Search results for "Biological"

Assessing metabolic constraints on the maximum body size of actinopterygians: locomotion energetics of Leedsichthys problematicus (Actinopterygii, Pa…

2018

Maximum sizes attained by living actinopterygians are much smaller than those reached by chondrichthyans. Several factors, including the high metabolic requirements of bony fishes, have been proposed as possible body‐size constraints but no empirical approaches exist. Remarkably, fossil evidence has rarely been considered despite some extinct actinopterygians reaching sizes comparable to those of the largest living sharks. Here, we have assessed the locomotion energetics of Leedsichthys problematicus, an extinct gigantic suspension‐feeder and the largest actinopterygian ever known, shedding light on the metabolic limits of body size in actinopterygians and the possible underlying factors th…

Evolutionary trends within Jurassic ammonoids.

2015

An evolutionary trend is a pattern of traits shifting in a given direction over a sufficiently long period of time to be detected. In this study, we examine trends among Jurassic ammonoids. First, a compilation of selected literature on evolutionary patterns and trends leads to the conclusion that such trends have rarely been studied among Jurassic ammonoids and even more rarely are they formally studied using statistical tests. Second, a preliminary survey of trends for the entire Jurassic at the family level (based on four published articles) suggests two sustained trends occurred each lasting nearly 10 myr: the Early Jurassic and Middle Jurassic radiations, which were related to the firs…

Stéphane Peigné (1973-2017) – Nécrologie

2020

Stephane Peigne nous a quittes le 4 Decembre 2017 apres avoir lutte avec courage pendant des mois contre une terrible maladie. Il avait espere l'avoir vaincue en 2016 mais elle l'a rattrape inexorablement. Il etait ne en 1973 dans une petite commune de l'Est de la France et avait suivi sa scolarite dans la region jusqu'a son Baccalaureat. Il commenca des etudes superieures a l'universite de Nancy, dans un cursus en Sciences de la Nature et de la Vie, pour les poursuivre a l'Universite de Bourgogne par une licence de Biologie suivie d'une maitrise d'Ecologie. Cependant cette orientation vers la recherche en biologie evolutive et ecologique ne lui suffisait plus et, desireux d'inclure le temp…

First occurrence of fossil vertebrates from the Carboniferous of Colombia

2020

Data concerning Paleozoic vertebrates from the South American continent are still scarce. In Colombia, occurrences were until now restricted to the Late Devonian fish assemblage from Floresta and, ...

Macrofossil evidence of Late Holocene presence of Aldrovanda vesiculosa L. in Central-Eastern Europe (Poland) and East Africa (Tanzania)

2015

International audience; To date, the seeds of waterwheel plant (Aldrovanda vesiculosa) were only found in Europe, in sediments of the Eemian and Mazovian Interglacials. The absence of A. vesiculosa seeds in European Holocene deposits is probably due to unfavorable climatic conditions, i.e. lower temperature, during this period: in temperate zones, A. vesiculosa reproduces mainly in a vegetative way; it rarely blooms and only occasionally produces seeds. In this paper, subfossil seeds of A. vesiculosa were identified in two peat bogs: one (Sucha Kobyła) in SE Poland and another one (Kyambangunguru) in SW Tanzania. Single seeds of this plant were found in a peat layer from the Polish site for…

Evaluating the influences of temperature, primary production, and evolutionary history on bivalve growth rates

2019

AbstractOrganismal metabolic rates reflect the interaction of environmental and physiological factors. Thus, calcifying organisms that record growth history can provide insight into both the ancient environments in which they lived and their own physiology and life history. However, interpreting them requires understanding which environmental factors have the greatest influence on growth rate and the extent to which evolutionary history constrains growth rates across lineages. We integrated satellite measurements of sea-surface temperature and chlorophyll-a concentration with a database of growth coefficients, body sizes, and life spans for 692 populations of living marine bivalves in 195 s…

Phylogenetic practices among scholars of fossil cephalopods, with special reference to cladistics.

2004

12 pages; International audience

The Italian Loci Classici Census

2012

Arable-weed flora and its pollen representation: A case study from the eastern part of France

2007

International audience; Local pollen deposition in human-influenced vegetation types is studied with the aim of establishing the relationship between arable-weed vegetation and its pollen representation as an aid in interpreting human presence and impact on vegetation from pollen assemblages. The study area is located in the Franche-Comté region, eastern part of France. The presence of plants within 100 m2 plots and their pollen representation in moss samples within the same plots was recorded from different crops and annual fallows. Patterns in the vegetation and pollen assemblages were investigated separately using principal coordinate analysis (PCoA). Procrustean co-inertia analysis (PCI…

An enigmatic marine reptile, Hispaniasaurus cranioelongatus (gen. et sp. nov.) with nothosauroid affinities from the Ladinian of the Iberian Range (S…

2017

An incomplete skull of a marine reptile with an atypical elongation of the postorbital region is described. The find comes from the Muschelkalk facies (Cañete Formation) of the Villora section (Iberian Range, Cuenca Province, Spain), characterised by a shallow marine (intertidal) environment and dated as Ladinian in age. The small skull has a rectangular shape, lacking, as preserved, upper temporal openings and a parietal foramen. The upper temporal openings might be secondarily closed. However, the absence of a parietal foramen and squamosals in the preserved part and the incompleteness of the pterygoids make a posteriorly postponed location of the upper temporal openings also conceivable.…