EARLY PLIOCENE (5 MA) SHARK-CETACEAN TROPHIC INTERACTION FROM LANGEBAANWEG, WESTERN COAST OF SOUTH AFRICA

We document an aspect of the marine paleoecology at Langebaanweg, a site that has produced an abundance of vertebrate fossils. Damage to the bone surfaces of cetacean fossils was not pathological as evident on the fossil seals from this site; the current study documents the damage and attempts to provide a parsimonious explanation. Literature reviews identified similar damage described elsewhere to be the result of shark feeding activity. Comparison of this material with Langebaanweg cetacean bones supports the interpretation that the damage resulted from shark teeth. Damage on the various skeletal elements appears to have been inflicted postmortem or, if they were made while the animal was alive, the whales did not survive the attack. Postmortem damage is also supported by the presence of bites on the dorsal, ventral, lateral, and medial surfaces of a pair of dentaries. Bites were inflicted by sharks with serrated teeth, as well as by sharks with unserrated teeth. Potential predators identified from the marks include white (Carcharodon spp.), Zambezi (bull) (Carcharhinus leucas), tiger (Galeocerdo sp.) and mako (Isurus sp.) sharks.