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RE: Carcharias [Was Re: Oviraptorids as Parrots?}
Colin McHenry wrote:
The placement of sand tigers/ grey nurses/ ragged tooths in the top ten
list of 'maneaters' may be a little dated. Every recent piece of info
I've found on them stresses their inoffensive nature as far as humans goes.
I found the exact same thing. I have heard/read that the sand tiger (or
grey nurse) was once *assumed* to be a man-eater because of its outwardly
fearsome appearance. However, this fearsome appearance might have been the
reason why they were blamed for attacks committed by other shark species (as
Colin mentioned); all along, they were probably just innocent bystanders.
Sand tigers are typically slow smimmers that often hover motionless in
shallow, coastal water (such as near where Colin swims). This makes them
very easy to kill. At one time they were killed by trophy-hunters, and I
believe _Carcharias taurus_ is the first shark species to be officially
protected. We humans are far more dangerous to sand tigers than they are to
They are certainly popular as a large shark for aquaria...
Their toothy, "sharky" appearance is one of the reasons why they are so
popular in public aquaria - plus the fact that they are relatively easy to
keep in captivity.
..or alternatively, the bad reputation is a hangover from days when its
'offensive' nature was presumed from its (admittedly impressive)
That's my bet.
Well, there are _Carcharias_ teeth in the Cretaceous of Queensland. Funny
to think that a very similar animal to something that lived alongside
plesiosaurs is still swimming around off the beach where I swim every
Oh yes, this is a dinosaur list... OK, ahem.... The thing about shark teeth
is that they are notoriously difficult to assign to individual taxa. With
_Carcharias_, although the dental record goes back to the Aptian, this
assignment is very controversial, and it is not really clear how ancient
_Carcharias_ is. (_C. taurus_ itself reportedly goes back to the Miocene.)
That's the problem with fossil sharks: the vast majority of species are
known only from teeth, which are usually found isolated and disarticulated.
So while it is possible that a _Carcharias_-like shark was swimming around
at the time of the dinosaurs (phew, got it in!), all we can really be sure
of was that there were sharks with _Carcharias_-like teeth around at this
time. Having said that, the overall morphology of modern _C. taurus_
appears to be quite plesiomorphic by lamniform standards, so Colin may be
absolutely right in saying that Cretaceous _Carcharias_ was very similar to
the modern sand tiger in appearance. (Something for you paleo-artists out
Can you imagine trying to reconstruct a phylogeny of theropods based almost
entirely upon teeth? That's the kind of task fossil shark experts are up
against. The occasional fossil shark skeleton does turn up (like
_Scapanorhynchus_, the Cretaceous goblin shark), but these are few and far
between compared to the huge abundance of isolated teeth.
GIS / Archaeologist http://heretichides.soffiles.com
Melbourne, Australia http://www.geocities.com/dannsdinosaurs
School of Environmental and Life Sciences (Geology)
University of Newcastle
Callaghan NSW 2308
Tel: +61 2 4921 5404
Fax: + 61 2 4921 6925
Colin McHenry & Sarah Johnston
14 Summer Place
Merewether Heights NSW 2291
+61 2 4963 2340