Remains of Garrigatitan meridionalis nov. gen. et sp. were found in two bonebeds of sequence 2 from the upper Campanian site of Velaux-La Bastide Neuve (Aix-en-Provence Basin, Bouches du Rhône ...department). The vertebrate assemblage is dominated by dinosaurs, including the titanosaur Atsinganosaurus velauciensis. Garrigatitan meridionalis presents three diagnostic characters: hourglass-shaped humeri (proximal and distal thirds of almost the same transversal width) in anterior and posterior views, ilium with a broad rounded hollow slightly posterior to the base of the pubic peduncle, proximolateral margin of the femur only slightly medially deflected. Garrigatitan was a small to medium-sized sauropod (sub/adult individuals between 4-6 metres and 2-2.5 tonnes), showing anatomical differences with Atsinganosaurus, and with the other Late Cretaceous Ibero-Armorican titanosaurs. Large titanosaurian specimens found at Velaux-La Bastide Neuve could belong to adult Garrigatitan individuals reaching a body length of at least 12 metres. Histological analysis of long bones shows features similar to other Late Cretaceous European titanosaurs, indicating that all individuals had reached skeletal maturity (presence of an EFS, heavy remodelling HOS 12 to 14). The new taxon is recovered within the clade Lirainosaurinae. Garrigatitan meridionalis increases the diversity of Late Cretaceous titanosaurs within the Ibero-Armorican Island.
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
, 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.
Though the Maastrichtian Phosphates of Morocco have yielded very rich marine vertebrate assemblages, plesiosaurs remain very scarce in these strata. The only hitherto recognized taxon was
...Plesiosaurus mauritanicus
Arambourg, 1952, regarded here as a
nomem dubium. Here we describe a new genus and species of elasmosaurid plesiosaur,
Zarafasaura oceanis, which represents the first valid elasmosaurid plesiosaur described from the latest Cretaceous of Africa, and the second one from this continent. A phylogenetic analysis of plesiosauroids indicates that
Zarafasaura oceanis has close affinities with elasmosaurids from the Late Cretaceous of North America and Japan. Among its distinctive suite of characters, the general shape and organisation of its squamosal and palate are unique among elasmosaurids. This new taxon completes our understanding of Late Cretaceous plesiosaur palaeobiodiversity and palaeobiogeography, and shows that Maastrichtian plesiosaurs were characterized by a quite high degree of endemism. They were also highly diversified and distributed worldwide, which supports the hypothesis of a catastrophic extinction of plesiosaurs at the K/T boundary.
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► Zarafasaura oceanis represents a new Cretaceous elasmosaurid plesiosaur from Morocco. ► First valid latest Cretaceous taxon from Africa and one of the latest plesiosaur. ► Widespread and diversified Maastrichtian plesiosaurs support sudden K/T extinction.
The Maastrichtian of Benguérir (eastern part of the Ganntour Basin, Morocco) consists of about 20m of phosphates displaying an alternance of soft phosphate levels, marly horizons and hard phosphatic ...limestones. Isolated teeth of selachians, actinopterygians and marine reptiles are extremely numerous in these phosphatic deposits and have been used for biostratigraphical, palaeodiversity and palaeoecological purposes.
Detailed field work allowed to establish an exhaustive list of the Benguérir marine vertebrate faunas with their biostratigraphical distribution through five main fossiliferous levels (L6 to L2) spanning all the Maastrichtian. Their importance for biochronological purposes and correlations with other Maastrichtian phosphate deposits worldwide appears noteworthy.
The selachians are currently represented by 60 species belonging to 32 genera and 7 orders. Among them, the genus Squalicorax is one of the most interesting concerning high-resolution biostratigraphy and correlations with other phosphate basins because of important rates of change noted between the 5 species recovered from base (e.g. occurrence of S. africanus) to top (e.g. strong representation of S. pristodontus) of the Maastrichtian. The marine reptiles include mainly mosasaurids but also scarcer plesiosaurs, chelonians and crocodyliforms, representing at least 14 taxa. The mosasaurid squamates are the most abundant and diversified with at least 8 species ranging all along the succession. The actinopterygians include mainly teleosts but also pycnodonts, also common in all levels and representing at least 7 taxa.
Selachians and reptiles show the same trends, in terms of species richness per level, even if the reptiles are less informative due to a less diversified assemblage. For sharks, L6 and L2 show a high percentage of genera and species occurring only in the layer concerned. The evolution of diversity in actinopterygian fishes is less clear because of their low diversity. The use of dissimilarity indices and agglomerative method underscores two distinct associations: a lower one including the levels L6 and L5, and an upper one comprising the levels L4 to L2. These two associations allow to separate a lower and an upper Maastrichtian level and are important for correlations all around the southern and eastern margins of the Tethys. Another clear faunal turnover occurs between L3 and L2, because of a high appearance rate in L2 (at least in sharks) suggesting an increase in prey abundance, as testified by the rapid increase of marine predator density.
Indeed, and through L6 to L2, a possible signal of an environmental damage affecting the predator community can be noted by faunal turnovers, even if no significant change in prey association was clearly detected.
From a palaeobiogeographical point of view, the faunal associations of Benguérir appear typical of the southern and eastern margins of the Tethys, with several typical species not occurring in the northern Tethys.
•This work is a comprehensive study in relation to the Maastrichtian of Benguérir.•Selachians and reptiles show the same trends of diversity from L6 up to L2.•A lower and upper Maastrichtian association is highlighted.•A possible environmental signal affecting the predator community is noted.•The associations of Benguérir appear typical of the southern margin of the Tethys.
Abstract
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.
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.
Ornithopod remains are reported from the Papo-Seco Formation (lower Barremian, Early Cretaceous) at Cape Espichel, south of Lisbon, in western central Portugal. The fossil material comes from the ...Boca do Chapim, Praia do Areia do Mastro and Praia do Guincho palaeontological sites. Some fossils are known from the 19
th
century and the beginning of the 20
th
century and other remains have been recently collected. Ornithopod and other vertebrate remains from the Papo-Seco Formation occur in limestones, marls, sandstones and conglomerates in a succession interpreted as being deposited in lagoonal and estuarine environments. A study of the available palaeontological material, including teeth and postcranial remains, suggests the presence of a large styracosternan-like iguanodontian, but does not allow confirmation of the occurrence of Iguanodon or Mantellisaurus. Ornithopod remains from the Papo-Seco Formation are provisionally assigned to Ornithopoda indet., Iguanodontia indet. and cf. Styracosterna indet., increasing the record of Portuguese ornithopods of early Barremian age.
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.
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.
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.
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.
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.
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