Fossil Darwin wasps (Hymenoptera: Ichneumonidae) from Baltic amber

Seven subfamilies of Darwin wasps (Hymenoptera, Ichneumonidae), Banchinae, Cryptinae, Orthocentrinae, Pherhombinae, Stilbopinae, Townesitinae and Tryphoninae in Baltic amber are reviewed. Two species, Rovenosa alexrasnitsyni Manukyan, sp. nov. and R. khalaimi Manukyan, sp. nov. (Stilbopinae) are described as new to science. The male of Rovenosa rasnitsyni Khalaim, 2011 is recorded and described for the first time. The discovery of the puparium of an aphidophagous syrphid fly (Diptera: Syrphidae) with an emergence hole characteristic for Diplazontinae is the first fossil evidence of the subfamily. The strong bias in composition of the Ichneumonidae fauna in Baltic amber is noted. The presence of certain taxa in amber is suggested to be primarily due to specific properties of the pine resin, and only secondarily due to their occurrence in the “amber” forest.

Morphology of the oldest fossil subfamily of Limoniidae (Diptera, Architipulinae) in the light of exceptionally preserved Mesozoic material

Based on known fossil evidence the extinct subfamily Architipulinae is considered to be the oldest evolutionary group of the Limoniidae, the largest family within the infraorder Tipulomorpha. The morphology of this subfamily, which includes 11 genera, has so far been based mainly on wing venation. New well-preserved representatives of the genus Cretolimonia Kalugina, 1986 were recovered from the Jurassic/Cretaceous boundary of Shevia and Daya, Transbaikalia, as well as from mid-Cretaceous amber from Kachin, Myanmar. This new material enriches our knowledge of the subfamily Architipulinae and of the genus Cretolimonia, and allows us to ascertain the detailed morphological structure of the female copulatory apparatus with spermathecae and the structure of the male hypopygium. The combination of detailed impression fossils with a specimen preserved three-dimensionally in resin has permitted study of the morphology of this Mesozoic fly genus almost to the level of modern genera. The paper includes descriptions of four new species of Cretolimonia: C. lukashevichae sp. nov., C. pseudojurassica sp. nov., C. dayana sp. nov. from sedimentary rocks, and C. mikolajczyki sp. nov. from Myanmar amber, supported with a key to all known species.

Muscle systems and motility of early animals highlighted by cnidarians from the basal Cambrian

Although fossil evidence suggest that various animal groups were able to move actively through their environment in the early stages of their evolution, virtually no direct information is available on the nature of their muscle systems. The origin of jellyfish swimming, for example, is of great concern to biologists. Exceptionally preserved muscles are described here in benthic peridermal olivooid medusozoans from the basal Cambrian of China (Kuanchuanpu Formation, ca. 535 Ma) that have direct equivalent in modern medusozoans. They consist of circular fibers distributed over the bell surface (subumbrella) and most probably have a myoepithelial origin. This is the oldest record of a muscle system in cnidarians and more generally in animals. This basic system was probably co-opted by younger early Cambrian jellyfish to develop capacities for the jet-propelled swimming within the water column. Additional lines of fossil evidence obtained from ecdysozoans (worms and panarthropods) show that the muscle systems of early animals underwent a rapid diversification through the early Cambrian and increased their capacity to colonize a wide range of habitats both within the water column and sediment at a critical time of their evolutionary radiation.

Rewinding the molecular clock in the genus Carabus (Coleoptera: Carabidae) in light of fossil evidence and the Gondwana split: A reanalysis

Molecular clocks have become powerful tools given increasing sequencing and fossil resources. However, calibration analyses outcomes depend on the choice of priors. Here, we revisited the seminal dating study published by Andújar and coworkers of the genus Carabus proposing that prior choices need re-evaluation. We hypothesized that reflecting fossil evidence and the Gondwanan split properly significantly rewinds the molecular clock. We re-used the dataset including five mitochondrial and four nuclear DNA fragments with a total length of 7888 nt. Fossil evidence for Oligocene occurrence of Calosoma was considered. Root age was set based on the fossil evidence of Harpalinae ground beetles in the Upper Cretaceous. Paleogene divergence of the outgroup taxa Ceroglossini and Pamborini is introduced as a new prior based on current paleontological and geological literature. The ultrametric time-calibrated tree of the extended nd5 dataset resulted in a median TMRCA Carabus of 53.92 Ma (HPD 95% 45.01–63.18 Ma), roughly 30 Ma older than in the Andújar study. The splits among C. rugosus and C. morbillosus (A), C. riffensis from the European Mesocarabus (B), and Eurycarabus and Nesaeocarabus (C) were dated to 17.58 (12.87–22.85), 24.14 (18.02–30.58), and 21.6 (16.44–27.43) Ma. They were decidedly older than those previously reported (7.48, 10.93, and 9.51 Ma). These changes were driven almost entirely by constraining the Carabidae time-tree root with a Harpalinae amber fossil at ~99 Ma. Utilizing the nd5 dating results of three well-supported Carabus clades as secondary calibration points for the complete MIT-NUC dataset led to a TMRCA of Carabus of 44.72 (37.54–52.22) Ma, compared with 25.16 Ma (18.41–33.04 Ma) in the previous study. Considering fossil evidence for Oligocene Calosoma and Late Cretaceous Harpalini together with the Gondwanan split as a new prior, our new approach supports the origin of genus Carabus in the Eocene. Our results are preliminary because of the heavy reliance on the nd5 gene, and thus will have to be tested with a sufficient set of nuclear markers. Additionally, uncertainties due to dating root age of the tree based on a single fossil and outgroup taxon affect the results. Improvement of the fossil database, particularly in the supertribe Carabitae, is needed to reduce these uncertainties in dating Carabus phylogeny.