Crocodylus Explained

Crocodylus is a genus of true crocodiles in the family Crocodylidae.

Taxonomy

The generic name, Crocodylus, was proposed by Josephus Nicolaus Laurenti in 1768.[1] 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.[2]

Extant species

The 13–14 living species are:

Image Scientific name Taxon authority Common name Distribution
Crocodylus acutus (Cuvier, 1807) Southern Florida and the Atlantic and Pacific coasts of north Mexico to North America as far south as Peru and Venezuela, Cuba, Jamaica, Hispaniola and Grand Cayman.
Crocodylus halli [3] Murray, Russo, Zorrilla & McMahan, 2019 Hall's crocodilesouthern New Guinea
Crocodylus intermedius (Graves, 1819) Colombia and Venezuela
Crocodylus johnstoni Krefft, 1873 Northern regions of Australia
Crocodylus mindorensis Schmidt, 1935 Northern Sierra Madre Natural Park within the Luzon rainforest, San Mariano, Isabela, Dalupiri island in the Babuyan Islands, Abra (province) in Luzon and the Ligawasan Marsh, Lake Sebu in South Cotabato, Pulangi River in Bukidnon, and possibly in the Agusan Marsh Wildlife Sanctuary in Mindanao
Crocodylus moreletii (A. H. A. Duméril & Bibron, 1851) Morelet's crocodile or Mexican crocodile Mexico, Belize and Guatemala
Crocodylus niloticusLaurenti, 1768 Nile crocodile or African crocodile, (the subspecies found in Madagascar, C. n. madagascariensis, is sometimes called the black crocodile) Israel and Syria (historically), Somalia, Ethiopia, Uganda, Kenya, Egypt, the Central African Republic, the Democratic Republic of the Congo, Equatorial Guinea, Tanzania, Rwanda, Burundi, Zambia, Zimbabwe, Gabon, Angola, South Africa, Malawi, Mozambique, Sudan, South Sudan, Botswana, and Cameroon
Crocodylus novaeguineaeSchmidt, 1928 northern New Guinea
Crocodylus palustris(Lesson, 1831) Mugger crocodile, marsh crocodile, or Indian crocodile southern Iran, southern Pakistan, southern Nepal, India, Sri Lanka
Crocodylus porosus Schneider, 1801 Saltwater crocodile or estuarine crocodile Eastern India, Sri Lanka, Southeast Asia and Northern Australia
Crocodylus rhombifer (Cuvier, 1807) Cuba
Crocodylus siamensisSchneider, 1801 Indonesia (Borneo and possibly Java), Brunei, East Malaysia, Laos, Cambodia, Myanmar, Thailand and Vietnam.
Crocodylus suchusGeoffroy, 1807 West African crocodile or desert crocodile Mauritania, Benin, Liberia, Nigeria, Niger, Cameroon, Chad, Central African Republic, Equatorial Guinea, Senegal, Mali, Guinea, Gambia, Burkina Faso, Ghana, Gabon, Togo, Ivory Coast and Republic of Congo
Crocodylus raninus (Considered to be a synonym of Crocodylus porosus; its status remains unclear).[4] S. Müller & Schlegel, 1844 Borneo crocodileBorneo

Fossils

Crocodylus also includes five extinct species:[2]

Evolution

Crocodylus likely originated in Africa and radiated outwards towards Southeast Asia and the Americas, although an Australia/Asia origin has also been considered.[5] Phylogenetic evidence supports Crocodylus diverging from its closest recent relative, the extinct Voay of Madagascar, around 25 million years ago, near the Oligocene/Miocene boundary.[6]

Phylogeny

A 2018 tip dating study by Lee & Yates simultaneously using morphological, molecular (DNA sequencing), and stratigraphic (fossil age) data established the inter-relationships within Crocodylidae.[7] 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.[6]

The below cladogram shows the results of the latest study:

Notes and References

  1. Book: Laurenti . J.N. . Josephus Nicolaus Laurenti . 1768 . Specimen medicum, exhibens synopsin reptilium emendatam cum experimentis circa venena et antidota reptilium austriacorum . Medical Treatise, Exhibiting an Emended Synopsis of Reptiles, with Experiments Concerning Venoms and Antidotes for Austrian Reptiles . Vienna . Joan. Thom. Nob. de Trattnern . XV. Crocodylus . https://gdz.sub.uni-goettingen.de/id/PPN362231184?tify= . 53–55.
  2. Brochu . C.A. . species:Christopher A. Brochu . Storrs . G.W. . species:Glenn W. Storrs . 10.1080/02724634.2012.652324 . A giant crocodile from the Plio-Pleistocene of Kenya, the phylogenetic relationships of Neogene African crocodylines, and the antiquity of Crocodylus in Africa . Journal of Vertebrate Paleontology . 32 . 3 . 587 . 2012 . 2012JVPal..32..587B . 85103427 .
  3. Murray . Christopher M. . species:Christopher M. Murray . Russo . Peter . species:Peter Russo . Zorrilla . Alexander . species:Alexander Zorrilla . McMahan . Caleb D. . species:Caleb D. McMahan . 2019 . Divergent Morphology among Populations of the New Guinea Crocodile, Crocodylus novaeguineae (Schmidt, 1928) Diagnosis of An Independent Lineage and Description of A New Species. . Copeia . 107 . 3. 517–523 . 10.1643/CG-19-240 . free .
  4. www.reptile-database.org.
  5. Oaks. J.R.. species:Jamie Richard Oaks . A time-calibrated species tree of Crocodylia reveals a recent radiation of the true crocodiles . Evolution . 65. 11. 2011. 3285–3297. 10.1111/j.1558-5646.2011.01373.x. 22023592. 7254442. free.
  6. Hekkala . E. . Gatesy . J. . Narechania . A. . Meredith . R. . Russello . M. . Aardema . M. L. . Jensen . E. . Montanari . S. . Brochu . C. . Norell . M. . Amato . G. . 2021-04-27 . Paleogenomics illuminates the evolutionary history of the extinct Holocene "horned" crocodile of Madagascar, Voay robustus . Communications Biology . en . 4 . 1 . 505 . 10.1038/s42003-021-02017-0 . 33907305 . 8079395 . 2399-3642 . free.
  7. Lee, Michael S. Y. . species:Michael S.Y. Lee . Yates, Adam M. . species:Adam Michael Yates . 27 June 2018 . Tip-dating and homoplasy: reconciling the shallow molecular divergences of modern gharials with their long fossil . . 285 . 1881 . 10.1098/rspb.2018.1071 . 30051855 . 6030529 . free.