Vincent P.,Staatliches Museum fur Naturkunde Rosenstein 1 |
Bardet N.,CNRS Center for Research on Palaeobiodiversity and Palaeoenvironments |
Houssaye A.,University of Bonn |
Amaghzaz M.,Center Minier Of Khouribga |
Meslouh S.,Ministere de LEnergie
Gondwana Research | Year: 2013
Several clades of marine tetrapods, including the apex predators mosasaurs and plesiosaurs, disappeared during the mass extinction at the end of the Cretaceous, about 65. My ago. The extreme fossil richness of the Maastrichtian Phosphates of Morocco provides insights into the systematic diversity of the latest mosasaurs where about ten species are known. However, data of the coeval plesiosaurs are comparatively scarce. Up to now, only one species, the elasmosaurid Zarafasaura oceanis, is known. Here we describe new elasmosaurid plesiosaur post-cranial material from the Maastrichtian of the Oulad Abdoun Basin (Morocco) that provides new data about the taxonomical and morphological diversity of plesiosaurs in this area. Most of the new material consists of vertebrae that likely belong to a unique elasmosaurid taxon and differ from all other elasmosaurids documented so far. As Zarafasaura is known only from cranial material, it cannot be determined whether the new material may be assigned to this taxon. The new material shows that the latest Cretaceous plesiosaurs in this low latitude area (about 20°N) were rather gracile, most likely piscivorous taxa that occupied ecological niches similar to those of rather small mosasaurs (e.g., Halisaurus and ". Platecarpus" ptychodon) but distinct from those of most coeval large mosasaur taxa. These plesiosaur fossils are also remarkable in that they consist of both juvenile and adult specimens, suggesting limited segregation between individuals of different ontogenetic stages, a feature that might be attributed to upwelling-related, high nutrient input and food availability in this area during the Maastrichtian. Moreover, the possible occurrence, with older specimens, of a neonate specimen - one among the very few known worldwide - suggests a possible social structure organization. The new data contribute to increase our understanding of Late Cretaceous plesiosaur biodiversity and provide new insights into the ecology of latest Cretaceous marine apex predators. © 2012 International Association for Gondwana Research.
Contribution of the airborne aeromagnetic mapping to the structural identification of the aquifer system of the oasis' springs of Figuig, Morocco [Apport de la cartographie aéromagnétique à l'identification structurale du système aquifère des sources de l'oasis de Figuig (Maroc)]
Amar M.,Moulay Ismai University |
Manar A.,Ministere de LEnergie |
Boualoul M.,Moulay Ismai University
Bulletin de l'Institut Scientifique, Section Sciences de la Terre | Year: 2012
The residual magnetic field map of the Eastern High Atlas shows significant anomalies. Applying the reduction to pole on this map and applying the Tilt angle transformation then the calculation of Euler Deconvolution for the detection of faults, allowed us to improve our knowledge on the structure of the aquifer system of the oasis springs of Figuig. Indeed, the most important part of this aquifer is encompassed by the land of the Mesozoic cover.
Cappetta H.,Montpellier University |
Bardet N.,Paris-Sorbonne University |
Pereda Suberbiola X.,University del Pai s Vasco Euskal Herriko Unibertsitatea |
Adnet S.,Montpellier University |
And 3 more authors.
Palaeogeography, Palaeoclimatology, Palaeoecology | Year: 2014
The Maastrichtian of Bengue´rir (eastern part of the Ganntour Basin, Morocco) consists of about 20. m 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 Bengue´rir 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 Bengue´rir appear typical of the southern and eastern margins of the Tethys, with several typical species not occurring in the northern Tethys. © 2014.
Vincent P.,CNRS Center for Research on Palaeobiodiversity and Palaeoenvironments |
Bardet N.,CNRS Center for Research on Palaeobiodiversity and Palaeoenvironments |
Pereda Suberbiola X.,University of the Basque Country |
Bouya B.,Center Minier Of Khouribga |
And 2 more authors.
Gondwana Research | Year: 2011
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. © 2010 International Association for Gondwana Research.
Haddoumi H.,University Mohammed Premier |
Allain R.,CNRS Center for Research on Palaeobiodiversity and Palaeoenvironments |
Meslouh S.,Ministere de LEnergie |
Metais G.,CNRS Center for Research on Palaeobiodiversity and Palaeoenvironments |
And 6 more authors.
Gondwana Research | Year: 2015
We report the discovery in Mesozoic continental "red beds" of Anoual Syncline, Morocco, of the new Guelb el Ahmar (GEA) fossiliferous sites in the Bathonian Anoual Formation. They produced one of the richest continental biotic assemblages from the Jurassic of Gondwana, including plants, invertebrates and vertebrates. Both the sedimentological facies and the biotic assemblage indicate a lacustrine depositional environment. The flora is represented by tree trunks (three families), pollen (13 species, five major clades) and charophytes. It suggests local forests and humid (non-arid) conditions. The vertebrate fauna is dominated by microvertebrates recovered by screening-washing. It is rich and diverse, with at least 29 species of all major groups (osteichthyans, lissamphibians, chelonians, diapsids, mammals), except chondrichthyans. It includes the first mammals discovered in the Middle Jurassic of Arabo-Africa. The GEA sites yielded some of the earliest known representatives of osteoglossiform fishes, albanerpetontid and caudate amphibians, squamates (scincomorphans, anguimorphan), cladotherian mammals, and likely choristoderes. The choristoderes, if confirmed, are the first found in Gondwana, the albanerpetontid and caudatan amphibians are among the very few known in Gondwana, and the anguimorph lizard is the first known from the Mesozoic of Gondwana. Mammals (Amphitheriida, cf. Dryolestida) remain poorly known, but are the earliest cladotherians known in Gondwana. The GEA biotic assemblage is characterized by the presence of Pangean and Laurasian (especially European) taxa, and quasi absence of Gondwanan taxa. The paleobiogeographical analysis suggests either a major fossil bias in Gondwana during the Middle Jurassic, and an overall vicariant Pangean context for the GEA assemblage, or alternatively, noticeable Laurasian (European) affinities and North-South dispersals. The close resemblance between the Bathonian faunas of GEA and Britain is remarkable, even in a Pangean context. The similarity between the local Anoual Syncline Guelb el Ahmar and Ksar Metlili faunas raises questions on the ?Berriasian age of the latter. © 2015 International Association for Gondwana Research.