''Afairiguana avius'' is an

extinct Extinction is the termination of a kind of organism or of a group of kinds (taxon), usually a species. The moment of extinction is generally considered to be the death of the last individual of the species, although the capacity to breed and ...

iguanid The Iguanidae is a family of lizards composed of the iguanas, chuckwallas, and their prehistoric relatives, including the widespread green iguana. Taxonomy Iguanidae is thought to be the sister group to the collared lizards (family Crotaphy ...

lizard known from a nearly complete and articulated skeleton discovered in rocks of the Early

Eocene The Eocene ( ) Epoch is a geological epoch (geology), epoch that lasted from about 56 to 33.9 million years ago (mya). It is the second epoch of the Paleogene Period (geology), Period in the modern Cenozoic Era (geology), Era. The name ''Eocene' ...

-aged

Green River Formation The Green River Formation is an Eocene geologic formation that records the sedimentation in a group of intermountain lakes in three basins along the present-day Green River in Colorado, Wyoming, and Utah. The sediments are deposited in very fine ...

Wyoming Wyoming () is a U.S. state, state in the Mountain states, Mountain West subregion of the Western United States. It is bordered by Montana to the north and northwest, South Dakota and Nebraska to the east, Idaho to the west, Utah to the south ...

United States The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country primarily located in North America. It consists of 50 states, a federal district, five major unincorporated territorie ...

. As of the initial description, the skeleton represents the oldest complete

iguania Iguania is an infraorder of squamate reptiles that includes iguanas, chameleons, agamids, and New World lizards like anoles and phrynosomatids. Using morphological features as a guide to evolutionary relationships, the Iguania are believed t ...

n from the

Western Hemisphere The Western Hemisphere is the half of the planet Earth that lies west of the prime meridian (which crosses Greenwich, London, United Kingdom) and east of the antimeridian. The other half is called the Eastern Hemisphere. Politically, the term We ...

, and is the oldest representative of the extant iguanid

family Family (from la, familia) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its ...

anole Dactyloidae are a family of lizards commonly known as anoles () and native to warmer parts of the Americas, ranging from southeastern United States to Paraguay. Instead of treating it as a family, some authorities prefer to treat it as a subfami ...

Polychrotidae The Polychrotidae family (sometimes classified as the Polychrotinae subfamily instead) of iguanian lizards contains the living genus ''Polychrus'' (commonly called bush anoles) and the extinct genus ''Afairiguana''. The family Polychrotidae was o ...

Description

''Afairiguana'' is based on FMNH PR 2379, a skeleton collected from the Warfield Springs locality of the Fossil Butte Member of the Green River Formation. It was described in

2007 File:2007 Events Collage.png, From top left, clockwise: Steve Jobs unveils Apple's first iPhone; TAM Airlines Flight 3054 overruns a runway and crashes into a gas station, killing almost 200 people; Former Pakistani Prime Minister of Pakistan, Pr ...

by Jack Conrad, Olivier Rieppel, and

Lance Grande Roger Lansing Grande (born February 16, 1951), more commonly known as Lance Grande, is an evolutionary biologist and curatorial scientist. His research and work is focused on Paleontology, Ichthyology, Systematics and Evolution. He is best known fo ...

. The

type species In zoological nomenclature, a type species (''species typica'') is the species name with which the name of a genus or subgenus is considered to be permanently taxonomically associated, i.e., the species that contains the biological type specimen ...

is ''A. avius''. The genus is a combination of the

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

word for abstract () and ''iguana'', while the species name is derived from the

Latin Latin (, or , ) is a classical language belonging to the Italic branch of the Indo-European languages. Latin was originally a dialect spoken in the lower Tiber area (then known as Latium) around present-day Rome, but through the power of the ...

word meaning lost (''avius''), referring to the species' geographic distance from other polychrotids. FMNH PR 2379 is essentially complete, including some

cartilaginous Cartilage is a resilient and smooth type of connective tissue. In tetrapods, it covers and protects the ends of long bones at the joints as articular cartilage, and is a structural component of many body parts including the rib cage, the neck and ...

elements, but is somewhat weathered. The skeleton is articulated and is preserved on a

limestone Limestone ( calcium carbonate ) is a type of carbonate sedimentary rock which is the main source of the material lime. It is composed mostly of the minerals calcite and aragonite, which are different crystal forms of . Limestone forms whe ...

slab, on which it is exposed in

ventral Standard anatomical terms of location are used to unambiguously describe the anatomy of animals, including humans. The terms, typically derived from Latin or Greek language, Greek roots, describe something in its standard anatomical position. Th ...

view. It can be distinguished from other iguanians by details of the skull and lower jaw, the form of the ribs, and the location of the

autotomy Autotomy (from the Greek language, Greek ''auto-'', "self-" and ''tome'', "severing", wikt:αὐτοτομία, αὐτοτομία) or self-amputation, is the behaviour whereby an animal sheds or discards one or more of its own appendages, usual ...

planes in the tail vertebrae (the features that allow tail separation). It was a small animal, with the thigh bones being shorter than in length. Conrad ''et al.'' performed a

phylogenetic analysis In biology, phylogenetics (; from Greek φυλή/ φῦλον [] "tribe, clan, race", and wikt:γενετικός, γενετικός [] "origin, source, birth") is the study of the evolutionary history and relationships among or within groups o ...

and found ''Afairiguana'' to be a polychrotid iguanian. Upon description, it became both the oldest Western Hemisphere iguanian known from reasonably complete remains, and the oldest representative of a living iguanian family.

Paleoecology

''Afairiguana'' is one of several lizards known from the Fossil Butte Member of the Green River Formation. This rock unit represents part of

Fossil Lake Fossil Butte National Monument is a United States National Monument managed by the National Park Service, located west of Kemmerer, Wyoming, United States. It centers on an assemblage of Eocene Epoch (56 to 34 million years ago) animal and pla ...

, the smallest and shortest-lived of three prehistoric lake systems that make up the Green River Formation. The lake sediments include a volcanic ash dating to 51.66 million years ago, during the

Early Eocene In the geologic timescale the Ypresian is the oldest age or lowest stratigraphic stage of the Eocene. It spans the time between , is preceded by the Thanetian Age (part of the Paleocene) and is followed by the Eocene Lutetian Age. The Ypresian i ...

. The Warfield Springs locality may have been part of a delta system. Fossils are abundant in the rocks of Fossil Lake, and illustrate a diverse assemblage of plants, bivalves, snails, crustaceans, insects,

rays Ray may refer to: Fish * Ray (fish), any cartilaginous fish of the superorder Batoidea * Ray (fish fin anatomy), a bony or horny spine on a fin Science and mathematics * Ray (geometry), half of a line proceeding from an initial point * Ray (gra ...

, bony fish, salamanders, turtles, lizards, snakes, crocodilians, birds, and mammals.

References

External links

''Afairiguana''
in the

Paleobiology Database The Paleobiology Database is an online resource for information on the distribution and classification of fossil animals, plants, and microorganisms. History The Paleobiology Database (PBDB) originated in the NCEAS-funded Phanerozoic Marine Pale ...

{{Taxonbar, from=Q4688788 Anoles Eocene reptiles of North America Eocene lizards Fossil taxa described in 2007 Polychrotidae Lizard genera Prehistoric reptile genera