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Rhamphorhynchus is one of the best-known pterosaurs, with well over 100 specimens being held in public collections. Most of these represent juvenile animals, and the adults known are typically around 1 m in wingspan. Here we describe a near complete skeleton, preserved partially in 3D, of an animal with a wingspan of around 1.8 m, that is considerably larger than other known specimens, and is among the largest known non-pterodactyloid pterosaurs. This animal shows differences in the anatomy not seen in smaller specimens, revealing details of late-stage ontogeny in this genus. The specimen exhibits a disproportionate reduction in the size of the orbit and increase in the size of the lower temporal fenestra, a reduction in the proportional mandibular symphysis, and unusually laterally flattened teeth, which may point to a changing diet as these animals grew. These features show a transition from smaller to larger specimens of Rhamphorhynchus and also appear in other large specimens of rhamphorhyhchines and point to a consistent pattern in their development.

The Crato Formation (Lower Cretaceous, Brazil) is a Konservat-Lagerstätte preserving a great number of exceptionally well-preserved insects. Here, we sought to explore the preservational modes of two abundant aquatic and terrestrial groups of this unit, mayflies and crickets. To better understand how exceptional is their preservation, we also present detailed data on the modes of preservation of mayflies from the renowned Solnhofen limestones (Upper Jurassic, Germany). For the Crato Formation, out of 234 fossil mayflies and crickets, ten specimens were additionally analyzed using scanning electron microscopy coupled to energy dispersive X-ray spectroscopy (SEM-EDS), energy and micro-energy dispersive X-ray fluorescence (EDXRF and µEDXRF), and µRaman spectroscopy. For the Solnhofen limestones, 85 adult mayflies were analyzed, and five of them were subjected to SEM-EDS and µEDXRF analyses. The Crato specimens preserve several external and internal microfeatures. The areas with the highest fidelity of preservation are characterized by smaller and more closely-packed crystals when compared to less-preserved parts. We also recovered microscopic features that suggest the presence of microbial mats during the fossilization process. All the analyzed Crato specimens are preserved by replacement of tissues with iron oxides after pyritization. Sulfur occurs scattered in some regions of the crickets, but is associated with low iron counts, which may indicate the presence of sulfates post-dating pyrite oxidation. Additionally, the orthopterans have calcium phosphate preserving some of their structures. Differing from Crato insects, Solnhofen mayflies are overall poorly preserved as mere imprints, and their micron-scale morphology is obliterated by coarse mineral growth, whereas tissues are obliterated by calcite crystals alone or in combination with globular material. There is an elevated concentration of Si, K, Ca, Ti, Mn, and Fe in comparison to the host rock, which may be related to a yet unknown mineral phase(s). Although the paleoenvironments of the Crato Formation and the Solnhofen limestones are different, there are similarities in the style of preservation of their vertebrates and in some of their paleoenvironmental conditions such as anoxic hypersaline bottom waters and deposition of laminated limestones. However, the same does not apply to the preservation of insects, specifically mayflies, which are poorly preserved in the Solnhofen limestones.

Late Jurassic marine vertebrates are extraordinarily well preserved in several Plattenkalk Lagerstätten in central Europe. Among them, the Solnhofen Archipelago has yielded the very rare fish Coccolepis bucklandi, which was the first fossil chondrostean to be found in sediments younger than the Triassic. The type specimen of this species was lost, but it was rediscovered recently, prompting the alpha taxonomic revision of this iconic fish. A new species Coccolepis solnhofensis has been identified among the specimens referred to C. bucklandi. The two species differ in the distinctive distribution of scutes and fringing fulcra. Based on the available evidence, C. bucklandi is restricted to the Eichstätt Basin and the Lithacoceras eigeltingense ß Horizon of the Lithacoceras riedense Subzone (Hybonoticeras hybonotum Zone), and C. solnhofensis sp. nov. is limited to the Solnhofen Basin and the slightly younger Subplanites rueppellianus Subzone (Hybonoticeras hybonotum Zone). Therefore, the two species are geographically and stratigraphically separated. The diagnosis of Coccolepis is improved with the addition of new characters, and the genus is here restricted to the two early Tithonian species from the Solnhofen Archipelago. Among the four species previously described or referred to Coccolepis, the generic assignment of “Coccolepis” australis and “Coccolepis” liassica, remains unclear. Sunolepis yumenensis is here returned to its original genus, and the new combination Condorlepis woodwardi is proposed for this Early Cretaceous coccolepidid from Australia.

Ichthyosaurs from the Solnhofen Lagerstätte are among the only examples of soft tissue preservation in the major Middle Jurassic–middle Cretaceous family Ophthalmosauridae. However, few such specimens are currently described, and the taphonomical pathways for the preservation of soft tissue are not well understood. In order to answer this, two new ichthyosaur specimens, one nearly complete and one isolated tail, are described here. The nearly complete specimen is assigned to Aegirosaurus sp. It is accompanied by large amounts of incrustation pseudomorphs (epimorphs) of soft tissue preserved as apatite. It also preserves a nearly complete gastral basket, for the first time in ophthalmosaurids. Soft tissue samples were analyzed using X-ray diffraction (XRD) and scanning electron microscopy (SEM) coupled with energy dispersive spectroscopy (EDS) analysis. The analyses confirm the presence of apatite, with phosphate most likely derived from the body itself.

Polychelidan lobsters (Decapoda: Polychelida) are crustaceans with extant species which are restricted to deep water environments. Fossil species, however, used to live in more varied palaeoenvironments, from shallow water to deep water, and were more diverse morphologically. We redescribe two species of polychelidan lobsters, the Late Triassic Rosenfeldia triasica Garassino, Teruzzi & Dalla Vecchia, 1996 and the Late Jurassic Eryon oppeli Woodward, 1866, recently assigned to the same genus, Rosenfeldia, based upon only a few characters. Our investigation of all available material of both species leads us to distinguish these two species and to erect Rogeryon gen. nov. to accommodate Eryon oppeli. The palaeobiology of both species is interpreted for the first time. Rosenfeldia triasica with its stout first pereiopods and mandibles with both incisor and molar processes (documented for the first time in Polychelida) was benthic and probably fed either on slow-moving sedentary preys or was a scavenger. Rogeryon oppeli gen. et comb. nov. was benthic, visually adapted to shallow water palaeoenvironments, and possibly had a diet similar to that of slipper lobsters and horseshoe crabs. The redescription of these two species highlights the palaeobiological diversity of fossil polychelidans.

Larvae of malacostracan crustaceans represent a large fraction of modern day zooplankton. Plankton is not only a major part of the modern marine ecosystem, but must have played an important role in the ecosystems of the past as well. Unfortunately, our knowledge about plankton composition of the past is still quite limited. As an important part of today’s zooplankton, malacostracan larvae are still a rarity in the fossil record; many types of malacostracan larvae dominating the modern plankton have so far not been found as fossils. Here we report a new type of fossil malacostracan larva, found in the 150 million years old lithographic limestones of southern Germany (Solnhofen Lithographic Limestones). The three rather incomplete specimens mainly preserve the telson. A pronounced middle spine on the posterior edge of these specimens indicates that they are either larval forms of a clawed lobster or of an axiidean lobster, or of a closer relative to one of the two groups. The tergo-pleura are drawn out into distinct spines in one specimen, further supporting the interpretation as a larva of a clawed lobster or an early relative. The telson morphology also shows adaptations to a prolonged planktic life style, the latero-posterior edges are drawn out into distinct spines. Similar adaptations are known in larvae of the modern homarid lobster Nephrops norvegicus, not necessarily indicating a closer relationship, but convergent life styles. The new finds provide an important new insight into the composition of Mesozoic zooplankton and demonstrate the preservation potential of lithographic limestones.