''Crocodylus'' is a

genus Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...

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 more loosely to include all extant member ...

in the family

Crocodylidae 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 more loosely to include all extant membe ...

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 ' (1768) ...

in 1768. ''Crocodylus'' contains 13–14

extant Extant or Least-concern species, least concern is the opposite of the word extinct. It may refer to: * Extant hereditary titles * Extant literature, surviving literature, such as ''Beowulf'', the oldest extant manuscript written in English * Exta ...

(living) species and 5

extinct Extinction is the termination of an organism by the death of its Endling, last member. A taxon may become Functional extinction, functionally extinct before the death of its last member if it loses the capacity to Reproduction, reproduce and ...

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 Genus (; : genera ) is a taxonomic rank above species and below family as used in the biological classification of living and fossil organisms as well as viruses. In binomial nomenclature, the genus name forms the first part of the binomial s ...

Extant species

The 13–14 living species are:

Fossils

''Crocodylus'' also includes five

species A species () is often defined as the largest group of organisms in which any two individuals of the appropriate sexes or mating types can produce fertile offspring, typically by sexual reproduction. It is the basic unit of Taxonomy (biology), ...

: * † ''

Crocodylus anthropophagus ''Crocodylus anthropophagus'' is an extinct species of crocodile from the Pleistocene of Tanzania. It lived 1.84 million years ago. It was a large-sized predator reaching a length of . Etymology ''Crocodylus anthropophagus'' was first named by ...

'' is an extinct crocodile from Plio-Pleistocene of Tanzania. * † '' Crocodylus checchiai'' is an extinct crocodile from Late Miocene of Kenya. * † ''

Crocodylus falconensis ''Crocodylus falconensis'' is an extinct species of crocodile known from the early Pliocene of the lower part of the Vergel Member of the San Gregorio Formation of Venezuela. ''C. falconensis'' was named in 2013 after Falcón State and is though ...

'' is an extinct crocodile from Early Pliocene of Venezuela. * † ''

Crocodylus palaeindicus ''Crocodylus palaeindicus'' is an extinct species of crocodile from southern Asia. ''C. palaeindicus'' lived from the Miocene to the Pliocene. It may be an ancestor of the living Mugger crocodile. History ''C. palaeindicus'' was first named by ...

'' 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

While taxonomists generally agree that the crown group of ''Crocodylus'' appeared ~16 - 14 million years ago, there is an ongoing debate discussing whether the genus has an African or Indo-Pacific origin. Proponents of the African origin point towards

phylogenetic In biology, phylogenetics () is the study of the evolutionary history of life using observable characteristics of organisms (or genes), which is known as phylogenetic inference. It infers the relationship among organisms based on empirical dat ...

evidence suggesting that the most recent common ancestor of ''Crocodylus'' and its sister genus, ''

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 ...

,'' diverged around 25 million years ago near the

Oligocene The Oligocene ( ) is a geologic epoch (geology), epoch of the Paleogene Geologic time scale, Period that extends from about 33.9 million to 23 million years before the present ( to ). As with other older geologic periods, the rock beds that defin ...

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. This theory is supported by the existence of closely related African genera ''

Osteolaemus ''Osteolaemus'' is a genus of crocodiles. They are small, secretive crocodiles that occur in wetlands of West and Middle Africa. They are commonly known as the African dwarf crocodiles. Unlike other crocodiles, ''Osteolaemus'' are strictly noctur ...

'' and ''

Mecistops ''Mecistops'' is a genus of crocodiles, the slender-snouted crocodiles, native to sub-Saharan Africa. Taxonomy and etymology Traditionally placed in '' Crocodylus'', recent studies in DNA and morphology have shown that it is in fact basal to '' ...

''. Proponents of the Indo-Pacific origin claim that the origin of the genus closely coincides with the appearance of the oldest known species, ''

,'' in South Asia. Additionally, mitochondrial analysis consistently places Indo-Pacific species '' Crocodylus mindorensis'', ''

Crocodylus novaeguineae The New Guinea crocodile (''Crocodylus novaeguineae'') is a small species of crocodile found on the island of New Guinea north of the mountain ridge that runs along the centre of the island. The population found south of the mountain ridge, form ...

'', and ''

Crocodylus johnstoni The freshwater crocodile (''Crocodylus johnstoni)'', also known commonly as the Australian freshwater crocodile, Johnstone's crocodile, and the freshie, is a species of crocodile native to the northern regions of Australia. Unlike its much lar ...

'' in the basal-most clade of the genus. All known

New World The term "New World" is used to describe the majority of lands of Earth's Western Hemisphere, particularly the Americas, and sometimes Oceania."America." ''The Oxford Companion to the English Language'' (). McArthur, Tom, ed., 1992. New York: ...

and African ''crocodylus'' species have a much more recent evolutionary origin. While the exact origins of the genus remain uncertain, the most recent common ancestor of the species likely utilized osmoregulatory adaptations, including lingual salt glands, to radiate across the tropics.

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, thymine, cytosine, and guanine. The ...

), 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: lithost ...

(

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 preserve ...

age) data established the inter-relationships within

. 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 Crocodylinae is a subfamily of true crocodiles within the family Crocodylidae, and is the sister taxon to Osteolaeminae ( dwarf crocodiles and slender-snouted crocodiles). Taxonomy Crocodylinae was cladistically defined by Christopher Brochu ...

and

Osteolaeminae Osteolaeminae is a subfamily of true crocodiles within the family Crocodylidae containing the dwarf crocodiles and slender-snouted crocodiles, and is the sister taxon to Crocodylinae. Taxonomy Osteolaeminae was named by Christopher Brochu in ...

. The below

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

shows the results of the latest study:

References

{{Authority control Crocodylidae Extant Miocene first appearances Reptile genera Taxa named by Josephus Nicolaus Laurenti