Movatterモバイル変換

Scaldicetus

From Wikipedia, the free encyclopedia

Extinct genus of mammals

Scaldicetus Temporal range:Early Miocene-Early Pleistocene ~20.4–1.8 Ma PreꞒ Ꞓ O S D C P T J K Pg N ^[1]

Scaldicetus grandis teeth
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Chordata
Class:	Mammalia
Order:	Artiodactyla
Infraorder:	Cetacea
Superfamily:	Physeteroidea
Family:	Physeteridae
Genus:	†Scaldicetus Du Bus, 1867
Species
Scaldicetus carettidu Bus, 1867 (type) Scaldicetus grandis(du Bus, 1872)
Synonyms^[2]^[3]
List of synonyms S. caretti Balænodon physaloidesOwen, 1846 Belemnoziphius (Balænodon) physaloidesLankester, 1865 Physeter physaloidesvon Brandt, 1873 Hoplocetus physaloidesTrouessart, 1898 Hoplocetus crassidensLydekker, 1887 Hoplocetus curvidensGervais Hoplocetus obesusLeidy, 1868 Hoplocetus borgerhoutensisdu Bus Eucetus amblydonLydekker, 1887 Homœcetus villersiide Bus Dinoziphius carolinensisLeidy, 1877 Physeter carolinensisHay, 1902 Palæodelphis arcuatisdu Bus, 1872 Palæodelphis fusiformisdu Bus, 1872 Palæodelphis zonatusdu Bus, 1872 Palæodelphis pachyodondu Bus, 1872 Physodon fusiformisLydekker, 1887 Scaldicetus antwerpiensisde Bus, 1972 S. grandis Glossoptera lunebergicaLeibniz, 1749 Squalodon graleloupiStaring, 1857 Squalodon antwerpiensisLankester, 1865 Palæodelphis grandisdu Bus, 1872

Scaldicetus is an extinctgenus of highly predatorymacroraptorial sperm whale. Although widely used for a number of extinctphyseterids with primitive dental morphology consisting ofenameled teeth,Scaldicetus as generally recognized appears to be awastebasket taxon filled with more-or-less unrelated primitive sperm whales.^[4]

Taxonomy

[edit]

Scaldicetus is known from theMiocene toPleistocene deposits of Western Europe, the U.S. (California,Florida,Maryland,Virginia),Baja Peninsula, Peru,New South Wales, and Japan.^[5] However,Scaldicetus is probably agrade taxon, and fossil teeth assigned to it (largely due to the lack of distinguishing characteristics in fossil teeth alone) probably represent more-or-less unrelated sperm whales united by their primitive characteristics rather than actual ancestry.^[4] Consequently, this would inflate the genus's distribution.^[5]

The nameScaldicetus caretti was coined in 1867 from numeroussperm whale teeth collected inNeogene deposits nearAntwerp, Belgium^[6] probably from the early-to-middle MioceneBercham Formation. However, some of these remains may have beenreworked and redeposited into younger rocks. More remains also near Antwerp from theDiest Formation date to theTortonian (late Miocene).^[7]

Synonyms ofScaldicetus includePalaeodelphis,Homocetus, andEucetus. The genusPhysodon described by French paleontologistPaul Gervais in 1872 was previously considered a synonym, but it was declared anomen dubium in 2006.^[8]

Scaldicetus is sometimes classified into the dubioussubfamily Hoplocetinae along withDiaphorocetus,Idiorophus, andHoplocetus based on the presence of large, robust,enamel-coated teeth. Themacroraptorial sperm whalesLivyatan,Zygophyseter,Brygmophyseter, andAcrophyseter potentially also belong to this subfamily.^[5]

"Ontocetus" oxymycterus, described from the middle Miocene (Langhian) ofSanta Barbara, California, was assigned toScaldicetus in 2008,^[9] but was subsequently made thetype of a new genus,Albicetus.^[10]

Tooth anatomy

[edit]

Unlike the modern sperm whale which only has teeth on the bottom jaw,Scaldicetus had teeth in both jaws. Thelectotype forS. caretti had at least 45 teeth in total in its mouth in life. Like other macroraptorial sperm whales but unlike the modern sperm whale, the teeth were covered in a thickenamel coating, about 1.2–1.3 mm (0.047–0.051 in) thick. The teeth were moderately curved and were deeply rooted into the skull, implying a strong bite.^[7]

Like in other sperm whales, tooth dimensions vary widely; for the lectotype: the total length of the tooth root (the part of the tooth beneath thegum line) is between 106.9–203.5 mm (4.21–8.01 in) and the maximum total length of the entire tooth is 233 mm (9.2 in). Like in other macroraptorial sperm whales, tooth size increased from the back of the jaw to the front. The maximum diameter of the crown (the part of the tooth that is visible and erupts from the gum line) ranges from 16–32.5 mm (0.63–1.28 in), and diameter was greatest midway up the tooth.^[7]

Paleobiology

[edit]

The teeth of the lectotype ofS. caretti exhibitvertical root fractures which were probably brought on by chewing hard food or repetitive application of excessive force while chewing or biting. It is likely these injuries were sustained while biting a fairly large vertebrate, such as various marine mammals as other macroraptorial sperm whales are suspected of hunting.^[7]

However, thekiller whale–which preys on large marine mammals–is not known to exhibit these fractures, though this may be because killer whale teeth are more resistant to shock, having a smallerpulp cavity and, thus, a thicker tooth. Further, terrestrial carnivores that chew through bone display these fractures, and those that prey on larger prey have larger tooth roots. Like in the killer whale,Scaldicetus may have mashed its food in smaller pieces to ease swallowing, which would have increased the risk of hitting bone which would cause such fractures.^[7]

Like other macroraptorial sperm whales,Scaldicetus probably occupied the sameniche as the killer whale.^[5]

Paleoecology

[edit]

The Deist Formation, judging from themollusk assemblage, probably represented a shallow sea with volatileocean currents, movingsand bars, andmegaripples. Whale remains include acetotheriid baleen whale, the baleen whalePlesiocetus, akentriodontid dolphin, and thebeaked whaleZiphirostrum. Shark remains were not very common; those found belong to the extinctbroad-toothed mako (the ancestor of thegreat white shark), the extinct mako sharkIsurus desori, aSqualusdogfish, theangelshark, asand tiger shark, and aPristiophorussawshark.^[11]

References

[edit]

^"Scaldicetus in the Paleobiology Database".Fossilworks. Retrieved17 December 2021.
^Abel, O. (1905).Les odontocètes du Boldérien (miocène supérieur) d'Anvers [The odontocetes of Boldérien (Upper Miocene) of Antwerp] (in French). Bruxelles, Polleunis & Ceuterick printers. pp. 57–70.
^McKenna, Malcolm C., and Bell, Susan K. 1997. Classification of Mammals Above the Species Level. Columbia University Press, New York, 631 pp.
^^a ^bHirota, K.; Barnes, L. G. (1994). "A new species of Middle Miocene sperm whale of the genus Scaldicetus (Cetacea; Physeteridae) from Shiga-mura, Japan".The Island Arc.3 (4): 453.doi:10.1111/j.1440-1738.1994.tb00125.x.
^^a ^b ^c ^dToscano, A. (2013)."Nuevos restos de Scaldicetus (Cetacea, Odontoceti, Physeteridae) del Mioceno superior, sector occidental de la Cuenca del Guadalquivir (sur de España)" [New remains of upper Miocene Scaldicetus (Cetacea, Odontoceti, Physeteridae), western sector of the Guadalquivir basin (southern Spain)].Revista Mexicana de Ciencias Geológicas (in Spanish).30 (2).
^Du Bus, B.A.L., 1867. Sur quelques Mammifères du Cragd’Anvers.Bulletin de l'Académie Royale des Sciences, des Lettres et des Beaux-Arts de Belgique, 24: 562-577.
^^a ^b ^c ^d ^eLambert, O.; Bianucci, G. (2019). "How to break a sperm whale's teeth: dental damage in a large Miocene physeteroid from the North Sea basin".Journal of Vertebrate Paleontology.39 (4): e1660987.Bibcode:2019JVPal..39E0987L.doi:10.1080/02724634.2019.1660987.S2CID 204150420.
^Hampe, O. (2006)."Middle/late Miocene hoplocetine sperm whale remains (Odontoceti: Physeteridae) of North Germany with an emended classification of Hoplocetinae".Fossil Record.9 (1):61–86.doi:10.5194/fr-9-61-2006.
^Kohno N, Ray CE. Pliocene walruses from the Yorktown Formation of Virginia and North Carolina, and a systematic revision of the North Atlantic Pliocene walruses. Virginia Museum of Natural History Special Publication. 2008;14: 39–80.
^Boersma, A. T.;Pyenson, N. D. (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.Bibcode:2015PLoSO..1035551B.doi:10.1371/journal.pone.0135551.PMC 4674121.PMID 26651027.
^Bosselaers, M.; Herman, J.; Hoedemakers, K.; Lambert, O. (2004)."Geology and palaeontology of a temporary exposure of the late Miocene Deurne Sand Member in Antwerpen (N. Belgium)".Geologica Belgica.7 (1–2):27–39.

Odontocete genera

Kingdom:Animalia
Phylum:Chordata
Class:Mammalia
Order:Artiodactyla
Infraorder:Cetacea

Odontoceti

†Agorophius †Ankylorhiza †Archaeodelphis †Argyrocetus †Ashleycetus †Caolodelphis †Chilcacetus †Enigmatocetus †Eoplatanista †Inticetus †Macrodelphinus †Microcetus †Mirocetus †Neosqualodon †Olympicetus †Papahu †Patriocetus †Phoberodon †Phococetus †Prosqualodon †Sachalinocetus †Simocetus †Sulakocetus †Tangaroasaurus
†Xenorophidae	Albertocetus Cotylocara Echovenator Inermorostrum Xenorophus
†Waipatiidae	Awamokoa Ediscetus Nihohae Nihoroa Otekaikea Urkudelphis Waipatia
†Squalodontidae	Eosqualodon Squalodon
†Squaloziphiidae	Crisocetus? Squaloziphius Yaquinacetus
†Eurhinodelphinidae	Ceterhinops Eurhinodelphis Iniopsis Mycteriacetus Phocaenopsis Schizodelphis Vanbreenia Xiphiacetus Ziphiodelphis
Crown-Odontoceti	see below↓

Crown-Odontoceti

Physeteroidea

†Acrophyseter †Albicetus †Brygmophyseter †Eudelphis †Hoplocetus †Livyatan †Miophyseter †Rhaphicetus †Scaldicetus †Zygophyseter
Kogiidae	†Aprixokogia Kogia †Koristocetus †Nanokogia †Platyscaphokogia †Pliokogia †Praekogia †Scaphokogia †Thalassocetus?
Physeteridae	†Aulophyseter †Cozzuoliphyseter †Diaphorocetus †Idiophyseter †Idiorophus †Orycterocetus Physeter †Physeterula †Placoziphius †Thalassocetus?

Platanistoidea

†Aondelphis †Dolgopolis †Ensidelphis †Perditicetus †Eurhinodelphinidae? †Squalodontidae? †Waipatiidae?
†Allodelphinidae?	Allodelphis Arktocara Goedertius Ninjadelphis Zarhinocetus
†Squalodelphinidae?	Furcacetus Huaridelphis Macrosqualodelphis Medocinia Notocetus Phocageneus Squalodelphis
Platanistidae	†Araeodelphis †Dilophodelphis †Grimadelphis †Pachyacanthus? †Pebanista Platanista †Pomatodelphis †Prepomatodelphis †Zarhachis?

Ziphiidae

†Aporotus †Beneziphius †Caviziphius †Chavinziphius †Chimuziphius †Choneziphius †Dagonodum †Globicetus †Imocetus †Messapicetus †Nazcacetus †Nenga †Ninoziphius †Notoziphius †Pterocetus Tasmacetus †Tusciziphius †Xhosacetus †Ziphirostrum
Berardiinae	†Archaeoziphius Berardius †Microberardius
Ziphiinae	†Izikoziphius Ziphius
Hyperoodontinae	†Africanacetus Hyperoodon †Ihlengesi Indopacetus Mesoplodon

Delphinida	see below↓

Delphinida

†Albireo †Atocetus †Brevirostrodelphis †Cammackacetus †Delphinodon †Hadrodelphis †Herbeinodelphis †Liolithax †Lophocetus †Macrokentriodon †Miminiacetus †Odobenocetops †Pictodelphis †Pithanodelphis †Tagicetus †Westmorelandelphis
†Kentriodontidae	Belonodelphis? Kampholophos Kentriodon Platysvercus Sophianacetus Rudicetus Wimahl
Lipotidae	Lipotes †Parapontoporia †Prolipotes

Inioidea

†Awadelphis
Iniidae	†Brujadelphis †Goniodelphis Inia †Ischyrorhynchus †Isoninia? †Isthminia †Kwanzacetus †Meherrinia †Plicodontinia †Saurocetes
Pontoporiidae	†Atocetus? †Auroracetus †Brachydelphis †Piscorhynchus †Pliopontos †Pontistes †Protophocaena †Samaydelphis †Scaldiporia †Stenasodelphis Pontoporia

Delphinoidea

Monodontidae	†Bohaskaia †Casatia Delphinapterus †Denebola †Haborodelphis Monodon
Phocoenidae	†Archaeophocaena †Australithax †Haborophocoena †Lomacetus †Miophocaena Neophocaena †Numataphocoena Phocoena Phocoenoides †Piscolithax †Pterophocaena? †Semirostrum †Septemtriocetus

Delphinidae

†Arimidelphis †Australodelphis †Eodelphinus †Etruridelphis †Hemisyntrachelus Lagenorhynchus †Norisdelphis Orcinus †Platalearostrum †Pliodelphis †Pterophocaena?
Lissodelphininae	Cephalorhynchus Lissodelphis
Delphininae	Delphinus Lagenodelphis Sotalia Sousa Stenella Tursiops
Globicephalinae	Feresa Globicephala Grampus Orcaella Peponocephala Pseudorca Steno

Taxon identifiers
Scaldicetus	Wikidata:Q3008867 EoL:4440485 GBIF:4832471 IRMNG:1095482 Open Tree of Life:4118722 Paleobiology Database:36900

Retrieved from "https://en.wikipedia.org/w/index.php?title=Scaldicetus&oldid=1258137790"

Categories:

Hidden categories:

[8]ページ先頭