Search results for "Axon"

Fuciniceras paradoxus nov. sp. (Harpoceratinae, Ammonitina) du Domérien portugais. Réflexion sur le sens taxonomique d’un assemblage paradoxal de car…

2002

A new ammonite (Fuciniceras paradoxus) is described here. This Lower Domerian species is based on a recently revised collections which came from the Maria Pares section (Rabacal area, South of Coimbra, Portugal). Curiously, shell of F. paradoxus bears both diagnostic traits for the genus Protogrammoceras SPATH (e.g. acute ogival ventral area) and Fuciniceras HAAS (e.g. angulirursiradiate rib). Thus, the new species can be viewed as a morphological puzzle and as a challenge for taxonomists. The amazing collection of morphological traits previously suspected as highly improbable because of biomechanical constraints (1) confirms the inadequacy of the traditional use of the genera Protogrammoce…

Variations in Jurassic echinoid biodiversity at ammonite zone levels: Stratigraphical and palaeoecological significance

2020

After a relatively low but stable phase of taxonomic diversity during the Lias (Lower Jurassic), echinoids diversity strongly increases from Aalenian (Dogger-Middle Jurassic) to Kimmeridgian (Malm-Late Jurassic) and a conspicuous crisis takes place in Tithonian times, before the end of the Jurassic. During these major phases, minor decreases in diversity correspond with regressions (sea-level falls), mainly in the Middle Bathonian (Middle Jurassic). From the Aalenian to Callovian, the average duration of irregular echinoid species is about 3.8 m.y. whereas it is about 5.5 m.y. for the regular ones; the later value corresponding to the average duration of a Jurassic. From Callovian to Tithon…

Comparison of the functional responses of invasive and native amphipods

2008

While we can usually understand the impacts of invasive species on recipient communities, invasion biology lacks methodologies that are potentially more predictive. Such tools should ideally be straightforward and widely applicable. Here, we explore an approach that compares the functional responses (FRs) of invader and native amphipod crustaceans. Dikerogammarus villosus is a Ponto-Caspian amphipod currently invading Europe and poised to invade North America. Compared with other amphipods that it actively replaces in freshwaters, D. villosus exhibited significantly greater predation, consuming significantly more prey with a higher type II FR. This corroborates the known dramatic field imp…

Allometries of maximum growth rate versus body mass at maximum growth indicate that non-avian dinosaurs had growth rates typical of fast growing ecto…

2014

We tested if growth rates of recent taxa are unequivocally separated between endotherms and ectotherms, and compared these to dinosaurian growth rates. We therefore performed linear regression analyses on the log-transformed maximum growth rate against log-transformed body mass at maximum growth for extant altricial birds, precocial birds, eutherians, marsupials, reptiles, fishes and dinosaurs. Regression models of precocial birds (and fishes) strongly differed from Case's study (1978), which is often used to compare dinosaurian growth rates to those of extant vertebrates. For all taxonomic groups, the slope of 0.75 expected from the Metabolic Theory of Ecology was statistically supported. …

The beginning of the Neolithic in Nerja cave and la Cova de la Sarsa. Archaeological context and radiocarbon dating

2018

Las dataciones radiocarbónicas resultan una herramienta útil para establecer el marco cronológicode los contextos arqueológicos, aunque en ocasiones el adjetivo de «absoluto» se convierte en una categoría. En el caso del Neolítico antiguo, la selección de muestras singulares de vida corta de especies domésticas o restos de Homo sapiens en contextos neolíticos pretendía definir con mayor precisión la cronología de los momentos iniciales de su llegada a la península ibérica. Los casos documentados en las cuevas de Nerja y Sarsa son un buen ejemplo del debate que generan sus resultados, la problemática de sus secuencias y el contexto de discusión regional. Se muestran los resultados tras la va…

An adventive Panaeolus antillarum in Poland (Basidiomycota, Agaricales) with notes on its taxonomy, geographical distribution, and ecology

2014

Abstract Coprophilous fungus, Panaeolus antillarum rarely recorded in Europe, is reported here for the first time from the Augustow Plane, north-eastern Poland. This thermophilic species was found outdoors in August on horse dung mixed with straw. A chemical analysis did not confirm the presence of the psychoactive alkaloids in collected material. A complete description and illustration of the species based on Polish specimens are presented and notes on its taxonomy, ecology, world distribution and comparison with similar taxa — P. semiovatus var. semiovatus, P. semiovatus var. phalaenarum, and others are also provided.

Remigius’s Commentary to the Disticha Catonis in Anglo-Saxon Manuscripts

2007

'Mirabilia Indiae e le radici del discorso coloniale', in Maschere dell’Impero, ed. Carmelo Di Piazza – Daniela Corona – Marcella Romeo (Diagonali, 3…

2005

The essay takes into examination the medieval treatment of the so-called Marvels of India, with particualr regard to Anglo-saxon texts

Transcriptome data reveal syndermatan relationships and suggest the evolution of endoparasitism in acanthocephala via an epizoic stage

2014

The taxon Syndermata comprises the biologically interesting wheel animals ("Rotifera": Bdelloidea + Monogononta + Seisonidea) and thorny-headed worms (Acanthocephala), and is central for testing superordinate phylogenetic hypotheses (Platyzoa, Gnathifera) in the metazoan tree of life. Recent analyses of syndermatan phylogeny suggested paraphyly of Eurotatoria (free-living bdelloids and monogononts) with respect to endoparasitic acanthocephalans. Data of epizoic seisonids, however, were absent, which may have affected the branching order within the syndermatan clade. Moreover, the position of Seisonidea within Syndermata should help in understanding the evolution of acanthocephalan endoparas…

Redescription ofOdhneriella subtila (Skrjabin, 1959) (Digenea: Campulidae) from the intestine ofGlobicephala melaena (Traill, 1809) (Cetacea: Delphin…

1989

During parasitological investigations of long-finned pilot whales,Globicephala melaena (Traill, 1809), in the Faroe Islands, the trematode speciesOdhneriella subtila (Digenea: Campulidae), parasitising the small intestine, was detected. Skrjabin's (1959) original description of this species was based on a single individual. The collection and availability for study of several thousands of specimens permitted the redescription of this campulid and the noting of some new morphological characters. This trematode is reported for the first time from the long-finned pilot whale, and the Atlantic Ocean is a new locality record.