Problematic archaic whale Phococetus (Cetacea: Odontoceti) from the Lee Creek Mine, North Carolina, USA, with comments on geochronology of the Pungo River Formation

Boessenecker, Robert W.

doi:10.1007/s12542-018-0419-3

Cited by 3 publications

(2 citation statements)

References 35 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In a study of cetacean specimens from the Miocene Pungo River Formation and Pliocene Yorktown Formation of the Lee Creek Mine, further north in North Carolina, Whitmore and Kaltenbach ( [40]: [188][189] reported an odontocete mandible fragment (USNM 182924) with widely spaced double rooted alveoli and embrasure pits in line with the toothrow, which they speculated might represent a xenorophid. Boessenecker [41] agreed, noting that such mandibular embrasure pits are otherwise unknown amongst stem odontocetes. Boessenecker [41] further identified an isolated xenorophid bulla (CCNHM 936) from the Pungo River Formation, and speculated that such specimens perhaps represent reworking of Oligocene fossils into the base of the Pungo River Formation or perhaps the survival of these archaic taxa into the earliest Miocene.…”

Section: History Of Study Of the Xenorophidaementioning

confidence: 99%

“…Boessenecker [41] agreed, noting that such mandibular embrasure pits are otherwise unknown amongst stem odontocetes. Boessenecker [41] further identified an isolated xenorophid bulla (CCNHM 936) from the Pungo River Formation, and speculated that such specimens perhaps represent reworking of Oligocene fossils into the base of the Pungo River Formation or perhaps the survival of these archaic taxa into the earliest Miocene. More recent discoveries of xenorophid specimens apparently straddling the Oligocene-Miocene boundary [7] lend support to this latter hypothesis.…”

Section: History Of Study Of the Xenorophidaementioning

confidence: 99%

See 1 more Smart Citation

New Skeletons of the Ancient Dolphin Xenorophus sloanii and Xenorophus simplicidens sp. nov. (Mammalia, Cetacea) from the Oligocene of South Carolina and the Ontogeny, Functional Anatomy, Asymmetry, Pathology, and Evolution of the Earliest Odontoceti

Boessenecker,

Geisler

2023

Diversity

View full text Add to dashboard Cite

The early diverging, dolphin-sized, cetacean clade Xenorophidae are a short-lived radiation of toothed whales (Odontoceti) that independently evolved two features long thought to be odontocete synapomorphies: the craniofacial and cochlear morphology underlying echolocation and retrograde cranial telescoping (i.e., posterior migration of the viscerocranium). This family was based on Xenorophus sloanii, which, for the past century, has been known only by a partial skull lacking a braincase and tympanoperiotics, collected around 1900 from the Ashley Formation (28–29 Ma, Rupelian) near Ladson, South Carolina. A large collection of new skulls and skeletons (ChM PV 5022, 7677; CCNHM 104, 168, 1077, 5995) from the Ashley Formation considerably expands the hypodigm for this species, now the best known of any stem odontocete and permitting evaluation of intraspecific variation and ontogenetic changes. This collection reveals that the holotype (USNM 11049) is a juvenile. Xenorophus sloanii is a relatively large odontocete (70–74 cm CBL; BZW = 29–31 cm; estimated body length 2.6–3 m) with a moderately long rostrum (RPI = 2.5), marked heterodonty, limited polydonty (13–14 teeth), prominent sagittal crest and intertemporal constriction, and drastically larger brain size than basilosaurid archaeocetes (EQ = 2.9). Dental morphology, thickened cementum, a dorsoventrally robust rostrum, and thick rugose enamel suggest raptorial feeding; oral pathology indicates traumatic tooth loss associated with mechanically risky predation attempts. Ontogenetic changes include increased palatal vomer exposure; fusion of the nasofrontal, occipito-parietal, and median frontal sutures; anterior lengthening of the nasals; elaboration of the nuchal crests; and blunting and thickening of the antorbital process. The consistent deviation of the rostrum 2–5° to the left and asymmetry of the palate, dentition, neurocranium, mandibles, and vertebrae in multiple specimens of Xenorophus sloanii suggest novel adaptations for directional hearing driven by the asymmetrically oriented pan bones of the mandibles. A second collection consisting of a skeleton and several skulls from the overlying Chandler Bridge Formation (24–23 Ma, Chattian) represents a new species, Xenorophus simplicidens n. sp., differing from Xenorophus sloanii in possessing shorter nasals, anteroposteriorly shorter supraorbital processes of the frontal, and teeth with fewer accessory cusps and less rugose enamel. Phylogenetic analysis supports monophyly of Xenorophus, with specimens of Xenorophus simplicidens nested within paraphyletic X. sloanii; in concert with stratigraphic data, these results support the interpretation of these species as part of an anagenetic lineage. New clade names are provided for the sister taxon to Xenorophidae (Ambyloccipita), and the odontocete clade excluding Xenorophidae, Ashleycetus, Mirocetus, and Simocetidae (Stegoceti). Analyses of tooth size, body size, temporal fossa length, orbit morphology, and the rostral proportion index, prompted by well-preserved remains of Xenorophus, provide insight into the early evolution of Odontoceti.

show abstract

Section: History Of Study Of the Xenorophidaementioning

confidence: 99%

Section: History Of Study Of the Xenorophidaementioning

confidence: 99%

New Skeletons of the Ancient Dolphin Xenorophus sloanii and Xenorophus simplicidens sp. nov. (Mammalia, Cetacea) from the Oligocene of South Carolina and the Ontogeny, Functional Anatomy, Asymmetry, Pathology, and Evolution of the Earliest Odontoceti

Boessenecker,

Geisler

2023

Diversity

View full text Add to dashboard Cite

show abstract

Taphonomy and palaeoecology of the lower Miocene marine vertebrate assemblage of Ullujaya (Chilcatay Formation, East Pisco Basin, southern Peru)

Bianucci

Collareta

Bosio

et al. 2018

Palaeogeography, Palaeoclimatology, Palaeoecology

View full text Add to dashboard Cite

A redescription and re-evaluation ofKekenodon onamata(Mammalia: Cetacea), a late-surviving archaeocete from the Late Oligocene of New Zealand

Corrie

Fordyce

2022

Zoological Journal of the Linnean Society

View full text Add to dashboard Cite

Stem cetaceans (archaeocetes) have a substantial Eocene fossil record but are largely absent since the Eocene–Oligocene boundary. Putative Oligocene archaeocetes are mostly represented by fragmentary denticulate teeth, making systematic classification difficult. The New Zealand species Kekenodon onamata (Wharekuri Greensand, Duntroonian local Stage, Chattian) is one of the most widely mentioned Oligocene archaeocetes and is the single-named species of the family Kekenodontidae. The holotype includes heterodont teeth in addition to cranial and post-cranial elements, and partial tympanoperiotics, with potential for a strong phylogenetic signal. Hitherto, the strikingly disparate Kekenodon onamata has been excluded from published phylogenetic analyses, with its affinities largely remaining speculative. Here, a detailed anatomical account allows a redescription of Kekenodon onamata, and a comprehensive phylogenetic analysis. The phylogenetic analysis shows Kekenodon onamata as the latest-surviving archaeocete, sister-taxon to the Neoceti. The large heterodont teeth with patterns of extensive enamel macrowear suggest Kekenodon onamata utilized a raptorial feeding strategy and hunted hard-boned prey, such as other marine mammals and penguins. Combined with an estimated body size of c. 8 m, Kekenodon onamata probably occupied an apex predator ecological niche similar to the modern killer whale.

show abstract

Problematic archaic whale Phococetus (Cetacea: Odontoceti) from the Lee Creek Mine, North Carolina, USA, with comments on geochronology of the Pungo River Formation

Cited by 3 publications

References 35 publications

New Skeletons of the Ancient Dolphin Xenorophus sloanii and Xenorophus simplicidens sp. nov. (Mammalia, Cetacea) from the Oligocene of South Carolina and the Ontogeny, Functional Anatomy, Asymmetry, Pathology, and Evolution of the Earliest Odontoceti

New Skeletons of the Ancient Dolphin Xenorophus sloanii and Xenorophus simplicidens sp. nov. (Mammalia, Cetacea) from the Oligocene of South Carolina and the Ontogeny, Functional Anatomy, Asymmetry, Pathology, and Evolution of the Earliest Odontoceti

Taphonomy and palaeoecology of the lower Miocene marine vertebrate assemblage of Ullujaya (Chilcatay Formation, East Pisco Basin, southern Peru)

A redescription and re-evaluation ofKekenodon onamata(Mammalia: Cetacea), a late-surviving archaeocete from the Late Oligocene of New Zealand

Contact Info

Product

Resources

About