Enantiornis is a genus

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 predatory enantiornithine

Enantiornithes

Enantiornithes is an extinct group of primitive birds. They were the most abundant and diverse avialans of the Mesozoic. Almost all retained teeth and clawed fingers on each wing, but otherwise looked much like modern birds externally. Over 50 species of Enantiornithines have been named, but some...

 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...

. The type

Type species

In biological nomenclature, a type species is both a concept and a practical system which is used in the classification and nomenclature of animals and plants. The value of a "type species" lies in the fact that it makes clear what is meant by a particular genus name. A type species is the species...

 and only currently accepted species E. leali is from 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...

 rocks at El Brete, Argentina

Argentina

Argentina , officially the Argentine Republic , is the second largest country in South America by land area, after Brazil. It is constituted as a federation of 23 provinces and an autonomous city, Buenos Aires...

.

It was among the largest enantiornithine discovered to date, with a length of around one meter (excluding tail)http://dml.cmnh.org/2001Jul/msg01069.html and its ecological niche

Ecological niche

In ecology, a niche is a term describing the relational position of a species or population in its ecosystem to each other; e.g. a dolphin could potentially be in another ecological niche from one that travels in a different pod if the members of these pods utilize significantly different food...

 resembled that of a mid-sized vulture

Vulture

Vulture is the name given to two groups of convergently evolved scavenging birds, the New World Vultures including the well-known Californian and Andean Condors, and the Old World Vultures including the birds which are seen scavenging on carcasses of dead animals on African plains...

 or eagle

Eagle

Eagles are members of the bird family Accipitridae, and belong to several genera which are not necessarily closely related to each other. Most of the more than 60 species occur in Eurasia and Africa. Outside this area, just two species can be found in the United States and Canada, nine more in...

.

E. leali was possibly fairly closely related to Avisaurus

Avisaurus

Avisaurus is a genus of enantiornithine bird from the Late Cretaceous of North America.Two species are known; the type species A. archibaldi and A. gloriae...

, another genus of carnivorous enantiornithines, though its exact relationship is unclear. It is placed in a family

Family (biology)

In biological classification, family is* a taxonomic rank. Other well-known ranks are life, domain, kingdom, phylum, class, order, genus, and species, with family fitting between order and genus. As for the other well-known ranks, there is the option of an immediately lower rank, indicated by the...

 of its own, Enantiornithidae.

Other species from Asia

Asia

Asia is the world's largest and most populous continent, located primarily in the eastern and northern hemispheres. It covers 8.7% of the Earth's total surface area and with approximately 3.879 billion people, it hosts 60% of the world's current human population...

 that were previously placed in this genus are now split off. The former Enantiornis martini is now placed in Incolornis

Incolornis

Incolornis is an extinct genus of basal birds from the Late Cretaceous . Remains have been found in the Bissekty Formation in Uzbekistan.It is only known from fragmentary coracoids...

, while the former Enantiornis walkeri is now tentatively assigned to Explorornis

Explorornis

Explorornis is a genus of Mesozoic birds. It lived during the mid-late Turonian stage, around 90 million years ago.Unlinke many contemporary genera, which are only known from a handful of remains that cannot be compared among each other, Explorornis is known from a handful of coracoids which are...

. The reasons for this are that these birds were described when the diversity of enantiornithine birds was underestimated.