The Sail-Backed Reptile Ctenosauriscus from the Latest Early Triassic of Germany and the Timing and Biogeography of the Early Archosaur Radiation

Background Archosaurs (birds, crocodilians and their extinct relatives including dinosaurs) dominated Mesozoic continental ecosystems from the Late Triassic onwards, and still form a major component of modern ecosystems (>10,000 species). The earliest diverse archosaur faunal assemblages are known from the Middle Triassic (c. 244 Ma), implying that the archosaur radiation began in the Early Triassic (252.3–247.2 Ma). Understanding of this radiation is currently limited by the poor early fossil record of the group in terms of skeletal remains. Methodology/Principal Findings We redescribe the anatomy and stratigraphic position of the type specimen of Ctenosauriscus koeneni (Huene), a sail-backed reptile from the Early Triassic (late Olenekian) Solling Formation of northern Germany that potentially represents the oldest known archosaur. We critically discuss previous biomechanical work on the ‘sail’ of Ctenosauriscus, which is formed by a series of elongated neural spines. In addition, we describe Ctenosauriscus-like postcranial material from the earliest Middle Triassic (early Anisian) Röt Formation of Waldhaus, southwestern Germany. Finally, we review the spatial and temporal distribution of the earliest archosaur fossils and their implications for understanding the dynamics of the archosaur radiation. Conclusions/Significance Comprehensive numerical phylogenetic analyses demonstrate that both Ctenosauriscus and the Waldhaus taxon are members of a monophyletic grouping of poposauroid archosaurs, Ctenosauriscidae, characterised by greatly elongated neural spines in the posterior cervical to anterior caudal vertebrae. The earliest archosaurs, including Ctenosauriscus, appear in the body fossil record just prior to the Olenekian/Anisian boundary (c. 248 Ma), less than 5 million years after the Permian–Triassic mass extinction. These earliest archosaur assemblages are dominated by ctenosauriscids, which were broadly distributed across northern Pangea and which appear to have been the first global radiation of archosaurs

Yellow fever in Brazil: thoughts and hypotheses on the emergence in previously free areas

This article describes and discusses factors associated to the reemergence of yellow fever and its transmission dynamics in the states of São Paulo (Southeastern Brazil) and Rio Grande do Sul (Southern) during 2008 and 2009. The following factors have played a pivotal role for the reemergence of yellow fever in these areas: large susceptible human population; high prevalence of vectors and primary hosts (non-human primates); favorable climate conditions, especially increased rainfall; emergence of a new genetic lineage; and circulation of people and/or monkeys infected by virus. There is a need for an effective surveillance program to prevent the reemergence of yellow fever in other Brazilian states

Entomological investigation of a sylvatic yellow fever area in São Paulo State, Brazil Investigação entomológica em área de ocorrência de febre amarela silvestre no Estado de São Paulo, Brasil

Following reports of two autochthonous cases of sylvatic yellow fever in the State of São Paulo, Brazil, in 2000, entomological surveys were conducted with the objective of verifying the occurrence of vector species in forest environments close to or associated with riparian areas located in the western and northwestern regions of the State. Culicidae were captured in 39 sites distributed in four regions. Haemagogus leucocelaenus and Aedes albopictus were the most abundant species and were captured in all the regions studied. H. leucocelaenus was the most abundant species in the municipalities of Santa Albertina and Ouroeste, where the two cases of sylvatic yellow fever had been reported. Mosquitoes from the janthinomys/capricornii group were only found at eight sites in the São José do Rio Preto region, while Sabethes chloropterus was found at one site in Ribeirão Preto. H. leucocelaenus showed its capacity to adapt to a secondary and degraded environment. Our results indicate a wide receptive area for yellow fever transmission in the State of São Paulo, with particular emphasis on the possibility of H. leucocelaenus being involved in the maintenance of this sylvatic focus of the disease.<br>O registro de dois casos autóctones de febre amarela silvestre no Estado de São Paulo, Brasil, em 2000, desencadeou investigações entomológicas com o objetivo de verificar a ocorrência das espécies vetoras em ambientes florestais próximos ou associados às zonas ribeirinhas, situados nas regiões oeste e noroeste do Estado. As capturas foram realizadas em 39 localidades distribuídas por quatro regiões do Estado. Haemagogus leucocelaenus e Aedes albopictus foram as espécies mais abundantes e capturadas em todas as regiões. H. leucocelaenus foi a espécie mais abundante nos municípios de Santa Albertina e Ouroeste, onde os casos de febre amarela silvestre foram registrados. Mosquitos do grupo janthinomys/capricornii foram encontrados em oito localidades de São José do Rio Preto, enquanto Sabethes chloropterus uma única vez em localidade de Ribeirão Preto. Ficou evidenciada a aptidão de H. leucocelaenus para adaptar-se a ambiente secundário e degradado. Nossos resultados apontam para uma ampla área receptiva para a transmissão de febre amarela, com destaque para a possibilidade de H. leucocelaenus estar envolvido na manutenção deste foco silvestre da doença