[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index][Subject Index][Author Index]

Re: Agrosaurus--warning, salt required

In a message dated 98-02-12 01:02:16 EST, dannj@alphalink.com.au writes:

<< If anyone has the Agrosaurus macgillivrai paper handy, and is
 feeling in a giving mood, could someone please answer a few
 questions I have, such as:
 - the meaning of the name (generic and specific)
 - the length of the tibia
 While I've got the subject raised, does anyone know whether Agrosaurus
 is anchisaurid? Is there enough material to be anywhere certain?
 Any and all info will be appreciated, and feel free to reply off
 line. >>

Here is my file on Agrosaurus, as reconstructed from the orignial literature.
However, portions of this account >must be taken with several grains of
salt(!!)<, because it now seems that the specimen was mislabeled and was >not<
found in Australia, etc., etc. as in the original account, but is instead
simply a specimen of the British prosauropod Thecodontosaurus antiquus.


Order: Brontosauria
        Suborder: Prosauropoda
                Family: Thecodontosauridae

Describer: Harry Govier Seeley
Year described: 1891
Etymology: Uncertain because not provided by describer, but probably Agro-,
ized combining form of agros, a Greek word meaning "field" or "wild, rural
area"; and
-saurus, Latinized combining form of sauros, a masculine Greek noun for
"lizard"; thus, "wild-country lizard," describing the region of Australia
where the type specimen was discovered; alternatively: agra, a Greek word
meaning "hunting" or "prey," thus giving "hunting lizard," perhaps referring
to the claws of the type specimen
Type species: Agrosaurus macgillivrayi (by monotypy)
Current status: Provisionally valid genus; possible junior subjective synonym
of      Thecodontosaurus


Describer: Harry Govier Seeley
Year described: 1891
Etymology: To honor John Macgillivray, discoverer of the type specimen
Average adult size: Approximately 2-3 meters long
Average adult weight: Approximately 40-70 kg
Range: Northern Australia
Period: Probably Late Triassic (about 208-235 million years ago)
Diet: Plants
Current status: Provisionally valid species; type species of the genus
Agrosaurus;     referred to the genus Thecodontosaurus by Friedrich von Huene in

General description and taxonomic history:
        The astonishing thing about Agrosaurus is that we know anything 
about it. A British survey ship lands at a random point somewhere along the
coast of northern Queensland, an explorer comes ashore, does a bit of digging
around, finds some specimens, and, without realizing it, makes off not only
with the first dinosaur fossils ever found in Australia but with what is still
the only known Triassic Australian dinosaur and the only known Australian
prosauropod. As any vertebrate paleontologist will confirm, dinosaur fossils
of any kind are extremely rare in Australia, so the discovery of Agrosaurus
hammers at the bounds of credibility. Its existence helps to establish that
prosauropods in general and thecodontosaurids in particular had a worldwide
distribution during the Late Triassic epoch. The importance of Agrosaurus to
dinosaur biogeography makes it extremely frustrating that we do not know
precisely where the fossil was collected and cannot return to the spot,
perhaps to collect more.
        Harry Govier Seeley apparently discovered the Agrosaurus bones, unnamed 
misclassified, while rummaging around in the Mammal Gallery at the British
Museum of Natural History (now known simply as the Natural History Museum).
Even though he described the dinosaur as a small prosauropod allied with
Dimodosaurus (now referred to the genus Plateosaurus) and Massospondylus, many
later scientists considered Agrosaurus a Jurassic coelurosaur. This was
because of the small size of the bones, the uncertain dating of the specimen,
and the discovery of a small, serrated tooth, overlooked by Seeley, associated
with the type specimen.
        Although the Agrosaurus macgillivrayi type specimen is pretty meager, 
bones closely resemble those of the better-known British dinosaur
Thecodontosaurus antiquus. In fact, they look so much like Thecodontosaurus
bones that Friedrich von Huene referred Agrosaurus macgillivrayi to that genus
as a separate species, Thecodontosaurus macgillivrayi. Most paleontologists
remain more cautious and would leave the Australian species out of the British
genus until more complete specimens are discovered. But in any case, we may
guess that Agrosaurus, like Thecodontosaurus, was a small, primitive
prosauropod that may have walked and run on its hind legs and ate plants,
using its relatively large foreclaws for defense.
Type specimen: BMNH 49984, various hind limb bones (left tibia about 20 cm
long, proximal end of right tibia, partial right radius initially identified
by Seeley as a partial fibula, and two claws), all associated in a grayish
breccia matrix filled with bone splinters and evidently belonging to a single
animal, purchased July 1879 by the Museum of Natural History, London, England
from E. Charlesworth, agent for the estate of the then recently deceased S. I.
Waring, in whose collection the specimen had initially resided; in 1906,
Friedrich von Huene described a small, serrated, damaged tooth he found
associated with the specimen (and also reidentified the fibula as a radius),
but the tooth could just as likely have belonged to a scavenging predatory
dinosaur as to the type specimen, and there is no reason other than simple
association with the type specimen to consider it a genuine Agrosaurus tooth
Discoverer: John Macgillivray
When discovered: 1844, during a voyage to Australia by the survey ship HMS
Where discovered: Upper Triassic rocks at the tip of the York Peninsula,
                northern Queensland, Australia (better locality information 
Other important specimens: None known