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RE: Etymology of Ornithomimus sedens?
From: Ben Creisler
You can read Marsh’s original description at Google Books online. Note below
that the most important feature for Marsh is the coossification of the the
ilium, ischium, and pubis (made all caps here). I suspect the meaning he had in
mind for “sedens” is “fixed, firm, immovable, “ a meaning derived from the
original meaning “sit” for sedeo in Latin. In this case, it would refer to the
fact that all the bones in the pelvis are fixed firmly together. Click on the
highlighted link to Lewis and Short to check the different meanings
The remarkable Dinosaurs described by the writer, and referred to the present
genus, representing a distinct family, were mainly from fragmentary remains,
but differed widely from all forms then known. Since then explorations in the
same horizon further north have brought to light various other specimens, which
prove the group to be of great interest, but make it probable that they should
be referred, not to the Ornithopoda, but to the Theropoda.
The present species is based upon the nearly complete pelvis, with various
vertebrae, and some other parts of the skeleton. THE MOST STRIKING FEATURE OF
THE PELVIS IS THE FACT, THAT THE ILIUM, ISCHIUM, AND PUBIS ARE FIRMLY
COOSSIFIED WITH EACH OTHER, AS IN RECENT BIRDS. This character has been
observed hitherto among Dinosaurs, only in the genus Ceratosaurus described by
the writer from the Jurassic of Wyoming. The present pelvis resembles that of
Ceratosaurus in its general features, but there is no foramen in the pubis.
There are five vertebra in the sacrum, firmly coossified with each other, as
are also the sacral spines. The sacral vertebra' are grooved below, with the
sides of the centra excavated. The caudals have the diplosphenal articulation,
and the first caudal bears a chevron. All
some of them, at least, are apparently pneumatic. The sacrum measures fifteen
inches in length, and the twelve caudals following occupy a space of thirty-one
inches. The known remains indicate a reptile about eight or ten feet in length.
This came up in a chatroom discussion earlier tonight. In Latin the word
"sedens" means "seated," and the holotype of O. sedens is just the pelvic
region. However, I guessed that "se" could also be the prefix meaning "apart"
or "on one's own," while "dens" means "tooth": roughly, one apart from teeth.
Did Marsh in 1892 know that ornithomimids were toothless, and could the double
meaning be intentional?