An Eocene insect could hear conspecific ultrasounds and bat echolocation.

Hearing has evolved independently many times in the animal kingdom and is prominent in various insects and vertebrates for conspecific communication and predator detection. Among insects, katydid (Orthoptera: Tettigoniidae) ears are unique, as they have evolved outer, middle, and inner ear components, analogous in their biophysical principles to the mammalian ear. The katydid ear consists of two paired tympana located in each foreleg. These tympana receive sound externally on the tympanum surface (usually via pinnae) or internally via an ear canal (EC). The EC functions to capture conspecific calls and low frequencies, while the pinnae passively amplify higher-frequency ultrasounds including bat echolocation. Together, these outer ear components provide enhanced hearing sensitivity across a dynamic range of over 100 kHz. However, despite a growing understanding of the biophysics and function of the katydid ear, its precise emergence and evolutionary history remains elusive. Here, using microcomputed tomography (µCT) scanning, we recovered geometries of the outer ear components and wings of an exceptionally well-preserved katydid fossilized in Baltic amber (∼44 million years [Ma]). Using numerical and theoretical modeling of the wings, we show that this species was communicating at a peak frequency of 31.62 (± 2.27) kHz, and we demonstrate that the ear was biophysically tuned to this signal and to providing hearing at higher-frequency ultrasounds (>80 kHz), likely for enhanced predator detection. The results indicate that the evolution of the unique ear of the katydid, with its broadband ultrasonic sensitivity and analogous biophysical properties to the ears of mammals, emerged in the Eocene.

Giant Jurassic dragon lacewing larvae with lacustrine palaeoecology represent the oldest fossil record of larval neuropterans.

Neuropterans seem to be less specious among holometabolans, while they are in fact the relicts of a diverse group from the Mesozoic era. Their early radiation resulted in great family level morphological heterogeneity of extant neuropterans, especially of their larvae. The earliest previously reported fossil larvae of this group were from the Early Cretaceous, where they already showed high taxonomic diversity and an extremely wide range of variations in morphotypes. In this work, the earliest record of the larva of the neuropteran Palaeoneurorthus baii gen. et sp. nov. from the Middle Jurassic Daohugou Beds of China is described. The larvae, which have large and elongated bodies, straight stylets with curved apices, an extremely elongated cervix and an extended anterior lobe of pronotum, are placed in Nevrorthidae. The elongated cervix is probably a specialized adaptation for hunting small organisms. The palaeoenvironment of these larvae indicates that larvae of Nevrorthidae have exhibited stable aquatic ecology since the Middle Jurassic, and underwent a possible shift from lakes to more lotic yet constricted modern mountain rivulet habitats over time.

Late Holocene anthropogenic landscape change in northwestern Europe impacted insect biodiversity as much as climate change did after the last Ice Age.

Since the last Ice Age (ca 115 000-11 700 years ago), the geographical ranges of most plants and animals have shifted, expanded or contracted. Understanding the timing, geographical patterns and drivers of past changes in insect communities is essential for evaluating the biodiversity implications of future climate changes, yet our knowledge of long-term patterns is limited. We applied a network modelling approach to the recent fossil record of northwestern European beetles to investigate how their taxonomic and trait composition changed during the past 16 000 years. We found two major changes in beetle faunas 4000-3500 and 10 000-9500 years ago, coinciding with periods of human population growth in the Late Holocene and climate warming in the Early Holocene. Our results demonstrate that humans have affected insect biodiversity since at least the introduction of agropastoralism, with landscape-scale effects that can be observed at sites away from areas of direct human impact.

A new cockroach (Blattodea, Corydiidae) with pectinate antennae from mid-Cretaceous Burmese amber.

A new species of fossil cockroach, Fragosublattapectinata gen. et sp. nov., is described from mid-Cretaceous Burmese amber. The new species is assigned to the family Corydiidae based on the following combination of characters: pronotum with tubercles, tegmina obovate with smallish anal region and spinules on the antero-ventral margin of the front femur (type C1). The new species is the second reported cockroach with ramified antennae. This finding broadens the diversity of Blattodea in mid-Cretaceous Burmese amber and provides further evidence of convergent evolution for antennal structures among different insect lineages.

The first Cacomorphocerus species (Coleoptera, Cantharidae) from Rovno amber: a second species of the genus with 11-segmented antennae.

A new species of soldier beetles of the subfamily Cantharinae, Cacomorphocerus meridionalis sp. nov., is described from Upper Eocene Rovno amber. It is the second time that a Cacomorphocerus species with 11-segmented antennae has been discovered. The status of the tribe Cacomorphocerini is discussed.

Giant ants and their shape: revealing relationships in the genus Titanomyrma with geometric morphometrics.

Shape is a natural phenomenon inherent to many different lifeforms. A modern technique to analyse shape is geometric morphometrics (GM), which offers a whole range of methods concerning the pure shape of an object. The results from these methods have provided new insights into biological problems and have become especially useful in the fields of entomology and palaeontology. Despite the conspicuous successes in other hymenopteran groups, GM analysis of wings and fossil wings of Formicidae has been neglected. Here we tested if landmarks defining the wing shape of fossil ants that belong to the genus Titanomyrma are reliable and if this technique is able to expose relationships among different groups of the largest Hymenoptera that ever lived. This study comprises 402 wings from 362 ants that were analysed and assigned with the GM methods linear discriminant function analysis, principal component analysis, canonical variate analysis, and regression. The giant ant genus Titanomyrma and the parataxon Formicium have different representatives that are all very similar but these modern methods were able to distinguish giant ant types even to the level of the sex. Thirty-five giant ant specimens from the Eckfeld Maar were significantly differentiable from a collection of Messel specimens that consisted of 187 Titanomyrma gigantea females and 42 T. gigantea males, and from 74 Titanomyrma simillima females and 21 T. simillima males. Out of the 324 Messel ants, 127 are newly assigned to a species and 223 giant ants are newly assigned to sex with GM analysis. All specimens from Messel fit to the two species. Moreover, shape affinities of these groups and the species Formicium brodiei, Formicium mirabile, and Formicium berryi, which are known only from wings, were investigated. T. gigantea stands out with a possible female relative in one of the Eckfeld specimens whereas the other groups show similar shape patterns that are possibly plesiomorphic. Formicidae are one of the most dominant taxa in the animal kingdom and new methods can aid in investigating their diversity in the present and in deep time. GM of the ant wing delivers significant results and this core of methods is able to enhance the toolset we have now to analyse the complex biology of the ants. It can prove as especially useful in the future when incorporated into better understanding aspects of evolutionary patterns and ant palaeontology.

Evolution of insect wings and development - new details from Palaeozoic nymphs.

The nymphal stages of Palaeozoic insects differ significantly in morphology from those of their modern counterparts. Morphological details for some previously reported species have recently been called into question. Palaeozoic insect nymphs are important, however - their study could provide key insights into the evolution of wings, and complete metamorphosis. Here we review past work on these topics and juvenile insects in the fossil record, and then present both novel and previously described nymphs, documented using new imaging methods. Our results demonstrate that some Carboniferous nymphs - those of Palaeodictyopteroidea - possessed movable wing pads and appear to have been able to perform simple flapping flight. It remains unclear whether this feature is ancestral for Pterygota or an autapomorphy of Palaeodictyopteroidea. Further characters of nymphal development which were probably in the ground pattern of Pterygota can be reconstructed. Wing development was very gradual (archimetaboly). Wing pads did not protrude from the tergum postero-laterally as in most modern nymphs, but laterally, and had well-developed venation. The modern orientation of wing pads and the delay of wing development into later developmental stages (condensation) appears to have evolved several times independently within Pterygota: in Ephemeroptera, Odonatoptera, Eumetabola, and probably several times within Polyneoptera. Selective pressure appears to have favoured a more pronounced metamorphosis between the last nymphal and adult stage, ultimately reducing exploitation competition between the two. We caution, however, that the results presented herein remain preliminary, and the reconstructed evolutionary scenario contains gaps and uncertainties. Additional comparative data need to be collected. The present study is thus seen as a starting point for this enterprise.