Ovipositor and mouthparts in a fossil insect support a novel ecological role for early orthopterans in 300 million years old forests

Mitochondrial phylogenomics of pygmy grasshoppers (Orthoptera, Tetrigidae, Metrodorinae): descriptions of a new genus, two new species, and new synonyms from China

The Chinese wingless brachypronotal pygmy grasshoppers of the subfamily Metrodorinae have often been classified within the genus Macromotettixoides. In this study, two undescribed species of wingless brachypronotal pygmy grasshoppers belonging to Metrodorinae were collected. To elucidate their taxonomic positions, the complete mitochondrial genomes of these two species were sequenced and analyzed. Phylogenetic analyses were conducted using 13 protein-coding genes (PCGs) from 28 tetrigid mitogenomes. Genetic distances and divergence times were estimated. Our results indicate that one species represents a new genus within Metrodorinae, while the other is a new species of Macromotettixoides. Consequently, a new genus and two new species of Metrodolrinae from China are described and illustrated: Edentatettix Deng, gen. nov. containing Edentatettixleyeensis Deng, sp. nov., and Macromotettixoidesyaana Deng, sp. nov. Additionally, five new synonyms are proposed: Hainantettixangustivertex (Zha & Peng, 2021), syn. nov. and Macromotettixoidesangustivertex Zha & Peng, 2021, syn. nov. of Hainantettixstrictivertex Deng, 2020; Hyboellabadagongshanensis Zheng, 2013, syn. nov., Macromotettixoidesbadagongshanensis (Zheng, 2013), syn. nov., and Macromotettixoideswuyishana Zheng, 2013, syn. nov. of Macromotettixoidesjiuwanshanensis Zheng, Wei & Jiang, 2005. For the first time, edentate ovipositors constituting an important taxonomic character within Tetrigidae is reported and discussed.

Earliest evidence of granivory from China (Shanxi Formation) points to seeds as a food source and nursing habitat for insects in the earliest Permian humid tropical forests of Cathaysia

Three types of plant-insect interactions are identified on seeds from the lower Permian (Asselian) Shanxi and lower Shihhotse formations of the Taiyuan district, North China. This enhances the relatively meagre fossil record of seed predation in global late Paleozoic floras, adding the earliest record of granivory from Cathaysia. The dispersed seeds cannot be attributed with confidence to any particular plant group, but associated fossil leaves belong to a broad spectrum of plants, including Medullosales, Cycadales, Noeggerathiales, Gigantopteridales, Cordaitales, and Voltziales. Among 85 analysed seeds, six showed evidence of predation, referable to three damage types: DT074 and two new damage types that will be added to the forthcoming version of the fossil damage guide (DT274, DT430). These damage features indicate novel strategies of seed exploitation in the earliest Permian of China. The causal agents of the seed herbivory are difficult to resolve with certainty, but possible culprits include representatives of Palaeodictyopteroidea, although we cannot exclude other groups, such as Dictyoptera, Odonatoptera, Archaeorthoptera, Hemipteroidea or early holometabolan insects. The presence of damage features, together with a range of probable defensive structures (hairs, spines, apical horns, and thick integuments), suggests that an active arms race involving insects and plant reproductive structures was already well established by the early Permian.

A Tale's blade: Understanding evolutionary features of oviposition behavior based on Tettigoniidae (Insecta, Orthoptera, Ensifera) ovipositor morphology

A remarkable characteristic of katydids (Orthoptera, Tettigoniidae) is the elongated ovipositor, which is associated with oviposition behavior. The high degree of complexity of both sclerites and muscles arrangement of the ovipositor, is only similar to the ovipositor of Hymenoptera. Here we describe the morphology of the ovipositor within Tettigoniidae, and add descriptions of known oviposition behavior. Fifteen skeletal structures can be recognized, of these, three pairs of muscles are new while nine pairs were already described in the literature. The new muscles are ap2vf, anterior projection of second valvifer; bcov, blade complex of the ovipositor; and dbl, dorsal blade. The morphology of the ovipositor blade complex (bcov), the shape of the first valvifer (1vf), posterior intervalvular sclerite (piv), tergite IX (T9), anterior projection of the second valvifer (ap2vf), and the second valvifer (2vf), and their related muscles affect oviposition in Tettigoniidae. This contribution helps to understand katydid's oviposition behavior. Additionally, the new descriptions help in the search for new characters in Tettigoniidae.

Little bits of dragonfly history repeating exemplified by a new Pennsylvanian family

During its 320 Myr evolution, dragon- and damselfly (Odonata) wing morphology underwent intense modifications. The resulting diversity prompted comparative analyses focusing on phylogeny. However, homoplasy proved to plague wing-related characters. Concurrently, limited benefits were obtained from considering fossil taxa, similarly impacted. Herein, we investigate two aspects particularly affected by convergence, namely the acquisition of vein-like structuring elements derived from regular cross-venation, termed conamina; and the evolution of butter knife wing shape. Conamen implementation is found to be consistently linked with vein curvature sharpening, itself generating potential breaking points. Conamina therefore likely evolved to address wing integrity issues during ever-more-demanding flight performance. Moreover, an existing conamen is likely to trigger the acquisition of further, associated conamina. As for butter knife shape, previously documented in the extinct Archizygoptera and among damselflies, we report a new, 315 Ma occurrence with the rare species Haidilaozhen cuiae gen. et sp. nov. (family Haidilaozhenidae fam. nov.), from the Xiaheyan locality (China). The repeated acquisition of butter knife-shaped wing can be related to slow speed flight and, in turn, predator avoidance. In both cases of iterated regularities, the unique 'network-and-membrane' wing design proper to insects is found to compose a strong, constraining factor.

Diversity, Form, and Postembryonic Development of Paleozoic Insects

While Mesozoic, Paleogene, and Neogene insect faunas greatly resemble the modern one, the Paleozoic fauna provides unique insights into key innovations in insect evolution, such as the origin of wings and modifications of postembryonic development including holometaboly. Deep-divergence estimates suggest that the majority of contemporary insect orders originated in the Late Paleozoic, but these estimates reflect divergences between stem groups of each lineage rather than the later appearance of the crown groups. The fossil record shows the initial radiations of the extant hyperdiverse clades during the Early Permian, as well as the specialized fauna present before the End Permian mass extinction. This review summarizes the recent discoveries related to the documented diversity of Paleozoic hexapods, as well as current knowledge about what has actually been verified from fossil evidence as it relates to postembryonic development and the morphology of different body parts.