In an unpublished paper written by Jose Parodiz circa 1977, entitled Marine
Mollusca Collected in Yucatan, Jose documented Pleuroploca gigantea from
the Yucatan.  The entry in the manuscript reads
"124. Pleuroploca gigantea (Kiener, 1840). Loc. 1, 3, young specimens of
different sizes; many adult broken shells, and also egg cases. Maya sites
11, 12, 14, 14a, 15, 18, 20."

Site 1 = Isla Aguada, which is a semi-island on the Laguna de Terminos
opposite to Ciudad Carmen.

Site 3 = Champoton, 65 km. south of Campeche.

Maya Sites:
northern Yucatan 11-14a
11 = Dzibilchatum
12 = Isla Cancun Midden
14 = Balankanche
14a = Chichen Itza

southern Yucatan 15-20
15 = Barton Ramie
18 = Uxatucum
20 = Tikal

Jose did not collect the Mayan sites.  This was info he extracted from a
paper by E. Wyllis Andrews. 1969. The Archaeological Use and Distribution
of Mollusca in the Maya Lowlands. (Publication 34 of the Middle American
Research Institute, Tulane University, New Orleans).   For those not
familiar with Jose, he is the curator emeritus of malacology at the
Carnegie Museum of Natural History; a position he has held for some 20
years.  Prior to this he was curator from 1952-1981, and prior to that he
affiliated with a museum in Argentina for some 20 years.  A malacological
career spanning some 70 years!

Regards,
Charlie