Selected bivalves from the Ordovician of the Prague Basin

Univerzita Karlova v Praze, Přírodovědecká fakulta Ústav Geologie a Paleontologie Charles University in Prague, Faculty of Science Institute of Geology and Palaeontology Doktorský studijní program: Geologie Ph.D. study program: Geology Autoreferát disertační práce Summary of the Ph.D. Thesis Vybraní mlži z ordoviku pražské pánve Selected bivalves from the Ordovician of the Prague Basin Mgr. Marika Polechová Školitelé / Supervisors: doc. RNDr. Petr Kraft CSc., RNDr. Jiří Kříž CSc. Praha, 1. 4. 2013 1 Abstrakt Cílem této disertační práce je revize vybraných ordovických mlžů z pražské pánve. Ordovičtí mlži patřili dlouhodobě k opomíjené skupině paleozoických bezobratlých. Úvodní část disertační práce se skládá z pěti kapitol, ve kterých jsou popsány hlavní charakteristiky mlžů, dále jsou podrobně popsáni ordovičtí mlži s důrazem na jejich systematiku, diverzifikaci, paleobiogeografii a paleoekologii. Těžištěm práce je revize mlžů ze šáreckého a kosovského souvrství pražské pánve. Zvláštní pozornost je věnována evolučně důležitým skupinám Protobranchia Pelseneer, 1889 a Actinodontida Dechaseaux, 1952. Všechny kapitoly jsou doplněny o nejnovější poznatky, které byly publikovány v šesti článcích zaměřených zejména na systematiku, paleobiogeografii, paleoekologii, diverzifikaci a ranou evoluci vybraných...Univerzita Karlova v Praze, Přírodovědecká fakulta Ústav Geologie a Paleontologie Charles University in Prague, Faculty of Science Institute of Geology and Palaeontology Doktorský studijní program: Geologie Ph.D. study program: Geology Autoreferát disertační práce Summary of the Ph.D. Thesis Vybraní mlži z ordoviku pražské pánve Selected bivalves from the Ordovician of the Prague Basin Mgr. Marika Polechová Školitelé / Supervisors: doc. RNDr. Petr Kraft CSc., RNDr. Jiří Kříž CSc. Praha, 1. 4. 2013 1 Abstrakt Cílem této disertační práce je revize vybraných ordovických mlžů z pražské pánve. Ordovičtí mlži patřili dlouhodobě k opomíjené skupině paleozoických bezobratlých. Úvodní část disertační práce se skládá z pěti kapitol, ve kterých jsou popsány hlavní charakteristiky mlžů, dále jsou podrobně popsáni ordovičtí mlži s důrazem na jejich systematiku, diverzifikaci, paleobiogeografii a paleoekologii. Těžištěm práce je revize mlžů ze šáreckého a kosovského souvrství pražské pánve. Zvláštní pozornost je věnována evolučně důležitým skupinám Protobranchia Pelseneer, 1889 a Actinodontida Dechaseaux, 1952. Všechny kapitoly jsou doplněny o nejnovější poznatky, které byly publikovány v šesti článcích zaměřených zejména na systematiku, paleobiogeografii, paleoekologii, diverzifikaci a ranou evoluci vybraných...Institute of Geology and PaleontologyÚstav geologie a paleontologieFaculty of SciencePřírodovědecká fakult

Late Ordovician molluscs of the central and eastern Anti-Atlas, Morocco

More than 30 species of tergomyan, gastropod, bivalve and cephalopod molluscs are described from the Late Ordovician of central and eastern Anti-Atlas, Morocco. For the cephalopods this represents the first systematically known taxa of the region. Tergomyans and gastropods are most common in the more shaly part of the Lower Ktaoua Formation, while bivalves are more frequent in the sandy part of the Lower Second Bani Formation. A southern Gondwana aspect is evident for the tergomyan, gastropod and bivalve assemblages, sharing many taxa with Bohemia, while no clear signal is present for the cephalopods. The latter reflects insufficient knowledge of the fauna of large parts of these areas. The widely recognized Holopea? antiquata is transferred to the genus Radvanospira gen. nov.; other new gastropod taxa include Allossospira gen. nov., Tritonophon grandis sp. nov., Radvanospira baniensis sp. nov. and Lophospira latilabra sp. nov. Most of the diverse bivalve fauna and the few cephalopods are left in open nomenclature but new taxa include the bivalve Praenucula pojetai sp. nov. and the cephalopods Wadema tattai sp. nov. and Tafadnatoceras tiouririnense gen. et. sp. nov. The Late Ordovician bivalves from Morocco are dominated by pteriomorphs and protobranchs, inhabiting infaunal, semi-infaunal and epifaunal niches.Peer reviewe

The first fossil assemblage from the Ordovician of Águeda (Aveiro): litho and biostratigraphic implications

RESUMO: Apresentam-se os primeiros fósseis do Ordovícico de Águeda, provenientes de níveis de meta-argilitos intercalados numa sequência arenítica metamórfica de Arrancada do Vouga. A associação, moderadamente diversa, inclui trilobites [Crozonaspis cf. incerta (Deslongchamps) e Crozonaspis sp.], bivalves [Praenucula sp., Cardiolaria cf. beirensis (Sharpe), Praeleda cf. ribeiroi (Sharpe), Hemiprionodonta cf. lusitanica (Sharpe), Tancrediopsis escosurae? (Sharpe) e Myoplusia? sp.], gastrópodes (Bellerophontidae indet. e Platyceratidae indet.), braquiópodes (Heterorthina sp.), ostracodos (Conchoprimitia? sp.) e quitinozoários (Desmochitina minor Eisenack), os quais indicam a idade Dobrotiviano superior (ca. Darriwiliano superior Sandbiano inferior). A sequência metarenítica descrita apresenta afinidades com a Formação Cabril da Zona Centro-Ibérica de Portugal central. Do ponto de vista bio e litostratigráfico, a sucessão ordovícica de Águeda apresenta uma maior afinidade com os setores meridionais da ZCI, e não com o setor norte (e.g. Valongo), contrariamente às restantes áreas incluídas na faixa de cisalhamento Porto – Albergaria-a-Velha.ABSTRACT: The first Ordovician fossils from Águeda are presented, coming from dark mudstones between two sandstones successions at Arrancada do Vouga. The moderately diverse assemblage includes trilobites [Crozonaspis cf. incerta (Deslongchamps) and Crozonaspis sp.], bivalves [Praenucula sp., Cardiolaria cf. beirensis (Sharpe), Praeleda cf. ribeiroi (Sharpe), Hemiprionodonta cf. lusitanica (Sharpe), Tancrediopsis escosurae? (Sharpe) and Myoplusia? sp.], gastropods (Bellerophontidae indet. and Platyceratidae indet.), brachiopods (Heterorthina sp.), ostracods (Conchoprimitia? sp.) and chitinozoans (Desmochitina minor Eisenack), which indicate an upper Dobrotivian (ca. upper Darriwilian-lower Sandbian) age. The described succession shows affinities with the Cabril Formation, occurring in the Central Iberian Zone of central Portugal. From a bio- and lithostratigraphic point of view, the Águeda Ordovician sequence has a greater affinity with the southern of the ZCI, and not the northern sector (e.g. Valongo), contrary to the other areas included in the Porto-Albergaria-a-Velha shear zone.info:eu-repo/semantics/publishedVersio

Fossiles cambriens de la région barrandienne (République tchèque) conservés au Musée d'Histoire Naturelle de Lille

A complete list of fossils originating from the Cambrian of the Barrandian area and housed in the Musée d'Histoire Naturelle de Lille is compiled. The collection includes two agnostids, ten trilobites, one brachiopod and one echinoderm species, all collected at ten outcrops in the Buchava Formation of the Skryje-Týřovice Basin and most probably also at two outcrops in the Jince Formation of the Příbram-Jince Basin. A large part of the material was collected by Prof. Charles Barrois and Dr. Louis Dollé (both University of Lille) during the excursion organised before the Ninth International Geological Congress in Vienna in 1903. Other, poorly documented specimens were purchased from the enterprise Krantz towards the end of the 19th century and in the first years of 20th century. The geographic position and stratigraphy of outcrops, from which the material originates, are briefly discussed.Une liste complète des fossiles provenant du Cambrien de la région barrandienne déposés au Musée d'Histoire Naturelle de Lille a été établie. La collection comprend deux espèces d'agnostidés, dix trilobites, un brachiopode et un échinoderme ; les fossiles récoltés dans dix affleurements proviennent tous de la Formation Buchava du bassin de Skryje-Týřovice et probablement également de deux affleurements de la Formation Jince du bassin de Příbram-Jince. Une grande partie du matériel a été récoltée par le Professeur Charles Barrois et par le Dr. Louis Dollé (de l'Université de Lille) au cours de l'excursion organisée avant le VIIIème Congrès géologique national à Vienne en 1903. Les autres spécimens, mal documentés, ont été achetés à l'entreprise Krantz à la fin de 19ème siècle et dans les premières années du 20ème siècle. La situation géographique et la stratigraphie des affleurements d'où provient le matériel sont brièvement discutées

Observational evidence that maladaptive gene flow reduces patch occupancy in a wild insect metapopulation

Theory predicts that dispersal throughout metapopulations has a variety of consequences for the abundance and distribution of species. Immigration is predicted to increase abundance and habitat patch occupancy, but gene flow can have both positive and negative demographic consequences. Here, we address the eco-evolutionary effects of dispersal in a wild metapopulation of the stick insect Timema cristinae, which exhibits variable degrees of local adaptation throughout a heterogeneous habitat patch network of two host-plant species. To disentangle the ecological and evolutionary contributions of dispersal to habitat patch occupancy and abundance, we contrasted the effects of connectivity to populations inhabiting conspecific host plants and those inhabiting the alternate host plant. Both types of connectivity should increase patch occupancy and abundance through increased immigration and sharing of beneficial alleles through gene flow. However, connectivity to populations inhabiting the alternate host-plant species may uniquely cause maladaptive gene flow that counters the positive demographic effects of immigration. Supporting these predictions, we find the relationship between patch occupancy and alternate-host connectivity to be significantly smaller in slope than the relationship between patch occupancy and conspecific-host connectivity. Our findings illustrate the ecological and evolutionary roles of dispersal in driving the distribution and abundance of species. This article is protected by copyright. All rights reserved

Ecological character displacement in the face of gene flow: Evidence from two species of nightingales

<p>Abstract</p> <p>Background</p> <p>Ecological character displacement is a process of phenotypic differentiation of sympatric populations caused by interspecific competition. Such differentiation could facilitate speciation by enhancing reproductive isolation between incipient species, although empirical evidence for it at early stages of divergence when gene flow still occurs between the species is relatively scarce. Here we studied patterns of morphological variation in sympatric and allopatric populations of two hybridizing species of birds, the Common Nightingale (<it>Luscinia megarhynchos</it>) and the Thrush Nightingale (<it>L. luscinia</it>).</p> <p>Results</p> <p>We conducted principal component (PC) analysis of morphological traits and found that nightingale species converged in overall body size (PC1) and diverged in relative bill size (PC3) in sympatry. Closer analysis of morphological variation along geographical gradients revealed that the convergence in body size can be attributed largely to increasing body size with increasing latitude, a phenomenon known as Bergmann's rule. In contrast, interspecific interactions contributed significantly to the observed divergence in relative bill size, even after controlling for the effects of geographical gradients. We suggest that the divergence in bill size most likely reflects segregation of feeding niches between the species in sympatry.</p> <p>Conclusions</p> <p>Our results suggest that interspecific competition for food resources can drive species divergence even in the face of ongoing hybridization. Such divergence may enhance reproductive isolation between the species and thus contribute to speciation.</p