Hi all,
The oldest known fossil horseshoe crab (Lunataspis aurora) have been
reported from Ordovician rocks (445 Ma) in Canada. If confirmed, this
discovery pushes back the oldest known horseshoe crabs ~100 million years!
For more information, see the article below.
http://news.yahoo.com/s/livescience/20080128/sc_livescience/oldesthorseshoecrabf\
ossildiscovered
Best Regards,
Cary R. Easterday