Limenavis
Encyclopedia
Limenavis is a prehistoric bird
genus
from the Late Cretaceous
. It lived about 70 million years ago, around the Campanian
-Maastrichtian
boundary. Known from several broken bones, the remains of the only known species
Limenavis patagonica were found in rocks of the "lower member" of the Allen Formation
at Salitral Moreno, 20 km south of General Roca, Río Negro
(Argentina
).
It is quite certainly a carinatae
, a member of the clade
containing living birds and a few very closely related extinct Mesozoic
taxa such as Ichthyornis
. It was even proposed to have been a paleognath, perhaps related to the ancestors of tinamou
s or rhea
s. Though such birds must have existed by that time already, and most likely at least tinamou ancestors (basal Tinamiformes) did live in South America
by the Late Cretaceous, it is not too likely that L. patagonica is indeed a member of the Neornithes.
However, of all the prehistoric birds known to date, this species is certainly among those closest to the common ancestor of all living birds. Its generic name pays tribute to this fact: Limenavis, meaning "bird of the threshold" or "limit-bird", is derived from Latin
limen ("threshold") + avis ("bird"). The specific name patagonica refers to the specimen's Patagonia
n provenance.
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...
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...
from 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...
. It lived about 70 million years ago, around the Campanian
Campanian
The Campanian is, in the ICS' geologic timescale, the fifth of six ages of the Late Cretaceous epoch . The Campanian spans the time from 83.5 ± 0.7 Ma to 70.6 ± 0.6 Ma ...
-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...
boundary. Known from several broken bones, the remains of the only known species
Species
In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...
Limenavis patagonica were found in rocks of the "lower member" of the Allen Formation
Allen Formation
The Allen Formation is a geological formation in Argentina whose strata date back to the Late Cretaceous The Allen Formation is a geological formation in Argentina whose strata date back to the Late Cretaceous The Allen Formation is a geological formation in Argentina whose strata date back to the...
at Salitral Moreno, 20 km south of General Roca, Río Negro
General Roca, Río Negro
General Roca is a city in the northeast of the Argentine province of Río Negro, northern Patagonia. UN/LOCODE is ARGNR.It was founded on September 1, 1879 by Coronel Lorenzo Vintter during the Conquest of the Desert...
(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 is quite certainly a carinatae
Carinatae
This article is about bird taxonomy; for the topic in pottery and glassware design, see Carinate.The Carinatae are, in phylogenetic taxonomy, the last common ancestor of the Neornithes and Ichthyornis , and all its descendants...
, a member of the clade
Clade
A clade is a group consisting of a species and all its descendants. In the terms of biological systematics, a clade is a single "branch" on the "tree of life". The idea that such a "natural group" of organisms should be grouped together and given a taxonomic name is central to biological...
containing living birds and a few very closely related extinct 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...
taxa such as 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,...
. It was even proposed to have been a paleognath, perhaps related to the ancestors of tinamou
Tinamou
The tinamous are a family comprising 47 species of birds found in Central and South America. One of the most ancient living groups of bird, they are related to the ratites. Generally ground dwelling, they are found in a range of habitats....
s or rhea
Rhea (bird)
The rheas are ratites in the genus Rhea, native to South America. There are two existing species: the Greater or American Rhea and the Lesser or Darwin's Rhea. The genus name was given in 1752 by Paul Möhring and adopted as the English common name. Möhring's reason for choosing this name, from the...
s. Though such birds must have existed by that time already, and most likely at least tinamou ancestors (basal Tinamiformes) did live in South America
South America
South America is a continent situated in the Western Hemisphere, mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere. The continent is also considered a subcontinent of the Americas. It is bordered on the west by the Pacific Ocean and on the north and east...
by the Late Cretaceous, it is not too likely that L. patagonica is indeed a member of the Neornithes.
However, of all the prehistoric birds known to date, this species is certainly among those closest to the common ancestor of all living birds. Its generic name pays tribute to this fact: Limenavis, meaning "bird of the threshold" or "limit-bird", is derived from Latin
Latin
Latin is an Italic language originally spoken in Latium and Ancient Rome. It, along with most European languages, is a descendant of the ancient Proto-Indo-European language. Although it is considered a dead language, a number of scholars and members of the Christian clergy speak it fluently, and...
limen ("threshold") + avis ("bird"). The specific name patagonica refers to the specimen's Patagonia
Patagonia
Patagonia is a region located in Argentina and Chile, integrating the southernmost section of the Andes mountains to the southwest towards the Pacific ocean and from the east of the cordillera to the valleys it follows south through Colorado River towards Carmen de Patagones in the Atlantic Ocean...
n provenance.