2. FUTURE TRENDS
3. NO. OF SPECIES?
4. OTHER DEBATES
WANT MORE DETAIL? CHECK OUT KING & BURKE 1997
READ THE DEBATE ABOUT CAIMAN CLASSIFICATION
BACK TO THE
OTHER DEBATES IN CROC TAXONOMY
Crocodilian science is full of interesting debates! Here are some more.
SPECIES AND SUBSPECIES
In addition to the 23 recognised crocodilian species, there are a number of subspecies which are often discussed. Most of the commonly discussed subspecies (or species) are listed in the table below. The accepted ones are marked in blue, whereas the doubted or rejected ones are marked in red.
C. c. crocodilus
C. c. apaporiensis
C. c. fuscus
C. c. yacare
C. c. chiapasius
C. c. paraguayensis
C. c. matagrossiensis
C. l. chacoensis
C. n. africanus
C. n. chamses
C. n. corviei
C. n. madagascariensis
C. n. niloticus
C. n. pauciscutatus
C. n. suchus
C. n. novaeguineae
C. n. mindorensis
C. p. kimbula
C. p. minikanna
O. t. tetraspis
O. t. osborni
As you can see, there have been quite a few different subspecies proposed, and the above isn't even all of them! Subspecies are normally suggested when apparently geographically isolated populations show different morphological characters to the type species, but whether these actually deserve a different classification has been open to considerable debate. Brian Warren has written a very interesting and relevant discussion on caiman taxonomy which discusses some of the issues. In some cases, however, subspecies may turn out to be more than was originally thought: new evidence looking at the DNA of different populations of the African dwarf crocodile, Osteolaemus tetraspis, has revealed that the two different subspecies may be different enough to be classified as totally separate species.
There is another species which is sometimes discussed, Crocodylus raninus. This is thought to occur in Borneo and Kalimantan, and although there is some supportive evidence for it, hard data are still lacking and thus the species is not recognised. Many workers cannot discount the possibility that it might be simply a regional variation on Crocodylus novaeguineae or possibly a hybrid with another sympatric species (e.g. Crocodylus porosus).
SPELLINGS AND MISSPELLINGS
There is another fascinating debate which concerns the actual rules of nomenclature as it applies to the Australian freshwater crocodile. When Gerald Krefft originally described this crocodile, he called it Crocodylus johnsoni after its discoverer, Mr Johnson of Cardwell, Rockingham Bay, Queensland. Six months later he wrote a letter to Dr John E. Gray, who submitted a note to the Australian Museum, pointing out that the species should actually correctly be named Crocodylus johnstoni because its discoverer was actually called Mr Johnston. One wonders whether Krefft often made a habit of misspelling names, as the discoverer's real name was Mr Robert Johnstone! Regardless, Krefft made an error in naming the species through an honest mistake, which he later tried to correct. However, the ICZN (International Code of Zoological Nomenclature) states that in such a case, the original designation is the one which must stand.
Now this is where is gets even more interesting! A similar situation occurred with the American alligator, which was originally named as Alligator mississipiensis without the second "p". However, in this case the ICZN rule was overturned in favour of the current spelling Alligator mississippiensis. Why one, and not the other?
"I may be able to shed some light on this question. A proposal was published in 1956 by the then-secretary of the ICZN, Francis Hemming, to validate Daudin's original 1-'p' spelling. This is published in the Bulletin of Zoological Nomenclature (12:163-175). An objection was raised to this idea by Dr. J.A. Oliver of the New York Zoological Society, who sent a
supplementary application to the ICZN in October 1956. Oliver received
support for his application from four other practicing herpetologists
(including the venerable Hobart Smith).
His reasons were twofold: 1) the name is clearly a misspelling of the geographic locality, and so it should be emended, and 2) it appears as double 'p' in several scientific publications. Regardless of which argument swayed the commission, the application to have the name changed was successful. Volume I, section F of the 1958 Opinions and
Declarations Rendered by the International Commission on Zoological
Nomenclature contains the full account, including the Opinion ultimately
issued emending the spelling to the double 'p' version." Brian Warren
Very interesting! The logic behind changing the name for the American alligator appears to be the same for the Australian freshwater crocodile: the change would correct the misspelling of a proper noun, and the name appears as "johnstoni" in not just several but the majority of scientific publications on the animal. Many Australians ignore the ICZN ruling and use the spelling "johnstoni", although nobody has yet come to the official defence of the freshwater crocodile. Watch this space!
SPELLINGS AND MISSPELLINGS PART II
Another misconception which needs correcting regards the only member of the Gavialidae: the gharial. Or is it the gavial? The name gavial is often used instead of gharial, but which one of the two is right?
The correct common name for Gavialis gangeticus is the gharial. The reason for this is simple: mature male gharials have a bulbous growth on the tip
of their snout, which they blow air through to produce a buzzing sound during courtship. This
growth is known as a "ghara" in Hindu, which means "pot" or "jar" because
that's what it resembles. Gavial is simply a misspelling of this word, which made it into the genus spelling, and which has persisted over time. The use of gavial is not necessarily incorrect, and common names vary so much anyway from one region to another with different crocodilian species. This is why we prefer to use the scientific names to describe species, so there is no ambiguity about what we're talking about. However, there is always room for pedantry!