DALLAS, TX.- A one-of-a-kind plate displaying the remains of an fossil remains of an amphibian that choked to death on its prey — believed to be the only specimen of an "amphibian aspiration" known to exist — is estimated to bring $150,000+ to lead a world-class selection of fossils, meteorites and unusually large gemstones in Heritage Auctions' Nature & Science Signature® Auction, Oct. 19-20 in Dallas.

"This is definitely a one-of-a-kind, never-to-be-seen-again discovery," said Jim Walker, Director of Nature & Science at Heritage. "The site is closed, which makes this truly a museum piece. Not only is this one of the few fossil examples of this species, this is the only one known with an aspiration. All of these factors combines makes this especially rare and desirable."

The specimen dates to the Permian Period (299 to 251 million years ago) and very clearly shows the bones of an amphibian (Sclerocephalus haeuseri) intertwined with a smaller prey's skull located in the vicinity of the larger animal's throat. The plate has been expertly prepared and shows minute details, down to skin impressions and the tiny, sharp teeth the larger animal used to hook his hapless prey. Little did they know the tussle would be their last.

Of the more than 50 lots of fossil discoveries of various types and ages in the auction include a number of discoveries from Germany such as a dramatic Icthyosaur, dating from the Mesozoic Era, which may bring $20,000+, and a fossil gar (Atractosteus strausi), as found in the Messel Pit, which could sell for $3,000+.

A strong selection of Badlands vertebrates is led by an unusual and pristine fossil horse skull (Mesohippus bairdi) from the Early Oligocene Epoch, may cross the block for $15,000+. A rare juvenile fossil pig skull (Archaeotherium mortoni) may turn up $10,000+, and a fossil skull of an oreodont (Merycoidodon culbertsoni) — an extinct animal closely related to camels and pigs — complete with articulated bones, may exchange hands for $4,000+.

A selection of three dozen meteorites is led by a Gibeon meteorite as found in 1992 in Namibia with a naturally-formed hole, is expected to change hands for $50,000+, as well as an exceptional scalloped Gibeon meteorite, which may bring $26,000+.

Additional natural history rarities and collector's favorites include a rare and pristine egg from the extinct Elephant Bird (Aepyornis maximus). The creature is believed to have grown to over 10 feet (3 meters) in height and to have reached weights approaching 880 pounds. Its massive egg measures 11 inches long and is anticipated to sell for $50,000+.

An exceptional skull cast of STAN, the most complete Tyrannosaurus rex ever found, could sell for $12,000+, an extremely rare scorpion and Velvet mite encased in amber dating from the Oligocene Epoch (34 million to 23 million years ago), could change hands for $4,000+ and a rare cast of a Dodo Bird (Raphus cucullatus), could fetch $3,500.

A stellar line-up of more than 60 rare and exotic gemstones kicks off with a 5.22 carat natural ruby, from Vietnam, which could take top lot honors at $250,000 and a 31.5 carat natural purple spinel that may bring $78,000.