Dazai Osamu ve "Beklemek" Öyküsü - Ummakla Oyalanmak Arasında Gizemli Bekleyiş

The tendency for the mean body size of taxa within a clade to increase through evolution (Cope’s Rule) has been demonstrated in a number of terrestrial vertebrate groups. However, because avian body size is strongly constrained by flight, any increase in size during the evolution of this lineage should be limited – there is a maximum size that can be attained by a bird for it to be able to get off the ground. Contrary to previous interpretations of early avian evolution, we demonstrate an overall increase in body size across Jurassic and Cretaceous flying birds: taxon body size increases from the earliest Jurassic through to the end of the Cretaceous, across a time span of 70 Myr. Although evidence is limited that this change is directional, it is certainly nonrandom. Relative size increase occurred presumably as the result of an increase in variance as the avian clade diversified after the origin of flight: a progression towards larger body size is seen clearly within the clades Pygostylia and Ornithothoraces. In contrast, a decrease in body size characterizes the most crownward lineage Ornithuromorpha, the clade that includes all extant taxa, and potentially may explain the survival of these birds across the Cretaceous-Palaeogene boundary. As in all other dinosaurs, counter selection for small size is seen in some clades, whereas body size is increasing overal

Revision and new data on the Early and Middle Miocene soricids (Soricomorpha, Mammalia) from Central and South-Eastern France

International audienceNew or poorly known Soricids from the Early Miocene of Central France (Limagne d'Allier) and from the Middle Miocene of South-Eastern France (near Lyon) are studied; one new genus (Viretia) and a newspecies (Carposorex burkarti) are described. The soricid assemblages of the Early and late Early/Middle Miocene localities are totally different from each other and new information about appearance and evolution of the taxa are introduced. The following are lists of studied taxa for the beginning of the EarlyMiocene: Clapasorex bonisi, Clapasorex aff. sigei, Carposorex burkarti nov. sp., Soricella cf. discrepans, Oligosorex aff. antiquus and Crocidosoricinae indet, and for the late Early/Middle Miocene Dinosorex sansaniensis, Dinosorex pachygnathus, Heterosorex delphinensis, Miosorex desnoyersianus, Miosorex grivensis, Lartetium dehmi, Lartetium ziegleri, Turiasorex pierremeini, Viretia nov. gen. gracilidens, Paenelimnoecus micromorphus, Paenelimnoecus crouzeli and Hemisorex robustus