Results 31 to 40 of about 3,435 (159)

A reappraisal of the Italian record of the Cretaceous pachycormid fish Protosphyraena Leidy, 1857 [PDF]

, 2017
The genus Protosphyraena is known mainly from partial remains, consisting of isolated blade-like teeth, conical rostra and scythe-like pectoral fins. This paper provides a new insight into partial specimens of the genus Protosphyraena from the Cretaceous
Amalfitano, Jacopo, Carnevale, Giorgio, Fornaciari, Eliana, Giusberti, Luca   +3 more
core   +3 more sources

New craniodental materials of Falcarius utahensis (Theropoda: Therizinosauria) reveal patterns of intraspecific variation and cranial evolution in early coelurosaurians

The Anatomical Record, EarlyView.
Abstract Despite documented ecomorphological shifts toward an herbivorous diet in several coelurosaurian lineages, the evolutionary tempo and mode of these changes remain poorly understood, hampered by sparse cranial materials for early representatives of major clades. This is particularly true for Therizinosauria, with representative crania best known
William J. Freimuth, Lindsay E. Zanno
wiley   +1 more source

Dental crown morphological variation and heterodonty in carcharhiniform sharks

The Anatomical Record, EarlyView.
Abstract Elasmobranch teeth are highly mineralized structures that constitute the majority of the fossil record for this group. Despite their taxonomic and evolutionary significance, detailed descriptions of dental morphology remain scarce. The order Carcharhiniformes, the most diverse among sharks, comprises 304 valid species that display remarkable ...
Flávia Zanini, Karla D. A. Soares
wiley   +1 more source

Comparative cranial biomechanics reveal macroevolutionary trends in theropod dinosaurs, with emphasis on Tyrannosauroidea

The Anatomical Record, EarlyView.
Abstract Tyrannosaurus is viewed as a model organism in vertebrate paleontology, with numerous studies analyzing its feeding biomechanics. Nonetheless, the evolution of this feeding performance has been under‐addressed in Tyrannosauroidea, especially in basal tyrannosauroids. Here we used muscle‐force reconstruction and finite element analysis (FEA) to
Evan Johnson‐Ransom, Paul Gignac, Daniel E. Barta, Ryan N. Felice, Eric Snively   +4 more
wiley   +1 more source

Simulated ocean acidification affects shark tooth morphology

Frontiers in Marine Science
Changing ecological factors pose a challenge to many organisms. Global changes and the associated environmental changes have major impacts on marine organisms and threaten the biodiversity of marine ecosystems.
Maximilian Baum, Timo Haussecker, Oliver Walenciak, Steffen Köhler, Christopher R. Bridges, Sebastian Fraune   +5 more
doaj   +1 more source

Redescription of the Triassic cynodont Cistecynodon parvus and reassessment of its phylogeny

The Anatomical Record, EarlyView.
Abstract Cynodontia is an important subclade of Therapsida that first occurred in the late Permian. It includes extinct subclades which are the non‐mammaliaform cynodonts and Mammaliaformes, with the latter ultimately giving rise to crown mammals. The systematics of non‐mammaliaform cynodonts has been extensively studied and is relatively well‐resolved,
Erin S. Lund, Frederik P. Wolvaardt, Roger M. H. Smith, Jaganmoy Jodder, Julien Benoit   +4 more
wiley   +1 more source

Selachian faunas from the earliest Cretaceous Purbeck Group of Dorset, southern England. [PDF]

, 2002
Abundant selachian remains have been recovered from a number of horizons through the Purbeck Group at Durlston Bay, Lulworth Cove and Stair Hole in southern England.
Rees, J., Underwood, Charlie J.
core  

Scaling Behaviour and Complexity of the Portevin-Le Chatelier Effect

, 2006
The plastic deformation of dilute alloys is often accompanied by plastic instabilities due to dynamic strain aging and dislocation interaction. The repeated breakaway of dislocations from and their recapture by solute atoms leads to stress serrations and
A. SARKAR, Baird J. D., Brindley B. J., Cottrell A. H., Cottrell A. H., Gnedenko B. V., Le Chatelier F., Mandelbort B. B., Masson A. M., P. BARAT, Pincus S. M., Pink E., Portevin A., Richman J. S., Savart F.   +14 more
core   +1 more source

Evolutionary radiation of large‐bodied gorgonopsians from the lower Abrahamskraal formation of South Africa

The Anatomical Record, EarlyView.
Abstract The middle Permian represents a critical interval in therapsid evolution, when gorgonopsians emerged as some of the first specialized apex predators within terrestrial ecosystems. Despite their significance, the early diversification of Gorgonopsia in Gondwana remains poorly understood due to scarcity and fragmentary material.
Zanildo Macungo, Ricardo Araújo, Bruce S. Rubidge, Michael O. Day, Kathleen N. Dollman, Julien Benoit   +5 more
wiley   +1 more source

Hybrid fuzzy- proportionl integral derivative controller (F-PID-C) for control of speed brushless direct curren motor (BLDCM) [PDF]

, 2017
Hybrid Fuzzy proportional-integral-derivative (PID) controllers (F-PID-C) is designed and analyzed for controlling speed of brushless DC (BLDC) motor. A simulation investigation of the controller for controlling the speed of BLDC motors is performed to ...
Farag A. M., Elkarghali
core