Teviornis
Encyclopedia
Teviornis is a genus
of extinct bird
s. One species has been described, T. gobiensis. It lived in the Maastrichtian
stage at the end of the Late Cretaceous
period, some 70 million years ago. It is known from fossils collected from the Nemegt Formation
of Gobi, south Mongolia
.
The fossils include only the holotype
which are pieces of a crushed right forelimb. These pieces include a nearly complete right carpometacarpus
, two phalanges, the radiale and ulnare of the wrist, and a fragment of the distal right humerus. The catalog number of these fossils are given multiple times as PIN 4499-1, but they are listed as PIN 44991-1 on page 3, where the holotype is formally listed. This is probably a misprint.
The fossils were collected at the Gurilyn tsav locality, northwest corner of Umnogobi Aimak, Mongolia. They are in the collection
The genus name Teviornis is the Greek masculine word for bird combined with the name of Victor Tereschenko, the Paleontologist at the PIN who discovered the specimen. Gobiensis refers to the harsh Gobi Desert
in which the fossil was found. The fossils are in the collection of the Paleontological Institute, Russian Academy of Sciences, Moscow.
Teviornis was described by Kurochkin, et al. as a member of the Presbyornithidae
. These were stilt-legged, Anseriform
, waterfowl
which are extinct, but which flourished during the Late Cretaceous
and Paleogene
. If Teviornis does belong to the Presbyornithidae then, together with Vegavis
from Antarctica, there is evidence that relatives of today's waterfowl already were widespread and highly apomorphic by the end of the Mesozoic
.
A review of Kurochkin et al. was performed by Clarke and Norell in 2004. They concluded that some of the characters used by Kurochkin et al. to assign T. gobiensis to the Anseriformes
, such as an unbowed metacarpal III, are plesiomorphies which are primitive for Avialae
and also retained in some members of Ornithurae
. They found that the remaining characters used by Kurochkin et al. also had wider distribution than was assumed, or had an incompletely studied distribution. Moreover, Clarke et al. found no synapomorphies of Aves (sensu Gauthier), Neognathae
, or Galloanseres, preserved in PIN 4499-1. thus, they conclude, Teviornis cannot be assigned with any confidence to the Presbyornithidae.
Genus
In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...
of extinct bird
Bird
Birds are feathered, winged, bipedal, endothermic , egg-laying, vertebrate animals. Around 10,000 living species and 188 families makes them the most speciose class of tetrapod vertebrates. They inhabit ecosystems across the globe, from the Arctic to the Antarctic. Extant birds range in size from...
s. One species has been described, T. gobiensis. It lived in the Maastrichtian
Maastrichtian
The Maastrichtian is, in the ICS' geologic timescale, the latest age or upper stage of the Late Cretaceous epoch or Upper Cretaceous series, the Cretaceous period or system, and of the Mesozoic era or erathem. It spanned from 70.6 ± 0.6 Ma to 65.5 ± 0.3 Ma...
stage at the end of the Late 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...
period, some 70 million years ago. It is known from fossils collected from the Nemegt Formation
Nemegt Formation
The Nemegt Formation is a geological formation dating from the Late Cretaceous sedimentary from the Gobi Desert of Mongolia. It overlies and sometimes forms folds with the Barun Goyot Formation. It consists of river channel sediments and contains fossils of fish, turtles, crocodilians, birds and a...
of Gobi, south Mongolia
Mongolia
Mongolia is a landlocked country in East and Central Asia. It is bordered by Russia to the north and China to the south, east and west. Although Mongolia does not share a border with Kazakhstan, its western-most point is only from Kazakhstan's eastern tip. Ulan Bator, the capital and largest...
.
The fossils include only the holotype
Holotype
A holotype is a single physical example of an organism, known to have been used when the species was formally described. It is either the single such physical example or one of several such, but explicitly designated as the holotype...
which are pieces of a crushed right forelimb. These pieces include a nearly complete right carpometacarpus
Carpometacarpus
The carpometacarpus is the fusion of the carpal and metacarpal bone, essentially a single fused bone between the wrist and the knuckles. It is a smallish bone in most birds, generally flattened and with a large hole in the middle. In flightless birds, however, its shape may be slightly different,...
, two phalanges, the radiale and ulnare of the wrist, and a fragment of the distal right humerus. The catalog number of these fossils are given multiple times as PIN 4499-1, but they are listed as PIN 44991-1 on page 3, where the holotype is formally listed. This is probably a misprint.
The fossils were collected at the Gurilyn tsav locality, northwest corner of Umnogobi Aimak, Mongolia. They are in the collection
The genus name Teviornis is the Greek masculine word for bird combined with the name of Victor Tereschenko, the Paleontologist at the PIN who discovered the specimen. Gobiensis refers to the harsh Gobi Desert
Gobi Desert
The Gobi is a large desert region in Asia. It covers parts of northern and northwestern China, and of southern Mongolia. The desert basins of the Gobi are bounded by the Altai Mountains and the grasslands and steppes of Mongolia on the north, by the Hexi Corridor and Tibetan Plateau to the...
in which the fossil was found. The fossils are in the collection of the Paleontological Institute, Russian Academy of Sciences, Moscow.
Teviornis was described by Kurochkin, et al. as a member of the Presbyornithidae
Presbyornithidae
Presbyornithidae were a family of waterbirds with an apparently global distribution that lived until the Earliest Oligocene, but are now extinct...
. These were stilt-legged, Anseriform
Anseriformes
The order Anseriformes contains about 150 living species of birds in three extant families: the Anhimidae , Anseranatidae , and the Anatidae, which includes over 140 species of waterfowl, among them the ducks, geese, and swans.All species in the order are highly adapted for an aquatic existence at...
, waterfowl
Waterfowl
Waterfowl are certain wildfowl of the order Anseriformes, especially members of the family Anatidae, which includes ducks, geese, and swans....
which are extinct, but which flourished 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...
and Paleogene
Paleogene
The Paleogene is a geologic period and system that began 65.5 ± 0.3 and ended 23.03 ± 0.05 million years ago and comprises the first part of the Cenozoic Era...
. If Teviornis does belong to the Presbyornithidae then, together with Vegavis
Vegavis
Vegavis is a genus of extinct bird that lived during the Late Cretaceous of Antarctica, some 65 mya. It belonged to the clade Anseriformes...
from Antarctica, there is evidence that relatives of today's waterfowl already were widespread and highly apomorphic by the end of the Mesozoic
Mesozoic
The Mesozoic era is an interval of geological time from about 250 million years ago to about 65 million years ago. It is often referred to as the age of reptiles because reptiles, namely dinosaurs, were the dominant terrestrial and marine vertebrates of the time...
.
A review of Kurochkin et al. was performed by Clarke and Norell in 2004. They concluded that some of the characters used by Kurochkin et al. to assign T. gobiensis to the Anseriformes
Anseriformes
The order Anseriformes contains about 150 living species of birds in three extant families: the Anhimidae , Anseranatidae , and the Anatidae, which includes over 140 species of waterfowl, among them the ducks, geese, and swans.All species in the order are highly adapted for an aquatic existence at...
, such as an unbowed metacarpal III, are plesiomorphies which are primitive for Avialae
Avialae
Avialae is a clade of dinosaurs containing their only living representatives, birds , and the most immediate extinct relatives of birds.-Competing definitions:...
and also retained in some members of Ornithurae
Ornithurae
Ornithurae is the name of a natural group which includes all modern birds as well as their extinct relatives with plough-shaped pygostyles, a bone at the end of the tail which allows the tail feathers to fan and retract....
. They found that the remaining characters used by Kurochkin et al. also had wider distribution than was assumed, or had an incompletely studied distribution. Moreover, Clarke et al. found no synapomorphies of Aves (sensu Gauthier), Neognathae
Neognathae
Neognaths are birds within the subclass Neornithes of the class Aves. The Neognathae include virtually all living birds; their sister taxon Palaeognathae contains the tinamous and the flightless ratites....
, or Galloanseres, preserved in PIN 4499-1. thus, they conclude, Teviornis cannot be assigned with any confidence to the Presbyornithidae.
External links
- palaeos.com: 360.650 Galloanserae: Anseres: Anatoidea: Teviornis. Drawings of type carpometacarpusCarpometacarpusThe carpometacarpus is the fusion of the carpal and metacarpal bone, essentially a single fused bone between the wrist and the knuckles. It is a smallish bone in most birds, generally flattened and with a large hole in the middle. In flightless birds, however, its shape may be slightly different,...
and humerusHumerusThe humerus is a long bone in the arm or forelimb that runs from the shoulder to the elbow....
. Version of 2004-JUL-13. Retrieved 2007-NOV-08.