A new small duckbilled dinosaur (Hadrosauridae: Lambeosaurinae) from Morocco and dinosaur diversity in the late Maastrichtian of North Africa.

In the Late Cretaceous, northern and southern hemispheres evolved distinct dinosaurian faunas. Titanosaurians and abelisaurids dominated the Gondwanan continents; hadrosaurids, ceratopsians and tyrannosaurs dominated North America and Asia. Recently, a lambeosaurine hadrosaurid, Ajnabia odysseus, was reported from the late Maastrichtian phosphates of the Oulad Abdoun Basin Morocco, suggesting dispersal between Laurasia and Gondwana. Here we report new fossils from the phosphates of Morocco showing lambeosaurines achieved high diversity in the late Maastrichtian of North Africa. A skull represents a new dwarf lambeosaurine, Minqaria bata. Minqaria resembles Ajnabia odysseus in size, but differs in the ventrally positioned jugal facet and sinusoidal toothrow. The animal is small, ~ 3.5 m long, but the fused braincase shows it was mature. A humerus and a femur belong to larger hadrosaurids, ~ 6 m long, implying at least three species coexisted. The diversity of hadrosaurids in Europe and Africa suggests a dispersal-driven radiation, with lambeosaurines diversifying to take advantage of low ornithischian diversity. African lambeosaurines are small compared to North American and Asia hadrosaurids however, perhaps due to competition with titanosaurians. Hadrosaurids are unknown from eastern Africa, suggesting Moroccan hadrosaurids may be part of a distinct insular fauna, and represent an island radiation.

A new Cretaceous thyreophoran from Patagonia supports a South American lineage of armoured dinosaurs.

The early evolution of thyreophoran dinosaurs is thought to have occurred primarily in northern continents since most evidence comes from the Lower and Middle Jurassic of Europe and North America. The diversification into stegosaurs and ankylosaurs is obscured by a patchy fossil record comprising only a handful of fragmentary fossils, most with uncertain phylogenetic affinities. Here we report the discovery of a new armoured dinosaur from the early Late Cretaceous of Argentina, recovered phylogenetically using various datasets either as a basal thyreophoran or a stem ankylosaur, closely related to Scelidosaurus. It bears unusual anatomical features showing that several traits traditionally associated with the heavy Cretaceous thyreophorans did not occur universally. Jakapil kaniukura gen. et sp. nov. is the first definitive thyreophoran species from the Argentinian Patagonia. Unlike most thyreophorans, it seems to show a bipedal stance, as in Scutellosaurus. Jakapil also shows that early thyreophorans had a much broader geographic distribution than previously thought. It is a member of an ancient basal thyreophoran lineage that survived until the Late Cretaceous in South America.

Fast-running theropods tracks from the Early Cretaceous of La Rioja, Spain.

Theropod behaviour and biodynamics are intriguing questions that paleontology has been trying to resolve for a long time. The lack of extant groups with similar bipedalism has made it hard to answer some of the questions on the matter, yet theoretical biomechanical models have shed some light on the question of how fast theropods could run and what kind of movement they showed. The study of dinosaur tracks can help answer some of these questions due to the very nature of tracks as a product of the interaction of these animals with the environment. Two trackways belonging to fast-running theropods from the Lower Cretaceous Enciso Group of Igea (La Rioja) are presented here and compared with other fast-running theropod trackways published to date. The Lower Cretaceous Iberian fossil record and some features present in these footprints and trackways suggest a basal tetanuran, probably a carcharodontosaurid or spinosaurid, as a plausible trackmaker. Speed analysis shows that these trackways, with speed ranges of 6.5-10.3 and 8.8-12.4 ms-1, testify to some of the top speeds ever calculated for theropod tracks, shedding light on the question of dinosaur biodynamics and how these animals moved.

First palaeoneurological study of a sauropod dinosaur from France and its phylogenetic significance.

Despite continuous improvements, our knowledge of the palaeoneurology of sauropod dinosaurs is still deficient. This holds true even for Titanosauria, which is a particularly speciose clade of sauropods with representatives known from numerous Cretaceous sites in many countries on all continents. The data currently available regarding the palaeoneurology of titanosaurs is strongly biased towards Gondwanan forms (Argentina above all, but also India, Malawi and Australia). In contrast, the palaeoneurology of Laurasian titanosaurs is known only from a few taxa from Spain and Uzbekistan, despite the discovery in other countries of Laurasia of a number of neurocranial remains that would lend themselves well to investigations of this kind. To fill in this gap in our knowledge, we subjected a titanosaurian braincase from the uppermost Upper Cretaceous of southern France to X-ray computed tomographic scanning, allowing the generation of 3D renderings of the endocranial cavity enclosing the brain, cranial nerves and blood vessels, as well as the labyrinth of the inner ear. These reconstructions are used to clarify the phylogenetic position of the specimen from the Fox-Amphoux-Métisson site. A combination of characters, including the presence of two hypoglossal rami on the endocast, the average degree of development of the dorsal-head/caudal-middle-cerebral vein system and the relatively short and subequal lengths of the ipsilateral semicircular canals of the labyrinth, are particularly revealing in this respect. They suggest that, compared with the few other Laurasian titanosaurs for which in-depth palaeoneurological data are available, the French taxon is more derived than the distinctly more ancient, possibly non-lithostrotian titanosaur from the Uzbek site of Dzharakuduk but more basal than derived saltasaurids, such as the coeval or slightly more recent forms from the Spanish locality of Lo Hueco.

Ichnotaxonomic review of large ornithopod dinosaur tracks: temporal and geographic implications.

BACKGROUND: Large ornithopod tracks are known from the Upper Jurassic to the uppermost Cretaceous rocks of all continents but Antarctica. They include the tracks historically called Iguanodon footprints, iguanodontid footprints, hadrosaur/hadrosaurid footprints, and other large ornithopod tracks that have been used to define ichnotaxa. More than 40 ichnospecies based on large ornithopod tracks have been defined, but the validity of many of them is questionable. METHODOLOGY/PRINCIPAL FINDINGS: 34 ichnogenera and 44 ichnospecies have been analysed in this work. Many of them are considered to be invalid because they have been defined on the basis of poorly preserved tracks without diagnostic features, have an inadequate diagnosis, or are based on temporal and/or geographical criteria. Only eight ichnospecies belonging to the ichnogenera Caririchnium, Iguanodontipus and Hadrosauropodus are here regarded as valid. CONCLUSIONS/SIGNIFICANCE: The monospecific ichnogenus Iguanodontipus (I. burreyi) is characterized by a small, rounded heel and elongate, narrow digit impressions. Its distribution is limited to the Berriasian-Valanginian of Europe. Caririchnium consists of four ichnospecies (C. magnificum [type ichnospecies], C. kortmeyeri, C. billsarjeanti and C. lotus) with a large, rounded heel and short, wide digit impressions. This ichnogenus ranges from the Berriasian-Hauterivian to the Aptian-Albian of South America, North America, Asia and Europe. Finally, Hadrosauropodus (three ichnospecies: H. langstoni [type ichnospecies], H. leonardii and H. kyoungsookimi) shows a large, bilobed heel and short, wide digit impressions. It is known from the Aptian-Albian to the Maastrichtian of North America, Asia and Europe. The ichnofamily Iguanodontipodidae includes large iguanodontian tracks characterized mainly by mesaxonic, tridactyl and subsymmetrical pes tracks that are as wide as (or wider than) long and have one pad impression in each digit and one in the heel. Its distribution is confidently limited to the Cretaceous of Europe, Asia, North America and South America.

Island life in the Cretaceous - faunal composition, biogeography, evolution, and extinction of land-living vertebrates on the Late Cretaceous European archipelago.

The Late Cretaceous was a time of tremendous global change, as the final stages of the Age of Dinosaurs were shaped by climate and sea level fluctuations and witness to marked paleogeographic and faunal changes, before the end-Cretaceous bolide impact. The terrestrial fossil record of Late Cretaceous Europe is becoming increasingly better understood, based largely on intensive fieldwork over the past two decades, promising new insights into latest Cretaceous faunal evolution. We review the terrestrial Late Cretaceous record from Europe and discuss its importance for understanding the paleogeography, ecology, evolution, and extinction of land-dwelling vertebrates. We review the major Late Cretaceous faunas from Austria, Hungary, France, Spain, Portugal, and Romania, as well as more fragmentary records from elsewhere in Europe. We discuss the paleogeographic background and history of assembly of these faunas, and argue that they are comprised of an endemic 'core' supplemented with various immigration waves. These faunas lived on an island archipelago, and we describe how this insular setting led to ecological peculiarities such as low diversity, a preponderance of primitive taxa, and marked changes in morphology (particularly body size dwarfing). We conclude by discussing the importance of the European record in understanding the end-Cretaceous extinction and show that there is no clear evidence that dinosaurs or other groups were undergoing long-term declines in Europe prior to the bolide impact.

New evidence of shared dinosaur across Upper Jurassic Proto-North Atlantic: Stegosaurus from Portugal.

More than one century after its original description by Marsh in 1877, we report in this paper the first uncontroversial evidence of a member of the genus Stegosaurus out of North America. The specimen consists of a partial skeleton from the Upper Jurassic of Portugal, herein considered as Stegosaurus cf. ungulatus. The presence of this plated dinosaur in the upper Kimmeridgian-lower Tithonian Portuguese record and synchronic levels of the Morrison Formation of North America reinforces previous hypothesis of a close relationship between these two areas during the Late Jurassic. This relationship is also supported by geotectonic evidences indicating high probability of an episodic corridor between the Newfoundland and Iberian landmasses. Together, Portuguese Stegosaurus discovery and geotectonic inferences could provide a scenario with episodical faunal contact among North Atlantic landmasses during the uppermost Kimmeridgian-lowermost Tithonian (ca. 148-153 Ma ago).