A new megaspilid wasp from Eocene Baltic amber (Hymenoptera: Ceraphronoidea), with notes on two non-ceraphronoid families: Radiophronidae and Stigmaphronidae

Abstract

Ceraphronoids are some of the most commonly collected hymenopterans, yet they remain rare in the fossil record. Conostigmus talamasi Mikó and Trietsch, sp. nov. from Baltic amber represents an intermediate form between the type genus, Megaspilus, and one of the most species-rich megaspilid genera, Conostigmus. We describe the new species using 3D data collected with synchrotron-based micro-CT equipment. This non-invasive technique allows for quick data collection in unusually high resolution, revealing morphological traits that are otherwise obscured by the amber. In describing this new species, we revise the diagnostic characters for Ceraphronoidea and discuss possible reasons why minute wasps with a pterostigma are often misidentified as ceraphronoids. Based on the lack of ceraphronoid characteristics, we remove Dendrocerus dubitatus Brues, 1937, Stigmaphronidae, and Radiophronidae from Ceraphronoidea and consider them as incertae sedis. We also provide some guidance for their future classification.

Introducing Biomedisa as an open-source online platform for biomedical image segmentation

“…Biomedisa has been extensively tested and successfully applied to a wide range of 3D datasets from µCT, SR-µCT and MRI. Examples include a fossil wasp in amber 39 , a theropod dinosaur claw in amber, an ethanol-preserved bull ant queen, an ethanol-preserved hissing cockroach, a medaka (Japanese rice fish) scanned in agarose, human hearts 40 and mouse molar teeth 41 (see “Methods”, Fig. 5 and Supplementary Movie 2 ).…”

“…During its development, the random walk segmentation of Biomedisa was tested and already successfully employed in a number of studies 39 – 41 , 50 , 51 . It also played a crucial role in the description of parasitic wasps discovered in mineralized fly pupae 42 .…”

“…A ceraphronoid wasp ( Conostigmus talamasi (Hymenoptera: Ceraphronidae)) trapped in an approx. 33−55-million-year-old piece of Eocene Baltic amber (volume size: 1417 × 2063 × 2733 voxels) 39 . The specimen is stored at Senckenberg Deutsches Entomologisches Institut (Müncheberg, Germany) with collection number DEI-GISHym31819.…”

A semantically enriched taxonomic revision of Gryonoides Dodd, 1920 (Hymenoptera, Scelionidae), with a review of the hosts of Teleasinae

“…The authors exclusively used the identification key and the brief description of Teleasinae from Goulet and Huber, 1993, to classify the new fossil in Platygastroidea, Scelionidae and Teleasinae. This approach lacks taxonomic rigor and unfortunately has been widely applied in paleoentomology (Mikó et al 2018). The line drawing provided by Nel and Azar (2005) does not depict a teleasine, and we consider very unlikely that it is a platygastroid.…”