''Crocodylus halli'', also known as Hall's New Guinea crocodile, is a species of

crocodile Crocodiles (family (biology), 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 inclu ...

endemic Endemism is the state of a species being found in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also found elsew ...

to the island of

New Guinea New Guinea (; Hiri Motu Hiri Motu, also known as Police Motu, Pidgin Motu, or just Hiri, is a language of Papua New Guinea, which is spoken in surrounding areas of Port Moresby (Capital of Papua New Guinea). It is a simplified version of ...

. It is found on the southern half of the island, south of the

New Guinea highlands The New Guinea Highlands, also known as the Central Range or Central Cordillera, is a long chain of mountain ranges on the island of New Guinea, including the island's tallest peak, Puncak Jaya , the highest mountain in Oceania. The range is home ...

. It is named after Philip M. Hall, a researcher at the

University of Florida The University of Florida (Florida or UF) is a public land-grant research university in Gainesville, Florida. It is a senior member of the State University System of Florida, traces its origins to 1853, and has operated continuously on its ...

who performed the initial studies to clarify the species' distinctiveness.

Taxonomy

The species was formerly considered a distinct population of the closely related

New Guinea crocodile 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 ...

(''C. novaeguineae''), but

genetic analysis Genetic analysis is the overall process of studying and researching in fields of science that involve genetics and molecular biology. There are a number of applications that are developed from this research, and these are also considered parts of ...

as well as morphological analysis of its skull structure (namely the

postcrania Postcrania (postcranium, adjective: postcranial) in zoology and vertebrate paleontology is all or part of the skeleton apart from the skull. Frequently, fossil remains, e.g. of dinosaurs or other extinct tetrapods, consist of partial or isolated sk ...

and

maxilla The maxilla (plural: ''maxillae'' ) in vertebrates is the upper fixed (not fixed in Neopterygii) bone of the jaw formed from the fusion of two maxillary bones. In humans, the upper jaw includes the hard palate in the front of the mouth. The t ...

) has supported it being classified as its own species. The two species likely diverged within the last 3-8 million years, when the uplift of the New Guinea highlands created a barrier that divided them into separate populations. Despite the common ancestry of the two species, genetic analysis indicates that the

may be more closely related to the putative

Borneo crocodile ''Crocodylus raninus'', the Borneo crocodile, is an enigmatic species of freshwater crocodile endemic to the Southeast Asian island of Borneo.Anon. From crocs to croaks: Borneo's reptiles and amphibians''. Accessed on: 03:41, 4 August 2011 (UTC) ...

(''C. raninus'') than to Hall's New Guinea crocodile. This may indicate that ''C. novaeguinae'' and ''C. raninus'' diverged from each other even more recently than their ancestor did from ''C. halli'', or that the specimen used for ''C. raninus'' was actually a misidentified ''C. novaeguinae''.

Distribution

The species occurs in swamps, rivers, and lakes in the southern half of New Guinea. It is known to occasionally enter

estuaries An estuary is a partially enclosed coastal body of brackish water with one or more rivers or streams flowing into it, and with a free connection to the open sea. Estuaries form a transition zone between river environments and maritime environment ...

, such as the

Fly River The Fly River is the third longest river in the island of New Guinea, after the Sepik River and Mamberamo River, with a total length of and the largest by volume of discharge in Oceania, the largest in the world without a single dam in its catc ...

estuary. Variation is known from individuals across the range, with individuals from Lake Murray having a much wider skull than those from the

Aramia River The Aramia River is a river in southwestern Papua New Guinea. Aramia Riverin Geonames.org (cc-by) post updated 2013-05-07; database downloaded 2015-06-22 See also *List of rivers of Papua New Guinea This is a list of rivers of Papua New Guinea. ...

Behavior

The species nests during New Guinea's

wet season The wet season (sometimes called the Rainy season) is the time of year when most of a region's average annual rainfall occurs. It is the time of year where the majority of a country's or region's annual precipitation occurs. Generally, the sea ...

(November - April), in contrast to ''C. novaeguineae'', which nests near the end of the

dry season The dry season is a yearly period of low rainfall, especially in the tropics. The weather in the tropics is dominated by the tropical rain belt, which moves from the northern to the southern tropics and back over the course of the year. The te ...

(July - November).

In captivity

Three captive crocodiles at the St. Augustine Alligator Farm Zoological Park, formerly considered individuals of ''C. novaeguinae'', were actually found to be ''C. halli'' while the study was being conducted. These were used to substantiate observed differences between ''C. halli'' and ''C. novaeguinae''.

References

{{Taxonbar, from=Q68594258 Crocodylidae Reptiles described in 2019 Crocodilians of New Guinea