Reptile & Amphibian Forums

I'm a little confused over the two. Are they the same reptile or different? Two different reptile guides give different information. One calls it the Bengal or Clouded Monitor (Varanus bengalensis)the other simply Clouded Monitor (Varanus nebulosus). I'm kinda confused. Also, what are the maximum lengths of these Monitors? The first book mentioned says 175cm while the other says 95cm.

Thank you

http://mampam.50megs.com/monitors/bengalensis.html

Check out walter aufenburgs book on bengalensis, as it is the most reliable sorce of info on this remarkable species ever compiled.
http://www.alibris.com/search/search.cfm?qwork=631421&ptit=The Bengal Monitor&pauth=Auffenberg, Walter&pisbn=&pbest=35.80&pbestnew=1000000.00&pqty=7&pqtynew=0&matches=7&qsort=r

they are the same species, or they are different species, it depends on whether you are a lumper or a splitter. Some taxonomists (people that study the relationships of different species, families etc) like to lump similar animals together into a single species, others like to split slightly dissimilar animals into several species. It can be quite complex and often has little to do with how similar or different they look.

Bengals and cloudeds were considered to be a single species, Varanus bengalensis, but two subspecies, Varanus bengalensis bengalensis (Bengal monitor) and Varanus bengalensis nebulosus (clouded monitor). They have since been split into two species, Varanus bengalensis and Varanus nebulosus (there's a third, too, I think: Varanus vietnamensis). Sometimes they are published as different subspecies of the same species, other times as different species.

There is no such thing as vietnamensis, but simply nebulosus and bengalensis, which as you said are both bengalensis. Kinda like indicus in a way that they cover a vast range, and show variation, but are too genetically simular to be considered distinctively different. Vietnamenis was a name made up by the trade, but has no scientific gorunds.

Sorry, That's not quite correct. Varanus vietnamensis was described by Yang and Liu, 1994, from a specimen purchased in a market in Hekou, Yunnan (but presumably from adjacent Vietnam). This was discussed and placed in the synonymy of V. nebulosus by Boehme and Ziegler in 1997 (Amphibia-Reptilia 18: 207-211). In the same paper Boehme and Ziegler also support the opinion of Auffenberg (1994), who placed V. irrawadicus Yang and Li, 1987, into the synonymy of V. bengalensis. Lastly, Boehme and Ziegler report a specimen of V. bengalensis from Phuket Island, Thailand, which is otherwise within the range of V. nebulosus.

In a recent checklist of monitors of the world, Boehme (2003) considers V. bengalensis and V. nebulosus as separate but closely-related species. This is based in part on the occurrence of the two forms together, and in part on the existence of significant differences in hemipeneal structure between the two. Their distributions are basically complementary, with bengalensis occurring from Pakistan through India, Burma and northwestern Cambodia, meeting nebulosus in central Cambodia and on the upper Malay Peninsula. V. nebulosus occurs in eastern Cambodia, Laos and Vietnam, south through peninsular Malaysia, and on Sumatra and Java.

Hope that helps.
SS

I know of the Yang and Liu reports, but Ive heard that they have never been substantiated, and the desciption of vietnamensis is invalid. Are you aware of more on the credibilty of the claims?

Thnx

That's the point, Sum. Both V. irrawadicus and V. vietnamensis were validly *described*, meaning that the authors met the formal criteria for placing a name in trhe scientific literature, but Auffenberg (irrawadicus) and Boehme and Ziegler (vietnamensis) subsequently demonstrated that the features that were claimed to separate irrawadicus from bengalensis, or vietnamensis from nebulosus, were not sufficient to differentiate the new species from already-named species. Those new names then become what are called junior synonyms of the existing species names.

This is one way that the practice of taxonomy is self-correcting. Mistakes can be pointed out, and the scientific community accepts or rejects the arguments. While the names V. irrawadicus and V. vietnamensis will remain in the synonymy of bengalensis and nebulosus, respectively, the conclusion is that they do not refer to animals that are different from them. So yes, those names are "real", and no, they don't refer to valid species.

SS

It is much appreciated!