From: Jay Reynolds Freeman (freeman@netcom.com)
Date: Wed Jan 22 1997 - 12:32:36 MST
> [Discussion of size and existence of Tertiary predators]
I summarize from Terry A. Vaughn's _Mammalogy_, 3rd. ed., (Harcourt
Brace Jovanovich, 1986), which was used in the upper-division
mammalogy class I took at San Jose (California) State University two
years ago:
The fossil record for cats is not very complete, but the earliest,
(family _Nimravidae_, not _Felidae_) appeared in the Early Oligocene
(roughly 40 million years ago), with retractile claws and dentition
like modern cats, with additionally some having "saber-like" upper
canines. The book has an photograph of a complete fossil Oligocene
sabertooth skeleton, length perhaps a bit more than a meter from nose
to base of tail, and has drawings of skulls of several other Oligocene
large-toothed cats, that size and a little larger; later ones were
bigger still. This family lasted through the Pliocene. _Felidae_ --
the family to which modern cats belong -- appeared in the Miocene, but
later in the Miocene and in the Pliocene radiated into both
saber-toothed and non-saber-toothed species; some saber-toothed
_Felidae_ had skulls almost as large as those of modern lions.
Saber-toothed _Felidae_ survived until the end of the Pleistocene, and
may have coexisted with humans. "Saber teeth" are an adaptation that
has occurred at least four separate times in mammals, likely as a
specialized adaptation for killing large prey, likely by ambush.
> In any case it's more than a little remarkable that there is so few data
> about a possible big cat ancestor who could have hunted the occasional
> afarensis.
Sigh, not remarkable at all... Who funds paleontology?
> I'm 90% sure
> any predecessor of panthera genera couldn't have been around at
> lucy's time, and if it was, it was in its infancy, far from the
> maneater modern lions and leopards are.
Well, if you believe in evolution, the predator of _Panthera_ had to
be around :-). The rather limited outline presented by Vaughn
certainly suggests the presence of large, powerful cats at that time
(which is not to say that any of these were the direct ancestor of
_Panthera_).
> Any big cat that developed before the main group of big cats
> (panthera) must have been acynonix genera.
Vaughn shows _Acinonyx_ and _Panthera_ as both derived from a common
non-saber-toothed _Felindae_ ancestor, after the split of
saber-toothed _Felinidae_ from non-saber-toothed.
> ***The one thing i may have overlooked is that panthera genera
> probably developed from a large species of proto-acinonyx. So at
> best we have a transitional acinonyx-panthera at lucy's time (again:
> of which there doesn't seem to be any name or data).
Most people seem to think of _Acinonyx_ as more derived, having lost
its retractile claws (which its ancestors had had for tens of millions
of years).
-- Jay Freeman, First Extropian Squirrel
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