Dobsonflies, fishflies, and alderflies are all representatives of the group Megaloptera. Today, the group Megaloptera comprises around 400 formally described species, making it one of the smaller ingroups of Holometabola, the group of “flying insects” characterised by a strongly expressed metamorphosis. Like most holometabolans, megalopterans spend the majority of their lives as immatures, also known as larvae. These larvae are aquatic and predatory; some of these are very large and known as “hellgrammites”. The fossil record of megalopteran larvae is relatively poor, reaching back into the Triassic. On a qualitative level, the fossil larvae strongly resemble their modern counterparts. We report new finds such as Triassic sedimentary fossils and fossils in amber from the Cretaceous and Eocene. Together with the already known specimens, we compared the fossils to their modern counterparts, using quantitative morphology of different body regions. For further comparison, we also included larvae of other holometabolan lineages with similar life habits. Especially larvae of Gyrinidae, the group of whirligig beetles, are similar to megalopteran larvae in many aspects: the body is rather elongate, the mouthparts are prominent and forward-protruding, the trunk region has a pair of elongate gills on most segments. The analysis revealed that at least some of the fossil megalopteran larvae had morphologies not present in the modern fauna, indicating a certain loss of diversity over time.

The larvae of dragonflies and damselflies (Odonatoptera) exhibit great morphological diversity, underpinning their important role as aquatic predators in freshwater ecosystems. Depending on species, odonatopteran larvae develop through 10–15 moults, with the metamorphosis to a flying adult taking place in the last moult, so they spend most of their lifetime under water. This pattern of aquatic larvae and flying terrestrial adults is generally referred to as “merolimic”. Their highly prominent compound eyes as well as the specialised extendable mouthparts (“labial mask”), which can be moved forward rapidly, enable the larvae to efficiently capture prey. Prey items include small crustaceans, other merolimnic larvae, but also tadpoles and small fishes. Fossil finds of odonatopterans, including a possible larva, reach back into the Carboniferous, over 300 million years ago. We here report new finds of odontopteran larvae from a more unusual type of preservation, amber. Amber less often preserves aquatic specimens, making odonatopteran larvae in amber rather rare. The new fossil comes from about 100 million years old Kachin amber. So far, less than a handful of odonatoperan larvae have been reported from this deposit, hence expanding the known diversity of these larvae. This includes also larvae with rather slender labial masks. We compared the shapes of the labial masks within a quantitative frame to reconstruct the evolutionary changes of this structure.

Larvae of mantis shrimps (Stomatopoda) exhibit a great morphological diversity, reflecting their numerous ecological roles in the plankton. From hatching from their eggs to their adult stage they develop through numerous stages, each separated by a moult. Due to their long time spent in the plankton, the larvae reach relatively large sizes, up to several tens of millimetres. The larvae play an important role as active predators of smaller plankton animals, but also as prey of immatures of large predatory fishes, such as tuna, therefore occupying a crucial role in the marine food web, possibly even having economical significance. Their strongly pronounced compound eyes and strongly modified major appendages enable them to efficiently catch prey in the pelagic zone, especially smaller soft-skinned organisms, such as small-sized adults or larvae of other crustaceans. As larvae they drift in the planktic realm of the ocean, before continuing in a more benthic existence after metamorphosing. Their presence in the fossil record has been demonstrated by fossil finds since the Jurassic. Still, such larvae are still rare as fossils, while adults and post-metamorphic immatures are much more common and also reach further back in time, into the Carboniferous. We present here a quantitative morphological comparison of feeding structures of mantis shrimp larvae over time, exploring in how far their ecological roles might have changed or been retained through time.

The Transantarctic Basin preserves up to 4 km of Palaeozoic and Mesozoic sedimentary rocks, rich in fossil plants. Permian and Triassic floras are especially well represented, with both silicified and cuticle-bearing remains enabling detailed studies of high-latitude Gondwanan ecosystems. During the 13th GANOVEX Expedition (2018/2019), new Triassic plant-fossil sites were discovered in the Prince Albert Mountains. The most diverse site, an unnamed nunatak west of Timber Peak, yielded five Dicroidium species, Pteruchus africanus pollen organs, Heidiphyllum elongatum, and Dejerseya lobata leaves. Another horizon at the same site contained abundant cuticles of a single Dicroidium species with needle-like leaflets. Southeast of Timber Peak along the edge of the Polar Plateau, plant fossils include altered Heidiphyllum remains and a dense accumulation of two foliage types—needle-like Dicroidium and narrow-leaved Linguifolium—with dispersed seeds (Feruglioa, Carpolithus) and a small Pteruchus species. A third, species-rich assemblage was found in Southern Vicotria Land at Benson Knob in the Ricker Hills, with four Dicroidium species and minor amounts of Heidiphyllum and horsetails. These new discoveries expand known Triassic floral diversity in the Transantarctic Mountains. Particularly, the species-poor deposits offer valuable insights into organ associations, contributing to whole-plant reconstructions. Together, these findings contribute to a deeper understanding of Mesozoic polar forests in Gondwana.

The Chemnitz Fossil Forest represents the most completely preserved Permian ecosystem, buried 291 myr ago in the phreatomagmatic ashes of the Zeisigwald Tuff (Leukersdorf Formation, Chemnitz Basin, central Germany). Its fossils provide cell-scale insights into the anatomy and ecology of past life but also stand out for their unusual mineralogy, e.g., fluoritized wood. Another barely reflected feature are isometric crystal casts <1 mm in diameter that occur in the outer tissues and the adjacent rhyolitic tuff of the petrified stems. These clay-filled casts exhibit hexagonal and octagonal outlines when cut and are discussed to reflect early-diagenetic garnet formation and alteration due to high fluid pressure and metasomatosis in the ash. We discuss the formation of these casts based on reviewing previous studies and own preliminary XRD, SEM, and electron-microbe analyses and CL spectroscopy. In sum, these structures formed shortly during and after burial, as indicated by surrounding, plastically displaced tissues and well-preserved cells and intracellular fungi in the non-compacted trunks – evidence for a rapid, early-diagenetic silicification. The preferred occurrence in plants rich in parenchyma, the preservation of thermally labile tissues, uncharred wood and the silica CL prove that water and temperatures <250°C impacted authigenesis. The cast fill results from hydrothermal alteration and consists of kaolinite and iron-oxide-hydroxide aggregates that are dissected by xenotime veins. Mg and Ca contents are low (<2wt%). The results indicate the former presence of euhedral cubic minerals, whose formation and alteration resulted from burial in ‘cool’ ashes of a highly evolved magma and subsequent authigenesis.

Social media has become a key bridge between the scientific community and the broader public. Early Career Researchers (ECRs) in Latin America have increasingly embraced digital platforms to engage non-specialist audiences with geoscience content, especially during the COVID-19 pandemic. One such initiative is Divulgación Terróloga, a non-profit, self-funded science communication project launched on June 11, 2019, by Mexican ECRs. The project aims to communicate Earth system processes clearly and accurately in Spanish through Facebook and Instagram. Our content covers all Earth spheres topics and features regular posts that promote the visibility of geosciences and the scientific work of mainly ECRs. The section "Miércoles de Jóvenes Investigadores" (Young Researchers Wednesday) highlights the research of students and early-career scientists, while the section "Geocientíficos en Acción" (Geoscientists in Action) focuses on geoscientists working beyond academia. We also conduct interviews with established researchers to highlight diverse career paths. In this presentation, we share the scope, challenges, and impacts of running Divulgación Terróloga. By April 23, 2025, we have published ~360 posts, reached ~2200 people per post on average, and grown a following of over 5300, with our most popular post reaching nearly 60,000 views. The audience is gender-balanced (49% women, 51% men) and spans Latin America, the U.S., and Europe. Our posts have been translated automatically into English, French, and German. This talk aims to highlight the power of social media in promoting geoscience education, increasing the visibility of minorities in science, and building international networks in outreach.