Results 21 to 30 of about 2,538 (164)

Ontogeny and miniaturization of Alvarezsauridae (Dinosauria, Theropoda)

open access: yesBiological Communications, 2023
The ontogenetic status of the known specimens of alvarezsaurid theropod dinosaurs is revised. We present histological data that the holotype of Parvicursor remotus from the Upper Cretaceous Barungoyot Formation of Mongolia is not an adult individual, as ...
Alexander Averianov   +2 more
semanticscholar   +1 more source

Multiple optimality criteria support Ornithoscelida [PDF]

open access: yesRoyal Society Open Science, 2017
A recent study of early dinosaur evolution using equal-weights parsimony recovered a scheme of dinosaur interrelationships and classification that differed from historical consensus in a single, but significant, respect; Ornithischia and Saurischia were ...
Luke A. Parry   +2 more
doaj   +1 more source

New Late Cretaceous microvertebrate assemblage from the Campanian–Maastrichtian Williams Fork Formation, northwestern Colorado, USA, and its paleoenvironmental implications

open access: yesActa Palaeontologica Polonica, 2022
We describe a microvertebrate assemblage from the J&M site, of the Upper Cretaceous (Campanian–Maastrichtian) Williams Fork Formation. Breakdown of fossil bearing matrix was achieved with the use of heated dimethyl sulfoxide.
NICKOLAS A. BRAND   +5 more
doaj   +1 more source

Novel neuroanatomical integration and scaling define avian brain shape evolution and development

open access: yeseLife, 2021
How do large and unique brains evolve? Historically, comparative neuroanatomical studies have attributed the evolutionary genesis of highly encephalized brains to deviations along, as well as from, conserved scaling relationships among brain regions ...
Akinobu Watanabe   +4 more
doaj   +1 more source

New information on ornithopod dinosaurs from the Late Jurassic of Portugal [PDF]

open access: yesActa Palaeontologica Polonica, 2020
retaceous–Paleogene boundary. However, most of the attention has been given to derived forms (hadrosaurids). Herein, cranial and post-cranial ornithopod material from the Upper Jurassic Lourinhã Formation and housed at Museu da Lourinhã is described and ...
Filippo Maria Rotatori   +2 more
doaj   +1 more source

Ontogeny and variation in the skull roof and braincase of the hadrosaurid dinosaur Maiasaura peeblesorum from the Upper Cretaceous of Montana, USA [PDF]

open access: yesActa Palaeontologica Polonica, 2021
Five new partial skulls of the hadrosaurid dinosaur Maiasaura peeblesorum from the Linster Quarry bone bed (Two Medicine Formation, Campanian) in Montana, USA, provide the basis for a description of the skull roof and braincase morphology of this taxon ...
BRADLEY MCFEETERS   +2 more
doaj   +1 more source

A new titanosaurian (Dinosauria: Sauropoda) from the Upper Cretaceous (Campanian) Quseir Formation of the Kharga Oasis, Egypt

open access: yesJournal of Vertebrate Paleontology, 2022
Dinosaur fossils from the latest Cretaceous (Campanian–Maastrichtian) of Africa and the Arabian Peninsula are rare. Most discoveries to date have consisted of limited fossils that have precluded detailed phylogenetic and paleobiogeographic ...
E. Gorscak   +6 more
semanticscholar   +1 more source

New Iguanodon bernissartensis Axial Bones (Dinosauria, Ornithopoda) from the Early Cretaceous of Morella, Spain

open access: yesDiversity, 2022
Iguanodon bernissartensis is the most frequently and widely cited styracosternan ornithopod in Western Europe during the Early Cretaceous, although some of these assignments likely need to be revised to establish the true distribution of the taxon. Here,
J. M. Gasulla   +4 more
semanticscholar   +1 more source

A new, ‘hip’ way to breathe

open access: yeseLife, 2021
Ornithischians, one of the three major groups of dinosaurs, developed a unique mechanism to ensure airflow in the lungs.
Marc R Spencer
doaj   +1 more source

Why tyrannosaurid forelimbs were so short: An integrative hypothesis [PDF]

open access: yesActa Palaeontologica Polonica, 2022
The unusually shortened limbs of giant theropods, including abelisaurids, carcharodontosaurids, and derived tyrannosauroids such as Tyrannosaurus rex have long been an object of wonder, speculation, and even derision on the part of both ...
KEVIN PADIAN
doaj   +1 more source

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