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First off, amusing names.. the Aussie snake _Montypythonoides_. I
don't have the literature with me, but I recall that this one is now
thought to be a synonym of _Wonambi naracoortensis_ (am I right
Paul?). _Wonambi_ is one of the enormous madtsoiid snakes. They
apparently grew to 7-8 m or more and could have weighed over 800 kg.
I suspect madtsoiids were semiaquatic or amphibious, like giant
living _Eunectes_ (anacondas) and _Acrochordus_ (wart snakes / file
snakes / elephant trunk snakes), but there have been suggestions that
they were cave-dwelling climbers. Madtsoiids are no longer thought to
be close relatives of living pythons and boas, incidentally, and seem
instead to be an ultra-primitive sister-group to all other snakes.
Certainly in the skull they are more lizard-like than any other
There are supposed to be bits of _Paleosaniwa_ from Hell Creek which
indicate _V. komodoensis_ sized individuals (see Long and Welles,
_All New Dinosaurs and Their Friends_). As monitors can hold their
own against crocodiles and carnivorans today, I'm sure they were
smart enough to stay away from theropods. Hey, they might even have
been smarter than most theropods! However, there certainly were not
any _Megalania_-sized monitors in the Mesozoic: these animals are
Australia's giant Cenozoic reptiles (and super-abundant carpet
pythons: more of them per area than any other terrestrial vertebrate
carnivore apparently*) are probably something to do with Australian
low biomass.. or so the story goes (Downund escaped Pleistocene
glaciation, got no fertile soils, got comparatively few herbivores,
got virtually no mammalian carnivores). This theory, nice as it is,
has been invalidated by the large number of Australian marsupial
carnivores described in recent years: new dasyuromorphs, carnivorous
macropodids and thylacoleonids a-plenty.
*If you have the ref for this, I'd be real grateful.
Tom Holtz said that some workers now see this genus as a junior
synonym of _Varanus_. This is not a new idea, but one that goes back
to the middle of this century (see Heuvelmans 1958, for example,
where there is much talk of _V. priscus_ [sic, I think: _V. prisca_
is correct]). To my knowledge, however, the reverse is true.
_Megalania_ is now known to have unusual thickened frontal and a
nuchal crest (see Molnar 1990, _Mem. Ql. Mus._ 29: 437-44) - it is
odd, and is regarded by Molnar as the most derived of varanids.
_Megalania_ neural spines also have very robust neural spines. I
suppose these features could all be allometric, but it would also
seem reasonable to regard them as worthy of generic status.
Coincidentally, I've actually just finished writing an article on
tree monitors. You BCFers may be interested in the possibility that
arboreality may be the primitive condition for some parts of the
varanid family tree - thus explaining the arboreal youngsters of
species nested well into certain varanid clades (e.g. _V.
komodoensis_). Tree monitors (prasinoids) appear to be dwarfed
hyper-derived arboreal end members of the Indo-Australian varanid
World monitor expert (IMHO) is Robert George Sprackland. I don't
think I ever got round to emailing him.
"It was the year of fire"
One for Tom