An exceptionally preserved 110 million years old praying mantis provides new insights into the predatory behaviour of early mantodeans

Mantodeans or praying mantises are flying insects and well known for their raptorial behaviour, mainly performed by their first pair of thoracic appendages. We describe here a new, exceptionally preserved specimen of the early mantodean Santanmantis axelrodi Grimaldi, 2003 from the famous 110 million years old Crato Formation, Brazil. The incomplete specimen preserves important morphological details, which were not known in this specific form before for this species or any other representative of Mantodea. Unlike in modern representatives or other fossil forms of Mantodea not only the first pair of thoracic appendages shows adaptations for predation. The femora of the second pair of thoracic appendages bear numerous strong, erect spines which appear to have a sharp tip, with this strongly resembling the spines of the first pair of thoracic appendages. This indicates that individuals of S. axelrodi likely used at least two pairs of thoracic appendages to catch prey. This demonstrates that the prey-catching behaviour was more diverse in early forms of praying mantises than anticipated

35 million-year-old solid-wood-borer beetle larvae support the idea of stressed Eocene amber forests

Eocene amber is an important window into the past about 35 million years ago. The large quantities of resin produced by this forest of the past, resulting in amber, triggered the idea of a forest under stress. Recent findings of higher abundances of hoverfly larvae in Eocene amber, in the modern fauna often associated with wood-borer larvae, provided a hint that wood-borer larvae may have contributed to this stress. Yet, so far only few such larvae have been reported. We have compiled a dozen additional wood-borer larvae in amber, including a giant one of at least 35 mm length in Rovno amber. Heavily damaged fossils furthermore indicate that larger larvae of this type were prone to oxidation and that, at least some, enigmatic tube-like tunnels in larger amber pieces may represent remains of large wood-borer larvae. This find strongly indicates that wood-borer larvae were not rare, but common in the Eocene amber forest, which is compatible with the high abundances of hoverfly larvae and further supports the idea of a forest under stress. Whether the possible higher abundances of wood-borer larvae were the cause of the stress or a symptom of an already stressed forest remains so far unclear

The bigger, the better? Volume measurements of parasites and hosts: Parasitic barnacles (Cirripedia, Rhizocephala) and their decapod hosts

Rhizocephala, a group of parasitic castrators of other crustaceans, shows remarkable morphological adaptations to their lifestyle. The adult female parasite consists of a body that can be differentiated into two distinct regions: a sac-like structure containing the reproductive organs (the externa), and a trophic, root like system situated inside the hosts body (the interna). Parasitism results in the castration of their hosts, achieved by absorbing the entire reproductive energy of the host. Thus, the ratio of the host and parasite sizes is crucial for the understanding of the parasite's energetic cost. Using advanced imaging methods (micro-CT in conjunction with 3D modeling), we measured the volume of parasitic structures (externa, interna, egg mass, egg number, visceral mass) and the volume of the entire host. Our results show positive correlations between the volume of (1) entire rhizocephalan (externa + interna) and host body, (2) rhizocephalan externa and host body, (3) rhizocephalan visceral mass and rhizocephalan body, (4) egg mass and rhizocephalan externa, (5) rhizocephalan egg mass and their egg number. Comparing the rhizocephalan Sylon hippolytes, a parasite of caridean shrimps, and representatives of Peltogaster, parasites of hermit crabs, we could match their different traits on a reconstructed relationship. With this study we add new and significant information to our global understanding of the evolution of parasitic castrators, of interactions between a parasitic castrator and its host and of different parasitic strategies within parasitic castrators exemplified by rhizocephalans

Morphological responses to feeding in ticks (Ixodes ricinus)

Background: Ticks can survive long periods without feeding but, when feeding, ingest large quantities of blood, resulting in a more than 100-fold increase of body volume. We study morphological adaptations to changes in opisthosoma volume during feeding in the castor bean tick, Ixodes ricinus. We aim to understand the functional morphological features that accommodate enormous changes in volume changes. Methods: Using light and electron microscopy, we compare the cuticle and epidermis of the alloscutum, the epithelium of the midgut diverticula, and the tracheae of adult female ticks when fasting, semi-engorged, and fully engorged. Results: Our results add to an existing body of knowledge that the area of the epidermis increases by cellular differentiation, cellular hypertrophy, and changes in the shape of epithelial cells from pseudostratified to single layered prismatic in semi-engorged ticks, and to thin squamous epithelium in fully engorged ticks. We did not find evidence for cell proliferation. The midgut diverticula accommodate the volume increase by cellular hypertrophy and changes in cell shape. In fully engorged ticks, the epithelial cells of the midgut diverticula are stretched to an extremely thin, squamous epithelium. Changes in size and shape (and cell divisions) contribute to the accommodation of volume changes. Tracheae do not increase in size, but extend in length, thus following the volume changes of the opisthosoma in feeding ticks to secure oxygen supply to the internal organs. Conclusions: Changes of epithelial tissue configuration in the epidermis and the midgut diverticula are described as important components of the morphological response to feeding in ticks. We provide evidence for a previously unknown mechanism hosted in the endocuticle of the tracheae that allows the tracheae of castor bean ticks to expand when the body volume increases and the distance between the respiratory spiracle and the oxygen demanding tissue enlarges. This is the first report of expandable tracheae in arthropods

The first adult mantis lacewing from Baltic amber, with an evaluation of the post-Cretaceous loss of morphological diversity of raptorial appendages in Mantispidae

Mantis lacewings (Neuroptera: Mantispidae) are prominent and charismatic predatory representatives of Insecta. Nevertheless, representatives of the group are surprisingly scarce in Paleogene deposits after a relative abundance of specimens known from Cretaceous. Here we present Mantispa? damzenogedanica sp. nov., representing the first adult of Mantispidae described from Baltic amber and the only Eocene adult mantispid hitherto preserved in amber. The new fossil species is also among the earliest representatives of Mantispinae, certainly the oldest adult of this group described from amber. Additionally, we discuss the changes through time in the ecological morphospace within Mantispidae based on the morphological diversity (≈disparity) of the raptorial legs. Possible explanations for the post-Cretaceous decline in the morphological diversity of mantis lacewings are posited

Rekonstruktionen zur Evolution von Fortpflanzungsstrategien und Raubverhalten geflügelter Insekten: Was Fossilien über komplexe Verhaltensweisen verraten.

Heutige Vertreter der Insekten haben vielfältige Lebensweisen und Verhaltensstrategien entwickelt, wie beispielsweise zur Ernährung, zum Schutz gegen Fressfeinde, zu Reproduktionsstrategien und die Investition in Nachkommen. Um die Evolution dieser Strategien besser zu verstehen, kann die Einbeziehung von Fossilien wertvolle Hinweise liefern. So können fossile Überreste von Organismen oder Strukturen, welche von ihnen zu Lebzeiten verursacht wurden, für eine Rekonstruktion über das erstmalig zeitgeschichtliche Auftreten und der Entwicklung einer Strategie genutzt werden. Da jedoch die Untersuchung des Verhaltens von heute nicht mehr lebenden Organismen nicht möglich ist, können Hinweise dazu nur indirekt geschlussfolgert werden. Im Rahmen dieser Arbeit wurden daher folgende Aspekte näher beleuchtet und für Rekonstruktionen genutzt: (1) Die phylogenetische Position von fossilen Vertreten, (2) Spurenfossilien, (3) Gemeinsame Fossilisation mehrerer Individuen, (4) “Frozen Behaviour“, (5) Fossilisierte Eier und Ei-assoziierte Strukturen, sowie (6) Morphologische Anpassungen als Schwerpunkt der vorliegenden Arbeit. Die Anwendbarkeit und Limitationen der jeweiligen Ansätze wurden im Rahmen von Rekonstruktionen zu Aspekten von Raubverhalten und Reproduktionsstrategien (im Zusammenhang mit der Investition in die Nachkommen) von verschiedenen Vertretern der Arthropoden diskutiert. Die Insektengruppe Dictyoptera, welche die Gruppen Mantodea und Blattodea umfasst, hat sich als besonders geeignet für die Rekonstruktion von Verhaltensaspekten unter den genannten Aspekten und Ansätzen gezeigt. Heutige Dictyopteren zeigen eine enorme Spannbreite von verschiedenen Lebensweisen, von räuberisch und solitär lebend bei Mantiden, über verschiedene Abstufungen von Sozialverhalten bei Schaben, bis hin zur Eusozialität der Termiten (als Innengruppe der Blattodea). Des Weiteren ist diese Gruppe durch eine bemerkenswerte Autapomorphie gekennzeichnet, die Ablage von Eiern in einer Art kompakten Paket (Oothek). Die Ootheken von Dictyopteren sind sehr robust und wurden, wenn auch selten, fossil gefunden. Die Rekonstruktion des Ursprungs der Fähigkeit, Ootheken zu bilden, stellt ein Schlüsselmerkmal in der Rekonstruktion der evolutionären Entwicklung der gesamten Gruppe dar. Weitere Betrachtungen im Rahmen dieser Arbeit beleuchten die Entwicklung der Gruppe der Mantiden und deren Spezialisierung auf eine räuberische Lebensweise, wie sie bei heutigen Vertretern zu beobachten ist.Within insects, a variety of sophisticated lifestyles evolved, especially e.g. concerning reproduction, the investigation in the young, sociality, but also solitary lifestyle and specialisation to raptorial behaviour. Behavioural aspects of extinct arthropods are difficult to study, as it is only possible to reconstruct indirectly. However, there are some different approaches, which can provide further indications for reconstructing behavioural aspects based on fossils: (1) indirect phylogenetic evidence, (2) trace fossils, (3) cases of ‘frozen behaviour’, (4) investigation of fossilised aggregations, and (5) investigation of the morphology of the fossilised animals. But, it is only possible to draw inferences from these points with a comprehensive comparison of these findings with observations of modern counterparts. Due to the fact that necessary documentations are often missing for different groups in the literature, this can be a challenging task. The investigation of behavioural aspects of extinct arthropods is an important step towards for a better understanding of the evolution of strategies in extant species and could thus help unravelling ambiguous phylogenetic relationships among these this groups

<i>Grimmenichthys ansorgei</i>, gen. et sp. nov. (Teleostei, ‘Pholidophoriformes’), and other ‘pholidophoriform’ fishes from the early Toarcian of Grimmen (Mecklenburg-Western Pomerania, Germany)

<p>Rare finds of ‘pholidophoriform’ fishes from the early Toarcian (Early Jurassic) of Grimmen (Mecklenburg-Western Pomerania, Germany) are described. The specimens include two isolated dentaries, an isolated braincase, several isolated scales, and an articulated, but incomplete specimen. The isolated bones are described in open nomenclature, whereas the articulated specimen is assigned to a new genus and species. The new taxon, <i>Grimmenichthys ansorgei</i>, gen. et sp. nov., shows an autapomorphy (notch in anteroventral margin of preopercle present) and some synapomorphies (e.g., five or six infraorbital bones; lepisosteoid-type scales, deeper than long in predorsal region, present) of Pholidophoridae s.s. The abdominal vertebrae of <i>Grimmenichthys ansorgei</i>, gen. et sp. nov., are diplospondylous which is also the case in the pholidophorids <i>Pholidoctenus serianus</i> and <i>Malingichthys nimaiguensis</i>, but the pattern of mineralization of the hemichordacentra is different from the condition in both of these pholidophorid species.</p> <p><a href="http://zoobank.org:urn:lsid:zoobank.org:pub:55B9DFBC-0394-4243-80C2-B55744C156C0" target="_blank">http://zoobank.org:urn:lsid:zoobank.org:pub:55B9DFBC-0394-4243-80C2-B55744C156C0</a></p> <p>SUPPLEMENTAL DATA—Supplemental materials are available for this article for free at <a href="http://www.tandfonline.com/UJVP" target="_blank">www.tandfonline.com/UJVP</a></p> <p>Citation for this article: Konwert, M., and M. K. Hörnig. 2018. <i>Grimmenichthys ansorgei</i>, gen. et sp. nov. (Teleostei, ‘Pholidophoriformes’), and other ‘pholidophoriform’ fishes from the early Toarcian of Grimmen (Mecklenburg-Western Pomerania, Germany). Journal of Vertebrate Paleontology. DOI: 10.1080/02724634.2018.1451872.</p

Debris-carrying behaviour of bark lice immatures preserved in 100 million years old amber

&lt;jats:title&gt;Abstract&lt;/jats:title&gt;&lt;jats:p&gt;Camouflage strategies, including several types of concealments, are known for several insect groups today, such as immatures of some species within reduviid bugs (Hemiptera), lace wings (Neuroptera), caddisflies (Trichoptera) and bark lice (Psocodea). However, camouflage has only rarely been reported in the fossil record. Here we report findings of four bark lice preserved in 100 Million year old amber from Myanmar, which represent the first fossil evidence for masking behaviour in Cretaceous representatives of Psocodea. All four of these, probably not conspecific, and immature bark lice carry sand granules and organic material atop their back, which probably resulted in camouflaging them against the background (e.g. bark) to avoid detection by predators. We briefly summarise concepts of camouflage and examples of decoration behaviour within insects, as well as possible “receiver” (i.e. predators) of the camouflage of the herein described bark lice. The exact phylogenetic position of the specimens remains unclear, due to the scarce fossil record of Cretaceous immatures of Psocodea, as well as extant immatures. This demonstrates the importance of findings as reported here, as a wide knowledge of morphology and development of a certain group is crucial to get an insight into their evolution and reconstructing environments in deep time.&lt;/jats:p&gt

Mass occurrence of small isopodan crustaceans in 100-million-year-old amber: an extraordinary view on behaviour of extinct organisms

&lt;jats:title&gt;Abstract&lt;/jats:title&gt;&lt;jats:p&gt;Within Isopoda (woodlice and relatives), there are lineages characterised by a parasitic lifestyle that all belong to Cymothoida and likely form a monophyletic group. Representatives of Epicaridea (ingroup of Cymothoida) are parasitic on crustaceans and usually go through three distinct larval stages. The fossil record of Epicaridea is sparse and thus little is known about the palaeoecology and the origin of the complex life cycle of modern epicarideans. We present an assemblage of over 100 epicarideans preserved in a single piece of Late Cretaceous Myanmar amber. All individuals are morphologically similar to cryptoniscium stage larvae. The cryptoniscium stage usually constitutes the third and last larval stage. In modern representatives of Epicaridea, the cryptoniscium larvae are planktic and search for suitable host animals or adult females. These fossil specimens, though similar to some extant species, differ from other fossil epicaridean larvae in many aspects. Thus, a new species (and a new genus), &lt;jats:italic&gt;Cryptolacruma nidis&lt;/jats:italic&gt;, is erected. Several factors can favour the preservation of multiple conspecific animals in a single piece of amber. However, the enormous density of epicarideans in the herein presented amber piece can only be explained by circumstances that result in high local densities of individuals, close to the resin-producing tree.&lt;/jats:p&gt