Basal dinosauriform and theropod dinosaurs from the mid-late Norian (Late Triassic) of Poland: implications for Triassic dinosaur evolution and distribution

Palaeontology ◽  
2014 ◽  
Vol 57 (6) ◽  
pp. 1121-1142 ◽  
Author(s):  
Grzegorz Niedźwiedzki ◽  
Stephen L. Brusatte ◽  
Tomasz Sulej ◽  
Richard J. Butler
Keyword(s):  
Late Triassic ◽  
Theropod Dinosaurs ◽  
Dinosaur Evolution

scholarly journals A review of Palaeozoic and Mesozoic tetrapods from Greenland

2018 ◽  
Vol 66 ◽  
pp. 21-46 ◽  
Author(s):  
Marco Marzola ◽  
Octávio Mateus ◽  
Jesper Milàn ◽  
Lars B. Clemmensen
Keyword(s):  
Late Jurassic ◽  
Early Jurassic ◽  
Late Carboniferous ◽  
Late Triassic ◽  
Late Devonian ◽  
Early Triassic ◽  
Shallow Marine ◽  
East Greenland ◽  
Marine Deposits ◽  
Theropod Dinosaurs

This article presents a synthesis of Palaeozoic and Mesozoic fossil tetrapods from Greenland, including an updated review of the holotypes and a new photographic record of the main specimens. All fossil tetrapods found are from East Greenland, with at least 30 different known taxa: five stem tetrapods (Acanthostega gunnari, Ichthyostega eigili, I. stensioi, I. watsoni, and Ymeria denticulata) from the Late Devonian of the Aina Dal and Britta Dal Formations; four temnospondyl amphibians (Aquiloniferus kochi, Selenocara groenlandica, Stoschiosaurus nielseni, and Tupilakosaurus heilmani) from the Early Triassic of the Wordie Creek Group; two temnospondyls (Cyclotosaurus naraserluki and Gerrothorax cf. pulcherrimus), one testudinatan (cf. Proganochelys), two stagonolepids (Aetosaurus ferratus and Paratypothorax andressorum), the eudimorphodontid Arcticodactylus, undetermined archosaurs (phytosaurs and both sauropodomorph and theropod dinosaurs), the cynodont Mitredon cromptoni, and three mammals (Haramiyavia clemmenseni, Kuehneotherium, and cf. ?Brachyzostrodon), from the Late Triassic of the Fleming Fjord Formation; one plesiosaur from the Early Jurassic of the Kap Stewart Formation; one plesiosaur and one ichthyosaur from the Late Jurassic of the Kap Leslie Formation, plus a previously unreported Late Jurassic plesiosaur from Kronprins Christian Land. Moreover, fossil tetrapod trackways are known from the Late Carboniferous (morphotype Limnopus) of the Mesters Vig Formation and at least four different morphologies (such as the crocodylomorph Brachychirotherium, the auropodomorph Eosauropus and Evazoum, and the theropodian Grallator) associated to archosaurian trackmakers are known from the Late Triassic of the Fleming Fjord Formation. The presence of rich fossiliferous tetrapod sites in East Greenland is linked to the presence of well-exposed continental and shallow marine deposits with most finds in terrestrial deposits from the Late Devonian and the Late Triassic.

scholarly journals Using step width to compare locomotor biomechanics between extinct, non-avian theropod dinosaurs and modern obligate bipeds

2017 ◽  
Vol 14 (132) ◽  
pp. 20170276 ◽  
Author(s):  
P. J. Bishop ◽  
C. J. Clemente ◽  
R. E. Weems ◽  
D. F. Graham ◽  
L. P. Lamas ◽  
...  
Keyword(s):  
Stride Length ◽  
Direct Evidence ◽  
Bird Species ◽  
Late Triassic ◽  
Step Width ◽  
Abrupt Decrease ◽  
Kinematic Data ◽  
Terrestrial Locomotion ◽  
Theropod Dinosaurs ◽  
Transverse Distance

How extinct, non-avian theropod dinosaurs locomoted is a subject of considerable interest, as is the manner in which it evolved on the line leading to birds. Fossil footprints provide the most direct evidence for answering these questions. In this study, step width—the mediolateral (transverse) distance between successive footfalls—was investigated with respect to speed (stride length) in non-avian theropod trackways of Late Triassic age. Comparable kinematic data were also collected for humans and 11 species of ground-dwelling birds. Permutation tests of the slope on a plot of step width against stride length showed that step width decreased continuously with increasing speed in the extinct theropods ( p < 0.001), as well as the five tallest bird species studied ( p < 0.01). Humans, by contrast, showed an abrupt decrease in step width at the walk–run transition. In the modern bipeds, these patterns reflect the use of either a discontinuous locomotor repertoire, characterized by distinct gaits (humans), or a continuous locomotor repertoire, where walking smoothly transitions into running (birds). The non-avian theropods are consequently inferred to have had a continuous locomotor repertoire, possibly including grounded running. Thus, features that characterize avian terrestrial locomotion had begun to evolve early in theropod history.

scholarly journals Birds and hard ticks (Acari: Ixodidae), with discussions about hypotheses on tick evolution

2017 ◽  
Vol 16 (1) ◽  
pp. 13-29
Author(s):  
Alberto GUGLIELMONE ◽  
Santiago NAVA
Keyword(s):  
Early Cretaceous ◽  
Late Triassic ◽  
Marine Birds ◽  
Hard Ticks ◽  
Theropod Dinosaurs ◽  
Extant Species ◽  
Natural Hosts ◽  
Break Up ◽  
Uncertain Time ◽  
The Relationship

The relationship between birds (Aves) and hard ticks (Ixodidae) was analyzed for the 386 of 725 tick extant species whose larva, nymph and adults are known as well as their natural hosts. A total of 136 (54 Prostriata= Ixodes, 82 Metastriata= all other genera) are frequently found on Aves, but only 32 species (1 associated with Palaeognathae, 31 with Neognathae) have all parasitic stages feeding on birds: 25 Ixodes (19% of the species analyzed for this genus), 6 Haemaphysalis (7%) and 1 species of Amblyomma (2%). The species of Amblyomma feeds on marine birds (MB), the six Haemaphysalis are parasites of non-marine birds (NMB), and 14 of the 25 Ixodes feed on NMB, one feeds on NMB and MB, and ten on MB. The Australasian Ixodes + I. uriae clade probably originated at an uncertain time from the late Triassic to the early Cretaceous. It is speculated that Prostriata first hosts were Gondwanan theropod dinosaurs in an undetermined place before Pangaea break up; alternatively, if ancestral monotromes were involved in its evolution an Australasian origin of Prostriata seems plausible. As for Prostriata the Motherland of Ixodida is probably Gondwana.

BITE MARKS ON AN AETOSAUR (ARCHOSAURIA, SUCHIA) OSTEODERM: ASSESSING LATE TRIASSIC PREDATOR-PREY ECOLOGY THROUGH ICHNOLOGY AND TOOTH MORPHOLOGY

Palaios ◽  
2021 ◽  
Vol 36 (1) ◽  
pp. 28-37
Author(s):  
SUSAN M. DRYMALA ◽  
KENNETH BADER ◽  
WILLIAM G. PARKER
Keyword(s):  
Dorsal Surface ◽  
Terrestrial Ecosystems ◽  
Ventral Surface ◽  
Late Triassic ◽  
Tooth Morphology ◽  
Major Barrier ◽  
Protective Function ◽  
Predator Prey ◽  
Bite Marks ◽  
Theropod Dinosaurs

ABSTRACT Trace fossils such as bite marks provide rare, direct evidence of animal behavior, including predator-prey interactions. We present an osteoderm of the aetosaur Typothorax coccinarum from the Late Triassic Chinle Formation of Arizona with several punctures and scores, interpreted here as bite marks, preserved as evidence of predation/scavenging by a large carnivore. The marks include a single bite producing four subparallel fusiform pits on the ventral surface and several additional marks, including striated scores, on the dorsal surface. These traces are described and compared with known contemporaneous carnivorous taxa to determine the source of the bite marks. Some Triassic carnivores, including theropod dinosaurs can be ruled out because of tooth shape and serration densities. Phytosaurs and large paracrocodylomorphs remain as likely candidates based on tooth morphology. Although some phytosaur teeth are too rounded to produce the marks seen in this specimen, we demonstrate that the more lingually flattened teeth typically found in the posterior section of the snout are sufficiently mediolaterally compressed to produce a fusiform pit. A protective function for aetosaur osteoderms cannot be confirmed presently, but the extensive carapace these bones formed would have been a major barrier to both scavengers and active predators and may preserve more feeding/predation traces than previously thought. The bite marks described herein support the hypothesis that aetosaurs were prey items of large archosauromorphs, expanding our understanding of the complex, and seemingly carnivore dominated Late Triassic terrestrial ecosystems of North America.

scholarly journals A palaeoequatorial ornithischian and new constraints on early dinosaur diversification

2014 ◽  
Vol 281 (1791) ◽  
pp. 20141147 ◽  
Author(s):  
Paul M. Barrett ◽  
Richard J. Butler ◽  
Roland Mundil ◽  
Torsten M. Scheyer ◽  
Randall B. Irmis ◽  
...  
Keyword(s):  
South America ◽  
Growth Rates ◽  
Mass Extinction ◽  
Fossil Record ◽  
Early Jurassic ◽  
Late Triassic ◽  
Evolution Of Sociality ◽  
Northern South America ◽  
Dinosaur Evolution ◽  
Broad Scale

Current characterizations of early dinosaur evolution are incomplete: existing palaeobiological and phylogenetic scenarios are based on a fossil record dominated by saurischians and the implications of the early ornithischian record are often overlooked. Moreover, the timings of deep phylogenetic divergences within Dinosauria are poorly constrained owing to the absence of a rigorous chronostratigraphical framework for key Late Triassic–Early Jurassic localities. A new dinosaur from the earliest Jurassic of the Venezuelan Andes is the first basal ornithischian recovered from terrestrial deposits directly associated with a precise radioisotopic date and the first-named dinosaur from northern South America. It expands the early palaeogeographical range of Ornithischia to palaeoequatorial regions, an area sometimes thought to be devoid of early dinosaur taxa, and offers insights into early dinosaur growth rates, the evolution of sociality and the rapid tempo of the global dinosaur radiation following the end-Triassic mass extinction, helping to underscore the importance of the ornithischian record in broad-scale discussions of early dinosaur history.

scholarly journals The first 50 Myr of dinosaur evolution: macroevolutionary pattern and morphological disparity

2008 ◽  
Vol 4 (6) ◽  
pp. 733-736 ◽  
Author(s):  
Stephen L Brusatte ◽  
Michael J Benton ◽  
Marcello Ruta ◽  
Graeme T Lloyd
Keyword(s):  
Taxonomic Diversity ◽  
Early Jurassic ◽  
Late Triassic ◽  
Steady Increase ◽  
Morphological Disparity ◽  
Ecological Release ◽  
Driving Mechanisms ◽  
Faunal Abundance ◽  
Evolutionary Radiation ◽  
Dinosaur Evolution

The evolutionary radiation of dinosaurs in the Late Triassic and Early Jurassic was a pivotal event in the Earth's history but is poorly understood, as previous studies have focused on vague driving mechanisms and have not untangled different macroevolutionary components (origination, diversity, abundance and disparity). We calculate the morphological disparity (morphospace occupation) of dinosaurs throughout the Late Triassic and Early Jurassic and present new measures of taxonomic diversity. Crurotarsan archosaurs, the primary dinosaur ‘competitors’, were significantly more disparate than dinosaurs throughout the Triassic, but underwent a devastating extinction at the Triassic–Jurassic boundary. However, dinosaur disparity showed only a slight non-significant increase after this event, arguing against the hypothesis of ecological release-driven morphospace expansion in the Early Jurassic. Instead, the main jump in dinosaur disparity occurred between the Carnian and Norian stages of the Triassic. Conversely, dinosaur diversity shows a steady increase over this time, and measures of diversification and faunal abundance indicate that the Early Jurassic was a key episode in dinosaur evolution. Thus, different aspects of the dinosaur radiation (diversity, disparity and abundance) were decoupled, and the overall macroevolutionary pattern of the first 50 Myr of dinosaur evolution is more complex than often considered.

The roles of herbivory and omnivory in early dinosaur evolution

2010 ◽  
Vol 101 (3-4) ◽  
pp. 383-396 ◽  
Author(s):  
Paul M. Barrett ◽  
Richard J. Butler ◽  
Sterling J. Nesbitt
Keyword(s):  
Relative Abundance ◽  
Competitive Interactions ◽  
Late Triassic ◽  
Current Evidence ◽  
Faunal Turnover ◽  
Rapid Diversification ◽  
Ecological Dominance ◽  
Dinosaur Evolution ◽  
Carnian Stage ◽  
Trophic Specialisation

ABSTRACTHerbivorous and omnivorous dinosaurs were rare during the Carnian stage of the Late Triassic. By contrast, the succeeding Norian stage witnessed the rapid diversification of sauropodomorphs and the rise of the clade to ecological dominance. Ornithischians, by contrast, remained relatively rare components of dinosaur assemblages until much later in the Mesozoic. The causes underlying the differential success of ornithischians and sauropodomorphs remain unclear, but might be related to trophic specialisation. Sauropodomorphs replaced an established herbivore guild consisting of rhynchosaurs, aetosaurs and basal synapsids, but this faunal turnover appears to have been opportunistic and cannot be easily attributed to either competitive interactions or responses to floral change. Consideration of diversity patterns and relative abundance suggests that the ability to eat plants might have been a major factor promoting sauropodomorph success, but that it was less important in the early evolution of Ornithischia. On the basis of current evidence it is difficult to determine the diet of the ancestral dinosaur and scenarios in which omnivory or carnivory represent the basal condition appear equally likely.

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