Gilles Merzeraud
University of Montpellier
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Featured researches published by Gilles Merzeraud.
PLOS ONE | 2013
Julien Benoit; Sylvain Adnet; Essid El Mabrouk; Hayet Khayati; Mustapha Ben Haj Ali; Laurent Marivaux; Gilles Merzeraud; Samuel Merigeaud; Monique Vianey-Liaud; Rodolphe Tabuce
Sea cows (manatees, dugongs) are the only living marine mammals to feed solely on aquatic plants. Unlike whales or dolphins (Cetacea), the earliest evolutionary history of sirenians is poorly documented, and limited to a few fossils including skulls and skeletons of two genera composing the stem family of Prorastomidae (Prorastomus and Pezosiren). Surprisingly, these fossils come from the Eocene of Jamaica, while stem Hyracoidea and Proboscidea - the putative sister-groups to Sirenia - are recorded in Africa as early as the Late Paleocene. So far, the historical biogeography of early Sirenia has remained obscure given this paradox between phylogeny and fossil record. Here we use X-ray microtomography to investigate a newly discovered sirenian petrosal from the Eocene of Tunisia. This fossil represents the oldest occurrence of sirenians in Africa. The morphology of this petrosal is more primitive than the Jamaican prorastomids’ one, which emphasizes the basal position of this new African taxon within the Sirenia clade. This discovery testifies to the great antiquity of Sirenia in Africa, and therefore supports their African origin. While isotopic analyses previously suggested sirenians had adapted directly to the marine environment, new paleoenvironmental evidence suggests that basal-most sea cows were likely restricted to fresh waters.
PLOS ONE | 2013
Laurent Marivaux; Anusha Ramdarshan; El Mabrouk Essid; Wissem Marzougui; Hayet Khayati Ammar; Renaud Lebrun; Bernard Marandat; Gilles Merzeraud; Rodolphe Tabuce; Monique Vianey-Liaud
Background Molecular clock estimates of crown strepsirhine origins generally advocate an ancient antiquity for Malagasy lemuriforms and Afro-Asian lorisiforms, near the onset of the Tertiary but most often extending back to the Late Cretaceous. Despite their inferred early origin, the subsequent evolutionary histories of both groups (except for the Malagasy aye-aye lineage) exhibit a vacuum of lineage diversification during most part of the Eocene, followed by a relative acceleration in diversification from the late Middle Eocene. This early evolutionary stasis was tentatively explained by the possibility of unrecorded lineage extinctions during the early Tertiary. However, this prevailing molecular view regarding the ancient origin and early diversification of crown strepsirhines must be viewed with skepticism due to the new but still scarce paleontological evidence gathered in recent years. Methodological/Principal Findings Here, we describe new fossils attributable to Djebelemur martinezi, a≈50 Ma primate from Tunisia (Djebel Chambi). This taxon was originally interpreted as a cercamoniine adapiform based on limited information from its lower dentition. The new fossils provide anatomical evidence demonstrating that Djebelemur was not an adapiform but clearly a distant relative of lemurs, lorises and galagos. Cranial, dental and postcranial remains indicate that this diminutive primate was likely nocturnal, predatory (primarily insectivorous), and engaged in a form of generalized arboreal quadrupedalism with frequent horizontal leaping. Djebelemur did not have an anterior lower dentition as specialized as that characterizing most crown strepsirhines (i.e., tooth-comb), but it clearly exhibited a transformed antemolar pattern representing an early stage of a crown strepsirhine-like adaptation (“pre-tooth-comb”). Conclusions/Significance These new fossil data suggest that the differentiation of the tooth-comb must postdate the djebelemurid divergence, a view which hence constrains the timing of crown strepsirhine origins to the Middle Eocene, and then precludes the existence of unrecorded lineage extinctions of tooth-combed primates during the earliest Tertiary.
Comptes Rendus De L Academie Des Sciences Serie Ii Fascicule A-sciences De La Terre Et Des Planetes | 1999
Gilles Merzeraud; laude Colombié
Two types of carbonate facies have been identified in the Sinemurian series of the western margin of the Southeast Basin, and attributed to successive depositional settings of carbonate sedimentation. The first setting is a low-angle and low-energy shallow marine carbonate platform. The second setting indicates a high-energy carbonate ramp. This dramatic change in depositional conditions occurs in a regional context of extension, and can be attributed to localised fault activity resulting in differential subsidence. The combined effect of these two processes gradually modified the platform topography and initiated the changes observed in the depositional profiles.
Historical Biology | 2018
Sylvain Adnet; Medhi Mouana; Anne-Lise Charruault; El Mebrouk Essid; Hayet Khayati Ammar; Wissem Marzougui; Gilles Merzeraud; Rodolphe Tabuce; Monique Vianey-Liaud; Laurent Marivaux
Abstract Hypolophin ‘dasyatids’ are a common group of large stingrays today frequenting the Indo-Pacific inshores. Being often harvested in their restricted area, few are known about their biology and their evolutionary history despite a very peculiar dental pattern making it easy to track their fossil record. An abundant material consisting of isolated teeth from Late Bartonian (38–40 Ma) lagoonal deposits of Djebel el Kébar, Tunisia, allows to describe a new stingray, Pastinachus kebarensis nov. sp. This taxon represents the oldest occurrence for this genus but also the oldest fossil record for hypolophins. A dental comparison of these fossils with 3D rendered models of fresh specimens testifies that early hypolophin representatives had already a strongly arcuate and bulbous upper jaw, interlocking with a broad and elongated tooth plate on the lower jaw. This new fossil and its fossil relatives (here updated), indicate a pre-Bartonian origination for hypolophins in western Neotethys, and reveal a rapid and widespread colonization of the proto-Mediterranean Sea, western Atlantic and Indo-Pacific coasts during the late Paleogene–early Neogene. Finally, it is worth noting that early hypolophin representatives seemingly entered freshwater habitats occasionally as modern cowtail stingrays do.
Comptes Rendus De L Academie Des Sciences Serie Ii Fascicule A-sciences De La Terre Et Des Planetes | 1999
Magali Geiller; Anne-Marie Karpoff; Philippe Larqué; Gilles Merzeraud
The mineralogical assemblages, particularly clay mineral associations, from the siliciclastic deposits of the Paris Basin are related to the variable detrital input as well as to conditions prevailing in the basin during early deposition processes or pedogenetic evolution. During Rhaetian and Hettangian times, the depositional dynamics as defined by sedimentological and hydrodynamic studies (Geiller, 1997) are specified by successive mineralogical associations. The clay assemblage analyses are a useful tool for reservoir facies studies and characterization.
Sedimentology | 2007
Youri Hamon; Gilles Merzeraud
Palaeogeography, Palaeoclimatology, Palaeoecology | 2016
Mohammed Achalhi; Philippe Münch; Jean-Jacques Cornée; Ali Azdimousa; Mihaela Carmen Melinte-Dobrinescu; Frédéric Quillévéré; Hara Drinia; Séverine Fauquette; Gonzalo Jiménez-Moreno; Gilles Merzeraud; Abdelkhalak Ben Moussa; Younes El Kharim; Najat Feddi
Sedimentary Geology | 2016
Jean-Jacques Cornée; Philippe Münch; Mohammed Achalhi; Gilles Merzeraud; Ali Azdimousa; Frédéric Quillévéré; Mihaela Carmen Melinte-Dobrinescu; Christian Chaix; Abdelkhalak Ben Moussa; Johanna Lofi; Michel Séranne; Pierre Moisette
Comptes Rendus Geoscience | 2014
Jean-Jacques Cornée; Philippe Münch; Mihaela Carmen Melinte-Dobrinescu; Abdelkhalak Ben Moussa; Frédéric Quillévéré; Hara Drinia; Ali Azdimousa; Abdelouahed Ouazani Touhami; Gilles Merzeraud; Séverine Fauquette; Michel Corsini; Pierre Moissette; Najat Feddi
American Journal of Physical Anthropology | 2014
Laurent Marivaux; El Mabrouk Essid; Wissem Marzougui; Hayet Khayati Ammar; Sylvain Adnet; Bernard Marandat; Gilles Merzeraud; Anusha Ramdarshan; Rodolphe Tabuce; Monique Vianey-Liaud; Johan Yans