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A new genus of palaeomacromiid dragonflies, Curviarculia , based on Curviarculia delicata sp. nov. and Curviarculia lamasi sp. nov., is erected from the upper Paleocene Maíz Gordo Formation of north–western Argentina. Phylogenetic relationships within Palaeomacromiidae are discussed, leading to a new family diagnosis. 相似文献
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A new family of dragonflies, Palaeomacromiidae, based on Palaeomacromia multicellulata gen. et sp. nov., is described from the Late Paleocene Maíz Gordo Formation of north-western Argentina. The present discovery demonstrates that the present knowledge of the Early Cenozoic insect fauna of the Neotropical region remains very poor. 相似文献
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A new family of damselflies, based on Latibasalia elongata gen. et sp. nov. and L. quispeae gen. et sp. nov., is erected from the Upper Palaeocene Maíz Gordo Formation, north-western Argentina. Latibasaliidae fam. nov. can be included in the Zygoptera: Caloptera: Eucaloptera: Amphipterygida: Amphipterygoidea. Its phylogenetic relationships within the clade Eucaloptera Bechly, 1996 are discussed. Within Amphipterygoidea, Latibasaliidae could be closely related to Pseudolestidae or to the 'thaumatoneurid' genera Petrolestes and Congqingia because they share the absence of secondary antenodal crossveins of first and second rows and the absence of antesubnodal crossveins. These characters could be potential synapomorphies of these taxa but they are somewhat homoplastic within the Zygoptera. 相似文献
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A new genus and species of “libellulid” dragonfly, Austrolibellula noroestenia nov. gen., nov. sp., of the group Italoansida BECHLY, 1996, is described. The specimen comes from the Maíz Gordo Formation (late Paleocene) that crops out in northwestern Argentina. Its phylogenetic relationships within Cavilabiata BECHLY, 1996 are discussed. 相似文献
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The lower slope of the drowned Alpine Adnet Reef was recolonized in Hettangian time by sponge communities of hexactinellid (hexactinosid and lyssacinosid) taxa and a few demosponges. Special taphonomic processes caused an excellent preservation of these sponges. The preservation allows to define several growth forms and to study original spicule configurations of the mainly non-rigid skeletons. Sponge faunas of presumably similar associations are known from adjacent basins, but only by isolated spicules of completely collapsed specimens. In Adnet the sponges are embedded in biodetrital limestones of the Schnöll Formation. Orientation and distribution of the sponges reflect autochthonous faunas that have been mixed with dislocated individuals by local water currents. The predominance of erect sponge types indicates intermediate sedimentation rates and/or occasional high-energy events. Sponge types and community structures are comparable with those ones from Middle Paleozoic mud mounds. Several hiatuses, mostly characterized by ferromanganese crusts have been kept free of sponge settlement. Carbon stable isotopes of the sponge-rich sequence show a small negative δ13Ccarb excursion that covers the period from Lower Hettangian to Lower Sinemurian.This revised version was published online in May 2005 because several displayed passages had been inadvertently deleted in the original published version. 相似文献
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Abstract: The partial, articulated skeleton of a pleurodiran turtle from the Nova Olinda Member of the Crato Formation (Araripe Basin) of north-east Brazil displays an impression of the outline of the soft tissues surrounding the left hind limb. The external mould of the soft tissue surface preserves only the gross morphology of the limb although the outline of the limb is well defined. It appears to be an external mould of the limb's surface, which formed prior to the decay of the integument. The limb skeleton is mostly fully articulated. This style of preservation is comparable with the mouldic preservation found in such famous fossils as the feathered Archaeopteryx specimens of the Solnhofen limestone. Although soft-tissue preservation is occasionally encountered in the Crato Formation, this is the first documented occurrence of mouldic preservation of body outline reported for this Konservat-Lagerstätten. The new specimen is referred to the pelomedusoid Araripemys and represents a new species, A. arturi sp. nov., which is described here. 相似文献
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Abstract: Soft-tissue preservation of the hind gut, or anal sac, in the tegmen of Tubulusocrinus (gen. nov.) doliolus (Wright) from the Mississippian (Visean, Asbian) Pittenweem Formation at St Andrews, Scotland, is the first of its kind known in crinoids; it sheds important new light on the nature of the cladid tegmen. Many cladid crinoids had a calcite-plated anal sac that may have functioned like a chimney to prevent fouling of the ambulacra. The tubular, uncalcified anal sac of Tubulusocrinus may have functioned like a hose by pointing down current between the arms to avoid fouling of the ambulacra. Its smaller size may also have required less energy to produce than a heavy-plated sac. The hind gut is apparently preserved by haematite replacement, which was probably altered from original authigenic pyrite that formed soon after catastrophic burial. 相似文献