Superregnum: Eukaryota
Cladus: Unikonta
Cladus: Opisthokonta
Cladus: Holozoa
Regnum: Animalia
Subregnum: Eumetazoa
Cladus: Bilateria
Cladus: Nephrozoa
Superphylum: Deuterostomia
Phylum: Chordata
Subphylum: Vertebrata
Infraphylum: Gnathostomata
Megaclassis: Osteichthyes
Cladus: Sarcopterygii
Cladus: Rhipidistia
Cladus: Tetrapodomorpha
Cladus: Eotetrapodiformes
Cladus: Elpistostegalia
Superclassis: Tetrapoda
Cladus: Reptiliomorpha
Cladus: Amniota
Cladus: Synapsida
Cladus: Eupelycosauria
Cladus: Sphenacodontia
Cladus: Sphenacodontoidea
Cladus: Therapsida
Cladus: Theriodontia
Cladus: Cynodontia
Cladus: Eucynodontia
Cladus: Probainognathia
Cladus: Prozostrodontia
Cladus: Mammaliaformes
Classis: Mammalia
Subclassis: Trechnotheria
Infraclassis: Zatheria
Supercohors: Theria
Cohors: Eutheria
Infraclassis: Placentalia
Cladus: Boreoeutheria
Superordo: Laurasiatheria
Cladus: Scrotifera
Cladus: Ferungulata
Cladus: Euungulata
Ordo: Artiodactyla
Cladus: Artiofabula
Cladus: Cetruminantia
Subordo: Whippomorpha
Infraordo: Cetacea
Cladus: †Archaeoceti
Familia: †Protocetidae
Subfamiliae: Georgiacetinae – Makaracetinae – Pappocetinae – Protocetinae
Overview of genera
†Aegyptocetus – Artiocetus – Babiacetus – Carolinacetus – Crenatocetus – Eocetus – Gaviacetus – Georgiacetus – Indocetus – Maiacetus – Makaracetus – Natchitochia – Pappocetus – Phiomicetus – Protocetus – Qaisracetus – Rodhocetus – Takracetus – Togocetus
Name
Protocetidae Stromer, 1908
References
Geisler, J.H.; Sanders, A.E.; Luo, Z-x. 2005: A new protocetid whale (Cetacea: Archaeoceti) from the late middle Eocene of South Carolina. American Museum novitates, (3480 ) DOI: 10.1206/0003-0082(2005)480[0001:ANPWCA]2.0.CO;2
PHILIP D. GINGERICH, IYAD S. ZALMOUT, MUNIR UL-HAQ, & M. AKRAM BHATTI, 2005, Contributions from the Museum of Paleontology, The University of Michigan 31(9): 197–210 [1]
McLeod, S.A.; Barnes, L.G. 2008: A new genus and species of Eocene protocetid archaeocete whale (Mammalia, Cetacea) from the Atlantic Coastal Plain. Science series, Natural History Museum of Los Angeles County, 41: 73–98.
Vernacular names
日本語: プロトケトゥス科
中文: 原鯨科
Protocetidae, the protocetids, form a diverse and heterogeneous group of extinct cetaceans known from Asia, Europe, Africa, South America, and North America.
Description
Skeletal drawing of Maiacetus.
Drawing of Rodhocetus.
There were many genera, and some of these are very well known (e.g., Rodhocetus). Known protocetids had large fore- and hindlimbs that could support the body on land, and it is likely that they lived amphibiously: in the sea and on land. It is unclear at present whether protocetids had flukes (the horizontal tail fin of modern cetaceans). However, what is clear is that they are adapted even further to an aquatic life-style. In Rodhocetus, for example, the sacrum – a bone that in land-mammals is a fusion of five vertebrae that connects the pelvis with the rest of the vertebral column – was divided into loose vertebrae. However, the pelvis retain a sacroiliac joint. Furthermore, the nasal openings are now halfway up the snout; a first step towards the telescoped condition in modern whales. Their supposed amphibious nature is supported by the discovery of a pregnant Maiacetus,[2] in which the fossilised fetus was positioned for a head-first delivery, suggesting that Maiacetus gave birth on land. The ungulate ancestry of these early whales is still underlined by characteristics like the presence of hooves at the ends of toes in Rodhocetus.
Taxonomy
Skeletal drawing of Aegicetus.
Drawing of Georgiacetus.
The protocetid subfamilies were proposed by Gingerich et al. 2005. They placed Makaracetus in its own subfamily (Makaracetinae) based on its unique adaptations for feeding (including only two incisors in each premaxilla). They then erected two subfamilies for the rest of the protocetids based on their degree of aquatic adaptation:[3]
Protocetinae- Protocetines are Lutetian protocetids with generalized skulls retaining three incisors in the premaxilla and three molars in the maxilla. To the extent postcrania are known (primarily from Rodhocetus, and more recently Peregocetus),[4] they possess a pelvis similar to those in land-living mammals, a sacrum articulated to the ilia and innominates and large hindlimbs used for foot-powered propulsion.[3] Genera:
Aegyptocetus
Artiocetus
Dhedacetus
Gaviacetus
Indocetus
Kharodacetus
Maiacetus
Peregocetus
Phiomicetus
Protocetus
Qaisracetus
Rodhocetus
Takracetus
Togocetus
Georgiacetinae- Georgiacetines are Bartonian protocetids, considered transitional to the basilosaurids. Their skulls and dentition are similar to those of protocetines, but the pelvis in Georgiacetus and Aegicetus indicate a reduced sacroiliac joint, with no substantial articulation between backbone and innominates. Until recently, no hindlimb material was known for this subfamily, although the pelvic morphology seemed to hint at a tail-based rather than foot-based mode of aquatic locomotion. The discovery of Aegicetus supports this notion.[3][5] Genera:
Aegicetus
Babiacetus
Carolinacetus
Crenatocetus
Georgiacetus
Natchitochia
Pappocetus
Tupelocetus
Notes
"Protocetidae". paleobiodb.org. Retrieved 2021-09-03.
Gingerich et al. 2009
Gingerich et al. 2005, Table 1, pp. 207–8
Olivier L, Bianucci G, Salas-Gismondi R, Di Celma C, Steurbaut E, Urbina M & de Muizon C (2019). "An amphibious whale from the Middle Eocene of Peru reveals early South Pacific dispersal of quadrupedal cetaceans". Current Biology 29(8): p. 1352–1359.e3.
Gingerich P.D., Antar M.S.M., Zalmout I.S. (2019). "Aegicetus gehennae, a new late Eocene protocetid (Cetacea, Archaeoceti) from Wadi Al Hitan, Egypt, and the transition to tail-powered swimming in whales". PLoS ONE 14(12):e0225391
References
Gingerich, Philip D; ul-Haq, Munir; von Koenigswald, Wighart; Sanders, William J; Smith, B Holly; Zalmout, Iyad S (2009). "New Protocetid Whale from the Middle Eocene of Pakistan: Birth on Land, Precocial Development, and Sexual Dimorphism". PLOS ONE. 4 (2): e4366. Bibcode:2009PLoSO...4.4366G. doi:10.1371/journal.pone.0004366. PMC 2629576. PMID 19194487.
Gingerich, Philip D.; Zalmout, Iyad S.; Ul-Haq, Munir; Bhatti, M. Akram (2005). "Makaracetus bidens, a new protocetid archaeocete (Mammalia, Cetacea) from the early middle Eocene of Balochistan (Pakistan)" (PDF). Contributions from the Museum of Paleontology. 31 (9): 197–210. OCLC 742723177. Retrieved 1 March 2013.
Stromer, Ernst (1908). Die Archaeoceti des ägyptischen Eozäns: Beiträge zur paläontologie und geologie Österreich-Ungarns und des Orients (PDF). W. Braumüller. OCLC 21174007. Retrieved 1 July 2013.
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