Theronia? furensis, 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 : 656-657

Theronia? furensis n. sp.

( Fig. 8 )

urn:lsid:zoobank.org:act:1DBBFE33-BF2E-4D19-A4CB-7E2792C50A5D

TYPE MATERIAL. — Holotype female: FUR-11207 (part and counterpart; leg. E. Rettig).

ETYMOLOGY. — The species epithet refers to the formation of origin.

TYPE HORIZON AND LOCALITY. — Denmark, Jutland, Limfjord region, MorsØ Kommune , Klinten ved Klitgård . Cement stone.

DIAGNOSIS. — Taxonomic placement: the placement of this taxon in Pimplinae is rather unequivocal from the combination of characters indicated in Table 1 . Furthermore, the claws seem somewhat enlarged, even though this interpretation is somewhat uncertain. The propodeum has at least some distinct carinae, a feature that is rare in extant Pimplinae which mostly have their propodeal carination at least partially reduced. The exception are some members of the genera Crusopimpla , Xanthopimpla , Lissopimpla Kriechbaumer and the Theronia group of genera, which all share a rather short metasoma and robust ovipositor with the current species. The first is a now extinct genus currently comprising only two species; we here added two additional ones and complemented the genus definition by an important character, which had not been visible in the previously known fossils: the high ratio of vein 1-Cu to cu-a in the hind wing (nervellus broken below the middle, see under Crusopimpla violina ). Crusopimpla thus can be ruled out as placement for this fossil, which has vein 1-Cu a little shorter than cu-a. The remaining three genera would all fit in that respect, but the colour pattern of this species points to the Theronia group as a most likely placement: Xanthopimpla species have a light ground colour of the mesosoma, and Lissopimpla can be identified by extended light colouring on the mesosoma and a black patch in the fore wing. Placement in Theronia or any of its related genera must however be regarded as tentative, as most members of this genus group also have a yellow or orange ground colour of the mesosoma. Species diagnosis: from most extant members of the Theronia genus group and also from most other pimplines from the Fur formation, this species can be distinguished on the basis of the colouration, i.e., dark mesosoma and head and entirely orange metasoma (except for T1) and orange legs. It only shares this colour pattern with Crusopimpla ? violina , see under that latter species for differential characters.

DESCRIPTION

Preservation

Lateral to dorso-lateral view. Head with first few segments of antennae. Mesosoma rather well preserved, including partial propodeal carination; all four wings nearly complete, all legs partially visible, often including claws. Metasoma almost complete; ovipositor sheaths nearly entirely preserved, with tip distinct. Partial Diptera fossil with wing fragment, partial legs and partial abdomen overlaying wasp fossil.

Body 11. 1 mm. Black or dark brown, orange on mouth parts, at least base of antennae, all legs including coxae and tarsi, metasoma from tergite 2, ovipositor sheaths dark brown; basal c. 3rd of pterostigma whitish.

Head. Rather small and roundish, antenna with short scape and pedicel.

Mesosoma. Rather short and stout; deep notauli visible over at least a third of mesoscutum, a little converging but still far apart when they become invisible; scutellum rather short; mesopleuron at least with lower and probably also upper lateral portion of epicnemical carina visible. Propodeum about as long as high, with some distinct carination, corresponding to at least one transverse and a partial median longitudinal and pleural carinae. Fore wing 9.5 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 3.5 × longer than wide; 1cu-a meeting M + Cu slightly distal to 1-M; 3-Cu clearly longer than 2cu-a; radial cell 3.2 × longer than wide. Hind wing w ith 1-Rs 1.5 × longer than 1rs-m, 1-Cu a little shorter than cu-a (counterpart), but end of the latter a bit uncertain.Legs all partially preserved, mostly with femora and tibiae rather indistinct, but tarsi visible even with claws, some of which vaguely show what is probably a basal lobe.

Metasoma. Rather stout, with T1 less than 1.5 × as long as wide, with strong median longitudinal carina converging at least on basal two-thirds; T2 transverse, less than 0.8 × as long as wide, remaining segments even shorter. Ovipositor sheaths c. 0.25 × as long as fore wing, their tips partly open to allow extrusion of ovipositor tips.

Figures

FIG. 8. — Holotype of Theronia? furensis n. sp. (FUR-11207), photograph (A) and interpretative drawing (B), where dotted lines represent uncertain and/or interpolated interpretations. Blue lines indicate a fossil Diptera which is partly overlaying the Darwin wasp fossil. One fore and the two hind wings have been moved up and down, respectively, for clarity. Scale bar: 1 mm.