A SECOND RECORD OF A XIPHIORHYNCHINE BILLFISH RESEMBLING XIPHIORHYNCHUS AEGYPTIACUS FROM THE CHANDLER BRIDGE FORMATION OF SOUTH CAROLINA

A partial billfish rostrum from the Chandler Bridge Formation (Early Chattian, Oligocene) Wallace Ackerman Site, Summerville, South Carolina, U.S.A., is described and identified as Xiphiorhynchus sp. cf. aegyptiacus. The Chandler Bridge Formation is a sequence of marine clays and assorted siliciclastics likely deposited in a coastal environment, (Katuna et al. 1997). The new specimen is compared with species of Xiphiorhynchus, especially Xiphiorhynchus aegyptiacus (from the Birket Qarun Formation, early upper Eocene) as well as a Xiphiorhynchus indet. (ChM PV8137, also from the Chandler Bridge Formation). Examining the angle of taper, depth to width ratio of the cross section, and other morphological features, we established that the new specimen has a marked similarity to these two; we conclude that it and ChM PV8137 likely either represent either a relict population of the late Eocene X. aegyptiacus or a closely related, as-yet unnamed species endemic to South Carolina.