''Crocodylus'' is a

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of living and fossil organisms as well as viruses. In the hierarchy of biological classification, genus comes above species and below family. In binomial nom ...

of true

crocodiles Crocodiles (family Crocodylidae) or true crocodiles are large semiaquatic reptiles that live throughout the tropics in Africa, Asia, the Americas and Australia. The term crocodile is sometimes used even more loosely to include all extant memb ...

in the family Crocodylidae.

Taxonomy

The

generic Generic or generics may refer to: In business * Generic term, a common name used for a range or class of similar things not protected by trademark * Generic brand, a brand for a product that does not have an associated brand or trademark, other ...

name, ''Crocodylus'', was proposed by

Josephus Nicolaus Laurenti Josephus Nicolaus Laurenti (4 December 1735, Vienna – 17 February 1805, Vienna) was an Austrian naturalist and zoologist of Italian origin. Laurenti is considered the auctor of the class Reptilia ( reptiles) through his authorship of ' (1 ...

in 1768. ''Crocodylus'' contains 13–14 extant (living) species and 5 extinct species. There are additional extinct species attributed to the genus ''Crocodylus'' that studies have shown no longer belong, although they have not yet been reassigned to new genera.

Extant species

The 13–14 living species are:

Fossils

''Crocodylus'' also includes five extinct

species In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate s ...

: * † '' Crocodylus anthropophagus'' is an extinct crocodile from Plio-Pleistocene of Tanzania. * † ''

Crocodylus checchiai ''Crocodylus checchiai'' is an extinct species of crocodile from the Miocene to Pliocene of Libya and Kenya. ''C. checchiai'' was named in 1947 based on a skull from the Sahabi Formation. Remains from the lower Nawata Formation in the Turkana ...

'' is an extinct crocodile from Late Miocene of Kenya. * † '' Crocodylus falconensis'' is an extinct crocodile from Early Pliocene of Venezuela. * † '' Crocodylus palaeindicus'' is an extinct crocodile the Miocene to the Pleistocene of southern Asia. * † ''

Crocodylus thorbjarnarsoni ''Crocodylus thorbjarnarsoni'' is an extinct species of crocodile from the Pliocene and Pleistocene of the Turkana Basin in Kenya. It is closely related to the species ''Crocodylus anthropophagus'', which lived during the same time in Tanzania. ' ...

'' is an extinct crocodile from Plio-Pleistocene of Kenya.

Evolution

''Crocodylus'' likely originated in Africa and radiated outwards towards Southeast Asia and the Americas, although an Australia/Asia origin has also been considered.

Phylogenetic 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 ...

evidence supports ''Crocodylus'' diverging from its closest recent relative, 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 ...

'' of

Madagascar Madagascar (; mg, Madagasikara, ), officially the Republic of Madagascar ( mg, Repoblikan'i Madagasikara, links=no, ; french: République de Madagascar), is an island country in the Indian Ocean, approximately off the coast of East Africa ...

, around 25 million years ago, near the Oligocene/

Miocene The Miocene ( ) is the first epoch (geology), geological epoch of the Neogene Period and extends from about (Ma). The Miocene was named by Scottish geologist Charles Lyell; the name comes from the Greek words (', "less") and (', "new") and mea ...

boundary.

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), 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: lithostra ...

(

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 Crocodylidae. In 2021, Hekkala ''et al.'' were able to use

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 ...

, extracting DNA from the extinct ''

'', to better establish the relationships within Crocodylidae, including the subfamilies Crocodylinae and Osteolaeminae. 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 ...

shows the results of the latest study:

References

{{Taxonbar, from=Q309495 Crocodylidae Extant Miocene first appearances Reptile genera Taxa named by Josephus Nicolaus Laurenti