''Alexornis'' is a

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 ...

enantiornithine The Enantiornithes, also known as enantiornithines or enantiornitheans in literature, are a group of extinct avialans ("birds" in the broad sense), the most abundant and diverse group known from the Mesozoic era. Almost all retained teeth and c ...

bird Birds are a group of warm-blooded vertebrates constituting the class (biology), class Aves (), characterised by feathers, toothless beaked jaws, the Oviparity, laying of Eggshell, hard-shelled eggs, a high Metabolism, metabolic rate, a fou ...

s from the La Bocana Roja Formation of

Baja California Baja California, officially the Free and Sovereign State of Baja California, is a state in Mexico. It is the northwesternmost of the 32 federal entities of Mexico. Before becoming a state in 1952, the area was known as the North Territory of B ...

Mexico Mexico, officially the United Mexican States, is a country in North America. It is the northernmost country in Latin America, and borders the United States to the north, and Guatemala and Belize to the southeast; while having maritime boundar ...

.Tykoski, R. S., & Fiorillo, A. R. (2010). An enantiornithine bird from the lower middle Cenomanian of Texas. ''Journal of Vertebrate Paleontology'', 30(1), 288-292. This geological formation has been dated to the late

Cretaceous The Cretaceous ( ) is a geological period that lasted from about 143.1 to 66 mya (unit), million years ago (Mya). It is the third and final period of the Mesozoic Era (geology), Era, as well as the longest. At around 77.1 million years, it is the ...

period, and more specifically to the

Cenomanian The Cenomanian is, in the International Commission on Stratigraphy's (ICS) geological timescale, the oldest or earliest age (geology), age of the Late Cretaceous epoch (geology), Epoch or the lowest stage (stratigraphy), stage of the Upper Cretace ...

and

Turonian The Turonian is, in the International Commission on Stratigraphy, ICS' geologic timescale, the second age (geology), age in the Late Cretaceous epoch (geology), Epoch, or a stage (stratigraphy), stage in the Upper Cretaceous series (stratigraphy), ...

ages, about 93.6 mya. The

type Type may refer to: Science and technology Computing * Typing, producing text via a keyboard, typewriter, etc. * Data type, collection of values used for computations. * File type * TYPE (DOS command), a command to display contents of a file. * ...

and only known

species A species () is often defined as the largest group of organisms in which any two individuals of the appropriate sexes or mating types can produce fertile offspring, typically by sexual reproduction. It is the basic unit of Taxonomy (biology), ...

is ''Alexornis antecedens''. The scientific name as a whole means "Alex's ancestral bird"; ''Alexornis'' from the given name of

ornithologist Ornithology, from Ancient Greek ὄρνις (''órnis''), meaning "bird", and -logy from λόγος (''lógos''), meaning "study", is a branch of zoology dedicated to the study of birds. Several aspects of ornithology differ from related discip ...

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. He was also an elected member of both the American Philosophical Soc ...

Ancient Greek Ancient Greek (, ; ) includes the forms of the Greek language used in ancient Greece and the classical antiquity, ancient world from around 1500 BC to 300 BC. It is often roughly divided into the following periods: Mycenaean Greek (), Greek ...

''ornis'', "bird", and ''antecedens'',

Latin Latin ( or ) is a classical language belonging to the Italic languages, Italic branch of the Indo-European languages. Latin was originally spoken by the Latins (Italic tribe), Latins in Latium (now known as Lazio), the lower Tiber area aroun ...

for "going before" or "ancestral". ''A. antecedens'' is known only from a single fragmentary skeleton including shoulder, wing, and leg bones, but lacking a skull. It was about the size of a sparrow, weighing only about . The specimen was discovered in 1971 and formally described in 1976 by

Pierce Brodkorb William Pierce Brodkorb (September 29, 1908, Chicago – July 18, 1992, Gainesville, Florida) was an American ornithologist and paleontologist. Interested in birds since childhood, he was taught to prepare birds at the age of 16. Later, he rec ...

. Brodkorb considered the species to be similar to some modern birds, and at the time, recognized it as one of the few known Cretaceous "land birds" after ''

Gobipteryx minuta ''Gobipteryx'' (from Gobi eferring to the Gobi Desert where it was first discovered and Greek pteryx "wing") is a genus of prehistoric bird from the Campanian Age of the Late Cretaceous Period.Elżanowski, A. (1974)"Preliminary note on the Pal ...

'', as most other Cretaceous birds at the time were thought to be aquatic or semi-aquatic.

Classification

''Alexornis'' was originally described as an early member of the modern bird group and, more specifically, as a possible ancestor of the

order Order, ORDER or Orders may refer to: * A socio-political or established or existing order, e.g. World order, Ancien Regime, Pax Britannica * Categorization, the process in which ideas and objects are recognized, differentiated, and understood ...

Coraciiformes The Coraciiformes are a group of usually colourful birds including the kingfishers, the bee-eaters, the rollers, the motmots, and the todies. They generally have syndactyly, with three forward-pointing toes (and toes 3 & 4 fused at their b ...

(

kingfishers Kingfishers are a family, the Alcedinidae, of small to medium-sized, brightly coloured birds in the order Coraciiformes. They have a cosmopolitan distribution, with most species living in the tropical regions of Africa, Asia, and Oceania, ...

and relatives) and

Piciformes Nine families of largely arboreal birds make up the order Piciformes (), the best-known of them being the Picidae, which includes the woodpeckers and close relatives. The Piciformes contain about 71 living genera with a little over 450 species, ...

(

woodpecker Woodpeckers are part of the bird family (biology), family Picidae, which also includes the piculets, wrynecks and sapsuckers. Members of this family are found worldwide, except for Australia, New Guinea, New Zealand, Madagascar and the extreme ...

s and relatives). However, when the first recognized enantiornithine fossils were discovered, it soon became clear that ''Alexornis'' was an additional member of this group.Walker, C. A., Buffetaut, E., & Dyke, G. J. (2007). Large euenantiornithine birds from the Cretaceous of southern France, North America and Argentina. ''Geological Magazine, London'', 144(6), 977. Enantiornithes are characterized by a reversed articulation of the ''scapula'' and ''coracoid'' bones in the shoulder, and in 1983 Larry Martin showed that Brodkorb has accidentally switched these two bones in his original description, confused by their reversed anatomy.Martin, L. 1983. The origin and early radiation of birds. In Perspectives in Ornithology, Essays Presented for the Centennial of the American Ornithologists’ Union, pp. 291-338. In the past, ''Alexornis'' has been allied with the similarly sized

Central Asia Central Asia is a region of Asia consisting of Kazakhstan, Kyrgyzstan, Tajikistan, Turkmenistan, and Uzbekistan. The countries as a group are also colloquially referred to as the "-stans" as all have names ending with the Persian language, Pers ...

n genus '' Kizylkumavis'', based on characteristics which are known to unite them with other Cretaceous birds in the group Enantornithes.

Evgeny Kurochkin Yevgeny Nikolayevich Kurochkin (Евгений Николаевич Курочкин; 12 July 1940 - 13 December 2011) was a Russian paleornithologist at the Paleontological Institute of the Russian Academy of Sciences. He served as President of ...

argued in 1996 that ''Alexornis'' formed a natural group, the Alexornithidae, with ''Kizylkumavis'' and a second type of central Asian bird, '' Sazavis''. Among the enantiornithes, ''Alexornis'' shares many similarities of its skeletal anatomy with South American birds from about the same time period, including ''

Martinavis ''Martinavis'' is a genus of enantiornithine birds which existed in what is now southern France, North America and Salta Province, Argentina during the late Cretaceous period. It was named by Cyril A. Walker, Eric Buffetaut and Gareth J. Dyke in ...

'' and ''

Elbretornis ''Elbretornis'' is an extinct genus of enantiornithine which existed in what is now Salta Province, Argentina during the late Cretaceous period. Etymology It was named by Cyril A. Walker and Gareth J. Dyke in 2009, and the type and so far onl ...

'', and is united with them in the group

Euenantiornithes The Enantiornithes, also known as enantiornithines or enantiornitheans in literature, are a group of extinct avialans ("birds" in the broad sense), the most abundant and diverse group known from the Mesozoic era. Almost all retained teeth and cl ...

.Walker, C. A., & Dyke, G. J. (2009). Euenantiornithine birds from the late Cretaceous of El Brete (Argentina). ''Irish Journal of Earth Sciences'', 27(1), 15-62.

References

{{Taxonbar, from=Q4254960 Enantiornithes Bird genera Late Cretaceous birds of North America Fossil taxa described in 1976 Taxa named by Pierce Brodkorb