Physeteroidea

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Physeteroidea
Temporal range: Oligocene to recent 25–0  Ma
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Social group of the sperm whale, Physeter macrocephalus
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Order: Artiodactyla
Infraorder: Cetacea
Parvorder: Odontoceti
Superfamily: Physeteroidea
Gray 1868
Families

Physeteroidea is a superfamily that includes three extant species of whales: the sperm whale, in the genus Physeter , and the pygmy sperm whale and dwarf sperm whale, in the genus Kogia. In the past, these genera have sometimes been united in a single family, the Physeteridae, with the two Kogia species in the subfamily Kogiinae; however, recent practice is to allocate the genus Kogia to its own family, the Kogiidae , leaving the Physeteridae as a monotypic (single extant species) family, although additional fossil representatives of both families are known.

Contents

Characteristics

Sperm whale and bottlenose whale Sperm whale and Bottlenose whale.JPG
Sperm whale and bottlenose whale

The sperm whale (Physeter macrocephalus) is the largest species of toothed whale, with adult bulls (males) growing to be about 15–18 m (49–59 ft) long, and weighing about 45–70 metric tons (44–69 long tons; 50–77 short tons). The two kogiid species are much smaller, around 2.5 to 3.5 m (8 ft 2 in to 11 ft 6 in) in length, and weighing 350–500 kg (770–1,100 lb).

The bodies of physeteroids are robustly proportioned, with paddle-shaped flippers. The lower jaw is always relatively small and thin relative to the upper jaw. The nasal bones of these whales are distinctly asymmetrical, with the blowhole being located on the left side of the head; in the sperm whale, this is near the top of the head, while on the kogiids it is further forward. All species have a large number of similar, and relatively simple, teeth. In the kogiids, and sometimes also in the sperm whale, the teeth in the upper jaw do not erupt, and are sometimes altogether absent. [1]

The eyes of physeteroids are unable to swivel in their sockets, and possess only a vestigial anterior chamber. Echolocation likely is a far more important sense to these animals than vision. [1]

Another common characteristic is the spermaceti, a semiliquid waxy white substance filling the 'case' or spermaceti organ in the whale's head, which plays a primary role in the production and directional manipulation of focused clicking sounds used for echolocation in the extant great sperm whale (Physeter macrocephalus). [2] All three species dive to great depths to find food, although the sperm whale is believed to dive much deeper than either of the kogiids. Members of both families eat squid, fish, and even sharks.

Gestation lasts from 9 to 15 months, depending on species. The single calf remains with the mother for at least two years, before being weaned. Physeteroids do not reach full sexual maturity for several years. All species congregate in 'pods' or herds, consisting of mostly females, calves, and adolescent males, although these pod sizes are typically smaller in the kogiids. [1]

Evolution

The earliest sperm whale fossils are known from the late Oligocene – about 25 million years ago, [3] [4] with an ancestry tracing back from the latest Eocene before diverging from the remainder of the odontocetid line, leading to the dolphins, and porpoises.

The fossil record suggests that sperm whales were more common in the Miocene, during which basal lineages (such as Zygophyseter and Brygmophyseter ) existed; other fossil genera assigned to the Physeteridae include Ferecetotherium , Helvicetus , Idiorophus , Diaphorocetus , Aulophyseter , Orycterocetus , Scaldicetus , and Placoziphius , while kogiid fossil genera include Kogiopsis , Scaphokogia , and Praekogia . [4] The earliest kogiids are known from the late Miocene, around 7 million years ago. [5]

The close relationship between extant Physeteridae and Kogiidae is confirmed in recent molecular studies using mitochondrial cytochrome b,; [6] [7] on the basis of these analyses, their nearest relatives appear to be the Ziphiidae on one hand, and the Mysticeti and Platanistidae on the other. The last cited paper also favours the grouping of Physeteridae and Kogiidae in a single superfamily, Physeteroidea, as has sometimes previously been suggested. Bianucci & Landini, 2006 [8] suggest that Diaphorocetus, Zygophyseter, Naganocetus, and Aulophyseter antedate the inferred split of the Kogiidae and Physeteridae, thus would restrict the family Physeteridae to those genera that postdate this split (a cladistic view).

Classification

Sperm whale mother with calf Sperm whale mother with calf.jpg
Sperm whale mother with calf

They are members of the Odontoceti, the suborder containing all the toothed whales and dolphins. Suggestions that the sperm whales might be a sister group to the baleen whales were refuted by molecular and morphological data, confirming the monophyly of Odontoceti including sperm whales. [9] One extant species of the genus Physeter is placed in the family Physeteridae. Two species of the related extant genus Kogia, the pygmy sperm whale K. breviceps and the dwarf sperm whale K. simus, are sometimes also placed in this family, or else are placed in their own family, the Kogiidae. [10]

A summary of the classification of extant and extinct (†) taxa is:

Livyatan melvillei skull Livyatan melvillei skull.jpg
Livyatan melvillei skull

Nomina dubia

Related Research Articles

<span class="mw-page-title-main">Kogiidae</span> Family of mammals

Kogiidae is a family comprising at least two extant species of Cetacea, the pygmy and dwarf sperm whales. As their common names suggest, they somewhat resemble sperm whales, with squared heads and small lower jaws, but are much smaller in size, with much shorter skulls and more notable dorsal fins than sperm whales. Kogiids are also characterized by a "false gill slit" behind their eyes.

<i>Zygophyseter</i> Extinct genus of sperm whales

Zygophyseter varolai is an extinct sperm whale that lived during the Tortonian age of the Late Miocene 11.2 to 7.6 million years ago. It is known from a single specimen from the Pietra Leccese Formation in Italy. It was a member of a stem group of fossil macroraptorial sperm whales also including Brygmophyseter, Acrophyseter, and Livyatan. It probably grew to be around 6.5 to 7 meters in length and shared some characteristics with other raptorials, such as large teeth with tooth enamel that were functional in both the upper and lower jaws which the modern sperm whale lacks. It also had a beak, the ability to echolocate prey, and could have probably swum faster than the modern-day sperm whale which can reach 4 kilometers per hour (2.5 mph). These were probably used in the capture of large prey, such as large fish, seals, and whales. In fact, its common name, the killer sperm whale, refers to its feeding habits that would have had a resemblance to the modern-day killer whale.

<i>Brygmophyseter</i> Extinct genus of toothed whale (fossil)

Brygmophyseter, known as the biting sperm whale, is an extinct genus of toothed whale in the sperm whale family with one species, B. shigensis. When it was first described in 1994, the species was placed in the genus Scaldicetus based on tooth morphology, but this was later revised in 1995. In 2006, it was classified into the genus Naganocetus, which is considered to be a junior synonym. The only known specimen, a nearly complete skeleton, was dated to be around 16–15 million years old. Brygmophyseter is thought to have been 6.5–7 meters (21–23 ft) long, and it probably had 11 or 12 teeth in the upper and lower jaws. Brygmophyseter is part of a group of macroraptorial sperm whales which tended to be apex predators using their large teeth to catch struggling prey such as whales. It had a spermaceti organ which was probably used for biosonar like in the modern sperm whale. The whale has made an appearance on The History Channel's TV series Jurassic Fight Club.

<i>Livyatan</i> Extinct genus of sperm whale from the Miocene epoch

Livyatan is an extinct genus of macroraptorial sperm whale containing one known species: L. melvillei. The genus name was inspired by the biblical sea monster Leviathan, and the species name by Herman Melville, the author of the famous novel Moby-Dick about a white bull sperm whale. Herman Melville often referred to whales as "Leviathans" in his book. It is mainly known from the Pisco Formation of Peru during the Tortonian stage of the Miocene epoch, about 9.9–8.9 million years ago (mya); however, finds of isolated teeth from other locations such as Chile, Argentina, United States (California), South Africa and Australia imply that either it or a close relative survived into the Pliocene, around 5 mya, and may have had a global presence. It was a member of a group of macroraptorial sperm whales and was probably an apex predator, preying on whales, seals and so forth. Characteristically of raptorial sperm whales, Livyatan had functional, enamel-coated teeth on the upper and lower jaws, as well as several features suitable for hunting large prey.

<i>Acrophyseter</i> Extinct genus of sperm whales

Acrophyseter is a genus of extinct sperm whale that lived in the Late Miocene off the coast of what is now Peru. The genus comprises two species: A. deinodon and A. robustus. It is part of a group of macroraptorial sperm whales that all share several features for hunting large prey, such as deeply rooted and thick teeth. Acrophyseter measured 4–4.5 metres (13–15 ft) in length, making it the smallest macroraptorial sperm whale currently known. Because of its short pointed snout and strongly curved front teeth, it probably fed on the large marine vertebrates of its time, such as seals and other whales.

<i>Albicetus</i> Extinct genus of mammals

Albicetus is a genus of stem-sperm whales that lived during the Miocene Epoch, around 15 million years ago, and was discovered in Santa Barbara, California in 1909. It was categorized for decades as belonging to a group of extinct walruses erroneously thought to be sperm whales. It was named Albicetus, meaning "white whale", is a reference to the leviathan in Herman Melville's classic 1851 novel Moby-Dick.

<i>Kogia pusilla</i> Small fossil whale from Italy

Kogia pusilla is an extinct species of sperm whale from the Middle Pliocene of Italy related to the modern-day dwarf sperm whale and pygmy sperm whale. It is known from a single skull discovered in 1877, and was considered a species of beaked whale until 1997. The skull shares many characteristics with other sperm whales, and is comparable in size to that of the dwarf sperm whale. Like the modern Kogia, it probably hunted squid in the twilight zone, and frequented continental slopes. The environment it inhabited was likely a calm, nearshore area with a combination sandy and hard-rock seafloor. K. pusilla likely died out due to the ice ages at the end of the Pliocene.

<i>Idiorophus</i> Extinct genus of mammals

Idiorophus is a genus of extinct toothed whales in the family Physeteridae. Fossils have been found in the Colhuehuapian Gaiman Formation of Argentina and the Libano Sandstone in Italy.

Eudelphis is an extinct genus of sperm whale belonging to Physeteroidea that lived in the ancient North Sea basin about 16-11 million years ago, during the middle Miocene (Langhian).

<span class="mw-page-title-main">Macroraptorial sperm whale</span> Predatory grouping of extinct whales

Macroraptorial sperm whales were highly predatory whales of the sperm whale superfamily (Physeteroidea) of the Miocene epoch that hunted large marine mammals, including other whales, using their large teeth. They consist of five genera: Acrophyseter, Albicetus, Brygmophyseter, Livyatan and Zygophyseter. All species are known by at least a skull, and are informally grouped without a family designation. They were all likely the apex predator of their habitats, comparable to the modern day killer whale, and achieved great lengths, with one species—Livyatan—measuring about 13.5–17.5 m (44–57 ft).

Hoplocetus is an extinct genus of raptorial cetacean of the sperm whale superfamily, Physeteroidea. Its remains have been found in the Miocene of Belgium, France, Germany and Malta, the Pliocene of Belgium and France, and the Pleistocene of the United Kingdom and South Carolina.

References

  1. 1 2 3 Lockyer, Christina (1984). Macdonald, D. (ed.). The Encyclopedia of Mammals . New York: Facts on File. pp.  204–209. ISBN   978-0-87196-871-5.
  2. ↑ Huggenberger, Stefan; Andre, Michel; Oelschlager, Helmut H. A. (2014). "The nose of the sperm whale - overviews of functional design, structural homologies and evolution". Journal of the Marine Biological Association of the United Kingdom. 96 (4): 783–806. doi:10.1017/S0025315414001118. hdl: 2117/97052 . S2CID   27312770.
  3. ↑ Stucky, R. E. & McKenna, M. C. (1993). Mammalia. Pp. 739–771 in Benton, M. J. ed.: The Fossil Record 2. Chapman & Hall, London.
  4. 1 2 Mchedlidze, G. A. (2009). Perrin, William F.; Wursig, Bernd; Thewissen, J. G. M. (eds.). Encyclopedia of Marine Mammals (2 ed.). 30 Corporate Drive, Burlington Ma. 01803: Academic Press. ISBN   978-0-12-373553-9. Archived from the original on 2009-11-09.{{cite book}}: CS1 maint: location (link)
  5. ↑ Perrin, W. F., Würsic, B. & Thewissen, J. G. M. eds.: Encyclopedia of Marine Mammals. Academic Press, San Diego, 1414 pp.
  6. ↑ Verma, S. K.; Sinha, R. K.; Singh, L. (2004). "Phylogenetic position of Platanista gangetica: insights from the mitochondrial cytochrome b and nuclear interphotoreceptor retinoid-binding protein gene sequences". Molecular Phylogenetics and Evolution. 33 (2): 280–288. doi:10.1016/j.ympev.2004.06.018. PMID   15336663.
  7. ↑ May-Collado, L.; Agnarsson, I. (2006). "Cytochrome b and Bayesian inference of whale phylogeny". Molecular Phylogenetics and Evolution. 38 (2): 344–354. doi:10.1016/j.ympev.2005.09.019. PMID   16325433.
  8. ↑ Bianucci, G.; Landini, W. (2006). "Killer sperm whale: a new basal physeteroid (Mammalia, Cetacea) from the Late Miocene of Italy" (PDF). Zoological Journal of the Linnean Society. 148: 103–131. doi: 10.1111/j.1096-3642.2006.00228.x .
  9. ↑ Heyning, John E (October 1997). "Sperm Whale Phylogeny Revisited: Analysis of the morphological evidence". Society for Marine Mammalogy. 4 (13): 596–613. doi:10.1111/j.1748-7692.1997.tb00086.x.
  10. ↑ Mead, J. G.; Brownell, R. L. Jr. (2005). "Order Cetacea". In Wilson, D. E.; Reeder, D. M. (eds.). Mammal Species of the World: A Taxonomic and Geographic Reference (3rd ed.). Johns Hopkins University Press. pp. 723–743. ISBN   978-0-8018-8221-0. OCLC   62265494.
  11. 1 2 Lambert, Oliver; Bianucci, Giovanni; de Muizon, Christian (2008). "A new stem-sperm whale (Cetacea, Odontoceti, Physeteroidea) from the Latest Miocene of Peru". Comptes Rendus Palevol. 7 (6): 361–369. Bibcode:2008CRPal...7..361L. doi:10.1016/j.crpv.2008.06.002. S2CID   85723286.
  12. ↑ Lambert, O.; Bianucci, G.; Post, K.; Salas-Gismondi, R.; Urbina, M.; Reumer, J. (2010). "The giant bite of a new raptorial sperm whale from the Miocene epoch of Peru". Nature. 466 (7302): 105–108. Bibcode:2010Natur.466..105L. doi:10.1038/nature09067. PMID   20596020. S2CID   4369352.
  13. ↑ Kimura, T.; Hasegawa, Y. (2022). "A New Physeteroid from the Lower Miocene of Japan". Paleontological Research. 26 (1): 87–101. doi:10.2517/PR200021. S2CID   245478545.
  14. ↑ Lambert, Oliver; de Muizon, Christian; Urbina, Mario; Bianucci, Giovanni (2020). "A new longirostrine sperm whale (Cetacea, Physeteroidea) from the lower Miocene of the Pisco Basin (southern coast of Peru)". Journal of Systematic Palaeontology. 18 (20): 1707–1742. doi:10.1080/14772019.2020.1805520. S2CID   221838686.
  15. ↑ Florencia Paolucci; Marta S. Fernández; Mónica R. Buono; José I. Cuitiño (2021). "Aulophyseter rionegrensis (Cetacea: Odontoceti: Physeteroidea) from the Miocene of Patagonia (Argentina): a reappraisal". Zoological Journal of the Linnean Society. 192 (4): 1293–1322. doi: 10.1093/zoolinnean/zlaa137 .
  16. ↑ Perez, Cione, Cozzuol, Varela. "A sperm whale (Cetacea: Physeteroidea) from the Parana Formation (Late Miocene) of Entre Rios, Argentina. Environment and taphonomy". Ameghiniana.
  17. ↑ Velez-Juarbe, Jorge; Wood, Aaron R.; Gracia, Carlos De; Hendy, Austin J. W. (2015-04-29). "Evolutionary Patterns among Living and Fossil Kogiid Sperm Whales: Evidence from the Neogene of Central America". PLOS ONE. 10 (4): e0123909. Bibcode:2015PLoSO..1023909V. doi: 10.1371/journal.pone.0123909 . ISSN   1932-6203. PMC   4414568 . PMID   25923213.
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