ABSTRACT

An exposed Late Eocene Archaeocete whale near Matherville, Wayne County, Mississippi was discovered in Spring 1993. Although this specimen consisted mainly of marginally-preserved thoracic and cervical vertebra, with a few rib fragments, a pre-molar tooth with intact enamel was recovered from an indurated block of the Pachuta Marl Member, Yazoo Formation.

Although paleotemperature analyses of Tertiary strata have been routinely made using calcareous microfossils, this specimen represents one of the few isotopic measurements of a homeothermic animal. Stable-isotopic analysis has been made of phosphate tooth enamel of this specimen, and when combined with isotopic analysis of carbonate and phosphate of bone (rib fragments and the cervical vertebra) from the same animal, provides the opportunity to assess previously-published Late Eocene paleotemperature estimates. Estimates of isotopic fractionation of this Late Eocene whale from local sea water are complicated by the fact that there is no modern analog of this fossil whale.