Theronia? nigriscutum, Holmgren, 1859

Klopfstein, Seraina, 2022, High diversity of pimpline parasitoid wasps (Hymenoptera, Ichneumonidae, Pimplinae) from the lowermost Eocene Fur Formation (Denmark), Geodiversitas 44 (23), pp. 645-664 : 658

Theronia? nigriscutum n. sp.

( Fig. 9 )

urn:lsid:zoobank.org:act:0000D63C-F7FE-468C-9150-D313E71589D3

TYPE MATERIAL. — Holotype female: MOL-MHM-5412 (part and counterpart; MOL; leg. H. Madsen, 1995).

ETYMOLOGY. — This species is named for its dark mesoscutum.

TYPE HORIZON AND LOCALITY. — Denmark, Jutland, Limfjord region, MorsØ Kommune , Ejerslev . Silstrup Member, +25-30 (Blok “E”).

DIAGNOSIS. — Taxonomic placement: this species shows most of the typical pimpline characters listed in Table 1 , although the ovipositor appears somewhat more slender than in other species of this subfamily from the Fur Formation. The nervellus, which is broken above the middle, and the yellow or orange ground colour fits well with members of the Theronia genus group, although the current specimen appears somewhat more elongate, especially in terms of the hind femora. Generic placement must thus be regarded as tentative only, as many diagnostic characters such as details of the propodeum are not well visible in the single specimen of this species.

Species diagnosis: this species shares its colour pattern with some Xanthopimpla and Theronia -group species, including X. crescendae n. sp. and Epitheronia stigmatica n. comb. from the same formation. From the latter two, it can easily be distinguished by the uniformly dark colour of the antennae. It is in general more slender than all known extant and fossil Xanthopimpla and most Theronia -group species, especially in terms of the hind legs.

DESCRIPTION

Preservation

Dorsal view, but T1 mostly replaced by hind coxae. Head large parts of both antennae present. Mesosoma with mes-

oscutum rather well preserved, remainder somewhat less so; front wings complete, hind wings almost complete, hind legs partially visible. Metasoma almost complete, except first tergite, in whose place the hind coxae show rather prominently; ovipositor sheaths nearly entirely preserved, with tip distinct.

Body 10.8 mm. Orange with dark brown head, antennae, mesoscutum, wing veins, and ovipositor sheaths.

Head. Rather small and roundish, antenna with about 30 flagellomeres, basal segments about 1.5 × longer than wide, median and apical segments square to transverse.

Mesosoma. Rather slender; deep notauli visible over at least half of mesoscutum, first a little converging, then nearly parallel. Propodeum not well preserved, maybe with some carination indicated. Fore wing 8.7 mm; areolet closed, quadrate, with uneven sides, 4-M very short, 2r-m a bit shorter than 3r-m; 2m-cu with two bullae, clearly bent outwards; pterostigma about 3.8 × longer than wide; 1cu-a meeting M + Cu opposite of 1-M; 3-Cu clearly longer than 2cu-a; radial cell 3 × longer than wide. Hind wing with 1-Rs 1.5 × longer than 1rs-m, 1-Cu probably about 0.8 × as long as cu-a, but end of the latter a bit uncertain. Hind legs partially preserved, rather slender, hind femur not conspicuously thickened as in other Fur Formation pimplines with yellow or orange ground colour.

Metasoma. Rather stout, with T1 a little longer than wide; T2 transverse, about 0.6 × as long as wide, remaining segments even shorter. Ovipositor sheaths c. 0.4 × as long as fore wing.

Figures

FIG. 9. — Holotype of Theronia? nigriscutum n. sp. (MOL-MHM-5412), photograph (A) and interpretative drawing (B), where dotted lines represent uncertain and/ or interpolated interpretations. Scale bar: 2 mm.