Madma gen. nov. (feminine)

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

Madma gen. nov. (feminine)

Etymology.

The genus name comes from the French word “Mademoiselle”, which means “Miss”. " Madma " is also a Filipino word for “Madam”. The word is chosen to create a wordplay together with the name of the type species (see below).

Type species.

Madma oisella sp. nov.

Systematic placement.

The presence of a sternaulus, a pentagonal areolet, and the outwards bowed 2m-cu with two bullae, reminds of Claseinae at first. But in Claseinae the sternaulus is not reaching to the posterior end of the mesopleuron, the carination on the propodeum is largely reduced, the areolet smaller and the ovipositor is rather long, which makes this subfamily unlikely. Several characters associate this fossil with crown Phygadeuontinae : the petiolate T1 with the spiracle behind the middle; the long sternaulus that reaches the posterior margin of the mesopleuron above mid-height of the mid coxa; the short ovipositor with a nodus on the dorsal and oblique teeth on the ventral valve; and the two bullae in fore wing vein 2m-cu ( Townes 1970a; Santos 2017). However, the wide and unevenly pentagonal areolet with 4M significantly shorter than 2 + 3M, and the presence of a tooth on the apical margin of the fore tibia, do not occur in extant phygadeuontines. The tooth on the fore tibia is a homoplastic character occurring in multiple subfamilies across the ichneumonid tree, including Tryphoninae , Ctenopelmatinae , Tersilochinae , Metopiinae , Anomaloninae , Campopleginae and the more distantly related Eucerotinae and Labeninae ( Townes 1969, 1970a, 1970b, 1971); it is thus not informative for the subfamily placement. The wide, pentagonal areolet is a rather plesiomorphic character which only occurs in the Cretaceous Labenopimplinae ( Kopylov 2010b) and in extant and fossil Labeninae ( Townes 1969; McKellar et al. 2013; Spasojevic et al. 2018b), including a tentative labenine from Cretaceous Canadian amber ( McKellar et al. 2013), Albertocryptus dossenus . Madma clearly differs from Labenopimplinae and Labeninae based on the shape and position of T1 relative to the metacoxal cavities, but resembles A. dossenus in both areolet shape, two bullae in 2m-cu and the petiolate T1; it differs from it in the number of flagellomeres (17 in A. dossenus ) and the much stouter scape, T1 and hind coxae. The wide pentagonal areolet, together with other plesiomorphic characters, such as two bullae in 2m-cu and a long, strong carinae on T1 and long ovipositor, suggest Madma being a stem lineage of Phygadeuontinae or, less likely, its position further down the Ichneumoniformes tree. Given that Phygadeuontinae are currently polyphyletic ( Santos 2017), we in fact also cover the latter scenario when placing the fossil in Phygadeuontinae ; once Phygadeuontinae are revised in the light of further phylogenetic evidence, this placement will have to be reviewed.

Diagnosis.

Madma gen. nov. differs from all other Phygadeuontinae genera in having a bilobed posterior transverse carina on the mesosternum, a tooth on the apical margin of the fore tibia and an unevenly pentagonal areolet with 4M shorter than 2 + 3M. In addition, the genus is characterised by the following characters: 2m-cu curved outwards, with two bullae; mesopleuron with complete sternaulus curved around middle, reaching posterior margin of mesopleuron above mid-height of mid coxa; T1 petiolate with parallel and long latero-median carinae almost reaching its posterior margin; ovipositor slightly longer than height of metasoma at apex, straight and its apex with a nodus on upper valve and oblique teeth on lower valve.