large palps (which reach well into the mesopleuron) (Fig. 13C, D ). Occipital carina partially defined. Epicnemial carina partially defined. Mesopleuron and metapleuron strongly sculptured, mostly by transverse striation (Fig. 13D ). Anteromesoscutum and scutellar disc mostly sculptured with strong punctures (Fig. 13E ). Scutellar disc with sharp carina around margins and slightly protruding posteriorly (Fig. 13D, E ). Scutellar disc with rugose band of sculptured postero-medially. Propodeum with median longitudinal and transverse carinae strongly defined (Fig. 13F, G ). Fore wing with relatively small, quadrangular areolet (Fig. 13A ). Pterostigma mostly white-yellow, except for posterior 0.3 which is light brown. Hind wing with vannal lobe entirely setose. Metacoxa relatively short, not surpassing posterior margin of T2. Metatibia spines relatively short (around 0.3 × length of first segment of metatarsus). T1 with median sulcus on anterior half, posterior half relatively strongly sculptured (Fig. 13G ). T2 sub-quadrate, with longitudinal striae (Fig. 13G ). Hypopygium relatively short, not extending beyond last tergites. Ovipositor very short, ovipositor sheaths with very few and sparse setae near apex (Fig. 13D ).

Putative autapomorphies and potentially related genera.

Gilbertnixonius belongs to the Microplitini group of genera (sensu Mason 1981). It is the only genus within that group with both longitudinal and transverse carina on propodeum, but without having an areola ( Alloplitis and the new genus Tobleronius described below have those carinae, although sometimes incomplete, but they also have a complete areola). The presence of an epicnemial carina is very unique, as it is only present in Microgastrinae in the unrelated genus Fornicia and in some species of Snellenius (e.g., Mason 1981, Whitfield et al. 2002, Fernandez-Triana et al. 2015); but Snellenius does not have the propodeum carination pattern of Gilbertnixonius . The presence of an incomplete occipital carina is a highly unusual feature in Microgastrinae , only shared with at some, or perhaps all, species of Alloplitis , Philoplits and Tobleronius (see a discussion of that character under the description of Tobleronius below, for more details on lineages within Microplitini having a complete or partial occipital carina).

Biology.

Host unknown.

Distribution.

The only species known is found in the Oriental region (Thailand).

Molecular data.

The DNA barcode of the holotype specimen (BIN BOLD:AAZ9883) is very unique, 13.2% different from the closest Microgastrinae sequence in BOLD.

Etymology.

The genus name refers to and honors the British braconid expert Gilbert E. J. Nixon in recognition of his significant contributions to the knowledge of parasitoid wasps of the world. Nixon papers on Microgastrinae were of capital importance in the second half of the past century, and paved the way for further studies, including the present one. The gender of the genus is neuter.

Species.

Only one species is known.

Figures

Figure 13. Gilbertnixonius biem female holotype. A Fore wing B Habitus C Head frontal D Mesosoma and metasoma, lateral E Head dorsal F Mesosoma dorsal G Propodeum and metasoma, dorsal.