1,720,979 research outputs found
Structure and evolution of mammoth molar enamel
No full textThis work investigates the structure of Eurasian Plio–Pleistocene Mammuthus enamel, with attention to diagenesis and individual variability. A focal point of this study was to determine whether morphological trends in Mammuthus molars were accompanied by correlated enamel microstructure changes. In the examined four taxa the enamel of the cheek teeth consists of three layers delimited by two major discontinuities in enamel prism direction. Noticeably, the enamel capping the occlusal end of the unworn molar plates retains a less derived two−layered structure, similar to that found in the basal proboscidean Moeritherium. In Mammuthus meridionalis the third deciduous premolar is differentiated from all other teeth in having more strongly decussating Hunter−Schreger bands in the middle layer, as a possible reinforcement of the very thin enamel. Evidence from this analysis shows that, in the transition from late Middle Pliocene M. rumanus to Late Pleistocene M. primigenius, the middle enamel layer, which is made up of prisms at an angle to the occlusal surface, providing greater resistance against wear, increased its relative thickness. This is consistent with the hypothesis that Mammuthus adapted to a more abrasive diet. Comparison with other proboscidean taxa indicates that the schmelzmuster (enamel pattern) found in Mammuthus is a synapomorphy of the Elephantoidea
Mammuthus meridionalis (Mammalia, Proboscidea, Elephantidae) from the 'Sabbie Gialle' of Oriolo (Cava La Salita, Faenza, Northern Italy) and other European late populations of southern mammoth
No full textNew finds of Mammuthus meridionalis from 'La Salita di Oriolo' quarry (Faenza, Emilia Romagna, Italy) are described. The 'Sabbie gialle' outcropping at Oriolo yielded several mammal species pointing out an early Galerian age (late Early Pleistocene) for the whole assemblage. A comparison with the type population of M. m. meridionalis from Upper Valdarno (Tuscany; Italy; Tasso Faunal Unit; early Early Pleistocene) and younger samples from Italy and other European localities allows to draw a possible scenario of the late evolution of the southern mammoth. On the basis of the systematic study two distinct lineages of southern mammoth are recognised. One, currently known only from Italy, is represented by several findings, among which are the Oriolo specimens and those referred to M.m. vestinus, characterized by large size, specialized skull and primitive dentition. A second group of forms, making its first occurrence in the early Galerian, presents instead derived dental morphology and is here referred to as M.meridionalis ex gr. tamanensis. During the middle Galerian (early Middle Pleistocene) the latter is replaced throughout Eurasia by the more evolved steppe mammoth M.trogontherii, a probable off-shoot of this group, while the forms belonging to the M.m.vestinus group became extinct without descendants
Mammuthus cf. primigenius (Proboscidea, Mammalia), a new faunal element from the late middle Pleistocene of the Conca river (Cattolica, Romagna, Italy)
No full textRemains of a mammoth from the late middle Pleistocene fluvio-lacustrine deposits outcropping along the flow of the Conca river (Cattolica, Romagna, Italy), are described. The material is referred to M. cf. primigenius, wich represents a new element of the Conca fossil mammal fauna, attributed by Conti et al. (1982) to the penultimate cold stage. The morphometric characters of the Conca mammoth do not exclude the possibility it belongs to a more primitive form than typical late Pleistocene M. primigenius
Vertebrate records | Early pleistocene
No full textThis chapter introduces the beginning of Pleistocene vertebrate records, starting from an overview of the latest Pliocene events and the Plio-Pleistocene transition. Understanding the Early Pleistocene vertebrate record is impossible without the knowledge of the events characterizing the setting of Early Pleistocene land vertebrate communities. Three taxa are selected to describe evolutionary and dispersal patterns within the Early Pleistocene. These are the dispersals and evolutionary history of the genus Canis, of elephants, and of voles. The last section offers an overview of the Early Pleistocene herpetofauna
Early Pleistocene
No full textThis chapter introduces the beginning of Pleistocene vertebrate records, starting from an overview of the latest Pliocene events and the Plio-Pleistocene transition. Understanding the early Pleistocene vertebrate record is impossible without the knowledge of the events characterizing the setting of early Pleistocene land vertebrate communities. Three taxa are selected to describe evolutionary and dispersal patterns within the early Pleistocene. These are the dispersals and evolutionary history of the genus Canis, of elephants, and of voles. The last section offers an overview of the early Pleistocene herpetofauna
Chasmaporthetes melei n. sp. an endemic hyaenid (Carnivora, Mammalia) from the Monte Tuttavista fissure fillings (Late Pliocene to early Pleistocene; Sardinia, Italy
No full textOccurrence of large carnivores in island ecosystems is unusual, especially in the case of top predators. Here, a new endemic hyaenid species, Chasmaporthetes melei, from the late Late Pliocene to earliest Pleistocene fissure fillings of Monte Tuttavista, Orosei, Sardinia, is described. Although smaller, C. melei is morphologically comparable with the Plio-Pleistocene Eurasian hunting-hyena Chasmaporthetes lunensis, a possible ancestor of the Sardinian species. C. melei displays all the characteristic feeding adaptations of Chasmaporthetes, including a derived enamel structure similar to the condition in extant bone-crushing hyaenas. C. melei was an active predator that nonetheless included a relatively large amount of bone in its diet
Political corruption, individual behaviour and the quality of institutions
No full textIs the corrupt behaviour of public officials a politically relevant kind of wrong only when it causes the malfunctioning of institutions? We challenge recent institutionalist approaches to political corruption by showing a sense in which the individual corrupt behaviour of certain public officials is wrong not only as a breach of personal morality but in inherently politically salient terms. To show this sense, we focus on a specific instance of individual corrupt behaviour on the part of public officials entrusted with the power to implement public rules in a liberal democracy. Although not necessarily unlawful, their behaviour is politically wrong qua corrupt when it contradicts surreptitiously the requirement of public justification that undergirds the public order. Then, we distinguish this form of corruption as surreptitious action from such unlawful but publicly justifiable kinds of political misbehaviour as civil disobedience.</jats:p
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
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