6 resultados para Vertebrates, Fossil.

em Biblioteca Digital da Produção Intelectual da Universidade de São Paulo


Relevância:

20.00% 20.00%

Publicador:

Resumo:

Scientific collections are important sources of material for many areas of ornithological research. Although firearms (particularly shotguns) have been the standard for avian scientific collecting for more than 100 years, their use is restricted in many areas of the world. We describe a cheap, relatively silent, and effective air shotgun for collecting birds weighing up to 50 g at distances up to 4 m. This air shotgun is capable of shooting birdshot, uses hollow metal rivets connected to plastic straws as shot shells, and represents a simple adaptation of any 0.177 or 0.22 cal single-shot, break-barrel air rifle with at least 25 joules of muzzle energy. This air shotgun will be especially useful for focused sampling of birds (and other small vertebrates) in situations where firearm use or transport is restricted.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

The limestones of ltaborai Basin (Middle Paleocene), Rio de Janeiro, Brazil, harbor a rich fossil fauna of pulmonate snails. Here two new pulmonate species are described: Brasilennea guttula sp. nov. (Cerionidae) and Eoborus rotundus sp. nov. (Strophocheilidae). B. guttula is the third species of its genus endemic from Itaborai, characterized mainly by its conspicuous shell shaped like a "water drop", with an acuminated spire. E. rotundus is the second of its genus from ltaborai, characterized mainly by its rounded outline and its relative small size. Moreover, a record of Plagiodontes aff. dental us (WOOD 1828) (Orthalicidae) is presented here for the first time for Itaborai Basin.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Fossils of the gastropods Diodora patagonica, Zidona dufresnei, Olivancillaria carcellesi, Lamniconus lemniscatus carcellesi and the bivalve Arcinella brasiliana are registered for the first time from the outcrops of Chui Creek, on the coastal plain of Rio Grande do Sul State, southernmost Brazil, together with other taxa previously known elsewhere. The specimens were collected in a shallow Pleistocene marine facies exposed at the base of the banks of the creek, in a fossil concentration possibly formed by storm events. The taxa described here live in shallow environments (with the exception of A. brasiliana and Z. dufresnei) with sandy bottoms (except for D. patagonica, T patagonica, B. odites, C. rhizophorae and A. brasiliana). The presence of L. lemniscatus carcellesi, found living today only in Uruguay and Argentina, indicates a wider distribution for this taxon during the late Pleistocene.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

A remarkable cervid bone accumulation occurs at a single passage (named Cervid Passage; CP) at Lapa Nova, a maze cave in eastern Brazil. CP lies away from cave entrances, is a typical pitfall passage and contains bone remains of at least 121 cervids, besides few bats, peccaries and rodents remains. There is no evidence of water (or sediment) flow at the site and in general bones lack post depositional alterations and display anatomical proximity, suggesting that the majority of the remains found inside CP (mainly cervids) are due to animals that after entering the cave got trapped in the site. Observations suggest that two entrances could have provided access to cervids (and the few other animals, besides bats), either by falling inside the cave or by entering by their own free will. Once inside the cave, the maze pattern would make route finding difficult, and of all passage intersections, only the one leading to CP would result in a non-return situation, starving the animal to death. Radiocarbon dates suggest that animal entrapment occurred during at least 5 thousand years, during the Holocene. The reasons why mainly cervids were found are unknown but they are probably related to the biology of this group coupled with the fact that caves provide several specific taphonomic processes that may account for a strong bias in bone accumulation. Indeed, the frequent occurrence of Cervidae in both the fossil and sub-fossil record in Brazilian caves may be related to an overall high faunal abundance or may suggest that these animals were especially prone to enter caves, perhaps in search of nutrients (as cave saltpetre) or water.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Background: We describe the first occurrence in the fossil record of an aquatic avian twig-nest with five eggs in situ (Early Miocene Tudela Formation, Ebro Basin, Spain). Extensive outcrops of this formation reveal autochthonous avian osteological and oological fossils that represent a single taxon identified as a basal phoenicopterid. Although the eggshell structure is definitively phoenicopterid, the characteristics of both the nest and the eggs are similar to those of modern grebes. These observations allow us to address the origin of the disparities between the sister taxa Podicipedidae and Phoenicopteridae crown clades, and traces the evolution of the nesting and reproductive environments for phoenicopteriforms. Methodology/Principal Findings: Multi-disciplinary analyses performed on fossilized vegetation and eggshells from the eggs in the nest and its embedding sediments indicate that this new phoenicopterid thrived under a semi-arid climate in an oligohaline (seasonally mesohaline) shallow endorheic lacustine environment. High-end microcharacterizations including SEM, TEM, and EBSD techniques were pivotal to identifying these phoenicopterid eggshells. Anatomical comparisons of the fossil bones with those of Phoenicopteriformes and Podicipediformes crown clades and extinct palaelodids confirm that this avian fossil assemblage belongs to a new and basal phoenicopterid. Conclusions/Significance: Although the Podicipediformes-Phoenicopteriformes sister group relationship is now well supported, flamingos and grebes exhibit feeding, reproductive, and nesting strategies that diverge significantly. Our multi-disciplinary study is the first to reveal that the phoenicopteriform reproductive behaviour, nesting ecology and nest characteristics derived from grebe-like type strategies to reach the extremely specialized conditions observed in modern flamingo crown groups. Furthermore, our study enables us to map ecological and reproductive characters on the Phoenicopteriformes evolutionary lineage. Our results demonstrate that the nesting paleoenvironments of flamingos were closely linked to the unique ecology of this locality, which is a direct result of special climatic (high evaporitic regime) and geological (fault system) conditions.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

We report the discovery of 12 new fossil groups (FGs) of galaxies, systems dominated by a single giant elliptical galaxy and cluster-scale gravitational potential, but lacking the population of bright galaxies typically seen in galaxy clusters. These FGs, selected from the maxBCG optical cluster catalog, were detected in snapshot observations with the Chandra X-ray Observatory. We detail the highly successful selection method, with an 80% success rate in identifying 12 FGs from our target sample of 15 candidates. For 11 of the systems, we determine the X-ray luminosity, temperature, and hydrostatic mass, which do not deviate significantly from expectations for normal systems, spanning a range typical of rich groups and poor clusters of galaxies. A small number of detected FGs are morphologically irregular, possibly due to past mergers, interaction of the intra-group medium with a central active galactic nucleus (AGN), or superposition of multiple massive halos. Two-thirds of the X-ray-detected FGs exhibit X-ray emission associated with the central brightest cluster galaxy (BCG), although we are unable to distinguish between AGN and extended thermal galaxy emission using the current data. This sample representing a large increase in the number of known FGs, will be invaluable for future planned observations to determine FG temperature, gas density, metal abundance, and mass distributions, and to compare to normal (non-fossil) systems. Finally, the presence of a population of galaxy-poor systems may bias mass function determinations that measure richness from galaxy counts. When used to constrain power spectrum normalization and Omega(m), these biased mass functions may in turn bias these results.