Odontornithes
Encyclopedia
Odontornithes is an obsolete and disused taxonomic
term proposed by O. C. Marsh for birds possessing teeth, notably the genera Hesperornis
and Ichthyornis
from the Cretaceous
deposits of Kansas
.
In 1875 March divided this "subclass" into Odontolcae, with the teeth standing in grooves, and Odontotormae, with the teeth in separate alveoles or sockets. In his 1880 work, Odontornithes: A monograph on the extinct toothed birds of North America, he added the Saururae, represented by Archaeopteryx
, as a third order.
The resulting classification was paraphyletic, not accurately resolving evolution
ary relationships. In the present case, the Odontornithes are not a monophyletic assembly, and the fact of their possessing teeth proves nothing but that some birds still retained these organs during the Late Cretaceous
. This indicates that birds, as a group, are the descendants of toothed reptiles, to the exclusion of the Chelonia (turtles and tortoises) with which various authors had attempted to connect them. No fossil birds of later than Cretaceous age are known to have teeth.
Étienne Geoffroy Saint-Hilaire
stated in 1821 that he had found a considerable number of tooth buds
in the upper and lower jaws of the Rose-ringed Parakeet
. Émile Blanchard
felt justified in recognizing flakes of dentine. However, M. Braun and especially P. Fraisse showed later that the structures in question are of the same kind as the well-known serrated " teeth " of the bill of anserine
birds. In fact the papillae observed in the embryonic birds are the soft cutaneous extensions into the surrounding horny sheath of the bill
, comparable to the well-known nutritive papillae in a horse's hoof
. They are easily exposed in the well-macerated under jaw of a parrot, after removal of the horny sheath. Occasionally calcification occurs in or around these papillae, as it does regularly in the egg tooth
of the embryos of all birds.
The best known of the "Odontornithes" are Hesperornis regalis, standing about 3ft. high, the somewhat taller H. crassipes
, and Ichthyornis dispar. Hesperornis
looked somewhat similar to a loon
, while Ichthyornis
was quite similar to a gull
or petrel
. However, they were entirely distinct groups of birds and merely shared with modern birds some distant ancestry in the Early Cretaceous
. The Hesperornis lineage may have derived even sooner or possibly independently from the ancestors of modern birds.
Taxonomy
Taxonomy is the science of identifying and naming species, and arranging them into a classification. The field of taxonomy, sometimes referred to as "biological taxonomy", revolves around the description and use of taxonomic units, known as taxa...
term proposed by O. C. Marsh for birds possessing teeth, notably the genera Hesperornis
Hesperornis
Hesperornis is a genus of flightless aquatic birds that spanned the first half of the Campanian age of the Late Cretaceous period . One of the lesser-known discoveries of the paleontologist O. C. Marsh in the late 19th century Bone Wars, it was an important early find in the history of avian...
and Ichthyornis
Ichthyornis
Ichthyornis is a genus of toothed seabirds from the Late Cretaceous of North America. Its fossil remains are known from the chalks of Alberta, Alabama, Kansas, New Mexico, Saskatchewan, and Texas, in strata that were laid down in the Western Interior Seaway during the Turonian-Campanian ages,...
from the Cretaceous
Cretaceous
The Cretaceous , derived from the Latin "creta" , usually abbreviated K for its German translation Kreide , is a geologic period and system from circa to million years ago. In the geologic timescale, the Cretaceous follows the Jurassic period and is followed by the Paleogene period of the...
deposits of Kansas
Kansas
Kansas is a US state located in the Midwestern United States. It is named after the Kansas River which flows through it, which in turn was named after the Kansa Native American tribe, which inhabited the area. The tribe's name is often said to mean "people of the wind" or "people of the south...
.
In 1875 March divided this "subclass" into Odontolcae, with the teeth standing in grooves, and Odontotormae, with the teeth in separate alveoles or sockets. In his 1880 work, Odontornithes: A monograph on the extinct toothed birds of North America, he added the Saururae, represented by Archaeopteryx
Archaeopteryx
Archaeopteryx , sometimes referred to by its German name Urvogel , is a genus of theropod dinosaur that is closely related to birds. The name derives from the Ancient Greek meaning "ancient", and , meaning "feather" or "wing"...
, as a third order.
The resulting classification was paraphyletic, not accurately resolving evolution
Evolution
Evolution is any change across successive generations in the heritable characteristics of biological populations. Evolutionary processes give rise to diversity at every level of biological organisation, including species, individual organisms and molecules such as DNA and proteins.Life on Earth...
ary relationships. In the present case, the Odontornithes are not a monophyletic assembly, and the fact of their possessing teeth proves nothing but that some birds still retained these organs during the Late Cretaceous
Late Cretaceous
The Late Cretaceous is the younger of two epochs into which the Cretaceous period is divided in the geologic timescale. Rock strata from this epoch form the Upper Cretaceous series...
. This indicates that birds, as a group, are the descendants of toothed reptiles, to the exclusion of the Chelonia (turtles and tortoises) with which various authors had attempted to connect them. No fossil birds of later than Cretaceous age are known to have teeth.
Étienne Geoffroy Saint-Hilaire
Étienne Geoffroy Saint-Hilaire
Étienne Geoffroy Saint-Hilaire was a French naturalist who established the principle of "unity of composition". He was a colleague of Jean-Baptiste Lamarck and expanded and defended Lamarck's evolutionary theories...
stated in 1821 that he had found a considerable number of tooth buds
Tooth development
Tooth development or odontogenesis is the complex process by which teeth form from embryonic cells, grow, and erupt into the mouth. Although many diverse species have teeth, non-human tooth development is largely the same as in humans...
in the upper and lower jaws of the Rose-ringed Parakeet
Rose-ringed Parakeet
The Rose-ringed Parakeet , also known as the Ringnecked Parakeet, is a gregarious tropical parakeet species that has an extremely large range. Since the trend of the population appears to be increasing, the species has been evaluated as Least Concern by IUCN in 2009.Rose-ringed parakeets are...
. Émile Blanchard
Émile Blanchard
Charles Émile Blanchard was a French zoologist and entomologist.Blanchard was born in Paris. His father was an artist and naturalist and Émile began natural history very early in life. When he was 14 years old, Jean Victoire Audouin , allowed him access to the laboratory of the Muséum national...
felt justified in recognizing flakes of dentine. However, M. Braun and especially P. Fraisse showed later that the structures in question are of the same kind as the well-known serrated " teeth " of the bill of anserine
Anserine
Anserine is a dipeptide found in the skeletal muscle and brain of mammals, and birds.It is an antioxidant and helps reduce fatigue....
birds. In fact the papillae observed in the embryonic birds are the soft cutaneous extensions into the surrounding horny sheath of the bill
Beak
The beak, bill or rostrum is an external anatomical structure of birds which is used for eating and for grooming, manipulating objects, killing prey, fighting, probing for food, courtship and feeding young...
, comparable to the well-known nutritive papillae in a horse's hoof
Hoof
A hoof , plural hooves or hoofs , is the tip of a toe of an ungulate mammal, strengthened by a thick horny covering. The hoof consists of a hard or rubbery sole, and a hard wall formed by a thick nail rolled around the tip of the toe. The weight of the animal is normally borne by both the sole...
. They are easily exposed in the well-macerated under jaw of a parrot, after removal of the horny sheath. Occasionally calcification occurs in or around these papillae, as it does regularly in the egg tooth
Egg tooth
In some egg-laying animals, the egg tooth is a small, sharp, cranial protuberance used by offspring to break or tear through the egg's surface during hatching...
of the embryos of all birds.
The best known of the "Odontornithes" are Hesperornis regalis, standing about 3ft. high, the somewhat taller H. crassipes
Hesperornis
Hesperornis is a genus of flightless aquatic birds that spanned the first half of the Campanian age of the Late Cretaceous period . One of the lesser-known discoveries of the paleontologist O. C. Marsh in the late 19th century Bone Wars, it was an important early find in the history of avian...
, and Ichthyornis dispar. Hesperornis
Hesperornis
Hesperornis is a genus of flightless aquatic birds that spanned the first half of the Campanian age of the Late Cretaceous period . One of the lesser-known discoveries of the paleontologist O. C. Marsh in the late 19th century Bone Wars, it was an important early find in the history of avian...
looked somewhat similar to a loon
Loon
The loons or divers are a group of aquatic birds found in many parts of North America and northern Eurasia...
, while Ichthyornis
Ichthyornis
Ichthyornis is a genus of toothed seabirds from the Late Cretaceous of North America. Its fossil remains are known from the chalks of Alberta, Alabama, Kansas, New Mexico, Saskatchewan, and Texas, in strata that were laid down in the Western Interior Seaway during the Turonian-Campanian ages,...
was quite similar to a gull
Gull
Gulls are birds in the family Laridae. They are most closely related to the terns and only distantly related to auks, skimmers, and more distantly to the waders...
or petrel
Petrel
Petrels are tube-nosed seabirds in the bird order Procellariiformes. The common name does not indicate relationship beyond that point, as "petrels" occur in three of the four families within that group...
. However, they were entirely distinct groups of birds and merely shared with modern birds some distant ancestry in the Early Cretaceous
Early Cretaceous
The Early Cretaceous or the Lower Cretaceous , is the earlier or lower of the two major divisions of the Cretaceous...
. The Hesperornis lineage may have derived even sooner or possibly independently from the ancestors of modern birds.