author={Julia A. Clarke},
  • J. Clarke
  • Published 2004
  • Biology, Environmental Science
Abstract Charles Darwin commented that Ichthyornis, as one of the “toothed birds” from the Late Cretaceous of Kansas, offered some of “the best support to the theory of evolution” (in litt., C. Darwin to O.C. Marsh, August 31, 1880). Ichthyornis figures no less prominently today. It is one of the closest outgroups to crown clade Aves, and remains one of the only Mesozoic avialans known from more than a handful of specimens. As such, Ichthyornis is an essential taxon for analyses of deep… 

A redescription of Chaoyangia beishanensis (Aves) and a comprehensive phylogeny of Mesozoic birds

Unique among ornithurines, Chaoyangia possesses two dorsal processes on the ischium, and thus remains a valid taxon and is included in a cladistic analysis to test morphological hypotheses regarding its systematic position.

Anatomy of Parahesperornis: Evolutionary Mosaicism in the Cretaceous Hesperornithiformes (Aves)

The Hesperornithiformes constitute the first known avian lineage to secondarily lose flight in exchange for the evolution of a highly derived foot-propelled diving lifestyle, thus representing the

A New Ornithuromorph (Aves: Ornithothoraces) Bird from the Jehol Group Indicative of Higher-Level Diversity

The discovery of a new bird from the Lower Cretaceous Yixian Formation, Liaoning Province, China, which represents a new species, but bears similarities to Hongshanornis longicresta from the same formation of Inner Mongolia, and represents a clade of specialized ‘shorebirds’ whose elongate hindlimbs indicate ecological adaptations different from those of other Jehol ornithuromorphs.

Ichthyornis sp. (Aves: Ichthyornithiformes) from the lower Turonian (Upper Cretaceous) of western Kansas

Abstract FHSM VP-2139 is the proximal end of a right carpometacarpus of the Late Cretaceous toothed seabird, Ichthyornis sp. (Aves: Ichthyornithiformes), housed in the Sternberg Museum of Natural

A new basal ornithuromorph bird (Aves: Ornithothoraces) from the Early Cretaceous of China with implication for morphology of early Ornithuromorpha

A comprehensive phylogenetic analysis resolved the new taxon in a basal position that is only more derived than Archaeorhynchus and Jianchangornis among ornithuromorphs, increasing the morphological diversity of basal ornithuomorphs.

An Elaphrocnemus-Like Landbird and Other Avian Remains from the Late Paleocene of Brazil

A new avian taxon is described, Itaboravis elaphrocnemoides, from the late Paleocene fissure fillings of São José de Itaboraí in Brazil, which is tentatively classified in the Cariamae, but also note morphological similarities of the humerus to that of the palaeognathous Tinamidae.

The oldest Archaeopteryx (Theropoda: Avialiae): a new specimen from the Kimmeridgian/Tithonian boundary of Schamhaupten, Bavaria

The iconic primeval bird Archaeopteryx was so far mainly known from the Altmühltal Formation of Bavaria, southern Germany, with one specimen having been found in the overlying Mörnsheim Formation, but a new specimen from the earliest Tithonian Painten Formation of Schamhaupten (Bavaria) represents the so far oldest representative of the genus.

A species-level phylogeny of the Cretaceous Hesperornithiformes (Aves: Ornithuromorpha): implications for body size evolution amongst the earliest diving birds

The results of this study support the monophyly of the Hesperornithiformes, which is recovered as the sister clade to the avian crown group, Neornithes, who are monophyletic while the Baptornithidae are polyphyletic.

A Confuciusornithiform (Aves, Pygostylia)-Like Tarsometatarsus from the Early Cretaceous of Siberia and a Discussion of the Evolution of Avian Hind Limb Musculature

A new isolated tarsometatarsus from the Early Cretaceous Ilek Formation Shestakovo-3 locality in western Siberia is described, revealing a primitive stage in the evolution of the neornithine condition.



Systematic relationships of the palaeogene family Presbyornithidae (Aves: Anseriformes)

The often suggested close relationship of anseriform and galliform birds is not confirmed by osteology, and the Anseriformes and the Phoenicopteridae form a monophyletic clade that is the sister to the remaining ciconiiform birds.

On the Morphology and Phylogeny of the Palaeognathae (Ratitae and Crypturi) and Neognathae (Carinatae)

The author of this important memoir has undertaken the task of revising and extending the authors' knowledge of the anatomy of the existing members of the former group of birds, and the thorough manner in which it has been carried out forms a model of what such researches should be.

A New Carinate Bird from the Late Cretaceous of Patagonia (Argentina)

A new bird from the Late Cretaceous of Patagonia (Argentina), known from associated wing elements, is described and its phylogenetic position evaluated and it is named a new taxon Limenavis patagonica.

Fossil that fills a critical gap in avian evolution

The new taxon, Apsaravis ukhaana, is the best-preserved specimen of a Mesozoic ornithurine bird discovered in over a century and provides data important for assessing morphological evolution across Avialae, with implications for the monophyly of Enantiornithes and Sauriurae.

New information on the anatomy and relationships of Dromaeosaurus albertensis (Dinosauria: Theropoda)

Repreparation and restudy of the holotype of Dromaeosaurus albertensis has produced new anatomical information useful for evaluating the relationships of dromaeosaurids.

A New Partial Mandible of Ichthyornis

In 1872, O. C. Marsh described a new Cretaceous bird Ichthyornis dispar based on a posteranial skeleton and referred the toothed "Colonosaurus" jaws to IchthyORNis dispar stating that "there cannot now be a reasonable doubt that all are parts of the same bird".

A New Hesperornithid and the Relationships of the Mesozoic Birds

One of the most important avian fossils is a nearly complete skeleton of a hesperornithid from the late Cretaceous Niobrara Chalk Formation of western Kansas found by H. T. Martin in 1894, that provides the basis for a re-evaluation of the relationships of the HesperORNithiformes to other Mesozoic birds.

A phylogenetic analysis of basal Anseriformes, the fossil Presbyornis, and the interordinal relationships of waterfowl

The phylogenetic hypothesis is used to reconstruct an evolutionary scenario for selected ecomorphological characters in the galliform-anseriform transition, to predict the most parsimonious states of these characters for Presbyornis, and to propose a phylogenetic classification of the higher-order taxa of waterfowl.

The origin and early diversification of birds

Numerical cladistic analysis of 73 cranial and postcranial characters has resulted in a highly corroborated hypothesis describing the phylogenetic pattern of early avian evolution. Using “non-avian


The importance of the critical fossils seems to reside in their relative primitive‐ness, and the simplest explanation for their more conservative nature is that they have had less time to evolve.