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EARLY MANIRAPTORS PT II



Hi all. I made several confusing points a while back in a post on Jurassic
maniraptors. Here's an attempt to clear them up and provide a bit more info.
This kind of stuff is news to a lot of people (like, those who argue that bird-
like theropods only post-date their bird descendants;-)). 

>From what I hear there's a variety of new Jurassic maniraptors in the works.
On a recent TV show ('The Great Dinosaur Trail'.. same series where the name
_Neovenator_ was flashed up [shudder..]), Bakker was talking all about 'raptors'
in the Morrison. I assumed he was talking about theropods in general -
apparently he's got a site where large and small theropods together chewed up
a bunch of _Apatosaurus_ leg bones (see CAMPING THEROPODS in the archives). But
he seemed to make it clear enough that he really was talking about Morrison
_dromaeosaurs_. What the..? 

Little teeth provisionally referred to the Maniraptora are described and figured
in Metcalf et al. (1992) - these come from the Gloucestershire Bathonian (Mid
Jurassic) site here in England. I think they're also discussed by Metcalf and
Walker (1993) in _In the Shadow of the Dinosaurs_, but I don't have that to
hand. An amazing assortment of other small Bathonian taxa are reported from the
same site, as are a few bigger things like a cetiosaur and a big megalosaur.
There are also confusing rumours of a small, relatively complete theropod with
big hooked claws. This one did the rumour circuit early last year, but still
nothing on it. Expect more on April 1st I guess.. 

Anyhow, at least one of these Bathonian teeth is labelled tentatively as
'dromaeosaurid-like (juvenile?)'. Feduccia and colleagues might like to note
that dromaeosaurid-like animals were, therefore, around prior to the Lower
Cretaceous (as Tom Holtz has pointed out previously). Michael Benton (1993)
provided an excellent overview of the same Bathonian site, of the maniraptoran
tooth he says: 'New findings include some of the world's oldest frogs,
salamanders and lizards, as well as some of the oldest members of the
Maniraptora, the group that includes birds and their nearest dinosaurian
relatives'. The ceratosaur present in the deposit (restored, basically, as a
_Coelophysis_ in the dioramas) should not cause confusion with any Welsh sites
(new coelophysid footprints), or anything from.. say, the Isle of Skye for
example. Of course, it has. Me, I'm waiting for that new _Sarcosaurus_ skull.

And a possible maniraptoran tail vert has been reported from the Isle of Skye
too, leading Neil Clark to adorn the cover of _Scottish Journal of Geology_ (and
a mug, and a bunch of t-shirts apparently) with some cetiosaur-attacking 
feathery little dromaeosaur-look-alikes. Last I heard, Neil had not verified the
identity of the vert. Neil? I think the Isle of Skye stuff is Bajocian-
Bathonian, but having said that it's probably not. Anyway, it's definitely mid-
Jurassic.

KOPARION. Dan Chure (1994) described _Koparion douglassi_, and suggested that
it was a troodont. As it's Morrison (Kimmeridgian), this would be the earliest
troodont reported ASAIK. Jerry Harris told me, though, that Dan has now changed
his mind, and _Koparion_ is not troodont after all. So, what the hell is it?
 
Jerry also mentioned... 'very troodontid-like teeth from the Middle Jurassic of
England.'. Well that's the second time I've heard of these, but I don't think
I've seen them in the literature. Troodont teeth are distinctive, with big
coarse serrations along the posterior carinae, so I would have thought I'd
remembered them. Can someone point me to a citation?

As for the earliest reliably reported ornithomimid, _Pelecanimimus polyodon_
from the Las Hoyas deposits, Jerry points out that it's Hauterivian-Barremian.
He adds:

> The lesser known but similar deposits in Lleida have been dated as
> Berriasian-Valanginian, but I don't know how much I trust the dates of
> either set.

I haven't heard of these deposits (Lleida ones). Anything we should be
interested in? Sigh, too many animals, not enough time. At least I got the
conodonts out of the way..

_REFS_

BENTON, M. 1993. Diversity and Evolution of the Dinosaurs. _National
Environmental Research Council News_ 27: 30-33

CHURE, D. 1994. _Koparion douglassi_, a New Dinosaur from the Morrison Formation
(Upper Jurassic) of Dinosaur National Monument: the Oldest Troodontid
(Theropoda: Maniraptora). _BYU Geology Studies_ 40: 11-15

METCALF, S.J., VAUGHAN, R.F., BENTON, M.J., COLE, J., SIMMS, M.J. and DARTNALL,
D.L. 1992. A new Bathonian (Middle Jurassic) microvertebrate site, within the
Chipping Norton Limestone Formation at Hornsleasow Quarry, Gloucestershire.
_Proceedings of the Geologists' Assoc._ 103: 321-342

DARREN NAISH