Abstract
We describe fossil kogiid periotics from the Lower Pliocene upper Bone Valley Formation in central Florida and the Lower to Upper Pliocene Yorktown Formation at Lee Creek Mine, North Carolina. The fossils show diagnostic characters that identify them as belonging to Kogiidae, such as three spines in the anterior process, presence of an incudal process, and a posterior process oriented along the long axis of the bone. Morphological comparisons and morphometric and statistical analyses of periotic proportions confirm the presence of a large and a small morphotype within the sample. The large morphotype (mean length = 39.76 mm) belongs to an unknown kogiid that occurs in both formations, whereas the small morphotype (mean length = 28.64 mm), referred to aff. Kogia sp., occurs only in the Yorktown Formation. The cooccurrence of two taxa in North Carolina may represent one of the earliest evidences of sympatry in kogiids and may demonstrate that this ecological behavior has been part of the natural history of this group at least since the deposition of the Yorktown Formation at Lee Creek (∼4.8–3.1 Ma). In addition, the occurrence of the large morphotype in the upper Bone Valley Formation, herein reported for the first time, shows that we are still far from understanding the diversity of marine mammals of that formation and that revision of newly acquired material is necessary.
Vélez-Juarbe, Jorge