230px, Ichthyornis skeletons Odontognathae is a disused name for a

paraphyletic In taxonomy (general), taxonomy, a group is paraphyletic if it consists of the group's most recent common ancestor, last common ancestor and most of its descendants, excluding a few Monophyly, monophyletic subgroups. The group is said to be pa ...

group of toothed prehistoric birds. The group was originally proposed by

Alexander Wetmore Frank Alexander Wetmore (June 18, 1886 – December 7, 1978) was an American ornithologist and avian paleontologist. He was the sixth Secretary of the Smithsonian Institution. Early life and education The son of a Country Physician, Frank Al ...

, who attempted to link fossil birds with the presence of teeth, specifically of the orders Hesperornithiformes and

Ichthyornithiformes Ichthyornithes is an extinct group of toothed avialans very closely related to the common ancestor of all modern birds. They are known from fossil remains found throughout the late Cretaceous period of North America, though only two genera, ''Ich ...

. As such they would be regarded as

transitional fossil A transitional fossil is any fossilized remains of a life form that exhibits traits common to both an ancestral group and its derived descendant group. This is especially important where the descendant group is sharply differentiated by gross a ...

s between the

reptile Reptiles, as most commonly defined are the animals in the class Reptilia ( ), a paraphyletic grouping comprising all sauropsids except birds. Living reptiles comprise turtles, crocodilians, squamates (lizards and snakes) and rhynchocephalians ( ...

-like " Archaeornithes" like ''Archaeopteryx'' and

modern birds Birds are a group of warm-blooded vertebrates constituting the class Aves (), characterised by feathers, toothless beaked jaws, the laying of hard-shelled eggs, a high metabolic rate, a four-chambered heart, and a strong yet lightweig ...

. They were described by

Romer A Reference Card or "Romer" is a device for increasing the accuracy when reading a grid reference from a map. Made from transparent plastic, paper or other materials, they are also found on most baseplate compasses. Essentially, it is a speciall ...

as birds with essentially modern anatomy, but retaining teeth. Romer, A. S. & Parsons, T. S. (1985): ''The Vertebrate Body.'' (6th ed.) Saunders, Philadelphia.

Traits

Unlike the dinosaur-like " Archaeornithes", the various types of birds assigned to the Odontognathae had short tails with a

plowshare In agriculture, a plowshare ( US) or ploughshare ( UK; ) is a component of a plow (or plough). It is the cutting or leading edge of a moldboard which closely follows the coulter (one or more ground-breaking spikes) when plowing. The plowshar ...

-shaped

pygostyle Pygostyle describes a skeletal condition in which the final few caudal vertebrae are fused into a single ossification, supporting the tail feathers and musculature. In modern birds, the rectrices attach to these. The pygostyle is the main compon ...

and a well developed

carina Carina may refer to: Places Australia * Carina, Queensland, a suburb in Brisbane * Carina Heights, Queensland, a suburb in Brisbane * Carina, Victoria, a locality in Mildura Serbia * Carina, Osečina, a village in the Kolubara District ...

for flight muscle. They also shared the feature of intramandibular articulation, something that is actually absent in ''

Archaeopteryx ''Archaeopteryx'' (; ), sometimes referred to by its German name, "" ( ''Primeval Bird''), is a genus of bird-like dinosaurs. The name derives from the ancient Greek (''archaīos''), meaning "ancient", and (''ptéryx''), meaning "feather" ...

'', but found in many of its

theropod Theropoda (; ), whose members are known as theropods, is a dinosaur clade that is characterized by hollow bones and three toes and claws on each limb. Theropods are generally classed as a group of saurischian dinosaurs. They were ancestrally c ...

relatives. The brains of the "odontognath" birds appear to be somewhat simpler than those of

and have retained some "reptilian" traits. Ornithologist

Alan Feduccia John Alan Feduccia (born 25 April 1943) is a paleornithologist specializing in the origins and phylogeny of birds. He is S. K. Heninger Distinguished Professor Emeritus at the University of North Carolina. Feduccia's authored works include thre ...

has used this, and the presence of the intramandibular articulation (a trait also found in

mosasaur Mosasaurs (from Latin ''Mosa'' meaning the 'Meuse', and Greek ' meaning 'lizard') comprise a group of extinct, large marine reptiles from the Late Cretaceous. Their first fossil remains were discovered in a limestone quarry at Maastricht on th ...

s and living varanid lizards) as arguments that the Odontognathae and thus the birds as a whole have not evolved from theropod dinosaurs, but non-dinosaur thecodonts. This theory is contested by most

paleontologists Paleontology (), also spelled palaeontology or palæontology, is the scientific study of life that existed prior to, and sometimes including, the start of the Holocene epoch (roughly 11,700 years before present). It includes the study of fossi ...

Classification

Classically, Odontognathae was considered one of three superorders of

Neornithes Birds are a group of warm-blooded vertebrates constituting the class Aves (), characterised by feathers, toothless beaked jaws, the laying of hard-shelled eggs, a high metabolic rate, a four-chambered heart, and a strong yet lightweigh ...

(modern birds) as opposed to Archaeornithes (the ancient birds). Today the name Neornithes is commonly used for the bird

crown group In phylogenetics, the crown group or crown assemblage is a collection of species composed of the living representatives of the collection, the most recent common ancestor of the collection, and all descendants of the most recent common ancestor. ...

, the Odontognathae being united with them the group

Ornithurae Ornithurae (meaning "bird tails" in Greek) is a natural group which includes the common ancestor of ''Ichthyornis'', ''Hesperornis'', and all modern birds as well as all other descendants of that common ancestor. Classification Ernst Haeckel coi ...

.Gauthier, Jacques, de Queiroz, Kevin (2001). "Feathered dinosaurs, flying dinosaurs, crown dinosaurs, and the name 'Aves'". in ''New Perspective on the Origin and Evolution of Birds: Proceedings of the International Symposium in Honor of John H. Ostrom''. Yale Peabody Museum. Yale University. New Haven, Conn. USA

Notes

{{reflist Prehistoric ornithurans Paraphyletic groups