1,455 research outputs found
New systematic insights about plio-pleistocene moles from poland
The generic attribution of the Plio-Pleistocene Polish moles ?Neurotrichus polonicus and ?Neurotrichus skoczeni has been questioned several times in the past. The fossil material belonging to ?Neurotrichus polonicus and ?Neurotrichus skoczeni is re-evaluated here and a new diagnosis is provided on the basis of qualitative considerations. In addition, a Geometric Morphometric analysis of the humerus has been performed including both extant and extinct Neurotrichini and Urotrichini taxa for comparison. Our results proved the unique morphology of the Polish material suggesting a distinct taxonomic state. The morphological variations evidenced by the humeral shape analysis agree with the observed qualitative differences and support a new generic allocation. The new genus Rzebikia gen. nov. is proposed for all the material previoulsly ascribed to ?Neurotrichus polonicus and ?Neurotrichus skoczeni
Macroevolutionary patterns in cranial and lower jaw shape of ceratopsian dinosaurs (dinosauria, ornithischia). phylogeny, morphological integration, and evolutionary rates
Organisms: Ceratopsians were herbivorous, beaked dinosaurs, ranging from 1 m to 9 m in body length, usually four-footed, and with a bony frill that extended backwards from the cranium over the nape of the neck. Known from Asia, Europe, and North America, they appeared in the Late Jurassic and persisted until the end of the Late Cretaceous.
Questions: Which evolutionary processes drive the phenotypic evolution of skulls and lower jaws within Ceratopsia? What is the degree of morphological integration between the skull and lower jaw, and between the snout and frill among clades? Finally, are there any morphological evolution rate shifts across the ceratopsian phylogeny?
Data: Photographs from 121 ceratopsian skulls and 122 lower jaws in lateral view, both from original photos and published pictures. Fifty-five ceratopsian species are represented in the sample.
Methods: We investigated cranial and lower jaw shape changes across ceratopsians applying two-dimensional geometric morphometrics. We also investigated the morphological variation of the snout and the frill. Using phylogenetic generalized least squares regression, we estimated the degree of phylogenetic signal in size and shape data, as well as in the shape-size relationship. We performed phenotypic evolutionary rate analysis on shape data to describe phenotypic shifts across the phylogeny. Using a rarefied version of Escoufier's RV coefficient, we tested morphological integration between skulls and lower jaws, and between snouts and frills. Finally, we explored the potential link between cranial and frill shape evolution in ceratopsians and the radiation of angiosperms using a linear regression model.
Results: Skull, snout, and frill shapes differ among clades (with the exception of leptoceratopsids and protoceratopsids). Lower jaws show distinct morphologies among groups. Size and shape changes are phylogenetically structured. The frill drives the morphological variation of the skull, co-varying much more with the lower jaw than with the snout. The frill appears to evolve to co-vary better with the lower jaw in the more morphologically derived clades than in basal ones. A significant linear relationship does exist between cranial shape and angiosperm occurrences, suggesting the hypothesis that the frill evolved in response to changes in dietary compositions associated with the turnover between gymnosperms and angiosperms during the Cretaceous. Significant negative shifts in evolutionary rates characterize skull, snout, frill, and lower jaw shapes, corresponding to nodes where psittacosaurids diverge from other taxa. In contrast, a significant positive shift in skull and snout shape rate of evolution characterizes the clade Ceratopsoidea.
Conclusion: The frill is the main driving force in the overall cranial shape within Ceratopsia and evolved secondarily to better co-vary with the lower jaw to produce a more efficient masticatory apparatus. The changes in frill shape are correlated with the angiosperm diversification that occurred in the Cretaceous and thus correlated with changes in diet. Ceratopsians exhibit a slowdown in the phenotypic evolutionary rate in the Early Cretaceous and an acceleration of the phenotypic rate in the Late Cretaceous
Males resemble females. re-evaluating sexual dimorphism in protoceratops andrewsi (neoceratopsia, protoceratopsidae)
BACKGROUND: Protoceratops andrewsi (Neoceratopsia, Protoceratopsidae) is a well-known dinosaur from the Upper Cretaceous of Mongolia. Some previous workers hypothesized sexual dimorphism in the cranial shape of this taxon, using qualitative and quantitative observations. In particular, width and height of the frill as well as the development of a nasal horn have been hypothesized as potentially sexually dimorphic.
METHODOLOGY/PRINCIPAL FINDINGS: Here, we reassess potential sexual dimorphism in skulls of Protoceratops andrewsi by applying two-dimensional geometric morphometrics to 29 skulls in lateral and dorsal views. Principal Component Analyses and nonparametric MANOVAs recover no clear separation between hypothetical "males" and "females" within the overall morphospace. Males and females thus possess similar overall cranial morphologies. No differences in size between "males" and "females" are recovered using nonparametric ANOVAs.
CONCLUSIONS/SIGNIFICANCE: Sexual dimorphism within Protoceratops andrewsi is not strongly supported by our results, as previously proposed by several authors. Anatomical traits such as height and width of the frill, and skull size thus may not be sexually dimorphic. Based on PCA for a data set focusing on the rostrum and associated ANOVA results, nasal horn height is the only feature with potential dimorphism. As a whole, most purported dimorphic variation is probably primarily the result of ontogenetic cranial shape changes as well as intraspecific cranial variation independent of sex
Spatial Coordinate Transformations with Noisy Data
The parametric transformation of spatial coordinates between different reference frames is traditionally dealt with a stepwise approach which imposes a suboptimal treatment in the presence of noisy data. The chapter explains briefly the drawbacks of this approach and then presents an alternative scheme for spatial coordinate transformations that improves the classic stepwise solution when using noisy coordinates of known stochastic structure. The proposed methodology is simple in principle, although its numerical implementation with nonlinear parametric models is a bit more involved and it relies on the joint least squares adjustment of the observed coordinates using their full stochastic model over all points of interest. The mathematical framework and the related properties of this “stacking” approach are presented in detail, along with a numerical example that demonstrates its feasibility for practical problems in geospatial applications
Mesolithic to Neolithic in Greece. Continuity, discontinuity or change of course?
The paper reviews the status of the Mesolithic/Neolitihc interface in Greece. It is argued that the old dichotomy between “indigenists” and “diffusionists” concerning the neolithization of Greece is simplistic. Instead it is proposed that the discussion should be focused on two separate issues: one factual, emphasizing the form of phenomena and their archaeological description and one interpretive focusing more on content. Concerning the first issue, the hypothesis is made that the discontinuity in the Mesolithic/Neolithic interface is probably the result of the incomplete archaeological record and the biased research on long-term Neolithic sites in Thessaly. As for the second issue, the shift to the Neolithic can be better understood as an effort to control society and its conflicts by manipulating physical and conceptual resources and by constructing new identities.V članku predstavljamo hipoteze o prehodu iz mezolitika v neolitik v Grčiji. Menimo, da je staro nasprotje med “avtohtonisti” in “difuzionisti” o neolitizaciji Grčije preveliko poenostavljanje. Zato predlagamo, da se razprava osredotoči na dve ločeni vprašanji: prvo se tiče dejstev, kjer je poudarek na obliki pojava in njegovem arheološkem zapisu, drugo pa je interpretativno in osredotočeno bolj na vsebino. Glede prvega vprašanja postavimo hipotezo, da je diskontinuiteta prehoda mezolitik/neolitik verjetno posledica nepopolnega arheološkega zapisa in pristranskih raziskav na kontinuiranih neolitskih najdiščih v Tesaliji. Glede drugega vprašanja menimo, da lahko prehod v neolitik bolje razumemo, če v njem vidimo prizadevanje za nadzor družbe in njenih nasprotij z obvladovanjem fizičnih in pojmovnih virov in z oblikovanjem novih identitet
Paths to modernity: Dimitrios R. Theocharis and post-war Greek prehistory
No abstract availabl
Paths to modernity: Dimitrios R. Theocharis and post-war Greek prehistory
No abstract availabl
The biological diversity complex: a history of environmental government
The thesis understands biodiversity as a complex consisting of a form of environmentalism, a mode of governance for the global South, and a set of policy prescriptions all mobilized by the guiding idea of ‘genetic gold,’ the belief that biodiversity possesses significant latent economic value. The thesis primarily analyses the historical origins of biodiversity and the formation of a rationality of governing centred on genetic gold, deploying tools and methods from the work of Michel Foucault. It further applies these insights into the examination of two specific regulatory mechanisms developed within this project of environmental governance: the mechanism for securing access to genetic resources and the fair and equitable sharing of benefits arising from their utilisation, and local and indigenous community participation in biodiversity conservation and utilisation. The aim of this research is a dual critique. First, the unpacking of the complexity of the biodiversity concept and its integrative rendering of biodiversity loss as a governance problem constitutes a critique of environmental law’s enthusiastic acceptance and subsequent regulation of biodiversity as genetic gold. Secondly, the conception of a broader governance complex pervaded by non-legal forms of knowledge, expertise and practices challenges an international environmental law that continues to regard itself as the instrumental centre of environmental concern and discourse
Le lucertole (Lacertidae, Squamata) del Pliocene, Pleistocene e Olocene delle Baleari
Abstract not availabl
Web-based Geographical Visualization of Container Itineraries
Around 90% of the world cargo is transported in maritime containers, but only around 2% are physically inspected. This opens the possibility for illicit activities. A viable solution is to control containerized cargo through information-based risk analysis. Container route-based analysis has been considered a key factor in identifying potentially suspicious consignments. Essential part of itinerary analysis is the geographical visualization of the itinerary. In the present paper, we present initial work of a web-based system’s realization for interactive geographical visualization of container itinerary.JRC.G.4-Maritime affair
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