| 1. |
- Bajdek, Piotr, et al.
(författare)
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Residues from the Upper Permian carnivore coprolites from Vyazniki in Russia - key questions in reconstruction of feeding habits
- 2017
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Ingår i: Palaeogeography, Palaeoclimatology, Palaeoecology. - : ELSEVIER SCIENCE BV. - 0031-0182 .- 1872-616X. ; 482, s. 70-82
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Tidskriftsartikel (refereegranskat)abstract
- Residues of twenty-five coprolite fragments collected from the Upper Permian of Vyazniki (European Russia) were studied in detail. The phosphatic composition, general shape and size, and bone inclusions of these specimens indicate that medium to large-sized carnivores, such as therocephalian therapsids or early archosauriforms, were the most likely coprolite producers. The contents of the examined fossils (i.e. Scale, bone and tooth fragments, mineral grains, and microbial structures) do not differ significantly among the samples, implying fairly comparable feeding habits of their producers. Fragments of large tooth crowns in two of the analyzed samples imply that either (1) the coprolite producer swallowed the cranial elements of its prey or (2) the coprolite producer broke and swallowed its own tooth while feeding (such tooth damage is known in archosaurs that have tooth replacement, e.g. crocodiles and dinosaurs). Indeed, the most complete tooth fragment in these fossils is serrated, most likely belonging to an early archosauriform known from skeletal records from the Late Permian of Vyaznilci. Another coprolite fragment contains the etched tooth of a lungfish, while putative actinopterygian fish remains (scales and small fragments of bones) are abundant in some samples. Mineral particles (mostly quartz grains, feldspars and mica) may have been swallowed accidentally. The preserved microbial colonies (mineralized fossil fungi and bacteria or their pseudomorphs), manifested in the coprolites as Fe-rich mineral structures, seem to have developed on the expelled feces rather than on the items before they were swallowed.
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| 2. |
- Blazcjowski, Blazcj, et al.
(författare)
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Limulitella tejraensis, a new species of limulid (Chelicerata, Xiphosura) from the Middle Triassic of southern Tunisia (Saharan Platform)
- 2017
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Ingår i: Journal of Paleontology. - : Cambridge University Press (CUP). - 0022-3360 .- 1937-2337. ; 91:5, s. 960-967
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Tidskriftsartikel (refereegranskat)abstract
- Numerous well-preserved remains of a new limulid species from the Anisian-lower Ladinian (Middle Triassic) of the Tejra section of southern Tunisia are described. Comparisons are made with limulids from the Triassic deposits of Europe and Australia. The new specimens are congeneric with the type species of Limulitella, but show some morphological differences. Here we describe Limulitella tejraensis new species, a small limulid with semicircular prosoma, small and triangular opisthosoma, well-defined axial ridge, and pleurae along both ridges of the opisthosoma. The Tunisian Limulitella fossils are associated with conchostracans, bivalves, gastropods, and microconchids. Sedimentological and paleontological data from the Tejra section suggest freshwater to brackish-water conditions during the formation of the fossil-bearing interval and the influence of marine transgression into a playa-like environment. Supposed adaptation to the stressful environment sheds new light on the origin and survival of the extant limulines. This is the first report of limulid body fossils from the Triassic of North Africa and the first documentation of Limulitella in the Middle Triassic of northern Gondwanaland.
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| 3. |
- Gierlinski, Gerard D., et al.
(författare)
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Possible hominin footprints from the late Miocene (c. 5.7 Ma) of Crete?
- 2017
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Ingår i: Proceedings of the Geologists' Association. - : Elsevier BV. - 0016-7878. ; 128:5-6, s. 697-710
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Tidskriftsartikel (refereegranskat)abstract
- We describe late Miocene tetrapod footprints (tracks) from the Trachilos locality in western Crete (Greece), which show hominin-like characteristics. They occur in an emergent horizon within an otherwise marginal marine succession of Messinian age (latest Miocene), dated to approximately 5.7 Ma (million years), just prior to the Messinian Salinity Crisis. The tracks indicate that the trackmaker lacked claws, and was bipedal, plantigrade, pentadactyl and strongly entaxonic. The impression of the large and non-divergent first digit (hallux) has a narrow neck and bulbous asymmetrical distal pad. The lateral digit impressions become progressively smaller so that the digital region as a whole is strongly asymmetrical. A large, rounded ball impression is associated with the hallux. Morphometric analysis shows the footprints to have outlines that are distinct from modern non-hominin primates and resemble those of hominins. The interpretation of these footprints is potentially controversial. The print morphology suggests that the trackmaker was a basal member of the Glade Hominini, but as Crete is some distance outside the known geographical range of pre-Pleistocene hominins we must also entertain the possibility that they represent a hitherto unknown late Miocene primate that convergently evolved human-like foot anatomy.
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| 4. |
- Nesbitt, Sterling J., et al.
(författare)
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The earliest bird-line archosaurs and the assembly of the dinosaur body plan
- 2017
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Ingår i: Nature. - : NATURE PUBLISHING GROUP. - 0028-0836 .- 1476-4687. ; 544:7651, s. 484-
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Tidskriftsartikel (refereegranskat)abstract
- The relationship between dinosaurs and other reptiles is well established(1-4), but the sequence of acquisition of dinosaurian features has been obscured by the scarcity of fossils with transitional morphologies. The closest extinct relatives of dinosaurs either have highly derived morphologies(5-7) or are known from poorly preserved(8,9) or incomplete material(10,11). Here we describe one of the stratigraphically lowest and phylogenetically earliest members of the avian stem lineage (Avemetatarsalia), Teleocrater rhadinus gen. et sp. nov., from the Middle Triassic epoch. The anatomy of T. rhadinus provides key information that unites several enigmatic taxa from across Pangaea into a previously unrecognized clade, Aphanosauria. This clade is the sister taxon of Ornithodira (pterosaurs and birds) and shortens the ghost lineage inferred at the base of Avemetatarsalia. We demonstrate that several anatomical features long thought to characterize Dinosauria and dinosauriforms evolved much earlier, soon after the bird-crocodylian split, and that the earliest avemetatarsalians retained the crocodylian-like ankle morphology and hindlimb proportions of stem archosaurs and early pseudosuchians. Early avemetatarsalians were substantially more species-rich, widely geographically distributed and morphologically diverse than previously recognized. Moreover, several early dinosauromorphs that were previously used as models to understand dinosaur origins may represent specialized forms rather than the ancestral avemetatarsalian morphology.
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| 5. |
- Niedźwiedzki, Grzegorz, 1980-, et al.
(författare)
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Middle-Upper Triassic and Middle Jurassic tetrapod track assemblages of southern Tunisia, Sahara Platform
- 2017
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Ingår i: Journal of African Earth Sciences. - : PERGAMON-ELSEVIER SCIENCE LTD. - 1464-343X .- 1879-1956. ; 129, s. 31-44
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Tidskriftsartikel (refereegranskat)abstract
- Three tetrapod track assemblages from the early-middle Mesozoic of southern Tunisia are reported. The strata exposed at the Tejra 2 clay-pit near the Medenine and Rehach site, located in the vicinity of Kirchaou, contain the first tetrapod tracks found in the Triassic of Tunisia. The Middle Jurassic (early Aalenian) dinosaur tracks are reported from the Mestaoua plain near Tataouine. In the Middle Triassic outcrop of the Tejra 2 clay-pit, tridactyl tracks of small and medium-sized dinosauromorphs, were discovered. These tracks represent the oldest evidence of dinosaur-lineage elements in the Triassic deposits of Tunisia. Similar tracks have been described from the Middle Triassic of Argentina, France and Morocco. An isolated set of the manus and pes of a quadrupedal tetrapod discovered in Late Triassic Rehach tracksite is referred to a therapsid tracemaker. The Middle Jurassic deposits of the Mestaoua plain reveal small and large tridactyl theropod dinosaur tracks (Theropoda track indet. A-C). Based on comparison with the abundant record of Triassic tetrapod ichnofossils from Europe and North America, the ichnofauna described here indicates the presence of a therapsid-dinosauromorph ichnoassociation (without typical Chirotheriidae tracks) in the Middle and Late Triassic, which sheds light on the dispersal of the Middle-Upper Triassic tetrapod ichnofaunas in this part of Gondwana. The reported Middle Jurassic ichnofauna show close similarities to dinosaur track assemblages from the Lower and Middle Jurassic of northwestern Africa, North America, Europe and also southeastern Asia. Sedimentological and lithostratigraphic data of each new tracksite have been defined on published data and new observations. Taken together, these discoveries present a tantalizing window into the evolutionary history of tetrapods from the Triassic and Jurassic of southern Tunisia. Given the limited early Mesozoic tetrapod record from the region, these discoveries are of both temporal and geographic significance.
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| 6. |
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| 7. |
- Qvarnström, Martin, et al.
(författare)
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Synchrotron phase-contrast microtomography of coprolites generates novel palaeobiological data
- 2017
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Ingår i: Scientific Reports. - : Nature Publishing Group. - 2045-2322. ; 7
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Tidskriftsartikel (refereegranskat)abstract
- Coprolites (fossil faeces) reveal clues to ancient trophic relations, and contain inclusions representing organisms that are rarely preserved elsewhere. However, much information is lost by classical techniques of investigation, which cannot find and image the inclusions in an adequate manner. We demonstrate that propagation phase-contrast synchrotron microtomography (PPC-SR mu CT) permits high-quality virtual 3D-reconstruction of coprolite inclusions, exemplified by two coprolites from the Upper Triassic locality Krasiejow, Poland; one of the coprolites contains delicate beetle remains, and the other one a partly articulated fish and fragments of bivalves.
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| 8. |
- Skawinski, Tomasz, et al.
(författare)
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A re-evaluation of the historical "dinosaur' remains from the Middle-Upper Triassic of Poland
- 2017
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Ingår i: Historical Biology. - : TAYLOR & FRANCIS LTD. - 0891-2963 .- 1029-2381. ; 29:4, s. 442-472
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Forskningsöversikt (refereegranskat)abstract
- The so-called historical Polish discoveries of Triassic dinosaurs' have been repeatedly cited in papers and popular science books. Here, we re-evaluate each historical and purported Triassic dinosaur find from Poland. Additionaly, we describe several supposed dinosaur' bones collected by Polish geologists but only briefly mentioned: in regional geological journals, on collection labels, or in field notes. We attempt to assign all investigated specimens to the least inclusive taxon possible. Our revision indicates that part of this material represents non-dinosaur archosauromorph taxa. Most of the analysed specimens are fragmentary bones or isolated teeth and are indistinguishable from skeletal elements described from other well-known Triassic archosauromorph taxa. We conclude that fossils of dinosauriforms are present in the Upper Triassic of Silesia and Holy Cross Mountains. New analysis of Velocipes guerichi von Huene, 1932 holotype specimen from Kocury shows that it is the proximal part of fibula of a medium-sized theropod (or even neotheropod). Formally undescribed part of dinosauriform limb bone from the Holy Cross Mountains and V. guerichi from Silesia are the only identifiable dinosauromorph skeletal remains recognised in the Polish Triassic discovered prior to the description of Silesaurus opolensis Dzik, 2003 from the Upper Carnian of Krasiejow.
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| 9. |
- Talanda, Mateusz, et al.
(författare)
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Upper Triassic freshwater oncoids from Silesia (southern Poland) and their microfossil biota
- 2017
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Ingår i: Neues Jahrbuch für Geologie und Palaontologie - Abhandlungen. - : E SCHWEIZERBARTSCHE VERLAGSBUCHHANDLUNG. - 0077-7749. ; 284:1, s. 43-56
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Tidskriftsartikel (refereegranskat)abstract
- Oncoids are rare components of Keuper sediments across Europe. The exceptions are localities linked to the Upper Triassic "Wozniki Limestone" (formally Limestone Member from Wozniki) in Silesia, southern Poland. Numerous oncoids occur in breccia-like deposits in the Lipie Slaskie clay pit at Lisowice. The oncoid-bearing level is underlying by organic-rich carbonaceous mudstone and siltstone and covered by non-carbonaceous sandstone and grey wacke sandstone-mudstone heterolithic deposits. The oncoids are of various shapes and are built by agglutinated or skeletal stromatolites composed of a rhythmically grown dendroid micropeloidal framework. The agglutinated stromatolites are poor in microfabrics. The oncoids consist of a smooth or granular outer part and distinct core (carbonate, carbon-rich or phosphate), which may be a fossil (bivalve shell, wood fragment, charcoal piece, carbon-rich coprolite or hone fragment). Dark laminae of the cortex are carbonate-rich, whereas the light ones are silica-rich. They exhibit remains of bacterial/cyanobacterial filaments, as well as some rare and not well-discernible palynomorphs. Ostracods (cf. Darwinula sp.), small fragments of vertebrate bones (mainly fish remains), fragments of wood, plant cuticles and fragments of unionoid bivalves are associated with the oncoid accumulations. Thus, they may have been formed in a shallow freshwater environment and were buried by rapid flood events or mud runoff.
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| 10. |
- Zaton, Michal, et al.
(författare)
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The first direct evidence of a Late Devonian coelacanth fish feeding on conodont animals
- 2017
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Ingår i: The Science of Nature. - : Springer Berlin/Heidelberg. - 0028-1042 .- 1432-1904. ; 104:3-4
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Tidskriftsartikel (refereegranskat)abstract
- We describe the first known occurrence of a Devonian coelacanth specimen from the lower Famennian of the Holy Cross Mountains, Poland, with a conodont element preserved in its digestive tract. A small spiral and phosphatic coprolite (fossil excrement) containing numerous conodont elements and other unrecognized remains was also found in the same deposits. The coprolite is tentatively attributed to the coelacanth. Although it is unclear whether the Late Devonian coelacanth from Poland was an active predator or a scavenger, these finds provide the first direct evidence of feeding on conodont animals by early coelacanth fish, and one of the few evidences of feeding on these animals known to date. It also expands our knowledge about the diet and trophic relations between the Paleozoic marine animals in general.
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