Turtles of the Lee Creek Mine (Pliocene: North Carolina)

Abstract

Eleven taxa of turtles have been recovered from the Lee Creek Mine: a sideneck turtle ( Bothremys)\ six seaturtles ( Caretta, IChelonia, Lepidochelys, Procolpochelys, Syllomus, and Psephophorus); two pond turtles (probably Pseudemys and Trachemys); a softshell turtle (trionychid); and a giant tortoise ( Geochelone ). The fossils are largely disassociated skeletal elements and fragments derived from spoil piles created by drag-line mining of phosphate. The mining removes and discards the Yorktown Formation (Pliocene) and processes much of the Pungo River Formation (middle Miocene), hence the Lee Creek Mine turtles are mainly from the lower Pliocene. The turtle fauna appears to be a natural assemblage of extant and extinct taxa. Caretta and Syllomus are the most abundant fossils; a few specimens of each had some adherent Yorktown matrix. Geochelone fossils are next in abundance, although an order of magnitude less than Caretta and Syllomus. The other genera are each represented by fewer than 10 fragments or elements. Cranial and carapacial differences indicate that the Lee Creek Caretta represents a new species, C. patriciae. The Geochelone also differs from its eastern North American Pliocene contemporaries by its larger size and unique plastral morphology. The fossils of the other taxa are too few and fragmentary to identify reliably to species or genus.