Dolichogenidea Viereck, 1911

Fagan-Jeffries, Erinn P., Cooper, Steven J. B. & Austin, Andrew D., 2018, Three new species of Dolichogenidea Viereck (Hymenoptera, Braconidae, Microgastrinae) from Australia with exceptionally long ovipositors, Journal of Hymenoptera Research 64, pp. 177-190 : 177

Dolichogenidea Viereck

Dolichogenidea Viereck, 191 1: 173 (as a subgenus of Apanteles Foerster s.1.). Type species, by original designation, Apanteles (Dolichogenidea) banksi Viereck. Generic status by Mason 1981: 34. See Shenefelt (1972) for bibliographic history and Mason (1981) for discussion of relationships.

Diagnosis.

Fore wing areolet (second submarginal cell) absent (i.e. vein r-m absent); hind wing vannal lobe convex to almost straight and uniformly fringed by setae; propodeum often with a complete areola, sometimes areola reduced with at least posterior diverging carinae present, rarely with these carinae completely absent; metasoma with T2 variable in shape, but usually rectangular or subrectangular; hypopygium membranous mid-ventrally and expandable (sometimes folded inwards and hidden by laterotergites in dead specimens); ovipositor protruding from posterior metasoma, usually as long as or longer than length of metatibia.

Remarks.

In resurrecting Dolichogenidea , Mason (1981) allocated three of Nixon’s (1965) species-groups to the genus: the Dolichogenidea ultor -, Dolichogenidea laevigatus -, and Dolichogenidea longipalpis -groups. The Dolichogenidea longipalpis -group was erected by Nixon for a single European species, D. longipalpis (Reinhard, 1880), which has unusually long mouthpart palps. The Dolichogenidea ultor -group was defined by Nixon (1965) for those species with a complete or partially complete propodeal areola, and the Dolichogenidea laevigatus -group for species with the areola represented only by two basal diverging carinae, or the propodeum virtually completely devoid of carinae. However, there are numerous species that represent intermediates between these conditions, and Mason (1981) was instrumental in recognising that there were likely to be independent pathways for reduction and eventual loss of the areola ( Whitfield et al. 2018). Hence, it is very likely that neither the presence of a propodeal areola or its loss define monophyletic groups. This said, the three species described here most closely resemble the condition found in classic ' Dolichogenidea laevigatus -group species’, having a smooth and shiny propodeum, a transverse T2 (rather than triangular) and an ovipositor much longer than the metatibia.

Identification of the species described here.

Dolichogenidea is highly speciose and there are large numbers of undescribed species in Australia. Austin and Dangerfield (1992) estimated that fauna to be 50-70 species. However, it may be much larger than this given that a recent DNA barcoding study of Australian microgastrines recognised 236 species from 525 individuals, 42 of which belonged to Dolichogenidea ( Fagan-Jeffries et al. in press). Given this considerable number of additional species in Dolichogenidea , it is pointless to present a key to the described fauna; rather we provide the characters that distinguish the three species treated here from the six described species, as follows: the absence of a conspicuous white blotch on the gena separates the three species from D. lipsis , D. biroi , and D. tasmanica ; D. hyposidrae and D. eucalypti both have ovipositors significantly shorter than the metatibia and a clearly defined propodeal areola, whilst the species described here all have ovipositors significantly longer than the metatibia and a propodeal areola only indicated at most by short posterior diverging carinae; D. miris is separated by the presence of a partially defined areola with lateral costula, and a shorter T2 with strong rugose sculpturing, differing from the smooth or almost smooth T2 of the three new species here. In addition, the lengths of the ovipositor and sheaths of all undescribed Dolichogenidea we have seen in Australian collections do not exceed approximately 1.5 × that of the metatibia, compared with 1.8-4.2 × for the three new species.

The newly described species appear to be quite rare, although two are widespread (Fig. 1 ). After considerable collecting effort and searching of both pinned and ethanol museum material from all major Australian collections, only 14 specimens have been located.

Figures

Figure 1. Known distributions of D. xenomorph (blue circles) D. finchi (red squares) and D. mediocaudata (yellow star).