Instytut Zoologii Uniwersytetu Warszawskiego
Instytut Zoologii Uniwersytetu Warszawskiego
Sulej T.,Instytut Paleobiologii PAN |
Bronowicz R.,Wydzial Geologii Uniwersytetu Warszawskiego |
Talanda M.,Instytut Zoologii Uniwersytetu Warszawskiego |
Niedzwiedzki G.,Instytut Paleobiologii PAN
Earth and Environmental Science Transactions of the Royal Society of Edinburgh | Year: 2010
This paper reports a new assemblage from the Late Triassic (mid-late Carnian) at Woźniki near Czêstochowa (Poland). The Woźniki vertebrate assemblage is similar to that of Lisowice-Lipie Sulâskie, a new locality bearing vertebrates from latest Triassic (latest Norian-early Rhaetian) strata of southern Poland, in the presence of dicynodonts, shark spines, plagiosaurs and a cyclotosaur, but conchostracans and bivalves are similar to those from the Krasiejów site (late Carnian). The most complete specimen from Woźniki belongs to a dicynodont, and consists of cranial and postcranial bones of a single individual. It demonstrates that large dicynodonts were part of the Late Triassic vertebrate assemblage in Central Europe. Numerous tetrapod tracks and traces are associated with skeletal fossils at Woźniki. © 2011 The Royal Society of Edinburgh.
Dzik J.,Instytut Paleobiologii PAN |
Sulej T.,Instytut Zoologii Uniwersytetu Warszawskiego |
Niedzwiedzki G.,Instytut Zoologii Uniwersytetu Warszawskiego
Historical Biology | Year: 2010
Organic tissue of a recently found second specimen of feather-like Praeornis from the Karabastau Formation of the Great Karatau Range in southern Kazakstan, has a stable carbon isotope composition indicative of its animal affinity. Three-dimensional preservation of its robust carbonised shaft indicates original high contents of sclerotic organic matter, which makes the originally proposed interpretation of Praeornis as a keratinous integumental structure likely. The new specimen is similar to the holotype of Praeornis in the presence of three 'vanes' on a massive shaft not decreasing in width up to near its tip. Unlike it, the vanes are not subdivided into barbs and the pennate structure is expressed only in the distribution of organic-matter-rich rays. Similar continuous blades border the 'barbs' in the holotype, but the organic matter was removed from them by weathering. It is proposed that the three-vaned structure is a remnant of the ancestral location of scales along the dorsum and their original function in sexual display, similar to that proposed for the Late Triassic probable megalancosaurid Longisquama. Perhaps subsequent rotation around the shaft, in the course of evolution from an ancestral status similar to Praeornis towards the present aerodynamic and protective function of feathers, resulted in the tubular appearance of their buds. © 2010 Taylor & Francis.
Skawina A.,Instytut Zoologii Uniwersytetu Warszawskiego |
Dzik J.,Instytut Zoologii Uniwersytetu Warszawskiego
Zoological Journal of the Linnean Society | Year: 2011
Exceptionally well-preserved Late Triassic unionoids from Silesia, Poland, show prominently ornamented juvenile shells and umbonal muscle attachments that are similar to Margaritifera, which are anatomically the least derived among extant unionoids. Their phosphatized (originally chitinous and impregnated with calcium phosphate) gill supports lacked transverse connections, and occasionally some of them were separated from others, being thus at the filibranch grade, like their trigonioid ancestors. Several separate small foot elevator attachments in these unionoids indicate Trigonodidae adaptation to marine or brackish water, in which the original trigonioid strong single attachment was already split into two in the Early Triassic. The ribbing of juvenile shells suggests a change to deeper infaunal life for juvenile stages, and generally less efficient near-surface locomotion, with a wedge-like foot, in adults. Much later the unionoids became eulamellibranchial, which promoted the brooding of the fish that their larvae parasitize. To accomodate the classification of the order under this scenario of evolutionary changes, a new suborder Silesunionina is proposed for its filibranch members. It includes the Silesunionidae fam. nov., with the location of umbonal muscles similar to that in the extant underived unionoids, and the Unionellidae fam. nov., with umbonal muscles attached to the external wall of the umbonal cavity. The early Late Triassic (Carnian) Silesunio parvus gen. et sp. nov. and latest Triassic (Rhaetian) Tihkia(?) silesiaca sp. nov. are proposed. © 2011 The Linnean Society of London.