''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 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 name, ''Crocodylus'', was proposed by Josephus Nicolaus Laurenti 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'' is an extinct crocodile from Plio-Pleistocene of Tanzania. * † '' Crocodylus checchiai'' 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'' 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,'' 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'' and '' Mecistops''. Proponents of the Indo-Pacific origin claim that the origin of the genus closely coincides with the appearance of the oldest known species, '' Crocodylus palaeindicus,'' in South Asia. Additionally, mitochondrial analysis consistently places Indo-Pacific species '' Crocodylus mindorensis'', '' Crocodylus novaeguineae'', and '' Crocodylus johnstoni'' 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 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, extracting DNA from the extinct '' Voay'', to better establish the relationships within Crocodylidae, including the subfamilies Crocodylinae and Osteolaeminae. 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