Species List
Classification of Crocodilians

CLASSIFICATION | FUTURE TRENDS | HOW MANY SPECIES? | OTHER DEBATES
REFERENCES | SPECIES LIST


1. CLASSIFICATION

2. FUTURE TRENDS

3. NO. OF SPECIES?

4. OTHER DEBATES

5. REFERENCES



WANT MORE DETAIL? CHECK OUT KING & BURKE 1997
Link to King & Burke 1997
CROC CHECKLIST



READ THE DEBATE ABOUT CAIMAN CLASSIFICATION
Link to Brian Warren's Caiman Taxonomy discussion
CAIMAN TAXONOMY



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SPECIES LIST
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Estuarine crocodile


CURRENT CLASSIFICATION

If you thought that classifying crocodiles was easy, think again. There has been a lot of confusion over crocodilian taxonomy for decades, and the debate is still very lively!

Traditionally, the relationships between various species have been described using "Linnean ranks", which places organisms into increasingly specialised groups depending on their apparent shared characteristics. For example, crocodiles are covered in scales, have four legs and a tail, and bask in the sun. This is very similar to a green iguana, and hence both have been classified as reptiles, or more specifically the Class Reptilia. However, crocodiles are clearly physically different to green iguanas in other ways, show different behaviours, and live in totally different ecosystems. To reflect this, green iguanas are placed in the Order Squamata, and crocodiles are placed in the Order Crocodylia.

Taxonomists, however, do not necessarily agree on which species are more closely related to which others, and naming conventions can vary. Revision takes place all the time, which often makes matters more convoluted and leaves interested observers wondering just what to believe. The most recent revision and review of the Linnean system for crocodilians was undertaken by King & Burke (1997) (see link to left if you want to read it), and they classified crocodilians as follows:

CLASS REPTILIA
ORDER CROCODYLIA
FAMILY ALLIGATORIDAE
Genus Alligator
Alligator mississippiensis
Alligator sinensis
Genus Caiman
Caiman crocodilus
Caiman latirostris
Caiman yacare
Genus Melanosuchus
Melanosuchus niger
Genus Paleosuchus
Paleosuchus palpebrosus
Paleosuchus trigonatus
FAMILY CROCODYLIDAE
Subfamily Crocodylinae
Genus Crocodylus
Crocodylus acutus
Crocodylus cataphractus
Crocodylus intermedius
Crocodylus johnstoni*
Crocodylus mindorensis
Crocodylus moreletii
Crocodylus niloticus
Crocodylus novaeguineae
Crocodylus palustris
Crocodylus porosus
Crocodylus rhombifer
Crocodylus siamensis
Osteolaemus tetraspis
Subfamily Tomistominae
Genus Tomistoma
Tomistoma schlegelii
FAMILY GAVIALIDAE
Genus Gavialis
Gavialis gangeticus

Recent discussions in palaeontology have also resulted in the accepted use of another level above families to include extinct forms. This uses the suffix "-oidea" (i.e. Alligatoroidea, Crocodyloidea and Gavialoidea). However, the list of species shown above is perhaps the most widely recognised classification in use today, and is the one adopted by this website. Of course, the story does not end here. Much of the above is now being reappraised through phylogenetic taxonomy, and there are still many debates on areas yet to be adequately resolved with the current system (e.g. whether Tomistoma should be classified with the Crocodylidae or the Gavialidae, which will be discussed here in more detail in a later update).

* NB. King & Burke (1997) actually use the name Crocodylus johnsoni (without a "t") on the basis that it was the original spelling used by Krefft in 1873. However, there is debate over the preferred usage, and johnstoni is widely used (see discussion later).

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