Isisfordia
Encyclopedia
Isisfordia (holotype
QM F36211) is an extinct genus
of crocodyliform closely related to crocodilia
ns that lived during the Middle Cretaceous
(Albian
–Cenomanian
). Its fossil
s were discovered in the Winton Formation
in Isisford
, Queensland, Australia in the mid 1990s. Most of the animal was discovered, with the exception of the front portion of the skull. On a later expedition to the location, paleontologists discovered a complete skull which differed from the original specimen in size only.
ized remains led paleontologists
to suggest that the group including modern crocodilians first evolved
30 million years earlier than previously thought, during the Cretaceous
period on the supercontinent
Gondwana
. Analysis of the remains concluded that the vertebrae fit together as they do in modern crocodilians, via loose ball-and-socket joints, as well as a secondary palate similar to that in living crocodilians which allows them to let air pass into the lungs without entering the inside of the mouth.
Holotype
A holotype is a single physical example of an organism, known to have been used when the species was formally described. It is either the single such physical example or one of several such, but explicitly designated as the holotype...
QM F36211) is an extinct 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 crocodyliform closely related to crocodilia
Crocodilia
Crocodilia is an order of large reptiles that appeared about 84 million years ago in the late Cretaceous Period . They are the closest living relatives of birds, as the two groups are the only known survivors of the Archosauria...
ns that lived during the Middle 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...
(Albian
Albian
The Albian is both an age of the geologic timescale and a stage in the stratigraphic column. It is the youngest or uppermost subdivision of the Early/Lower Cretaceous epoch/series. Its approximate time range is 112.0 ± 1.0 Ma to 99.6 ± 0.9 Ma...
–Cenomanian
Cenomanian
The Cenomanian is, in the ICS' geological timescale the oldest or earliest age of the Late Cretaceous epoch or the lowest stage of the Upper Cretaceous series. An age is a unit of geochronology: it is a unit of time; the stage is a unit in the stratigraphic column deposited during the corresponding...
). Its fossil
Fossil
Fossils are the preserved remains or traces of animals , plants, and other organisms from the remote past...
s were discovered in the Winton Formation
Winton Formation
The Winton Formation is a Cretaceous formation in central-western Queensland, Australia. The sauropod dinosaur Austrosaurus is found in the early Cretaceous Winton formation....
in Isisford
Isisford, Queensland
Isisford is a small town located in central western Queensland, Australia. It is located on the Barcoo River, and is approximately 120 kilometres south east of the town of Longreach. At the 2006 census, Isisford and the surrounding area had a population of 262...
, Queensland, Australia in the mid 1990s. Most of the animal was discovered, with the exception of the front portion of the skull. On a later expedition to the location, paleontologists discovered a complete skull which differed from the original specimen in size only.
Relation to modern day crocodilians
The discovery of the fossilFossil
Fossils are the preserved remains or traces of animals , plants, and other organisms from the remote past...
ized remains led paleontologists
Paleontology
Paleontology "old, ancient", ὄν, ὀντ- "being, creature", and λόγος "speech, thought") is the study of prehistoric life. It includes the study of fossils to determine organisms' evolution and interactions with each other and their environments...
to suggest that the group including modern crocodilians first evolved
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...
30 million years earlier than previously thought, during the 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...
period on the supercontinent
Supercontinent
In geology, a supercontinent is a landmass comprising more than one continental core, or craton. The assembly of cratons and accreted terranes that form Eurasia qualifies as a supercontinent today.-History:...
Gondwana
Gondwana
In paleogeography, Gondwana , originally Gondwanaland, was the southernmost of two supercontinents that later became parts of the Pangaea supercontinent. It existed from approximately 510 to 180 million years ago . Gondwana is believed to have sutured between ca. 570 and 510 Mya,...
. Analysis of the remains concluded that the vertebrae fit together as they do in modern crocodilians, via loose ball-and-socket joints, as well as a secondary palate similar to that in living crocodilians which allows them to let air pass into the lungs without entering the inside of the mouth.