Foro (bird)
Encyclopedia
Foro is a mysterious genus
of bird
that lived during the early to mid-Eocene around the Ypresian
-Lutetian
boundary, some 48 million years ago. It is known from fossil
s found in the Green River Formation
of Wyoming
. Only a single species
, Foro panarium, is known.
Its relationships are unknown. It is sometimes placed in a distinct family
Foratidae. It may or may not be related to the Cuculiformes
(including turaco
s) and is sometimes seen as a "missing link
" between the cuckoos and/or turacos and the puzzling Hoatzi
of Amazonia. The latter might be related to any number of different modern birds however; its affinities constitute a major ornithological enigma.
In addition, the Eocene
genus Hoatzi from Argentina
has been allied to both the Hoatzin and Foro and even been considered congener
ic with the latter. What is certain is that the Cuculiformes, especially the turacos, are among the likelier candidates for the Hoatzin's closest living relatives. There is an ancestral hoatzin, Hoazinoides
, from the Early
or Middle Miocene
of Colombia
, which would at least not contradict the assumption that Foro panarium was an ancient member of the Hoatzin lineage or its predecessor. On the other hand, it has been proposed that the Hoatzin belongs to a highly distinct clade
of (probably) Cretaceous
origin, the Metaves. As nothing certain about the evolution
ary history of the Hoatzin lineage throughout the Paleogene
is known at all, F. panarium cannot support or contradict this hypothesis either.
What can be said is that Foro, with its stocky body and rather weak flight apparatus was in all likelihood a bird that did not fly vast distances. Consequently, it is not very likely that it is congeneric with Hoatzi, as North and South America were still separate by some 1600 km (994.2 mi) of shallow seas and the Central American island arc
when these birds lived, and seem to have shared only strong-flying and highly migratory
genera such as seabird
s. Being able to fly at all would still enable even a rather sedentary bird lineage to spread across all of the Americas by then of course; Foro and Hoatzi seem to be distinct genera, but nonetheless in some way related and possibly quite closely so.
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 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...
that lived during the early to mid-Eocene around the Ypresian
Ypresian
In the geologic timescale the Ypresian is the oldest age or lowest stratigraphic stage of the Eocene. It spans the time between and , is preceded by the Thanetian age and is followed by the Eocene Lutetian age....
-Lutetian
Lutetian
The Lutetian is, in the geologic timescale, a stage or age in the Eocene. It spans the time between and . The Lutetian is preceded by the Ypresian and is followed by the Bartonian. Together with the Bartonian it is sometimes referred to as the Middle Eocene subepoch...
boundary, some 48 million years ago. It is known from fossil
Fossil
Fossils are the preserved remains or traces of animals , plants, and other organisms from the remote past...
s found in the Green River Formation
Green River Formation
The Green River Formation is an Eocene geologic formation that records the sedimentation in a group of intermountain lakes. The sediments are deposited in very fine layers, a dark layer during the growing season and a light-hue inorganic layer in winter. Each pair of layers is called a varve and...
of Wyoming
Wyoming
Wyoming is a state in the mountain region of the Western United States. The western two thirds of the state is covered mostly with the mountain ranges and rangelands in the foothills of the Eastern Rocky Mountains, while the eastern third of the state is high elevation prairie known as the High...
. Only a single 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...
, Foro panarium, is known.
Its relationships are unknown. It is sometimes placed in a distinct 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...
Foratidae. It may or may not be related to the Cuculiformes
Cuculiformes
The near passerine bird order Cuculiformes traditionally included three families as below:* Musophagidae - turacos and allies* Cuculidae - cuckoos, coucals, roadrunners and anis* Opisthocomidae - Hoatzin...
(including turaco
Turaco
The turacos make up the bird family Musophagidae , which includes plantain-eaters and go-away-birds. In southern Africa both turacos and go-away-birds are commonly known as louries. They are semi-zygodactylous - the fourth toe can be switched back and forth...
s) and is sometimes seen as a "missing link
Missing Link
Missing link is a nonscientific term for any transitional fossil, especially one connected with human evolution; see Transitional fossil - Missing links and List of transitonal fossils - Human evolution.Missing Link may refer to:...
" between the cuckoos and/or turacos and the puzzling Hoatzi
Hoatzin
The Hoatzin , also known as the Hoactzin, Stinkbird, or Canje Pheasant, is a species of tropical bird found in swamps, riverine forest and mangrove of the Amazon and the Orinoco delta in South America...
of Amazonia. The latter might be related to any number of different modern birds however; its affinities constitute a major ornithological enigma.
In addition, the Eocene
Eocene
The Eocene Epoch, lasting from about 56 to 34 million years ago , is a major division of the geologic timescale and the second epoch of the Paleogene Period in the Cenozoic Era. The Eocene spans the time from the end of the Palaeocene Epoch to the beginning of the Oligocene Epoch. The start of the...
genus Hoatzi from 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...
has been allied to both the Hoatzin and Foro and even been considered congener
Congener
Congener has several different meanings depending on the field in which it is used. Colloquially, it is used to mean a person or thing like another, in character or action.-Biology:In biology, congeners are organisms within the same genus...
ic with the latter. What is certain is that the Cuculiformes, especially the turacos, are among the likelier candidates for the Hoatzin's closest living relatives. There is an ancestral hoatzin, Hoazinoides
Hoazinoides
Hoazinoides is an extinct genus of bird from the middle Miocene from the"Monkey Beds" of the Villavieja Formation of La Venta, Colombia. It is a member of the family Opisthocomidae, which also includes the hoatzin and several other extinct genera. The only known species is Hoazinoides magdalenae...
, from the Early
Early Miocene
The Early Miocene is a sub-epoch of the Miocene Epoch made up of two stages: the Aquitanian and Burdigalian stages....
or Middle Miocene
Middle Miocene
The Middle Miocene is a sub-epoch of the Miocene Epoch made up of two stages: the Langhian and Serravallian stages. The Middle Miocene is preceded by the Early Miocene....
of Colombia
Colombia
Colombia, officially the Republic of Colombia , is a unitary constitutional republic comprising thirty-two departments. The country is located in northwestern South America, bordered to the east by Venezuela and Brazil; to the south by Ecuador and Peru; to the north by the Caribbean Sea; to the...
, which would at least not contradict the assumption that Foro panarium was an ancient member of the Hoatzin lineage or its predecessor. On the other hand, it has been proposed that the Hoatzin belongs to a highly distinct 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...
of (probably) 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...
origin, the Metaves. As nothing certain about the evolution
Evolution
Evolution is any change across successive generations in the heritable characteristics of biological populations. Evolutionary processes give rise to diversity at every level of biological organisation, including species, individual organisms and molecules such as DNA and proteins.Life on Earth...
ary history of the Hoatzin lineage throughout the 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...
is known at all, F. panarium cannot support or contradict this hypothesis either.
What can be said is that Foro, with its stocky body and rather weak flight apparatus was in all likelihood a bird that did not fly vast distances. Consequently, it is not very likely that it is congeneric with Hoatzi, as North and South America were still separate by some 1600 km (994.2 mi) of shallow seas and the Central American island arc
Island arc
An island arc is a type of archipelago composed of a chain of volcanoes which alignment is arc-shaped, and which are situated parallel and close to a boundary between two converging tectonic plates....
when these birds lived, and seem to have shared only strong-flying and highly migratory
Bird migration
Bird migration is the regular seasonal journey undertaken by many species of birds. Bird movements include those made in response to changes in food availability, habitat or weather. Sometimes, journeys are not termed "true migration" because they are irregular or in only one direction...
genera such as seabird
Seabird
Seabirds are birds that have adapted to life within the marine environment. While seabirds vary greatly in lifestyle, behaviour and physiology, they often exhibit striking convergent evolution, as the same environmental problems and feeding niches have resulted in similar adaptations...
s. Being able to fly at all would still enable even a rather sedentary bird lineage to spread across all of the Americas by then of course; Foro and Hoatzi seem to be distinct genera, but nonetheless in some way related and possibly quite closely so.