First fossil tumbling flower beetle-type larva from 99 million-year-old amber

Beetle larvae often differ significantly in morphology from their adult counterparts. Therefore, it should be surprising that these immatures are often not considered to the same extent as the adult beetles. As an example, the fossil record of most beetle groups is largely represented by adult specimens. Representatives of Mordellidae, the group of tumbling flower beetles, have a cosmopolitan distribution with myriads of formally described species, based mostly on adult male specimens. Mordellidae is also well represented in the fossil record, but again only by adults;not a single fossil specimen of a larva has been reported until now. We report a new well-preserved beetle larva in 99 million-year-old Kachin amber. The larva possesses specialisations not known from the modern larvae of Mordellidae, but otherwise is clearly similar to them in many aspects. It appears possible that the fossil represents yet another holometabolan larva in Kachin amber that is associated with life within wood and/or fungi, and therefore, may have contributed to carbon cycling of the past

The first fossil false click beetle larva preserved in amber

We report a new and unusual beetle larva preserved in ca. 100 million-year-old Kachin amber. Larvae of many modern lineages of beetles are associated with wood, breaking it into smaller pieces or directly digesting it. With such a lifestyle, beetle larvae are important for carbon cycling. We can assume that this is not only the case in modern ecosystems, but was similar in the past. Yet, wood-associated beetle larvae seem so far rare in Kachin amber despite its otherwise rich record of many different ecotypes. Only recently, solid-wood-boring larvae and those living in decaying wood have been reported from this amber deposit. Larvae of the group Eucnemidae, false click beetles, which are also wood-associated, have so far been only known from sedimentary rock deposits. Here we report the first larva of a false click beetle preserved in amber. The fossil larva combines features of different modern lineages of Eucnemidae in a unique morphology that is not known in the modern fauna. The fossil adds to the growing number of wood-associated holometabolan larvae in Kachin amber and with this contributes to a more complete view on this now extinct community and ecosystem

EXPANDING THE RECORD OF LARVAE OF FALSE FLOWER BEETLES WITH PROMINENT TERMINAL ENDS

Beetle larvae contribute to the overall biomass with a great share, yet they often stay unnoticed and underexplored. Larvae of the group Scraptiidae, also called false flower beetles, lead a life hidden in the wood, not easily accessible for observers. There, they contribute to wood decomposition and carbon cycling. Even though their ecological role is of great importance, these larvae have been comparably rarely studied. This is true for extant as well as fossil representatives of this group. It seems that this knowledge gap is not based on the limited availability of material but results from insufficiently studied material. Here we report new specimens, of which seven are extant and twelve are fossil. Fossil specimens are either from 40-million-year-old Baltic amber (Eocene) or 100-million-year-old Myanmar amber (Cretaceous), the latter representing the oldest record of these larvae. All specimens considered here possess a large, elongated terminal end. We performed an outline analysis of the shape of this terminal end for all so far known larval specimens sufficiently well preserved (in total 33 specimens: 17 extant, 14 Eocene, 2 Cretaceous). There is a recognisable difference between Eocene and extant specimens, yet it remains unclear whether this is due to different represented larval stages or an effect of evolution

Molecular pathophysiology of human MICU1 deficiency.

Funder: Ministerium für Innovation, Wissenschaft und Forschung des Landes Nordrhein‐Westfalen; Id: http://dx.doi.org/10.13039/501100009591Funder: Bundesministerium für Bildung und Forschung; Id: http://dx.doi.org/10.13039/501100002347AIMS: MICU1 encodes the gatekeeper of the mitochondrial Ca2+ uniporter, MICU1 and biallelic loss-of-function mutations cause a complex, neuromuscular disorder in children. Although the role of the protein is well understood, the precise molecular pathophysiology leading to this neuropaediatric phenotype has not been fully elucidated. Here we aimed to obtain novel insights into MICU1 pathophysiology. METHODS: Molecular genetic studies along with proteomic profiling, electron-, light- and Coherent anti-Stokes Raman scattering microscopy and immuno-based studies of protein abundances and Ca2+ transport studies were employed to examine the pathophysiology of MICU1 deficiency in humans. RESULTS: We describe two patients carrying MICU1 mutations, two nonsense (c.52C>T; p.(Arg18*) and c.553C>T; p.(Arg185*)) and an intragenic exon 2-deletion presenting with ataxia, developmental delay and early onset myopathy, clinodactyly, attention deficits, insomnia and impaired cognitive pain perception. Muscle biopsies revealed signs of dystrophy and neurogenic atrophy, severe mitochondrial perturbations, altered Golgi structure, vacuoles and altered lipid homeostasis. Comparative mitochondrial Ca2+ transport and proteomic studies on lymphoblastoid cells revealed that the [Ca2+ ] threshold and the cooperative activation of mitochondrial Ca2+ uptake were lost in MICU1-deficient cells and that 39 proteins were altered in abundance. Several of those proteins are linked to mitochondrial dysfunction and/or perturbed Ca2+ homeostasis, also impacting on regular cytoskeleton (affecting Spectrin) and Golgi architecture, as well as cellular survival mechanisms. CONCLUSIONS: Our findings (i) link dysregulation of mitochondrial Ca2+ uptake with muscle pathology (including perturbed lipid homeostasis and ER-Golgi morphology), (ii) support the concept of a functional interplay of ER-Golgi and mitochondria in lipid homeostasis and (iii) reveal the vulnerability of the cellular proteome as part of the MICU1-related pathophysiology

The evolutionary history of wood-associated beetle larvae and the contribution of amber fossils

Beetles (Coleoptera) comprise more than 380,000 described species and are not only highly taxonomically diverse today but also ecologically and morphologically. The fossil record of beetles is not scarce, however, it is mostly represented by adult specimens. Beetle larvae, especially preserved in amber, have a reputation to be rare, and wood-associated beetle larvae have been claimed to be 'anecdotal'. It has been suggested that small and soft-bodied larvae do not get fossilized easily, especially the larvae leading a hidden way of life within the wood. I wanted to research whether they really are as rare in amber as it seems from the literature. In my thesis, I studied specimens preserved mostly in ~100-million-year-old Kachin, ~40-million-year-old Baltic, and ~25-million-year-old Mexican ambers. Through my contributions, in the form of 9 publications, I demonstrate that wood-associated beetle larvae can actually be considered relatively abundant in ambers. In fact, such finds should not surprise since the fossil larvae probably inhabited areas close to the origin of the plant resin. The resin dripped on the animal, or the animal stumbled or fell in. Once the animal became stuck and engulfed within the resin it became a biological inclusion within hardened and fossilized resin, now considered amber. However, the fossil record of diverse groups of beetles within ambers seems biased towards adults, especially males. The reports of beetle larvae stay scarce, even though they are of great importance for understanding the evolutionary history of beetles and their biodiversity. In Holometabola, a group including beetles as well, modern representatives have life cycles including an adult, a pupa, and larval stages. Interestingly, most of the lifespan of many extant beetles is spent in the larval stages. Therefore, larvae of beetles not only increase the morphological and often ecological diversity of the group but are a big, if not the biggest, part of the beetle biomass. In addition, the modern wood-associated beetle larvae have another important role, they help in breaking and decomposing of wood, therefore, enhancing carbon cycling. It seems that wood as a substrate offers many different microenvironments depending on the state it is in. In this study I differentiate several functional groups of modern representatives of beetle larvae that feed on wood in different states: hardwood borers, softwood borers, fungus-infected wood borers, submerged wood borers, and in-wood predators. Even though predators are not directly feeding on wood, they are often encountered within the wood, especially within the galleries and tunnels of wood-feeding larvae that they prey upon. I was wondering whether such differentiation of wood-associated larvae already existed within the extinct representatives of past faunas. In the scope of this thesis I present two publications with possible hardwood borers, three publications considering possible softwood borers (even though, one specimen is likely a larva of Holometabola, but possibly not of Coleoptera), one manuscript with fungus feeders, one publication and one manuscript with submerged-wood borers and two publications with in-wood predaceous beetle larvae. Therefore, the wood habitats were crawling with life also in ecosystems of the past. Within the incorporated manuscripts and publications, my co-authors and I presented the fossil beetle larvae and their morphological characters on images created with a digital microscope, x-ray microcomputed tomography, and synchrotron radiation micro-computed tomography. The (rendered) images were further processed with programs such as Adobe Photoshop or Inkscape for easier interpretation by readers. Additionally, many of the new fossil larvae showed morphologies unknown from modern beetle larvae. Hence implying that the morphologies of extinct beetle larvae differed and occupied a different range of morphospace than the morphologies known from the modern beetle larvae. In order to compare the range of morphologies through time within the morphospace we used the pipeline of programs SHAPE that uses an Elliptic Fourier Analysis and a Principal Component Analysis

Possible fungus-eating cucujiformian beetle larvae with setiferous processes from Cretaceous and Miocene ambers

Beetle larvae represent important components of the modern-day fauna. This should have been the case in the past as well. Yet, fossil beetle larvae are rare, or at least are rare in the literature, as identifying a beetle larva to a narrower taxonomic group is very challenging. This is even more complicated if prominent features have evolved convergently in several lineages. Yet, even in such cases, an ecological interpretation of the fossils is possible if the convergent character is coupled to a specific life habit. For example, different, not closely related, beetle larvae that possess setiferous processes. We here report on three beetle larvae, one from Miocene Mexican and two from Cretaceous Kachin amber, Myanmar. These larvae possess setiferous processes, most similar to the processes of modern representatives of Cucujiformia, especially of the groups Endomychidae, Erotylidae, Cerylonidae and Coccinellidae. Considering the shape of the entire habitus, we see the most similarities between the new larvae and the modern larvae of Endomychidae. However, the new larvae and the larvae of modern representatives differ in certain aspects, most prominently in the body size. The fossils are smaller than their extant counterparts with setiferous processes. Hence the fossils could represent larvae of Endomychidae, but the case remains unclear. Despite this uncertainty, we suggest a lifestyle of the fossil larvae as fungus-eaters on rotting wood. This lifestyle is not only known from extant larvae of Endomychidae, but also from other larvae with similar processes

The first fossil immature of Elmidae: an unusual riffle beetle larva preserved in Baltic amber

Elmidae, riffle beetles, have both adult and immature stages that show specializations for water environments. Fossils of adults of Elmidae are already known from amber, however a record of immatures was so far lacking. We report here the first fossil larva of Elmidae, preserved in Baltic amber. To be able to access details of the body hidden by inclusions and “Verlumung” we conducted, in addition to optical documentation methods, micro-CT and synchrotron documentation methods. The larva is characterised by prominent dorso-lateral and lateral processes and a plate-like ventral operculum at the end of the abdomen. The new fossil has similarities in the general body shape and the prominent characters with some modern larvae of Elmidae. The posterior protrusions on the trunk end possibly represent gills, which would imply that fossil larvae of Elmidae also led a water-related life style similar to modern representatives

Texas beetle larvae (Brachypsectridae) – the last 100 million years reviewed

Larvae of Brachypsectridae (Texas beetles) have often been considered rare. However, they are known from North America, Asia and Australia in the extant fauna, and from Miocene, Eocene and Cretaceous ambers. We review the overall record of extant and fossil larvae of Brachypsectridae represented in the literature. Furthermore, we present three new specimens, which were all documented via light microscopy. Two of the specimens are from Baltic amber, and the third one is from the Cretaceous amber of Myanmar; the latter was additionally documented via synchrotron radiation micro-computed tomography. The number of known extant specimens, more than 20, is unusually high compared to other small groups of beetles and with respect to the low number of eight formally described species. The number of fossil specimens from the Miocene, Eocene and Cretaceous is low, two to three specimens per time slice. This makes a comparison of morphological diversity difficult. Still such an analysis of overall body shape as well as of the anterior body region revealed no significant quantitatively recognisable changes over time. However, some qualitative changes in the morphology of the antenna and lateral processes from the Cretaceous to younger faunas could be identified

THE FIRST FOSSIL RECORD OF A MANTIS LACEWING PUPA, AND A REVIEW OF PUPAE IN MANTISPIDAE AND THEIR EVOLUTIONARY SIGNIFICANCE

During ontogenetic development, insects can undergo quite drastic changes (metamorphosis) until the adult stage is reached. A substantial part of this development in one group of Insecta, Holometabola, takes place during the pupa stage. Despite the pupa being recognised as an important phase, rather few depictions of pupae exist in the literature. We report here the first find of a fossil pupa of the lacewing group Mantispidae. The specimen represents an exuvia and is enclosed in Ukrainian Rovno amber, Eocene in age (c. 35–40 million years). We review the entire record of extant pupae of Mantispidae depicted in the literature or in online image repositories. With the aid of elliptic Fourier analysis, we compare the outline of the femur of the foreleg (raptorial appendage in the adults) of pupae and adults of Mantispidae. The pupae are all very similar concerning the femur, while the adults show a larger morphological diversity, particularly the extinct forms. Furthermore, our results indicate that the forelegs do not become increasingly complex throughout ontogenetic stages, but instead undergo an indirect development. According to the low variation in morphology seen in the pupa stage in Mantispidae, it is plausible that it represents a phylotypic stage for the group, i.e. a phase characterised by a significantly lower variability than other stages

Changes in the Morphological Diversity of Larvae of Lance Lacewings, Mantis Lacewings and Their Closer Relatives over 100 Million Years

Neuroptera, the group of lacewings, comprises only about 6000 species in the modern fauna, but is generally assumed to have been more diverse and important in the past. A major factor of the modern-day ecological diversity of the group, and supposedly in the past as well, is represented by the highly specialised larval forms of lacewings. Quantitative analyses of the morphology of larvae revealed a loss of morphological diversity in several lineages. Here we explored the diversity of the larvae of mantis lacewings (Mantispidae), lance lacewings (Osmylidae), beaded lacewings (Berothidae and Rhachiberothidae, the latter potentially an ingroup of Berothidae), and pleasing lacewings (Dilaridae), as well as fossil larvae, preserved in amber, resembling these. We used shape analysis of the head capsule and stylets (pair of conjoined jaws) as a basis due to the high availability of this body region in extant and fossil specimens and the ecological importance of this region. The analysis revealed a rather constant morphological diversity in Berothidae. Mantispidae appears to have lost certain forms of larvae, but has seen a drastic increase of larval diversity after the Cretaceous; this is in contrast to a significant decrease in diversity in adult forms