91 research outputs found
First Miocene rodent from Lebanon provides the 'missing link' between Asian and African gundis (Rodentia: Ctenodactylidae)
International audience5 Ctenodactylinae (gundis) is a clade of rodents that experienced, in Miocene time, their greatest diversification and widest distribution. They expanded from the Far East, their area of origin, to Africa, which they entered from what would become the Arabian Peninsula. Questions concerning the origin of African Ctenodactylinae persist essentially because of a poor fossil record from the Miocene of Afro-Arabia. However, recent excavations in the Late Miocene of Lebanon have yielded a key taxon for our understanding of these issues. Proafricanomys libanensis nov. gen. nov. sp. shares a variety of dental characters with both the most primitive and derived members of the subfamily. A cladistic analysis demonstrates that this species is the sister taxon to a clade encompassing all but one of the African ctenodactylines, plus a southern European species of obvious African extraction. As such, Proafricanomys provides the 'missing link' between the Asian and African gundis. The Ctenodactylinae is a subgroup of the Ctenodactylidae (Ctenohystrica) that likely appeared around the Oligocene-Miocene boundary. These unique animals have since experienced a remarkable evolution involving both a shift in habitats (from moist to arid) and distribution (from Asia to Africa). Our understanding of the phylogenetic relationships within the clade has been recently much improve
New Species of Rotundomys (Cricetinae) from the Late Miocene of Spain and Its Bearing on the Phylogeny of Cricetulodon and Rotundomys
The material of Rotundomys (Rodentia, Cricetinae) from the Late Miocene fossiliferous complex of Cerro de los Batallones (Madrid, Spain) is described and compared with all species currently placed in the genera Rotundomys and Cricetulodon. Both the morphology and size variation encompassed in the collection of specimens from Batallones suggest they belong to a single taxon different from the other known species of these genera. A new species Rotundomys intimus sp. nov. is, therefore, named for it. A cladistic analysis, which is the first ever published concernig these taxa, has been conducted to clear up the phylogenetic position of the new species. Our results suggest that Rotundomys intimus sp. nov. inserts between R. mundi and R. sabatieri as a relatively primitive taxon inside the clade Rotundomys. The new taxon is more derived than R. mundi in having a transversal connection between the metalophulid and the anterolophulid on some m1 but more primitive than R. sabatieri and the most evolved species of Rotundomys (R. montisrotuni +R.bressanus) in its less developed lophodonty showing distinct cusps, shallower valleys, and the presence of a subdivided anteroloph on the M1. The species of Cricetulodon do not form a monophyletic group. As a member of Rotundomys, Rotundomys intimus sp. nov. is more derived than all of these taxa in its greater lophodonty and the complete loss of the anterior protolophule, mesolophs, and mesolophid.Ministerio de Economía y Competitividad (MINECO)Universidad Complutense de MadridDepto. de Geodinámica, Estratigrafía y PaleontologíaFac. de Ciencias GeológicasTRUEpu
Causal evidence between monsoon and evolution of rhizomyine rodents
The modern Asian monsoonal systems are currently believed to have originated around the end of the Oligocene following a crucial step of uplift of the Tibetan-Himalayan highlands. Although monsoon possibly drove the evolution of many mammal lineages during the Neogene, no evidence thereof has been provided so far. We examined the evolutionary history of a clade of rodents, the Rhizomyinae, in conjunction with our current knowledge of monsoon fluctuations over time. The macroevolutionary dynamics of rhizomyines were analyzed within a well-constrained phylogenetic framework coupled with biogeographic and evolutionary rate studies. The evolutionary novelties developed by these rodents were surveyed in parallel with the fluctuations of the Indian monsoon so as to evaluate synchroneity and postulate causal relationships. We showed the existence of three drops in biodiversity during the evolution of rhizomyines, all of which reflected elevated extinction rates. Our results demonstrated linkage of monsoon variations with the evolution and biogeography of rhizomyines. Paradoxically, the evolution of rhizomyines was accelerated during the phases of weakening of the monsoons, not of strengthening, most probably because at those intervals forest habitats declined, which triggered extinction and progressive specialization toward a burrowing existence
Comorbidity of attention deficit hyperactivity disorder with personality disorders in homeless people.
Background: Attention deficit hyperactivity disorder (ADHD) is a condition that begins in childhood but can continue into adulthood, and may be the cause of many disadaptive behaviors, as in the case of homeless people, who often display a high incidence of personality disorders. The goal of this study is to analyze the comorbidity of ADHD with axis II disorders in a Spanish homeless population.
Results: The outcomes show high comorbidity between these two kinds of disorders, and that the prevalence of axis II disorders is higher among people with ADHD than among the general population.
Conclusions: From these results we can draw the conclusion that in homeless people ADHD in childhood continues into adulthood, when it is very often observed together with personality disorders. Finally, the implications of this study both for clinical practice and for future lines of research are discussed
Expert range maps of global mammal distributions harmonised to three taxonomic authorities
AimComprehensive, global information on species' occurrences is an essential biodiversity variable and central to a range of applications in ecology, evolution, biogeography and conservation. Expert range maps often represent a species' only available distributional information and play an increasing role in conservation assessments and macroecology. We provide global range maps for the native ranges of all extant mammal species harmonised to the taxonomy of the Mammal Diversity Database (MDD) mobilised from two sources, the Handbook of the Mammals of the World (HMW) and the Illustrated Checklist of the Mammals of the World (CMW).LocationGlobal.TaxonAll extant mammal species.MethodsRange maps were digitally interpreted, georeferenced, error-checked and subsequently taxonomically aligned between the HMW (6253 species), the CMW (6431 species) and the MDD taxonomies (6362 species).ResultsRange maps can be evaluated and visualised in an online map browser at Map of Life (mol.org) and accessed for individual or batch download for non-commercial use.Main conclusionExpert maps of species' global distributions are limited in their spatial detail and temporal specificity, but form a useful basis for broad-scale characterizations and model-based integration with other data. We provide georeferenced range maps for the native ranges of all extant mammal species as shapefiles, with species-level metadata and source information packaged together in geodatabase format. Across the three taxonomic sources our maps entail, there are 1784 taxonomic name differences compared to the maps currently available on the IUCN Red List website. The expert maps provided here are harmonised to the MDD taxonomic authority and linked to a community of online tools that will enable transparent future updates and version control
The vertebrate fauna from the “stipite” layers of the Grands Causses (Middle Jurassic, France)
The “stipites” are Bathonian (Middle Jurassic) coals that formed in an everglades-like environment and are now exposed in the Grands Causses (southern France). The vertebrate assemblage of the “stipites” and of the transitional layers to the carbonates in which they are interspersed are reviewed. To date, only small-sized and isolated vertebrate bones, teeth, and scales have been recovered. These record the presence of sharks (Hybodus, Asteracanthus), bony fishes (Lepidotes, Pycnodontiformes, Caturus, Aspidorhynchus), amphibians (Anura, Albanerpetontidae), and reptiles (Crocodylomorpha, Ornithischia, Theropoda). Despite its relatively limited taxonomic diversity, the vertebrate assemblage from the “stipites” and from their associated layers is notable for being one of the few of this age with both terrestrial and marine influences. Compared to other approximately coeval formations in Western Europe, the “stipites” vertebrate assemblage is surpassed in diversity only by those from the British Isles.This is a contribution to the research projects CGL2009–12143 and CGL2011-24829.Peer reviewedPeer Reviewe
First diatomyid rodent from the Early Miocene of Arabia
The Asian family Diatomyidae is known from the Early Oligocene to the present. Among living rodents, this group comprises only the recently discovered Laonastes aenigmamus from Laos. Fossil diatomyids are known from
only a few sites, in which they are often rare. The discovery of Pierremus explorator gen. nov. sp. nov. in the Lower Miocene of As-Sarrar (Saudi Arabia) raises to ten the
number of extinct diatomyid species recognized. Pierremus explorator is the first record of a diatomyid from the Afro-
Arabian plate. This discovery provides evidence that, together with other rodents (ctenodactylids, zapodids…), the diatomyids took advantage of the corridor that was
established between Afro-Arabia and Eurasia in Early Miocene times.The author is currently supported by the Ramón y Cajal Program and the research
project CGL2008-05813-CO2-01 directed by J. Morales (Museo nacional de Ciencias naturales-CSIC, Madrid).Peer reviewe
First potwarmus from the miocene of Saudi Arabia and the early phylogeny of murines (Rodentia:Muroidea)
Potwarmus is recorded for the first time in Saudi Arabia. The material comes from the Middle Miocene of the Hofuf Formation at Al-Jadidah. This species, Potwarmus flynni sp. nov., is described and compared with all species currently placed in the genera Potwarmus, Dakkamys, Paradakkamys, Vallaris, and some species of ‘Myocricetodon’ (i.e. the so-called ‘primitive dendromurids’) as well as with two of the most primitive definitive murines (namely Antemus chinjiensis and Progonomys debruijni). Potwarmus flynni sp. nov. differs from the above-mentioned species in having the anterior part of the m1 strongly reduced. A cladistic analysis provides evidence that this new Arabian taxon is close to Potwarmus primitivus and Potwarmus sp. nov. from Jebel Zelten (Libya), and also that this genus is unlikely to be the sister taxon to Antemus.The author is currently supported by the Juan de la Cierva Program (CGL2005-03900/BTE).Peer reviewe
Dental morphology and wear pattern in Tachyoryctes (Spalacidae, Rodentia)
Received February 2, 2012; accepted March 15, 2012 ; previously published online May 13, 2012Tachyoryctes , the most derived genus within the tribe Tachyoryctini (Rhizomyinae, Spalacidae, Rodentia), is known from Pliocene to Recent. It comprises four species: the fossil T. pliocaenicus and T. konjiti and the extant T. splendens and T. macrocephalus . A detailed description of the morphology and dental wear pattern of the cheek teeth of T. splendens is provided based on the study of 297 skulls. For the first and second lower and upper molars, fi ve stages of wear are recognized (0 – 4). The third lower and upper molars show four stages of wear (0 – 3). The dental wear pattern in T. splendens is comparable to that of the Pleistocene T. konjiti.My sojourn in Berlin and Paris were funded by the SYNTHESYS Project (http://www.synthesys.info/ ), which is financed by European Community Research Infrastructure Action under the FP7 “Capacities” Program and by the EDIT Gender Action Plan, respectively.My research is currently supported by the Ramón y Cajal Program and the research project CGL2011-24829.Peer reviewe
The tetralophodont pattern of the upper molars in juvenile Cannomys badius (Rodentia, Spalacidae)
International audienceCannomys and Rhizomys are the only living genera of the tribe Rhizomyini (Rhizomyinae, Spalacidae, Rodentia), which is known since the early Late Miocene (at approximately 10 Ma). The dental morphology of all living Rhizomyinae has been already described in detail. However, due to the scarcity of specimens of Cannomys in zoological collections, the teeth of juveniles in this taxon had not been described to date. The study of a specimen of this early age (MNCN 8449) shows that the second upper molars of Cannomys are tetralophodont like those of Rhizomys. One of the assumed differences between Cannomys and Rhizomys, namely the trilophodont second molars of Cannomys, is therefore inaccurate
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