Biology:Orycterocetus
Orycterocetus is an extinct genus of sperm whale from the Miocene of the northern Atlantic Ocean.
Classification
Orycterocetus is a member of Physeteroidea closely related to crown-group sperm whales. The type species, O. quadratidens, was first named by Joseph Leidy on the basis of two teeth, two partial mandibular rami, and a rib from Neogene deposits of Virginia.[1] Two more species were subsequently described, O. cornutidens Leidy 1856[2] and O. crocodilinus Cope, 1868,[3] the latter from the middle Miocene Calvert Formation.
Description
The distinction between O. quadratidens and O. crocodilinus is tentative, based on subtle dental differences such as the quadrate root cross-section in O. quadratidens, with overlapping morphology including conical shape, open pulp cavities, and longitudinal fluting; formal synonymy has not been established due to uncertain provenance of the type material. No other species are definitively assigned to the genus, though fragmentary remains, such as a partial mandible from the late Miocene [Pietra lecces formation]] in southern Italy, suggest possible intraspecific variation or undescribed diversity; this specimen exhibits a longer symphysis (estimated 400–420 mm) and 10–13 mandibular alveoli, provisionally attributed to Orycterocetus sp. and hinting at larger-bodied variants. Some unrecorded species may have exceeded 7 meters (23 ft) long. [4]
Orycterocetus is thought to have been 6.4 meters (21 ft) long. [5] Although much smaller than modern sperm whales the length is similar to that of Albicetus oxymycterus and Aulophyseter.
Paleobiology
Orycterocetus functioned as an piscivore in Miocene marine ecosystems, preying primarily on medium-sized fish. This predatory lifestyle is inferred from its robust, conical teeth suited for grasping and puncturing elusive, fast-moving prey in open water environments. The presence of functional, interlocking upper and lower dentition, with approximately 20 teeth per side in the upper jaw, further supports a lifestyle centered on active hunting rather than passive suction feeding.
References
- ↑ J. Leidy. 1853. [Observations on extinct Cetacea]. Proceedings of the Academy of Natural Sciences 6:377-378
- ↑ J. Leidy. 1856. Notice of remains of extinct vertebrated animals discovered by Professor E. Emmons. Proceedings of the Academy of Natural Sciences of Philadelphia 8:255-257
- ↑ E. D. Cope. 1867. An addition to the vertebrate fauna of the Miocene period, with a synopsis of the extinct Cetacea of the United States. Proceedings of the Academy of Natural Sciences of Philadelphia 19(4):138-157
- ↑ First discovery of the Miocene northern Atlantic sperm whale Orycterocetus in the Mediterranean Published by: Elsevier, September–October 2004
- ↑ Boersma AT, Pyenson ND (2015) Albicetus oxymycterus, a New Generic Name and Redescription of a Basal Physeteroid (Mammalia, Cetacea) from the Miocene of California, and the Evolution of Body Size in Sperm Whales. PLOS ONE 10(12): e0135551. https://doi.org/10.1371/journal.pone.0135551
Sources
- Cenozoic Seas: The View From Eastern North America by Edward J. Petuch
- Marine Mammals: Evolutionary Biology by Annalisa Berta and James L. Sumich
Template:Odontoceti Wikidata ☰ Q2711528 entry
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