107 research outputs found
Fossil taxa and molecular clock calibrations in Cervidae phylogeny: the challenge of the Middle-Late Miocene muntjac-like deer
Ancestral feeding state of ruminants reconsidered: earliest grazing adaptation claims a mixed condition for Cervidae
<p>Abstract</p> <p>Background</p> <p>Specialised leaf-eating is almost universally regarded as the ancestral state of all ruminants, yet little evidence can be cited in support of this assumption, apart from the fact that all early ruminants had low crowned cheek teeth. Instead, recent years have seen the emergence evidence contradicting the conventional view that low tooth crowns always indicate leaf-eating and high tooth crowns grass-eating.</p> <p>Results</p> <p>Here we report the results of two independent palaeodietary reconstructions for one of the earliest deer, <it>Procervulus ginsburgi </it>from the Early Miocene of Spain, suggesting that despite having lower tooth crowns than any living ruminant, this species included a significant proportion of grass in its diet.</p> <p>Conclusion</p> <p>The phylogenetic distribution of feeding styles strongly supports that leaf-grass mixed feeding was the original feeding style of deer, and that later dietary specialization on leaves or grass occurred independently in several lineages. Evidence for other ruminant clades suggests that facultative mixed feeding may in fact have been the primitive dietary state of the Ruminantia, which would have been morphologically expressed only under specific environmental factors.</p
LARGE MAMMAL TURNOVER AND DIVERSITY FROM THE PLIOCENE TO THE PLEISTOCENE IN ITALIAN PENINSULA
Patterns of mammalian species turnover, richness, and faunal composition are assessed on the basis of relative sampling quality and correlated with climatic changes. The most important faunal renewals took place at the early to middle Villafranchian, middle to late Villafranchian, and Early to Middle Pleistocene transitions. The turnover phase at Triversa to Montopoli FU transition corresponds to the Middle Pliocene climate worsening, and can be considered a starting point for the dispersal phases that occurred during the Middle and Late Pliocene. Around 1.9-1.7 Ma (Olivola and Tasso FUs) both a clear increase in diversity as well as a turnover pulse can be detected. The so-called "wolfevent" has to be regarded not only as a dispersal phase but also as a true turnover pulse that is related to the climatic changes occurring at the end of Pliocene. Finally, the transition from Early to Middle Pleistocene faunas represents a major community reorganization (dispersal followed by turnover phase) that shows a significant and progressive rejuvenation coincident with the onset of 100 ka climate cyclicity and vegetation changes related to the climate worsening. The results obtained support the argument that climatic changes are a forcing factor in the first appearances (number of first appearances (Nf ) and rate quotient of first appearance (RQf), including migrations) of mammal taxa.
Recursos patrimoniales de la cuenca neógena de Rubielos de Mora
El relleno sedimentario del mioceno de la cuenca lacustre de Rubielos de Mora ha sido foco de numerosos estudios geológicos y paleontológicos, debido principalmente al descubrimiento de pizarras bituminosas y ritmitas ricas en materia orgánica, que han dado fósiles de plantas, insectos y anfibios caracterizados por su excelente conservación. También yacimientos de mamíferos de interés bioestratigráfico que se conservan en los sedimentos del relleno. Sin embargo los estudios sobre el valor del patrimonio y del estado de conservación han recibido poca atención hasta ahora, a pesar de la excelencia de los afloramientos. Este trabajo pretende llenar este vacío con un análisis evaluativo de este patrimonio paleontológico, con la esperanza de que pueda ayudar a incorporar los recursos del patrimonio de la cuenca Rubielos de Mora en la planificación del territorio y las políticas de desarrollo de las autoridades regionales y/o locales. En el presente trabajo se discuten la conservación, la naturaleza y los posibles usos didácticos y geoturísticos de los recursos paleontológicos del Mioceno de la cuenca de Rubielos de Mora. Por otro lado, se hace un intento para estimar el valor patrimonial de los yacimientos de la cuenca de Rubielos de Mora, para evaluar las amenazas potenciales y proponer las posibles políticas de gestión y conservación geológica
Cardiac magnetic resonance as a risk re-stratification tool in apical hypertrophic cardiomyopathy
Apical hypertrophic cardiomyopathy (ApHCM) can result in the formation of a left ventricular apical aneurysm and progressive myocardial fibrosis, which is associated with a worse prognosis. We present the case of a 76-year-old man previously diagnosed with ApHCM seven years ago, who has been under clinical follow-up. Serial cardiac magnetic resonance (CMR) imaging was performed in 2013 and 2020 due to suspected apical aneurysm formation based on echocardiographic evaluation. The 2020 CMR imaging revealed an increase in myocardial fibrosis observed through late-gadolinium enhancement images and, for the first time, a small apical aneurysm that was not clearly visualized on two-dimensional echocardiography. The time course leading to the development of an ApHCM aneurysm is not well-defined and may impact the clinical course.Apical hypertrophic cardiomyopathy (ApHCM) can result in the formation of a left ventricular apical aneurysm and progressive myocardial fibrosis, which is associated with a worse prognosis. We present the case of a 76-year-old man previously diagnosed with ApHCM seven years ago, who has been under clinical follow-up. Serial cardiac magnetic resonance (CMR) imaging was performed in 2013 and 2020 due to suspected apical aneurysm formation based on echocardiographic evaluation. The 2020 CMR imaging revealed an increase in myocardial fibrosis observed through late-gadolinium enhancement images and, for the first time, a small apical aneurysm that was not clearly visualized on two-dimensional echocardiography. The time course leading to the development of an ApHCM aneurysm is not well-defined and may impact the clinical course
New finding of proboscidean remains in fluvial deposits affected by karstification. Early Pleistocene. Ebro Basin, Zuera (Zaragoza)
A partial tusk of Elephantidae indet. was recently discovered in Early
Pleistocene gravel deposits belonging to a terrace of the Gállego River, near
to Zuera village. Stratigraphic studies have allowed four sedimentary units to
be differentiated, named (from base to top) U1 to U4. The whole succession
is 35 m thick; the tusk remains were collected at the top of unit U1.
Preliminary report on the taphonomy suggests that this specimen could be
a reworked fossil. Evaporite dissolution related with karst processes caused
deformation structures in the overlying Quaternary deposits. Synform and
tubular shapes (delimited by faults) were generated. Karstification favoured
the preservation of the fossil remainsSe da a conocer el hallazgo de una defensa incompleta de Elephantidae
indet. en depósitos de gravas correspondientes a una terraza del río Gállego,
próxima a la localidad de Zuera, de edad Pleistoceno inferior tardío. Los
estudios estratigráficos realizados han permitido definir cuatro unidades
denominadas de base a techo como U1 a U4 que en conjunto integran una
sucesión de unos 35 m de espesor, situándose la defensa a techo de la
unidad U1. El análisis tafonómico preliminar parece indicar que se trataría
de un fósil reelaborado. Los depósitos se encuentran afectados por procesos
kársticos en evaporitas que han dado lugar a estructuras de deformación
con geometría sinforme laxa o tubular (delimitada por fallas). La existencia
de estos procesos kársticos ha favorecido la conservación del resto fósil
encontrad
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