Macrophyseter (talk | contribs) "raptor" should not be used to describe macroraptorials/raptorials. There are no sources anywhere that use "raptor" over "raptorial", as its definition only applies to birds and dromaeosaurids according to most dictionaries. If not, tell why in page talk. |
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''Acrophyseter'' consists two species. The species ''A. deinodon'' was discovered in the [[Pisco Formation]] in Peru, dating back to the [[Tortonian]]–[[Messinian]] stages of the [[Miocene]] around 6 [[mya (unit)|million years ago]] (mya). The [[holotype specimen]], MNHN SAS 1626, consists of a skull and jaw, with most of the teeth intact. The left side of the skull is absent.<ref name="lambert"/> |
''Acrophyseter'' consists two species. The species ''A. deinodon'' was discovered in the [[Pisco Formation]] in Peru, dating back to the [[Tortonian]]–[[Messinian]] stages of the [[Miocene]] around 6 [[mya (unit)|million years ago]] (mya). The [[holotype specimen]], MNHN SAS 1626, consists of a skull and jaw, with most of the teeth intact. The left side of the skull is absent.<ref name="lambert"/> |
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A second species of ''Acrophyseter'', ''A. robustus'', is known from a skull also from the Pisco Formation, labelled as MUSM 2182, dating back to the [[Serravallian]]-[[Tortonian]] stages of the Miocene. |
A second species of ''Acrophyseter'', ''A. robustus'', is known from a skull also from the Pisco Formation, labelled as MUSM 2182, dating back to the [[Serravallian]]-[[Tortonian]] stages of the Miocene.<ref name=lamber2017/> |
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The [[genus name]] ''Acrophyseter'' is derived from the Greek ''akros'', meaning acute, which describes the short, pointed, upturned snout; and ''Physeter'', which is the genus name for the modern [[sperm whale]] (''Physeter macrocephalus''). The species epithet ''deinodon'' is from the Greek ''deinos'', meaning terrible, and ''odon'', tooth.<ref name="lambert"/> |
The [[genus name]] ''Acrophyseter'' is derived from the Greek ''akros'', meaning acute, which describes the short, pointed, upturned snout; and ''Physeter'', which is the genus name for the modern [[sperm whale]] (''Physeter macrocephalus''). The species epithet ''deinodon'' is from the Greek ''deinos'', meaning terrible, and ''odon'', tooth.<ref name="lambert"/> |
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Revision as of 19:19, 5 December 2017
| Acrophyseter Temporal range: Late Miocene
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| Acrophyseter deinodon skull | |
Scientific classification 
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| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Mammalia |
| Order: | Artiodactyla |
| Infraorder: | Cetacea |
| Superfamily: | Physeteroidea |
| Family: | incertae sedis |
| Genus: | †Acrophyseter Lambert, Bianucci, and Muizon, 2008 |
| Type species | |
| A. deinodon | |
| Species | |
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Acrophyseter is a genus of stem-sperm whales that lived around 12-7 million years ago in waters off the coast of Peru. It consists two species: A. deinodon and A. robustus.[1]
Taxonomy
Acrophyseter, together with Brygmophyseter, Livyatan, and Zygophyseter, belong to a group of raptorial stem sperm whales, which have adaptations to hunting large prey. They all have large, deeply rooted teeth coated in enamel in both the upper and lower jaws, unlike the modern sperm whale (Physeter macrocephalus) which lacks enamel and teeth in the upper jaw.[2] Raptorials are thought to have either evolved these adaptations from a basilosaurid-like ancestor or independently once or twice within the group.[3] The extinct subfamily Hoplocetinae has been proposed to house this group, alongside the genera Scaldicetus, Diaphorocetus, Idiorophus, and Hoplocetus. This subfamily is paraphyletic, in that it does not consist of a common ancestor and all of its descendants.[4]
Acrophyseter consists two species. The species A. deinodon was discovered in the Pisco Formation in Peru, dating back to the Tortonian–Messinian stages of the Miocene around 6 million years ago (mya). The holotype specimen, MNHN SAS 1626, consists of a skull and jaw, with most of the teeth intact. The left side of the skull is absent.[1]
A second species of Acrophyseter, A. robustus, is known from a skull also from the Pisco Formation, labelled as MUSM 2182, dating back to the Serravallian-Tortonian stages of the Miocene.[3]
The genus name Acrophyseter is derived from the Greek akros, meaning acute, which describes the short, pointed, upturned snout; and Physeter, which is the genus name for the modern sperm whale (Physeter macrocephalus). The species epithet deinodon is from the Greek deinos, meaning terrible, and odon, tooth.[1]
| Relationships between Brygmophyseter and other sperm whales, raptorials in bold[5][3] |
Description
Unlike the modern sperm whales, A. deinodon had teeth on both its upper and lower jaws. The teeth were robust and deeply set into the roots, particularly the front teeth. The front teeth are more conical than the back teeth. The lower back teeth were close together, suggesting they were used for shearing, unlike the suction feeding used by today's sperm whales, which do not even have teeth on their upper jaws. The wearing of the front teeth occurred moreover on the sides, whereas on the bottom teeth it occurred more in the middle of the tooth. It had 12 teeth in the upper jaw and 13 teeth in the bottom jaw, and like other raptorials it had tooth enamel. The premaxillae bore three teeth, and the maxillae had nine teeth with short spacing in between each other. Unlike other sperm whales, the top of the premaxillae near the vomer lacked a deep groove. The last bottom teeth may have contacted the roof of the mouth.[1][3]
Like other sperm whales, Acrophyseter had a deep basin on the top of its skull, the supracranial basin. This basin in Acrophyseter overhung the orbit around the eye, but did not extend onto the snout, unlike in other raptorials. Unlike later species of sperm whales, Acrophyseter had two nostrils. The temporal fossae on the sides of the skull were as high as they were long, unlike in Zygophyseter and Brygmophyseter, which displaced the brow ridge. The area between the condyloid process, which connects the jaw with the skull, and the teeth was probably where the masseter muscles were. The brow ridge slopes down at an angle of around 55°. The nuchal crest on the back side of the skull had overhung the supracranial basin. The cheekbones were thin plates which limited the ear canals. The snout was short and, unlike in other sperm whales, had a distinct upward curve.[1] The left nostril was five times bigger than the right nostril, measuring 30 and 7.2 millimetres (1.18 and 0.28 in) across respectively.[3]
Acrophyseter was relatively small at around 3.9–4.3 metres (13–14 ft), estimated using the distance between the cheek bones, which is around half the size of the raptorial Zygophyseter. A. deinodon, unlike A. robustus, has a more pointed snout, foramina in the premaxillae, a groove on the right side of the snout, a sharp rim around the supracranial basin, and an angular coronoid process of the mandible.[3]
Paleobiology
Acrophyseter probably fed on comparatively large prey, such as the smaller whales such as Piscolithax, pinnipeds such as Acrophoca, and penguins such as Spheniscus urbinai that lived in the area then.
References
- ^ a b c d e Lambert, Olivier; Bianucci, Giovanni; Demuizon, Christian (2008). "A New Stem-Sperm Whale (Cetacea, Odontoceti, Physeteroidea) from the Latest Miocene of Peru". Comptes Rendus Palevol. 7: 361–369. doi:10.1016/j.crpv.2008.06.002.
- ^ Bianucci, G.; Landini, W. (2006). "Killer Sperm Whale: a New Basal Physeteroid (Mammalia, Cetacea) from the Late Miocene of Italy". Zoological Journal of the Linnean Society. 148: 103–131. doi:10.1111/j.1096-3642.2006.00228.x.
- ^ a b c d e f Lambert, O.; Bianucci, G.; de Muizon, C. (2017). "Macroraptorial Sperm Whales (Cetacea, Odontoceti, Physeteroidea) from the Miocene of Peru". Zoological Journal of the Linnean Society. 179: 404–474. doi:10.1111/zoj.12456.
- ^ Toscano, A.; Abad, M.; Ruiz, F.; Muñiz, F.; Álvarez, G.; García, E.; Caro, J. 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 Scaldicetus (Cetacea, Odontoceti, Physeteridae) from the Upper Miocene, Western Sector of the Guadalquivir Basin]. Revista Mexicana de Ciencias Geológicas (in Spanish). 30 (2).
- ^ Berta, A. (2017). The Rise of Marine Mammals: 50 Million Years of Evolution. Baltimore, Maryland: Johns Hopkins University Press. pp. 112–113. ISBN 978-1-4214-2326-5.
