The Herpetological Journal

pp. 81-90
Authors: Holman, J. Alan & Fritz, Uwe

Abstract: Middle and Late Miocene fossils of the box turtle genus Terrapene are reviewed. The oldest known Terrapene specimens originate from the Medial and Late Barstovian North American Land Mammal Ages of Nebraska. Two nuchal bones from the Egelhoff Local Fauna, Keya Paha County, Nebraska (Medial Barstovian Land Mammal Age, ca 14.5-13.0 million BP) and a left hyoplastron from the Stewart Quarry, Cherry County, Nebraska (Late Barstovian, ca 13.0-11.5 million BP) closely resemble recent Terrapene ornata. The presence of T. ornata-like box turtles in the Barstovian suggests that the extant species groups were already established by that time and that the genus Terrapene evolved distinctly before the Middle Miocene. An extinct subspecies of T. ornata, T. o. longinsulae Hay, 1908, is known from the Late Miocene (Clarendonian, ca 11.5-9.0 million BP) as well as from several Pliocene sites. It is unknown whether a Clarendonian Terrapene hyoplastron from the Ash Hollow Formation of Cherry County, Nebraska belongs to T. o. longinsulae or to another taxon. A nearly complete anterior plastral lobe from the Myers Farm Local Fauna, near Red Cloud, Webster County, Nebraska, from the Late Barstovian (ca 13.0-11.5 million BP) differs significantly from all other recent and fossil Terrapene taxa. This specimen serves as the holotype of a new extinct Terrapene species described herein. It is of unclear relationships and shares some characters with T. coahuila and others with T. nelsoni and T. ornata. A left humerus from the WaKeeney Local Fauna, Trego County, Kansas (Middle to Late Clarendonian Land Mammal Age, ca 10.0-9.0 million BP) compares well with humeri of recent Terrapene carolina and is the oldest Terrapene that resembles extant T. carolina. The second oldest one is from the latest Miocene McGeehee Site, Alachua County, Florida (Early Hemphillian, ca 8.5 million BP) and perhaps represents a fossil taxon known as T. carolina putnami Hay, 1908.

Keywords: NORTH AMERICA, NEOGENE, CHELONIA, PALAEONTOLOGY, FOSSIL