Lycorina? indura (Theobald, 1937) Spasojevic & Broad & Klopfstein, 2022

Spasojevic, Tamara, Broad, Gavin R. & Klopfstein, Seraina, 2022, Revision of 18 ichneumonid fossil species (Hymenoptera, Ichneumonidae) highlights the need for open nomenclature in palaeontology, Fossil Record 25 (1), pp. 187-212 : 187

Lycorina? indura (Theobald, 1937) comb. nov.

Fig. 15

* Pimpla indura Theobald, 1937

Material.

Holotype (part #1323/1 and counterpart #1323/2) examined at the NMBA.

Stratum.

Kleinkembs, Pays de Bade, Haut-Rhin, France. Early Oligocene (Rupelian), 33.9-28.4 Ma.

Description.

Sex unclear. Ventral aspect (see ‘Interpretation’ below) of head, base of antenna, mesosoma, base of fore wing, and T1-T4 of metasoma partly preserved. Body length ~9 mm.

Mostly dark brown in colour, with some light colouration on mesosoma and with metasoma mostly light-coloured, with base of T1 and paired dark markings on top of rounded swellings on T2 to T4.

Head rather short, with prominent eyes and clypeus and mandibles indicated. Antennae with scape and pedicel short, flagellar segments not discernible. Mesosoma not well preserved, with epicnemial carina complete at least ventrally; apparent constriction after mesoscutum probably due to lighter colouration on mesepimeron. Propodeum quite short. Wings very poorly preserved, but counterpart showing base of one fore wing with C, Sc + R, M + Cu on the left side in their normal position and Sc + R and M + Cu on the right side folded over, with 1cu-a meeting M + Cu opposite of 1M. Legs not preserved, but reddish-brown hind coxae visible in front of T1. Metasoma with broad T1, 0.8 × as long as broad; T2 0.8 ×, T3 0.7 × as long as wide; T2-T4 with paired, rounded swellings which bear traces coarse punctuation; diagonal grooves obvious on T2 and indicated on T1 and T3, transverse impressions unclear; remainder of metasoma not preserved.

Interpretation.

The interpretation of this fossil was difficult given the poor preservation. Some of the interpretation hinges upon the question of whether it shows its ventral or dorsal aspect. Theobald (Theobald 1937) concluded that he was looking at a dorsal aspect, that the mesosoma was "clearly segmented", and that he saw the three ocelli. However, we believe that the transverse line across the thorax represents the epicnemial carina, followed by the longitudinal mesosternal scrobe. Additional evidence for a ventral view is what we interpret as the two hind coxae lying in front of T1. Instead of very much enlarged ocelli, we think that the three light parts on the head represent the clypeus and mandibles. This interpretation is also in better agreement with the position of the antennae, which would be very low on the head if we were looking at a dorsal aspect. The metasoma is still interpreted as showing the tergites, but from inside; the sternites are usually so weakly sclerotized in ichneumonids that they are missing in fossils.

Overall, this fossil is badly preserved, with only the base of one fore wing visible and most of the mesosoma squashed so that no carination is discernible. The lack of complete fore wing venation makes even the family association seem uncertain; however, all the visible features correspond very well to ichneumonids, especially when comparing ventral view to other ichneumonid fossils (e.g., see the holotype of Acerataspis? revelata Brues). Several unusual features are very clearly visible, especially the diagonal grooves on T2 and paired dark swellings with strong punctation on T2 and T3. There are only a few ichneumonids with such strong diagonal grooves on the tergites: the tribe Glyptini in the subfamily Banchinae , some genera in Pimplinae , and the members of the subfamily Lycorininae . Only in the pimpline genus Xanthopimpla and in some Lycorina do the diagonal groves come together with a light colouration of the metasoma and two basal swellings, which are then often black-marked as in the fossil. In Xanthopimpla , however, the grooves are closer to the anterior margin; if dark markings are present on T2, they are usually part of the medial swollen area and thus lie behind the diagonal groves, which does not seem to be the case in this fossil. Furthermore, Xanthopimpla species have a yellow or orange mesosoma, although there is a recently described Xanthopimpla species from the Fur Formation with a dark mesoscutum ( Klopfstein 2021). The subfamily Lycorininae matches much more closely with the same arrangement of carinae and markings found in extant species, the mesosoma often dark and the rather short scapus. This subfamily comprises only the genus Lycorina , which shows the basal part of the median longitudinal carinae on the propodeum, even though this state is somewhat equivocal in the fossil. We thus transfer the species to Lycorina in the subfamily Lycorininae but mark it with a question mark given the poor preservation.

Tryphoninae Shuckard, 1840

Monoblastus ? Hartig, 1837

Figures

Figure 15. Lycorina? indura (Brues, 1910) comb. nov. A. Photograph of the holotype obtained from NMBA; B. Our interpretative drawing of the fossil. Thicker lines indicate outlines of body structures, thinner lines show characters inside these outlines, and dotted lines represent uncertain interpretations.