Octodontoidea is the most diverse clade of hystricognath rodents, and is richly recorded in South America since at least the Oligocene. A parsimony-based morphological phylogenetic analysis of a wide range of extant and extinct octodontoids recovered three major clades, here recognised as Echimyidae, Octodontidae, and Abrocomidae. Taxa previously assigned to Echimyidae or Octodontoidea incertae sedis are here interpreted for the first time as early representatives of Ctenomyinae (Octodontidae), Octodontinae or Abrocomidae. Based on our results, we estimate the divergence of octodontoid families and subfamilies to have occurred during the Late Oligocene, which is consistent with molecular estimates, but older than previous inferences based on the fossil record. Contrary to previous suggestions, we show the first appearances of modern members of Abrocomidae, Octodontinae and Ctenomyinae to be distinctly decoupled from the origin of these clades, with different stages in the evolutionary history of octodontoids seemingly following distinct phases of palaeoenvironmental change. Depending on the phylogenetic pattern, fossils from the stage of differentiation bear evolutionary information that may not be provided by crown groups, thus highlighting the unique and important contribution of fossils to our understanding of macroevolutionary patterns.

The synonymization of the cimolestan taxa Cymaprimadon and Chadronia from the Late Eocene Chadron Formation is consistently upheld, despite a lack of supporting evidence. Here we show that the synonymization is unjustified, owing to distinct differences between these taxa in the mandibular tooth count (1-1-3-3 vs. ?-1-4-3), the identity of the enlarged anterior mandibular tooth (incisor versus canine), and the morphology of the crown of m3 (e.g., paraconid on m3 in Cymaprimadon). We also refer a specimen recently collected from the Early Oligocene Brule Formation within the Badlands National Park (BADL 16917) to Chadronia sp., thus making it the youngest occurrence of a pantolestan from North America. Examination of an additional specimen (FMNH UC 349) revealed the presence of a further cimolestan taxon in the White River Group of South Dakota, although the poor quality of the locality and stratigraphic data associated with this specimen precludes erecting a formal name. In total, this study doubles the number of cimolestans from the Late Chadronian and Orellan (Ch4 to Or1) of North America from two to four, and extends the biostratigraphic range of Pantolesta into the North American Oligocene.

Fossil remains of reindeer (Rangifer tarandus) occurring outside their present range are an important indicator of formerly cold climatic conditions, but are easily confused with those of the red deer (Cervus elaphus). The locality of Kiputz IX has yielded one of the best-preserved Late Pleistocene reindeer populations of the southern Pyrenees, occurring in association with Bison priscus and the much more abundant Cervus elaphus. Fossil remains from this site are mostly complete and not affected by human intervention, thus creating the perfect conditions for reliable osteometric analyses. Here, we quantify diagnostic morphological features of the scapula and the humerus of Cervus elaphus and Rangifer tarandus to establish the potential of these bones to aid in interspecific discrimination. In the case of the scapula, the best species discriminator is the ratio of the minimum anteroposterior diameter of the scapular neck and the development of the articular process, while the breadth of the trochlea is the best discriminator in the case of the humerus.

The origins and evolutionary relationships of the pygmy right whale (Caperea marginata), the only living member of the Neobalaeninae, have been the subject of a long-standing debate. This phylogenetic uncertainty is compounded by a limited neobalaenine fossil record. Here, we report a Late Miocene mysticete mandible from Patagonia, Argentina, and provisionally refer it to Neobalaeninae, gen. et sp. indet. The new material represents only the third report of a fossil neobalaenine, and the first fossil occurrence of this lineage in the southwestern Atlantic. It is also the oldest specimen so far reported, thus corroborating the idea of an early divergence time for neobalaenines.

We re-describe Cetotherium riabinini, a little-known baleen whale from the Late Miocene of the Eastern Paratethys represented by an exceptionally well-preserved skull and partial skeleton. C. riabinini is shown to be closely related to C. rathkii, the only other member of the genus. Cetotheriids from the Eastern Paratethys are remarkable for their pachyosteosclerotic postcranial skeleton, and are among the youngest known cetaceans displaying this morphology. C. riabinini likely followed a generalised feeding strategy combining herpetocetine-like continuous suction feeding, as seen in the mallard Anas platyrhynchos, and eschrichtiid-like intermittent suction feeding. This hypothesis may explain the mechanism and function of cranial kinesis in baleen whales. Many characteristics of the mysticete skull likely evolved as a result of cranial kinesis, thus leading to multiple instances of morphological convergence across different phylogenetic lineages.

Recent Triassic discoveries have extended the record of near-mammals (Mammaliaformes) back to the Norian, about 215 Ma, and reveal a significant diversity of Late Triassic (Norian-Rhaetian) forms. We now add to this Late Triassic diversity a nearly complete double-rooted right lower molariform tooth (ZPAL V.33/734) from the Polish Upper Triassic that is significant because it comes from uppermost Norian—lower Rhaetian rocks and is the first discovery of a mammal-like tooth in the Mesozoic of Poland. The described tooth shows transitional dental morphology between advanced cynodonts and mammaliaforms and it appears to represent a basal mammaliaform (genus Hallautherium), probably belonging to Morganucodonta.

Evidence from the quadrate morphology in the American specimens of Presbyornis proved inconsistent with the hypothesis of close relationships of this anseriform genus to modern ducks and geese, but some character states remained uncertain. Here I describe in detail two fairly well preserved Presbyornis quadrates from Central Asia, which provide new evidence for the plesiomorphic, galliform-like morphology of this bone among the anseriforms. Most important, and contrary to a recent report, there is no caudomedial foramen that is present in the extant anseriforms. The only pneumatic foramen is in the basiorbital position, which is plesiomorphic for the galloanserines. At least six other plesiomorphic characters of the quadrate consistently suggest that the Presbyornithidae are stem-group anseriforms.

It has hitherto been hard to prove that any association of juvenile dinosaurs represents original behaviour rather than sedimentary accumulation, and it has been hard also to determine the ages of such juveniles. A previously described specimen, which consists of an “adult” Psittacosaurus with 34 fully articulated juveniles, turns out to be a composite: the “adult” skull probably has been added, and in any case it is below breeding age. Other juvenile-only clusters have been reported, but the best examples that likely reflect behaviour rather than sedimentary accumulation are specimens from the Early Cretaceous Lujiatun beds in NE China, which were entombed beneath pyroclastic flow deposits. A remarkable juvenile-only cluster of Psittacosaurus shows clear evidence of different ages (five 2-year olds and one 3-year old) based on bone histological analysis. These juveniles may have associated together as a close-knit, mixed-age herd either for protection, to enhance their foraging, or as putative helpers at the parental nest.

We present new nodosaurid teeth from the Valanginian of Bexhill, Sussex and the Barremian of the Isle of Wight, the first from the Lower Cretaceous of the United Kingdom. Teeth found during the mid-1800s from the Valanginian and ascribed to the nodosaurid Hylaeosaurus are probably from sauropod dinosaurs. The Isle of Wight tooth could possibly be referred to Polacanthus foxii, the teeth of which are unknown. These new English nodosaurid teeth are similar to those of North American and European Jurassic to Late Cretaceous nodosaurids, especially the American Gastonia, Texasetes, Mymoorapelta, Gargoyleosaurus, and the European Hungarosaurus.

Trigonoolithus amoae oogen. et oosp. nov. is described on the basis of abundant eggshell fragments from the La Cantalera 1 site in the Early Cretaceous (early Barremian) Blesa Formation, Teruel Province, northern Spain. The surface ornamentation, the most diagnostic feature of the new oogenus, consists of closely spaced sub-triangular or rounded protuberances that have not previously been reported in any other ootaxon. The eggshells present three distinct layers, with a gradual transition between prismatic and mammillary layers, and a poorly developed external layer with progressive prismatic to external layer transition, a combination of characters that allows them to be assigned to Prismatoolithidae. Phylogenetic analyses based on oological characters place Trigonoolithus at the base of Prismatoolithidae.

All currently known theropod specimens from the Czech Republic have been attributed to the crown clade Aves. However, an archosaur tooth in the Institute of Geological Sciences (Faculty of Science, Masaryk University), labelled as Teleosaurus, belongs to a non-avian theropod. The tooth comes from the Upper Jurassic (Oxfordian) carbonate rocks of Švédské šance (Brno-Slatina) and represents the first terrestrial vertebrate known from the Jurassic of the Czech Republic. The tooth is described here in detail and compared to anatomical descriptions of taxa, and comprehensive sets of quantitative and qualitative data. On the basis of the comparisons, it is concluded that the Moravian theropod was likely a basal representative of the clade Tetanurae, whose members were abundant in Europe during the Middle to Late Jurassic.

The Longguan dinosaur tracksite in the Sichuan Basin (China) is described. It is located in the uppermost part of the Upper Triassic Xujiahe Formation and displays a single, unusual trackway consisting of 19 deeply impressed pes imprints. All tracks have suffered from erosion over many years of exposure, but they still reveal interesting details such as conspicuous elongated grooves, interpreted here as toe and claw drag marks. The trackmaker, a medium-sized archosaur, was walking in a thick and relatively soft layer of sand. The elongated, oval shape of the footprints resembles the ichnogenus Eosauropus from North America and Europe, assigned to facultative bipedal sauropodomorphs. The Chinese track differs by inward rotation of the footprints toward the midline, whereas in Eosauropus, these are turned strictly outward. Other ichnotaxa and possible trackmakers are discussed, but presently, a distinct assignment cannot be given. The Longguan trackway enlarges the scarce footprint record from the Triassic of China.

Here we report a new Early Pleistocene record of agamid lizards (Agamidae indet.) from the Spanish locality of Quibas (ca. 1.3–1.0 Ma), which represents the latest evidence of the family in Western Europe. Up to now, the family Agamidae was considered to have disappeared in this region at 1.8 Ma. This new record implies the survival of agamid lizards for a large part of the Early Pleistocene in the southernmost Iberian Peninsula, probably because of favourable climatic and environmental conditions. Consequently, the formerly detected Pliocene / Pleistocene boundary is no longer recognisable in the evolution of the herpetological assemblages in Western Europe.

A partial postcranial skeleton (carapace, plastron, and other poorly preserved elements) of a turtle, from the late Oxfordian of the Betic Range of Spain, has recently been assigned to a new taxon, Hispaniachelys prebetica. This is one of the few European turtle taxa reported from pre-Kimmeridgian levels, and the oldest turtle so far known from southern Europe. The character combination identified in that taxon (including the presence of cleithra, and single cervical scale) did not allow its assignment to Plesiochelyidae, a group of turtles very abundant and diverse in the Late Jurassic of Europe. The revision of the single specimen assigned to this taxon led to the reinterpretation of some of its elements, being reassigned to Plesiochelyidae. This study confirms the presence of Plesiochelyidae in the Oxfordian. However, because the Spanish taxon does not present a unique combination of characters, it is proposed as a nomen dubium.

A new genus and species of a non-cyamodontoid placodont is described on the basis of an incomplete and disarticulated skeleton from Winterswijk, the Netherlands, dated as early Anisian (Lower Muschelkalk). The new taxon is unique in a ventrolateral expansion of the neural arches of the posterior presacral and sacral vertebrae, in which the transverse process is incorporated. It has a round, plate-like pubis and ischium, and the only preserved long bone indicates elongated limbs. The holotype, which is relatively large (>1.35 m) for a basal sauropterygian, has still un-fused halves of neural arches and no distinct neural spine developed yet. The new taxon is assigned to non-cyamodontoid placodonts based on its round girdle elements, the morphology of dorsal-, sacral-, and caudal ribs, the straight medial and mediolateral elements of gastral ribs, and the presence of un-sutured armour plates. In spite of the large size of the holotype, there is evidence that the animal was not yet fully grown, based on the paired neural arches, and general poor ossification of the bones. The un-fused halves of neural arches are interpreted as skeletal paedomorphosis, which is typical for vertebrates with a secondary marine life style. The sacral region seems to be highly flexible.

Cladocyclus is a genus of ichthyodectiform fish that is best known from fossils found in shallow marine Cretaceous deposits in Brazil and Morocco. Herein, a new species of Cladocyclus is described on the basis of a fossil that comprises an articulated skull and anterior part of the body, preserved as part and counter-part in what was originally a single eroded nodule of fluvially-deposited volcanolithic sandstone from the Lower Cretaceous (upper Albian) portion of the Winton Formation near Isisford, central-western Queensland, Australia. This specimen represents the first record of Cladocyclus in eastern Gondwana, and indicates that species of this fish may also have inhabited freshwater environments. The new species is assigned to the genus Cladocyclus based on the morphology of the cleithrum (the arms are oriented at approximately 90° to each other) and a mandibular articular facet that incorporates portions of the angular, the articular and the retroarticular. Cladocyclus geddesi sp. nov. can be distinguished from other congeners based on the possession of a more elongate horizontal arm of the cleithrum and a supraoccipital crest that is gently convex posteriorly. This discovery greatly expands the geographic range of Cladocyclus, and supports the idea of a distinct southern fish fauna in the seas surrounding the fragmenting Gondwanan landmasses during the mid-Cretaceous.

A new edrioblastoid Cambroblastus guolensis is described from the Furongian (late Cambrian) Sandu Formation (South China). This represents the second occurrence of a Cambrian edrioblastoid, and the first ever reported from Asia, extending the palaeogeographic range of this very rare echinoderm grade. Surprisingly it preserves a complete stem and a distal holdfast suggesting edrioblastoids were hard substrate attachers living in soft bottom quiet environments.

Fossil insects in amber are often preserved with life-like fidelity and provide a unique insight to forest ecosystems of the geological past. Baltic amber has been studied for more than 300 years but despite the large number of described fossil species (ca. 3500 arthropods) and abundance of fossil material, few attempts have been made to try and quantify statistically how well we understand the palaeodiversity of this remarkable Fossil-Lagerstätte. Indeed, diversity estimation is a relatively immature field in palaeontology. Ants (Hymenoptera: Formicidae) are a common component of the amber palaeobiota, with more than 100 described species representing approximately 5% of all inclusions encountered. Here we apply quantitative statistical species richness estimation techniques to Baltic amber data for the first time. We use species level data from a sample size of 12 769 specimens and conclude that around 29% of the Baltic amber ant fauna has yet to be discovered. The species richness accumulation curve clearly reaches its asymptote at around 9650 specimens, indicating this as the minimum sample size required for a reasonable estimate of species richness for ants alone. Hence, it is hardly surprising that previous studies concerning so-called “representative” samples of the entire palaeobiota, consisting of at most a few thousand inclusions do not agree with each other. Nonetheless, we demonstrate that it is possible to apply quantitative techniques to amber derived data and this should be the preferred approach wherever possible, rather than generating qualitative conclusions of little value for comparative purposes.

Usomyrma mirabilis gen. et sp. nov., belonging to the tribe Leptomyrmecini of the subfamily Dolichoderinae, are described based on two males from the late Eocene Danish Amber. Usomyrma differs from Leptomyrmex by a set of plesiomorphic and autapomorphic features. Distinctly plesiomorphic characters include the fore wing venation, i.e., the presence of the well developed pterostigma, the wide closed cell 3r and the big central closed cell that formed by the fusion of the cells (1 2r) mcu, and the structure of mandibles, which are elongate-triangular, with a well developed masticatory margin that, unlike Leptomyrmex, possesses a set of well developed, relatively long and sharp teeth. The most distinctive autapomorphy of Usomyrma is the structure of the antennae: although it remains 13-segmented, its second funicular segment is extremely elongate, much longer than any other segment, including the apical one. The generic composition of the tribe Leptomyrmecini is partly reassessed compared to the previously published data. We propose to establish a new informal Leptomyrmex genus-group within tribe Leptomyrmecini, including in it the extant genus Leptomyrmex, two fossil (Usomyrma gen. nov., Leptomyrmula) and a “Leptomyrmex” male from the Dominican Amber that probably represents a third extinct genus. Finally, a new, alternative evolutionary and zoogeographic scenario for the Leptomyrmex genus-group is proposed. We suggest that fore wing venation of Usomyrma is ancestral to other genera of this group. The next evolutionary step was the complete reduction of the closed central cell in Leptomyrmula, while conserving the pterostigma and a wide closed cell 3r. Then, in the modern Leptomyrmex males the pterostigma was reduced and the cell 3r became very narrow. Finally, the most apomorphic condition is illustrated by the venation of “Leptomyrmex” male from the Dominican Amber, which has no pterostigma and pterostigmal appendages, combined with the absence of the closed cell 3r. As a result, we suppose that the ancestor of Leptomyrmex might penetrate from Eurasia to Australia via South-East Asia, and then Leptomyrmex penetrated to South America, where the most advanced morphologically form (i.e., “Leptomyrmex” male from the Dominican Amber) arose, but extinct in Miocene.

The first fossil genus and species of Tetratomidae (Coleoptera) is described, from the Lower Cretaceous amber deposits of France. The new genus represents the first insect to be recognized inside an opaque piece of amber, through the use of propagation phase contrast X-ray microtomography using synchrotron radiation. This new finding proves the capabilities of this imaging technique in amber inclusions, as well as increases the knowledge of fossil tenebrionoids, a group scarcely recognized in the Cretaceous fossil record.

We describe deep-water ghost shrimp assemblages from the otherwise well known Oligocene Kiscell Clay in Hungary. The described fossorial shrimps (Decapoda: Callianassidae and Ctenochelidae) include: Ctenocheles rupeliensis (younger synonym Callianassa nuda) and Lepidophthalmus crateriferus (younger synonym Callianassa brevimanus). The fossil material of the former species is assigned to Ctenocheles based on the morphology of the major cheliped, particularly the pectinate fingers, bulbous propodus, cup-shaped carpus and elongated merus. Lepidophthalmus crateriferus from the Oligocene of Hungary is the first unequivocal fossil record of the genus, which is distinguished in the fossil record on the basis of the presence of a meral blade and meral hook on the major cheliped. Lepidophthalmus is today known exclusively from shallow-water environments. The finding of a deep-water fossil representative of Lepidophthalmus therefore appears to be a reverse of the common pattern of groups shifting environments from onshore to offshore over geological time, as seen in many taxa. The presence of Lepidophthalmus crateriferus comb. nov. in the Kiscell Clay therefore suggests different ecological requirements for at least some populations of this genus in the geological past.

One of the most fossiliferous and thickest sections of the marine Lower Devonian deposits was, for the first time investigated for the content of polychaete jaws (= scolecodonts). They are represented by elements of five genera and at least nine species but are not abundant and mostly fractured. Only a fraction of the specimens are sufficiently well preserved to allow genus and species-level identification. However, in some of them even the microstructure of the jaw wall can be observed. Over 90% of the determinable specimens are represented by the jaws of paulinitids which mostly belong to three species known from the Silurian of the Baltic region. Additionally, mochtyellids, atraktoprionids, skalenoprionids and, in the lower part of the sequence, polychaetaspids have been recorded. Two new species are established—Polychaetaspis kozlowskii sp. nov. and Atraktoprion podolicus sp. nov. Status of the genera Oenonites Hinde, 1879 and Kettnerites is discussed. Lectotype of the first is not determinable to the species level, while holotype of the type species of the second is probably missing and not determinable after the original illustration.

A new chambered hexactinellid sponge, Casearia devonica sp. nov., is described from the Lower Devonian of northern Spain (Cantabrian Mountains). The fossil represents the first evidence of chambered hexactinellid sponges from the Palaeozoic and the oldest representative of the order Hexactinosida. Casearia devonica sp. nov. occurred within small metre-sized mud mounds that developed in deeper water below the storm wave base.

The vertebrate fossil locality of La Roma 2, Spain (Upper Miocene, Late Vallesian, MN10) is characterised by a high abundance of mammalian coprolites, which provide direct clues to the diets and habitats of the organisms that produced them. X-ray diffraction analysis showed a sample of hyaena (cf. Lycyaena chaeretis) coprolites to be mostly composed of calcium phosphate. Ultrastructural SEM and TEM studies revealed three successive phases of preservation, including an initial phase of mineralisation that produced microspherulites within a very fine-grained cement. This indicates that most of the calcium phosphate present in the coprolites precipitated rapidly, which in turn facilitated the formation of negative moulds of faecal bacteria within the coprolite matrix.

Some paradigms in the impact-volcanic controversy that we regard as having first been established in the 1980s in fact can be traced much farther back in time, as exemplified by the heuristic neocatastrophic concepts proposed by Dmitri Sobolev and other progressive Russian scholars (Aleksey P. Pavlov, Mikhail A. Usov) of the early 20^th century. They were truly conceptual forerunners of the global catastrophe model in Earth history which is now widely accepted as the volcanic/ greenhouse scenario, even if preceding thought-provoking concepts of some leading European scholars (e.g., Svante Arrhenius, Jacques J. Ėbelmen) were unknown to them.

From time to time, scientific society is astonished by the discovery that supposedly modern concepts originated many decades ago. For example, mass extinction themes are still the subject of intense debate in mainstream science, but some paradigms have a beginning that can be traced far back in time.