Pappous gen. nov. (masculine)

Viertler, Alexandra, Klopfstein, Seraina, Jouault, Corentin & Spasojevic, Tamara, 2022, Darwin wasps (Hymenoptera, Ichneumonidae) in Lower Eocene amber from the Paris basin, Journal of Hymenoptera Research 89, pp. 19-45 : 19

Pappous gen. nov. (masculine)

Etymology.

Derived from the Greek word ( pappoús) for grandfather, which highlights the age of the genus.

Type species.

Pappous trichomatius sp. nov.

Systematic placement.

The most conspicuous character of this fossil is probably the dense pilosity on the compound eyes, which is rather rare in Ichneumonidae . However, there are a few genera or species with setose eyes in a large portion of the subfamilies ( Schizopyga Gravenhorst, 1829 and Dreisbachia Townes, 1962 in Pimplinae ; Trichomma Wesmael, 1849 and Ophionellus Westwood, 1874 in Anomaloninae , Cymodusa Holmgren, 1859 in Campopleginae , Collyria trichophthalma Thomson, 1877 in Collyriinae , etc.) ( Townes 1969, 1970b, 1971).

The fossil shares some similarities with taxa in the subfamily Orthocentrinae . First, the face of the fossil reminds of taxa in the Helictes genus-group, with a strongly convex clypeus both in front and profile view, a rather long malar space and tentorial pits that are placed much behind the clypeal plane ( Townes 1971). Second, the converging but almost box-like first tergite with the spiracle around the middle, and strong and parallel latero-median carinae also occur in Orthocentrinae . Third, there are also some Eusterinx , in the subgenus Eusterinx Trestis , that share the setose eyes. All Orthocentrinae possess a conspicuous fringe of setae along the inner side of the hind tibia, but this body part is unfortunately not visible. However, the relatively short and fully carinated propodeum speak against most Orthocentrinae , except Eusterinx , and the mentioned characteristics also appear in some Tryphoninae taxa, and since many characters in Orthocentrinae are very variable and seem plesiomorphic in the fossil, a placement in Orthocentrinae seems ill-advised.

Altough the setose eyes are a highly homoplastic character, it might give an important hint, as eyes with conspicuous setae occur rather often in Tryphoninae (e.g., Thymaris Förtster, 1869, Oedemopsis Tscheck, 1869, Zagryphus Cushman, 1919), in the tribe Oedemopsini ( Bennet 2015). Indeed, the combination of characteristics in this fossil are all consistent with a placement in Tryphoninae . The setose eyes and strongly tapered mandibles, the deeply impressed notauli, together with the full carination on the propodeum, lead to some genera in the tryphonine tribe Oedemopsini ( Bennet 2015; Broad et al. 2018). The mesosoma, the very strong juxtacoxal carina, the posterior transverse carina of the mesosternum, which forms a lobe with the lateral part and is medially expanded into two lobes, as well as the shape of the first tergite are rather similar to Acaenitellus Morley, 1913. The setose eyes and mandible shape on the other hand would point to a close resemblance to Thymaris and Neliopisthus Thomson, 1883. The latter also shares similarities in the first tergite, which is in some species tapered gradually with more or less parallel latero-median carina. But although the fossil shares many characteristics that are consistent within Oedemopsini , it also features differences, which are rare in this tribe: a strongly bowed 2m-cu, a rather stout and box-like first tergite, and a closed areolet. The latter is only present in Leptixys Townes, 1969 from Chile and Argentina, Debophanes Gauld, 1984 from Australia and the fossil species Thymariodes areolaris Kasparyan, 1988 from Baltic amber ( Bennet 2015). Although we have good arguments forplacing P. trichomatius in Oedemopsini , important characteristics, like an antenna with a median light-coloured band, simple tarsal claws and an ovipositor with a weakly sclerotized ventral valve ( Bennet 2015), which would distinguish this tribe from other Tryphoninae , are not visible. Therefore, we do not place the fossil in this tribe or any Tryphoninae tribe.Since the previously mentioned apomorphic characters in extant Tryphoninae , the stalked egg and the fringe of setae on the clypeus, are not visible in this fossil, we also label our placement of this fossil in Tryphoninae as tentative.

Diagnosis.

Pappous gen. nov. differs from the only known fossil genus of Oedemopsini , Thymariodes Kasparyan, 1988, described from Baltic amber, in having unidentate or strongly twisted mandibles, a convex clypeus in profile, a longer malar space, as well as a long and slender pterostigma, an outwards bowed 2m-cu and with vein 1Rs + M present. It also differs from Palaeometopius by the shape and dimension of the mandibles, the presence of conspicuous setae on the eyes, and a quadrate-oblique areolet shape. In addition, Pappous gen. nov. differs from extant genera in Oedemopsini by its closed quadrate-oblique areolet, a strongly carinated propodeum, and subquadrate and non-petiolate T1. Since Pappous does have a different character combination than extant Oedemopsini or other Tryphoninae genera, we propose a new genus.

The genus combines dense and conspicuous setae on the eyes, a convex clypeus with simple margin, the malar space about as long as base width of mandibles or a little longer, a weak oblique truncation of the scape, a strongly areolated propodeum with rather simple surface sculpture and complete juxtacoxal carinae, fore wing with closed quadrate-oblique areolet and a box-like first tergite.