''Teviornis'' is an

extinct Extinction is the termination of an organism by the death of its Endling, last member. A taxon may become Functional extinction, functionally extinct before the death of its last member if it loses the capacity to Reproduction, reproduce and ...

genus Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...

of presbyornithid which lived during the

Maastrichtian The Maastrichtian ( ) is, in the International Commission on Stratigraphy (ICS) geologic timescale, the latest age (geology), age (uppermost stage (stratigraphy), stage) of the Late Cretaceous epoch (geology), Epoch or Upper Cretaceous series (s ...

stage, around 70 million years ago. One species has been described, ''T. gobiensis''. It is the oldest known neognath along with '' Vegavis'', and its fossils are collected from the Nemegt Formation of

Mongolia Mongolia is a landlocked country in East Asia, bordered by Russia to the north and China to the south and southeast. It covers an area of , with a population of 3.5 million, making it the world's List of countries and dependencies by po ...

Discovery and naming

The fossils were collected at the Guriliin Tsav locality, northwest corner of Umnogobi Aimak, Mongolia. The

holotype A holotype (Latin: ''holotypus'') is a single physical example (or illustration) of an organism used when the species (or lower-ranked taxon) was formally described. It is either the single such physical example (or illustration) or one of s ...

consists of a crushed partial right forelimb. These pieces include a nearly complete right

carpometacarpus The carpometacarpus is a bone found in the hands of birds. It results from the fusion of the carpal and metacarpal bone, and is essentially a single fused bone between the wrist and the knuckles. It is a smallish bone in most birds, generally fla ...

, 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 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. The species name ''T. gobiensis'' refers to the harsh

Gobi Desert The Gobi Desert (, , ; ) is a large, cold desert and grassland region in North China and southern Mongolia. It is the sixth-largest desert in the world. The name of the desert comes from the Mongolian word ''gobi'', used to refer to all of th ...

in which the fossil was found. The fossils are in the collection of the

Paleontological Institute, Russian Academy of Sciences The Paleontological Institute, Russian Academy of Sciences (PIN; ) in Moscow is among a paleontological institute. An affiliate of the Russian Academy of Sciences, it includes collections from all over the former Soviet Union, as well as from other ...

, Moscow.

Classification

In 2002, ''Teviornis'' was described by Kurochkin, Dyke & Karhu as a member of the Presbyornithidae. These were stilt-legged, Anseriform,

waterfowl Anseriformes is an order of birds also known as waterfowl that comprises about 180 living species of birds in three families: Anhimidae (three species of screamers), Anseranatidae (the magpie goose), and Anatidae, the largest family, which i ...

which are

, but which flourished during the

Late Cretaceous The Late Cretaceous (100.5–66 Ma) is the more recent of two epochs into which the Cretaceous Period is divided in the geologic time scale. Rock strata from this epoch form the Upper Cretaceous Series. The Cretaceous is named after ''cre ...

and

Paleogene The Paleogene Period ( ; also spelled Palaeogene or Palæogene) is a geologic period and system that spans 43 million years from the end of the Cretaceous Period Ma (million years ago) to the beginning of the Neogene Period Ma. It is the fir ...

. If ''Teviornis'' does belong to the Presbyornithidae then, together with '' Vegavis'' from

Antarctica Antarctica () is Earth's southernmost and least-populated continent. Situated almost entirely south of the Antarctic Circle and surrounded by the Southern Ocean (also known as the Antarctic Ocean), it contains the geographic South Pole. ...

, there is evidence that relatives of today's waterfowl already were widespread and highly

apomorph In phylogenetics, an apomorphy (or derived trait) is a novel character or character state that has evolved from its ancestral form (or plesiomorphy). A synapomorphy is an apomorphy shared by two or more taxa and is therefore hypothesized to ha ...

ic by the end of the

Mesozoic The Mesozoic Era is the Era (geology), era of Earth's Geologic time scale, geological history, lasting from about , comprising the Triassic, Jurassic and Cretaceous Period (geology), Periods. It is characterized by the dominance of archosaurian r ...

. Clarke and Norell reviewed the specimen in 2004. They concluded that some of the characters used by Kurochkin et al. to assign ''T. gobiensis'' to the

Anseriformes Anseriformes is an order (biology), order of birds also known as waterfowl that comprises about 180 living species of birds in three families: Anhimidae (three species of screamers), Anseranatidae (the magpie goose), and Anatidae, the largest f ...

, such as an unbowed

metacarpal In human anatomy, the metacarpal bones or metacarpus, also known as the "palm bones", are the appendicular bones that form the intermediate part of the hand between the phalanges (fingers) and the carpal bones ( wrist bones), which articulate ...

III, are plesiomorphies which are primitive for

Avialae Avialae ("bird wings") is a clade containing the only living dinosaurs, the birds, and their closest relatives. It is usually defined as all theropod dinosaurs more closely related to birds (Aves) than to Deinonychosauria, deinonychosaurs, though ...

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 and Norell found no

synapomorphies In phylogenetics, an apomorphy (or derived trait) is a novel character or character state that has evolved from its ancestral form (or plesiomorphy). A synapomorphy is an apomorphy shared by two or more taxa and is therefore hypothesized to ...

Aves 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 lightweight ...

(sensu Gauthier),

Neognathae Neognathae (; ) is an infraclass of birds, called neognaths, within the class Aves of the clade Archosauria. Neognathae includes the majority of living birds; the exceptions being the tinamous and the flightless ratites, which belong instead to t ...

, or Galloanseres, preserved in PIN 4499–1, so they concluded that ''Teviornis'' cannot be confidently assigned to the Presbyornithidae.Clarke, Julia A., Norell, Mark A. (2004) "New Avialan Remains and a Review of the Late Cretaceous Nemegt Formation of Mongolia" "American Museum Novitates" Number 3447, 12pp. June 2, 2004 In 2016, De Pietri and colleagues reassessed the type specimen of ''Teviornis'' and confirmed the taxon's identity as a presbyornithid on the basis of the trochlea carpalis extension (a bony articular process that drives wing extension and flexion), elongate sulcus tendineus, metacarpal synostosis, etc. Certain morphological traits of the type specimen including the facies articularis dimension and the craniocaudally elongated fossa are also found in the other presbyornithids such as '' Wilaru'' and '' Telmabates''. Its non-curved

also confirms its identity as an anseriform outside the crown-group. A 2019 study also supports the placement of presbyornithids as stem anseriforms. In 2020, a possible Eocene presbyornithid specimen from

Algeria Algeria, officially the People's Democratic Republic of Algeria, is a country in the Maghreb region of North Africa. It is bordered to Algeria–Tunisia border, the northeast by Tunisia; to Algeria–Libya border, the east by Libya; to Alger ...

notably showed similarity to ''Teviornis'' based on the carpal trochlea extension and the shape of the fossa, supporting the taxonomic identity of ''Teviornis'' as a presbyornithid. Phylogenetic analysis showed different results: the 2023 study placed ''Teviornis'' as a presbyornithid, while the 2025 study placed ''Teviornis'' as a basal ornithurine.

Paleoenvironment

The type and only known locality of ''Teviornis'' is the "Guriliin Tsav" (also known as "Gurilyn Tsav" or "Gurlin Tsav") of the Nemegt Formation. Other dinosaurs recovered from Gurillin Tsav include the tyrannosaurid '' Tarbosaurus'', the ornithomimid '' Gallimimus'', the oviraptorid '' Oksoko'', the

hadrosaurid Hadrosaurids (), also hadrosaurs or duck-billed dinosaurs, are members of the ornithischian family Hadrosauridae. This group is known as the duck-billed dinosaurs for the flat duck-bill appearance of the bones in their snouts. The ornithopod fami ...

'' Saurolophus'', the pachycephalosaurid ''

Prenocephale ''Prenocephale'' (meaning "sloping head") is a genus of small pachycephalosaurid dinosaur from the Late Cretaceous Nemegt Formation of Mongolia. It was similar in many ways to its close relative, ''Homalocephale''. Discovery The holotype specime ...

'' and the enantiornithine '' Gurilynia''. Other animals from the same locality include the sichuanchelyid

turtle Turtles are reptiles of the order (biology), order Testudines, characterized by a special turtle shell, shell developed mainly from their ribs. Modern turtles are divided into two major groups, the Pleurodira (side necked turtles) and Crypt ...

''Mongolochelys'', the azhdarchid

pterosaur Pterosaurs are an extinct clade of flying reptiles in the order Pterosauria. They existed during most of the Mesozoic: from the Late Triassic to the end of the Cretaceous (228 million to 66 million years ago). Pterosaurs are the earli ...

and the

metatherian Metatheria is a mammalian clade that includes all mammals more closely related to marsupials than to placentals. First proposed by Thomas Henry Huxley in 1880, it is a more inclusive group than the marsupials; it contains all marsupials as well ...

mammal ( Gurlin Tsav skull).

References

External links

* palaeos.com
360.650 Galloanserae: Anseres: Anatoidea: ''Teviornis''
Drawings of type

and

humerus The humerus (; : humeri) is a long bone in the arm that runs from the shoulder to the elbow. It connects the scapula and the two bones of the lower arm, the radius (bone), radius and ulna, and consists of three sections. The humeral upper extrem ...

. Version of 2004-JUL-13. Retrieved 2007-NOV-08. {{Taxonbar, from=Q2297131 Fossil taxa described in 2002 Late Cretaceous birds of Asia Nemegt fauna Presbyornithidae