A new xenorophus‐like odontocete cetacean from the oligocene of North Carolina and a discussion of the basal odontocete radiation

Synopsis

Oligocene cetaceans in eastern North America are currently only reported from the area around Charleston, South Carolina, despite the relative abundance of Oligocene nearshore marine rocks from Mississippi across the Gulf Coast into Florida and the Carolinas. A new skull from Onslow Beach, North Carolina, here designated Albertocetus meffordorum, represents the first named Oligocene cetacean from eastern North America outside the Charleston area.

The skull is similar in size to Xenorophus sloani and Archaeodelphis patrius, but is more complete than the type specimen of either. The specimen is missing most of the rostrum and does not include any teeth. Both tympanic bullae and periotics are present and in place on the specimen. The holotype specimen includes portions of the mandibles, which were originally crushed on to the base of the skull. The anterior edge of the nasal is posterior to the level of the antorbital notch and the nasal roofs the nasal passage. The nasals, premaxillae and maxillae are posteriorly extended over the frontals, which are only visible in dorsal view just posterior to the nasals and the premaxillae and at the dorsal borders of the orbits. Much of the orbits are formed by the greatly enlarged lacrimals, a characteristic of Xenorophus and its close relatives. The intertemporal region includes a sagittal crest formed by the parietals and is bounded posteriorly by a nuchal crest formed by the parietals, squamosals and supraoccipitals. This new specimen, along with several others from Onslow Beach are placed in a new genus and species, within a new family of basal odontocetes, here named Xenorophidae.

Key words:

• Cetacea
• Odontoceti
• Xenorophidae
• Chattian
• Albertocetus meffordorum
• Archaeodelphis patrius

Notes

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