''Kambara'' 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 ...

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In the hierarchy of biological classification, genus com ...

mekosuchine Mekosuchinae is an extinct clade of Crocodilia, crocodilians from the Cenozoic of Australasia. They first appear in the fossil record in the Eocene in Australia, and survived until the arrival of humans: in the Pleistocene in Australia and within ...

crocodylian Crocodilia (or Crocodylia, both ) is an order of mostly large, predatory, semiaquatic reptiles, known as crocodilians. They first appeared 95 million years ago in the Late Cretaceous period (Cenomanian stage) and are the closest living re ...

that lived during the

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' ...

epoch in

Australia Australia, officially the Commonwealth of Australia, is a Sovereign state, sovereign country comprising the mainland of the Australia (continent), Australian continent, the island of Tasmania, and numerous List of islands of Australia, sma ...

Description

At around 55 million years old, remains of ''Kambara'' are among the oldest

Tertiary Tertiary ( ) is a widely used but obsolete term for the geologic period from 66 million to 2.6 million years ago. The period began with the demise of the non-avian dinosaurs in the Cretaceous–Paleogene extinction event, at the start ...

fossils found in Australia (although there are some recent

Cretaceous The Cretaceous ( ) is a geological period that lasted from about 145 to 66 million years ago (Mya). It is the third and final period of the Mesozoic Era, as well as the longest. At around 79 million years, it is the longest geological period of th ...

fossils that are twice that age). ''Kambara'' is the oldest known mekosuchine. The genus name comes from an Aboriginal term meaning "crocodile". There are currently four species of ''Kambara'' described: 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 ...

''K. murgonensis'' (Willis & Molnar, 1993), ''K. implexidens'' (Salisbury & Willis, 1996), ''K. molnari'' (Holt et al., 2005), and ''K. taraina'' (Buchanan, 2009). All four species have a generalised crocodylian body plan, growing to sizes similar to the modern

Saltwater Crocodile The saltwater crocodile (''Crocodylus porosus'') is a crocodilian native to saltwater habitats and brackish wetlands from India's east coast across Southeast Asia and the Sundaic region to northern Australia and Micronesia. It has been listed ...

, ''Crocodylus porosus''. ''Kambara'' shows an interesting characteristic of having multiple bite patterns within the same genus. ''Kambara murgonensis'' has a near complete

overbite Overbite is the extent of vertical ( superior-inferior) overlap of the maxillary central incisors over the mandibular central incisors, measured relative to the incisal ridges. The term overbite does not refer to a specific condition, nor is ...

, ''K. implexidens'' a more interlocking dentition and ''K. molnarai'' an intermediate condition. While initially thought to be the most primitive member of an

Australasia Australasia is a region that comprises Australia, New Zealand and some neighbouring islands in the Pacific Ocean. The term is used in a number of different contexts, including geopolitically, physiogeographically, philologically, and ecologica ...

n radiation of mekosuchine crocodylians, recent studies (Holt, et al., 2007) have suggested that this may not be the case, and that there are at least two separate lineages in Australia. ''Kambara'' and other mekosuchines are often thought to have been better adapted to movement on land than are living crocodilians. The degree of twisting or torsion in the

humerus The humerus (; ) is a long bone in the arm that runs from the shoulder to the elbow. It connects the scapula and the two bones of the lower arm, the radius and ulna, and consists of three sections. The humeral upper extremity consists of a roun ...

of ''Kambara'' is less than that of living crocodilians, and the shoulder joint of ''Kambara'' is stronger and allows for greater motion than those of modern species. However, ''Kambara'' is still thought to have been at least partially aquatic because its head is flattened like that of typical aquatic crocodilians. Fossils have been found at the

Murgon fossil site The Murgon fossil site is a paleontology, paleontological site of early Eocene age in south-eastern Queensland, Australia. It lies near the town of Murgon, some 270 km north-west of Brisbane. The Murgon site is important as the only site on ...

in south-eastern

Queensland ) , nickname = Sunshine State , image_map = Queensland in Australia.svg , map_caption = Location of Queensland in Australia , subdivision_type = Country , subdivision_name = Australia , established_title = Before federation , established_ ...

Phylogeny

A 2018

tip dating Tip dating is a technique used in molecular dating that allows the inference of time-calibrated phylogenetic trees. Its defining feature is that it uses the ages of the samples to provide time information for the analysis, in contrast with traditio ...

study by Lee & Yates simultaneously using morphological, molecular (

DNA sequencing DNA sequencing is the process of determining the nucleic acid sequence – the order of nucleotides in DNA. It includes any method or technology that is used to determine the order of the four bases: adenine, guanine, cytosine, and thymine. Th ...

), and

stratigraphic Stratigraphy is a branch of geology concerned with the study of rock layers (strata) and layering (stratification). It is primarily used in the study of sedimentary and layered volcanic rocks. Stratigraphy has three related subfields: lithostrati ...

(

fossil A fossil (from Classical Latin , ) is any preserved remains, impression, or trace of any once-living thing from a past geological age. Examples include bones, shells, exoskeletons, stone imprints of animals or microbes, objects preserved ...

age) data established the inter-relationships within

Crocodilia Crocodilia (or Crocodylia, both ) is an order of mostly large, predatory, semiaquatic reptiles, known as crocodilians. They first appeared 95 million years ago in the Late Cretaceous period ( Cenomanian stage) and are the closest living ...

, which was expanded upon in 2021 by Hekkala ''et al.'' using

paleogenomics Paleogenomics is a field of science based on the reconstruction and analysis of genomic information in extinct species. Improved methods for the extraction of ancient DNA (aDNA) from museum artifacts, ice cores, archeological or paleontological site ...

by extracting DNA from the extinct ''

Voay ''Voay'' is an extinct genus of crocodile from Madagascar that lived during the Late Pleistocene to Holocene, containing only one species, ''V. robustus''. Numerous subfossils have been found, including complete skulls, noted for their distinctiv ...

''. The below

cladogram A cladogram (from Greek ''clados'' "branch" and ''gramma'' "character") is a diagram used in cladistics to show relations among organisms. A cladogram is not, however, an evolutionary tree because it does not show how ancestors are related to d ...

from the latest studies shows the placement of ''Kambara'' within

Mekosuchinae Mekosuchinae is an extinct clade of crocodilians from the Cenozoic of Australasia. They first appear in the fossil record in the Eocene in Australia, and survived until the arrival of humans: in the Pleistocene in Australia and within the Holocene ...

References

* Buchanan, L.A. 2009. "''Kambara taraina'' sp. nov. (Crocodylia, Crocodyloidea), a new Eocene mekosuchine from Queensland, Australia, and a revision of the genus". ''Journal of Vertebrate Paleontology'' 29 (2): 473–486. * Holt, T. R., S. W. Salisbury, and P. M. A. Willis. 2005. A new species of mekosuchine crocodilian from the middle Palaeogene Rundle Formation, central Queensland. ''Memoirs of the Queensland Museum'' 50: 207–218. * Holt, T. R., S. W. Salisbury, T. H. Worthy, C. Sand and A. Anderson. 2007. New material of ''Mekosuchus inexpectatus'' (Crocodylia: Mekosuchinae) from the Quaternary of New Caledonia. CAVEPS 2007, Melbourne Australia. * Salisbury, S. W., and P. M. A. Willis. 1996. A new crocodylian from the early Eocene of south-eastern Queensland and a preliminary investigation of the phylogenetic relationships of crocodyloids. ''Alcheringa'' 20: 179–226. * Willis, P. M. A., R. E. Molnar, and J. D. Scanlon. 1993. An early Eocene crocodilian from Murgon, southeastern Queensland. ''Kaupia'' 3: 27–33.

External links

* Mekosuchinae Eocene crocodylomorphs Crocodiles of Australia Prehistoric pseudosuchian genera {{paleo-archosaur-stub