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Re: Favorite Paleotrivia?
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- Subject: Re: Favorite Paleotrivia?
- From: "David Marjanovic" <firstname.lastname@example.org>
- Date: Thu, 12 Mar 2009 23:39:44 +0100
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Fossils of the marine protozoan genus Nummulites (a single-celled
organism) are up to 15 cm across, making them larger than many fossil
birds and mammals
Well, "single-celled"... it cheats. Each of the tiny chambers has a nucleus
of its own.
(I don't think there are any dinosaurs that small?)
Adult nonavian ones? No.
The aïstopod *Phlegethontia* lacks parietals. Instead, the braincase itself
is completely ossified and closed on top of the brain. The ordinary skull
roof stops with the frontals, and then comes naked neurocranium.
Jennifer Clack's 2002 book Gaining Ground mentions that supraneural radials
(extra bones that interfinger with the neural spines) have been found in the
tail of an unspecified anthracosaur. This suggests the presence of a tail
fin with fin rays -- in an animal with 5 fingers per hand, 5 toes per foot,
and an amniote-like phalangeal formula.
Instead of molars, *Edaphosaurus* had fields of blunt teeth on the palate
and on the inside of the lower jaw (coronoid III and prearticular -- the
prearticular forms part of the anvil in the mammalian middle ear).
Derived captorhinids had several toothrows on the maxilla and the dentary
instead -- and this evolved twice independently.
I could go on for hours :-)