نتایج جستجو برای: trace fossil

تعداد نتایج: 91986  

Journal: :Nature communications 2012
Johan Lindgren Per Uvdal Peter Sjövall Dan E Nilsson Anders Engdahl Bo Pagh Schultz Volker Thiel

Fossil feathers, hairs and eyes are regularly preserved as carbonized traces comprised of masses of micrometre-sized bodies that are spherical, oblate or elongate in shape. For a long time, these minute structures were regarded as the remains of biofilms of keratinophilic bacteria, but recently they have been reinterpreted as melanosomes; that is, colour-bearing organelles. Resolving this funda...

2012
Silvina de Valais Sebastián Apesteguía Alberto C. Garrido

Ecological relationships among fossil vertebrate groups are interpreted based on evidence of modification features and paleopathologies on fossil bones. Here we describe an ichnological assemblage composed of trace fossils on reptile bones, mainly sphenodontids, crocodyliforms and maniraptoran theropods. They all come from La Buitrera, an early Late Cretaceous locality in the Candeleros Formati...

Journal: :Marine pollution bulletin 2011
Andreza P Ribeiro Rubens C L Figueira César C Martins Charles R A Silva Elvis J França Márcia C Bícego Michel M Mahiques Rosalinda C Montone

Admiralty Bay (Antarctica) hosts three scientific stations (Ferraz, Arctowski and Macchu Picchu), which require the use of fossil fuel as an energy source. Fossil fuels are also considered the main source of pollution in the area, representing important inputs of major pollutants (organic compounds) and trace metals and metalloids of environmental interest. Accordingly, this work presents the r...

2000
JAMES O. FARLOW

To what extent does ichnological diversity (the number of distinctive trace fossil morphologies) serve as a proxy for zoological diversity (species richness of trackmakers in the living fauna) in footprint assemblages made by terrestrial lower vertebrates? This question was investigated in a study of body form and trackway features of monitor lizards (varanids) from the Western Australian deser...

Journal: :Proceedings. Biological sciences 2014
M Gabriela Mángano Luis A Buatois

The rapid appearance of bilaterian clades at the beginning of the Phanerozoic is one of the most intriguing topics in macroevolution. However, the complex feedbacks between diversification and ecological interactions are still poorly understood. Here, we show that a systematic and comprehensive analysis of the trace-fossil record of the Ediacaran-Cambrian transition indicates that body-plan div...

2008
JON J. SMITH STEPHEN T. HASIOTIS

This study documents the traces and burrowing behaviors of nymphs of the prairie cicada Cicadetta calliope (Hemiptera: Cicadidae), as observed in neoichnological experiments. Cicada nymphs were collected from the C horizons of sandy Fluvents along the Kansas River east of Lawrence, Kansas. The nymphs appeared to be fifth instars, 13–17 mm long and 6–7 mm wide. Nymphs were placed in plastic encl...

2005
Roy E. Plotnick Karen Koy

Trace fossils are the only direct record of the behavior of ancient organisms. They thus provide critical indications of the early evolution of sensory systems and of the behavioral response to environmental heterogeneity. An important category of traces preserve the foraging behavior of organisms on or just below the seafloor. Previous conceptual and numerical models of such traces have been b...

2013
Jorge Walter Franz W Kellermanns Steven W Floyd John F Veiga Curtis Matherne

Despite the increasing sophistication of the literature on strategic consensus and the compelling arguments linking it to organizational performance, empirical research has produced mixed findings. To address this conundrum, we examine the contingent role of strategic alignment—that is, to what extent decision makers place importance on strategic priorities that are responsive to, or fit, the d...

2003
Walter R. Tschinkel

Many species of ants excavate complex, species-typical nests in soil. The basic structural units of many nests are descending tunnels connecting flattened, generally horizontal chambers of oval to lobed outline. The species-typical structure of many nests results from variation in the size, shape, number and arrangement of these basic elements. Nest architecture can be rendered by filling subte...

2011
Kimberly L. McArthur David Dickman

24 25 Vestibular responses play an important role in maintaining gaze and posture stability 26 during rotational motion. Previous studies suggest that these responses are state-dependent, their 27 expression varying with the environmental and locomotor conditions of the animal. In this 28 study, we simulated an ethologically relevant state in the lab in order to study state-dependent 29 vestibu...

نمودار تعداد نتایج جستجو در هر سال

با کلیک روی نمودار نتایج را به سال انتشار فیلتر کنید