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The petrosal and inner ear of Herpetocetus sp. (Mammalia: Cetacea) and their implications for the phylogeny and hearing of archaic mysticetes

Published online by Cambridge University Press:  20 May 2016

Jonathan H. Geisler  and
Zhexi Luo
Jonathan H. Geisler
Affiliation:
Department of Vertebrate Paleontology, American Museum of Natural History, New York, NY 10027
Zhexi Luo
Affiliation:
Section of Vertebrate Paleontology, Carnegie Museum of Natural History, Pittsburgh, PA 15213
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Abstract

This paper describes the petrosal (periotic) and the inner ear of Herpetocetus sp., an archaic mysticete whale (Mysticeti, Mammalia) from the Yorktown Formation (Pliocene) of North Carolina, USA. Parsimony analysis of 28 petrosal characters of Herpetocetus sp. and 11 other cetacean taxa supports the monophyly of mysticetes and the division of odontocetes and mysticetes. The in-group taxa of this analysis are: Herpetocetus, Parietobalaena, Pelocetus, Balaenidae, Eschrichtius, and Balaenopteridae. Odontocetes and the archaeocete Zygorhiza were used as successive outgroups to root phylogenetic trees and to establish character polarities. Among the modern mysticetes, the Balaenopteridae (rorquals) and the Eschrichtiidae (gray whales) are more closely related to each other than either is to the Balaenidae (bowhead and right whales). Several Miocene “cetotheriid” mysticetes and balaenids share some resemblance in the petrosal, suggesting their affinities. Quantitative information of the inner ear of Herpetocetus sp. was obtained by serial sectioning and computer graphic reconstruction. Herpetocetus sp. is much less developed than odontocetes in the cochlear structures that are crucial for high frequency hearing. Some cochlear structures in this fossil mysticete resemble more closely the non-echolocating modern mysticetes than early fossil toothed whales, indicating a possible specialization in low frequency hearing. This suggests that the archaic mysticetes of the Miocene and Pliocene did not have high frequency hearing necessary for echolocation. Herpetocetus sp. is similar to modern mysticetes but different from odontocetes in the spherical shape of the vestibule.

Type
Research Article
Information
Journal of Paleontology , Volume 70 , Issue 6 , November 1996 , pp. 1045 - 1066
Copyright
Copyright © The Paleontological Society 

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References

Adachi, J., and Hasegawa, M. 1995. Phylogeny of whales: dependence of inference on species sampling. Molecular Biology and Evolution, 12:177–179.Google Scholar
Árnason, U. 1974. Comparative chromosome studies in Cetacea. Hereditas, 77:1–36.Google Scholar
Árnason, U. 1981. Banding studies of the grey and sperm whale karyotypes. Hereditas, 95:277–281.Google Scholar
Árnason, U., and Best, P. B. 1991. Phylogenetic relationships within the Mysticeti (whalebone whales) based upon studies of highly repetitive DNA in all extant species. Hereditas, 114:263–269.Google Scholar
Árnason, U., and Gullberg, A. 1994. Relationship of baleen whales established by cytochrome b gene sequence comparison. Nature, 367:726–728.CrossRefGoogle ScholarPubMed
Árnason, U., and Ledje, C. 1993. The use of highly repetitive DNA for resolving cetacean and pinniped phylogenies, p. 75–80. In Szalay, F. S., Novacek, M. J., and McKenna, M. C. (eds.), Mammal Phylogeny—Placentals. Springer-Verlag, New York.Google Scholar
Barnes, L. G. 1976. Outline of Eastern North Pacific fossil cetacean assemblages. Systematic Zoology, 25:321–343.Google Scholar
Barnes, L. G. 1984. Whales, dolphins and porpoises: origin and evolution of the Cetacea, p. 139–153. In Gingerich, P. D. and Badgley, C. E. (eds.), Mammals—Notes for a Short Course. University of Tennessee, Department of Geological Sciences, Studies in Geology 8.Google Scholar
Barnes, L. G., and McLeod, S. A. 1984. The fossil record and phyletic relationships of gray whales, p. 3–32. In Jones, M. L., Swartz, S., and Leatherwood, S. (eds.), The Gray Whale, Academic Press, Inc., New York.Google Scholar
Barnes, L. G., and Mitchell, E. 1978. Cetacea, p. 582–602. In Maglio, V. J., and Cooke, H.B.S. (eds.), Evolution of African Mammals. Harvard University Press, Cambridge, Massachusetts.Google Scholar
Beneden, P. J. van. 1872. Les baleines fossiles d'Anvers. Bulletin de l'Académie Royale des Sciences de Belgique, (2) 34 (7):6–20.Google Scholar
Berta, A. 1994. What is a whale? Science, 263:180–181.CrossRefGoogle ScholarPubMed
Bruns, V., and Schmieszek, E. 1980. Cochlear innervation in the greater horseshoe bat: demonstration of an acoustic fovea. Hearing Research, 3:27–43.Google Scholar
Cifelli, R. L. 1982. The petrosal structure of Hyopsodus with respect to that of some other ungulates and its phylogenetic implications. Journal of Paleontology, 56:795–805.Google Scholar
Croft, W. N. 1950. A parallel grinding instrument for the investigation of fossils by serial sections. Journal of Paleontology, 24:693–698.Google Scholar
Crompton, A. W. 1955. Techniques for the study of Permo-Triassic Fossils of South Africa. South African Museums Association Bulletin, 6:57–60.Google Scholar
Crompton, A. W., and Luo, Z. 1993. The relationships of Liassic mammals Sinoconodon, Morganucodon oehleri, and Dinnetherium, p. 30–44. In Szalay, F. S., Novacek, M. J., and McKenna, M. C. (eds.), Mammal Phylogeny. Springer-Verlag, New York.Google Scholar
Czelusiniak, J., Goodman, M., Koop, B. F., Tagle, D. A., Shoshani, J., Braunitzer, G., Kleinschmidt, T. K., De Jong, W. W., and Matsuda, G. 1990. Perspectives from aminoacid and nucleotide sequences on cladistic relationships among higher taxa of Eutheria, p. 545–572. In Genoways, H. H. (ed.), Current Mammalogy. Volume 2. Plenum Press, New York.Google Scholar
Emlong, D. 1966. A new archaic cetacean from the Oligocene of Northwest Oregon. Bulletin, Museum of Natural History, University of Oregon, 3:1–51.Google Scholar
Felsenstein, J. 1985. Confidence limits on phylogenies: an approach using the bootstrap. Evolution, 39:783–791.Google Scholar
Felsenstein, J. 1988. Phylogenies from molecular sequences: inferences and relabilities. Annual Reviews of Genetics, 22:521–565.CrossRefGoogle Scholar
Fleischer, G. 1976a. Hearing in extinct cetaceans as determined by cochlear structure. Journal of Paleontology, 50:133–152.Google Scholar
Fleischer, G. 1976b. On bony microstructures in the dolphin cochlea, related to hearing. Neues Jahrbuch für Geologie und Paläontologie Abhandlungen, 151:166–191.Google Scholar
Fleischer, G. 1978. Evolutionary principles of the mammalian middle ear. Advancement in Anatomy, Embryology and Cell Biology, 55:3–70.Google Scholar
Fordyce, R. E. 1983. Rhabdosteid dolphins (Mammalia: Cetacea) from the Middle Miocene, Lake Frome area, South Australia. Alcheringa, 7:27–40.CrossRefGoogle Scholar
Fordyce, R. E. 1994. Waipatia maerewhenua, new genus and new species (Waipatiidae, New Family), an archaic late Oligocene dolphin (Cetacea: Odontoceti: Platanistoidea) from New Zealand, p. 147–176. In Berta, A., and Deméré, T. (eds.), Contributions in Marine Mammal Paleontology Honoring Frank C. Whitmore, Jr. Proceedings of the San Diego Society of Natural History, No. 29.Google Scholar
Fordyce, R. E., and Barnes, L. G. 1994. The evolutionary history of whales and dolphins, p. 419–455. In Wetherill, George W. (ed.), Annual Review of Earth and Planetary Sciences, Volume 22. Annual Reviews, Inc., Palo Alto, California.Google Scholar
Fraser, F. C., and Purves, P. E. 1960. Hearing in cetaceans. Evolution of the accessory air sacs and the structures of the outer and middle ear in recent cetaceans. Bulletin of British Museum (Natural History) Zoology, 7:1–140.Google Scholar
Gingerich, P. D. 1992. Marine mammals (Cetacea and Sirenia) from the Eocene of Gebel Mokattam and Fayum, Egypt: stratigraphy, age and paleoenvironments. Papers on Paleontology, Museum of Paleontology, University of Michigan, 30:1–84.Google Scholar
Gingerich, P. D., Raza, S. M., Arif, M., Anwar, M., and Zhou, X. 1994. New whale from the Eocene of Pakistan and the origin of cetacean swimming. Nature, 368:844–847.Google Scholar
Gingerich, P. D., and Russell, D. E. 1981. Pakicetus inachus, a new archaeocete (Mammalia, Cetacea) from the Early-Middle Eocene Kuldana Formation of Kohat (Pakistan). Contributions from the Museum of Paleontology, the University of Michigan, 25:235–246.Google Scholar
Gingerich, P. D., and Russell, D. E. 1990. Dentition of Early Eocene Pakicetus (Mammalia, Cetacea). Contributions from the Museum of Paleontology, the University of Michigan, 28:1–20.Google Scholar
Gingerich, P. D., Smith, B. H., and Simons, E. L. 1990. Hind limbs of Eocene Basilosaurus: evidence of feet in whales. Science, 249:154–157.Google Scholar
Gingerich, P. D., Wells, N. A., Russell, D. E., and Ibrahim Shah, S. M. 1983. Origin of whales in epicontinental remnant seas: new evidence from the Early Eocene of Pakistan. Science, 222:403–406.Google Scholar
Gottfried, M. D., Bohaska, D. J., and Whitmore, F. C. Jr. 1994. Miocene cetaceans of the Chesapeake Group, p. 229–238. In Berta, A., and Deméré, T. (eds.), Contributions in Marine Mammal Paleontology Honoring Frank C. Whitmore, Jr. Proceedings of the San Diego Society of Natural History, No. 29.Google Scholar
Graybeal, A., Rosowski, J., Ketten, D. R., and Crompton, A. W. 1989. Inner ear structure in Morganucodon, an early Jurassic mammal. Zoological Journal of Linnean Society (London), 96:107–117.Google Scholar
Guild, S. R. 1921. A graphic reconstruction method for the study of the organ of Corti. Anatomical Record, 22:141–157.Google Scholar
Heyning, J. E. 1989. Comparative facial anatomy of beaked whales (Ziphiidae) and a systematic revision among the families of extant Odontoceti. Contributions in Science, Natural History Museum of Los Angeles County, 405:1–64.Google Scholar
Heyning, J. E., and Mead, J. G. 1990. Evolution of the nasal anatomy of cetaceans, p. 67–79. In Thomas, J. A. and Kastelein, R. A. (eds.), Sensory Abilities of Cetaceans. Plenum Press, New York.Google Scholar
Kasuya, T. 1973. Systematic consideration of recent toothed whales based on morphology of tympano-periotic bone. The Scientific Reports of the Whale Research Institute (Tokyo), 25:1–103.Google Scholar
Kellogg, A. R. 1925. Additions to the Tertiary history of the pelagic mammals on the Pacific coast of North America II. Fossil cetotheres. Carnegie Institution of Washington Publications, 348:35–56.Google Scholar
Kellogg, A. R. 1928. The history of whales—their adaptation to the life in the water. Quarterly Review of Biology, 3:29–76; 174-208.Google Scholar
Kellogg, A. R. 1931. Pelagic mammals from the Temblor Formation of the Kern River region, California. Proceedings, California Academy of Science (Series 4), 19:217–397.Google Scholar
Kellogg, A. R. 1934a. The Patagonian fossil whalebone whale, Cetotherium moreni (Lydekker). Carnegie Institution of Washington Publication, No. 447 (Contributions to Paleontology II):63–81.Google Scholar
Kellogg, A. R. 1934b. A new cetothere from the Modelo Formation at Los Angeles, California. Carnegie Institution of Washington Publication, No. 447 (Contributions to Paleontology I): 83:104.Google Scholar
Kellogg, A. R. 1936. A review of Archaeoceti. Carnegie Institution of Washington Publications, 482:1–366.Google Scholar
Kellogg, A. R. 1965. Fossil marine mammals from the Miocene Calvert Formation of Maryland and Virginia. United States National Museum Bulletin, 247:1–63.Google Scholar
Kellogg, A. R. 1968. Supplement to description of Parietobalaena palmeri. United States National Museum Bulletin, 247:175–197.Google Scholar
Kermack, D. M. 1970. True serial-sectioning of fossil material. Biological Journal of Linnean Society, 2:47–53.Google Scholar
Ketten, D. R. 1992. The marine mammal ear: specializations for aquatic audition and echolocation, p. 717–750. In Webster, D. B., Fay, R. R., and Popper, A. N. (eds.), The Evolutionary Biology of Hearing. Springer-Verlag, New York.Google Scholar
Ketten, D. R., and Wartzok, D. 1990. Three-dimensional reconstructions of the dolphin ear, p. 81–105. In Thomas, J. A., and Kastelein, R. A. (eds.), Sensory Abilities of Cetaceans. Plenum Press, New York.Google Scholar
Luo, Z. 1989. The petrosal structures of Multituberculata (Mammalia) and the molar morphology of the early arctocyonids (Condylarthra: Mammalia). Unpublished Ph.D. Dissertation, Department of Paleontology, University of California at Berkeley, 422 p.Google Scholar
Luo, Z., and Crompton, A. W. 1994. Transformations of the quadrate (incus) through the transition from non-mammalian cynodonts to mammals. Journal of Vertebrate Paleontology, 14:341–374.CrossRefGoogle Scholar
Luo, Z., Crompton, A. W., and Lucas, S. G. 1995. Evolutionary origins of the mammalian promontorium and cochlea. Journal of Vertebrate Paleontology, 15:113–121.CrossRefGoogle Scholar
Luo, Z., and Eastman, E. R. 1995. The petrosal and inner ear structures of a squalodontoid whale: their implications on hearing evolution. Journal of Vertebrate Paleontology, 15:431–442.Google Scholar
Luo, Z., and Ketten, D. R. 1991. CT scanning and computerized reconstructions of the inner ear of multituberculate mammals. Journal of Vertebrate Paleontology, 11:220–228.CrossRefGoogle Scholar
Luo, Z., and Marsh, K. 1996. The petrosal and inner ear structure of a fossil kogine whale (Odontoceti, Mammalia). Journal of Vertebrate Paleontology, 16:328–348.Google Scholar
MacIntyre, G. T. 1972. The trisulcate petrosal pattern of mammals, p. 275–303. In Dobzhansky, T., Hecht, M. K., and Steere, W. C. (eds.), Evolutionary Biology (Volume 6).Google Scholar
MacPhee, R. D. E. 1981. Auditory regions of primates and eutherian insectivores: morphology, ontogeny and character analysis. Contributions to Primatology, 18:1–282.Google Scholar
Maddison, W. P., Donaghue, M. J., and Maddison, D. R. 1984. Outgroup analysis and parsimony. Systematic Zoology, 33:83–103.CrossRefGoogle Scholar
Maddison, W. P., and Maddison, D. R. 1992. MacClade Program (Version 3.0). Sinaurs and Associates, Sutherland, Massachusetts.Google Scholar
McKenna, M. C. 1987. Molecular and morphological analysis of high-level mammalian interrelationships, p. 55–93. In Patterson, C. (ed.), Molecules and Morphology in Evolution: Conflict or Compromise? Cambridge University Press, Cambridge and London.Google Scholar
McLeod, S. A., Whitmore, F. C. Jr., and Barnes, L. G. 1993. Evolutionary relationships and classification, Chapter 3, p. 45–70. In Burns, J. J., Montague, J. J., and Cowles, C. J. (eds.), The Bowhead Whale, Society for Marine Mammalogy Special Publication No. 2.Google Scholar
Mead, J. G. 1975. Anatomy of the external nasal passages and facial complex in the Delphinidae (Mammalia: Cetacea). Smithsonian Contributions to Zoology, 207:1–72.Google Scholar
Milinkovitch, M. C., Ortí, G., and Meyer, A. 1993. Revised phylogeny of whales suggested by mitochondrial ribosomal DNA sequence. Nature, 361:346–348.CrossRefGoogle Scholar
Milinkovitch, M. C., Ortí, G., and Meyer, A. 1995. Novel phylogeny of whales revisited but not revised. Molecular Biology and Evolution, 12:518–520.Google Scholar
Milinkovitch, M. C., Meyer, A., and Ortí, G. 1994. Phylogeny of all major groups of cetaceans based on DNA sequences from three mitochondrial genes. Molecular Biology and Evolution, 11:939–948.Google Scholar
Miller, G. S. 1923. The telescoping of the cetacean skull. Smithsonian Miscellaneous Papers, 76:1–67.Google Scholar
Morgan, G. S. 1994. Miocene and Pliocene marine mammal faunas from the Bone Valley Formation of Central Florida, p. 239–268. In Berta, A., and Deméré, T. (eds.), Contributions in Marine Mammal Paleontology Honoring Frank C. Whitmore, Jr. Proceedings of the San Diego Society of Natural History, No. 29.Google Scholar
Muizon, C. De. 1987. The affinities of Notocetus vanbenedeni, an early Miocene Platanistoid (Cetacea, Mammalia) from Patagonia, Southern Argentina. American Museum Novitates, 2904:1–27.Google Scholar
Muizon, C. De. 1990. A new Ziphiidae (Cetacea) from the Early Miocene of Washington State (USA) and phylogenetic analysis of the major groups of odontocetes. Bulletin du Muséum National d'Histoire Naturelle (4e sériel 12, section C), N$dG 3-4:279–326.Google Scholar
Muizon, C. De. 1994. Are the squalodonts related to the Platanistoids? p. 135–146. In Berta, A. and Deméré, T. (eds.), Contributions in Marine Mammal Paleontology Honoring Frank C. Whitmore, Jr. Proceedings of the San Diego Society of Natural History, No. 29.Google Scholar
Novacek, M. J. 1993a. Genes tell a new whale tale. Nature, 361:298–299.CrossRefGoogle Scholar
Novacek, M. J. 1993b. Patterns of diversity in the mammalian skull, p. 438–529. In Hanken, J., and Hall, B. K. (eds.), The Skull: Patterns of Structural and Systematic Diversity, Volume 2. The University of Chicago Press, Chicago, Illinois.Google Scholar
Oelschläger, H. A. 1986. Comparative morphology and evolution of the otic region in toothed whales (Cetacea, Mammalia). The American Journal of Anatomy, 177:353–368.Google Scholar
Oelschläger, H. A. 1990. Evolutionary morphology and acoustics in the dolphin skull, p. 137–162. In Thomas, J. A., and Kastelein, R. A. (eds.), Sensory Abilities of Cetaceans. Plenum Press, New York.Google Scholar
Olsen, F. R., and Whitmore, F. C. 1944. Machine for serial sectioning of fossil. Journal of Paleontology, 18:210–215.Google Scholar
Otten, E. 1987. A myocybernetic model of the jaw system of the rat. Journal of Neuroscience Methods, 21:287–302.Google Scholar
Packard, E. L., and Kellogg, R. 1934. A new cetothere from the Miocene Astoria Formation of Newport, Oregon. 1-62. Carnegie Institution of Washington Publication, No. 447 (Contributions to Paleontology II):83–104.Google Scholar
Philippe, H., and Douzery, E. 1994. The pitfalls of molecular phylogeny based on four species, as illustrated by the Cetacea/Artiodactyla relationships. Journal of Mammalian Evolution, 2:133–152.Google Scholar
Pilleri, G., Gihr, M., and Kraus, C. 1987. The organ of Corti in cetaceans—1. recent species. Investigations on Cetacea, 20:43–125.Google Scholar
Pollak, G. D. 1992. Adaptations of basic structures and mechanism in the cochlea and central auditory pathway of the mustache bat, p. 751–778. In Webster, D. B., Fay, R. R., and Popper, A. N. (eds.), The Evolutionary Biology of Hearing. Springer-Verlag, New York.Google Scholar
Pompeckj, J. F. von. 1922. Das Ohrsklett von Zeuglodon. Senckenbergiana, IV:44–100.Google Scholar
Poplin, C. M., and De Ricqlés, A. J. 1970. A technique of serial sectioning for the study of undercalcified fossils. Curator, 13:6–19.Google Scholar
Prothero, D. R. 1983. The oldest mammalian petrosals from North America. Journal of Paleontology, 57:1040–1046.Google Scholar
Purves, P. E. 1966. Anatomy and physiology of the outer and middle ear in cetaceans, p. 320–376. In Norris, K. S. (ed.), Whales, Dolphins, and Porpoises. University of California Press, Berkeley.Google Scholar
Ramprashad, F., Landolt, J. P., Money, K. E., Clark, D., and Laufer, J. 1978. A neuroanatomical study of the cochlea of the little brown bat (Myotis lucifugus). Journal of Comparative Neurology, 78:347–364.CrossRefGoogle Scholar
Ramprashad, F., Money, K. E., Landolt, J. P., and Laufer, J. 1979. A morphometric study of the cochlea of the little brown bat (Myotis lucifugus). Journal of Morphology, 160:345–358.Google Scholar
Reysenbach de Haan, F. W. 1966. Listening underwater: thoughts on sound and cetacean hearing, p. 583–595. In Norris, K. S. (ed.), Whales, Dolphins, and Porpoises. University of California Press, Berkeley.Google Scholar
Savage, D. E., and Russell, D. E. 1983. Mammalian Paleofaunas of the World. Addison-Wesley Publishing Company, Reading, Massachusetts, p. 432.Google Scholar
Schuknecht, H. G. 1953. Techniques for study of cochlear function and pathology in experimental animals. Archives of Otolaryngology, 58:377–397.Google Scholar
Segall, W. 1970. Morphological parallelisms of the bulla and auditory ossicles in some insectivores and marsupials. Fieldiana (Zoology), 51:169–205.Google Scholar
Swofford, D. L. 1993. PAUP: Phylogenetic Analysis Using Parsimony (3.11). Privately distributed by Illinois Natural History Survey, Champaign.Google Scholar
Thewissen, J. G. M., and Hussain, S. T. 1993. Origin of underwater hearing in whales. Nature, 361:444–445.Google Scholar
Thewissen, J. G. M., Hussain, S. T., and Arif, M. 1994. Fossil evidence of the origin of aquatic locomotion in archaeocete whales. Science, 263:210–212.Google Scholar
Ting, S-Y., and Li, C.-K. 1987. The skull of Hapalodectes (?Acreodi, Mammalia), with notes on some Chinese Paleocene mesonychids. Vertebrate PalAsiatica, 25:161–186.Google Scholar
Wever, E. G., McCormick, J. G., Palin, J., and Ridgway, S. H. 1971a. The cochlea of the dolphin, Tursiops truncatus: general morphology. Proceedings, National Academy of Science, USA, 68:2381–2385.Google Scholar
Wever, E. G., McCormick, J. G., Palin, J., and Ridgway, S. H. 1971b. Cochlea of the dolphin, Tursiops truncatus: the basilar membrane. Proceedings, National Academy of Science, USA, 68:2708–2711.Google Scholar
Wever, E. G., McCormick, J. G., Palin, J., and Ridgway, S. H. 1971c. Cochlea of the dolphin, Tursiops truncatus: hair cells and ganglion cells. Proceedings, National Academy of Science, USA, 68:2908–2912.Google Scholar
Wever, E. G., McCormick, J. G., Palin, J., and Ridgway, S. H. 1972. Cochlear structure in the dolphin, Lagenorhynchus. Proceedings, National Academy of Science, USA, 69:657–661.CrossRefGoogle ScholarPubMed
Whitmore, F. C. 1953. Cranial morphology of some Oligocene Artiodactyla. Geological Survey Professional Paper, 243(H):117–159.Google Scholar
Whitmore, F. C. 1987. A delphinoid ear bone from the Dam Formation (Miocene) of Saudi Arabia. Bulletin, British Museum of Natural History (Geology), 41:447–450.Google Scholar
Whitmore, F. C. 1994. Neogene climactic change and the emergence of the modern whale fauna of the North Atlantic Ocean, p. 224–228. In Berta, A., and Deméré, T. (eds.), Contributions in Marine Mammal Paleontology Honoring Frank C. Whitmore, Jr. Proceedings of the San Diego Society of Natural History, No. 29.Google Scholar
Whitmore, F. C., and Sanders, A. E. 1976. Review of the Oligocene Cetacea. Systematic Zoology, 25:304–320.Google Scholar
Williams, P. L., Williams, R., Dyson, M., and Bannister, L. H. 1989. Gray's Anatomy (37th edition). Churchill Livingstone, New York, 1598 p.Google Scholar
Wible, J. R. 1990. Petrosals of Late Cretaceous marsupials from North America, and a cladistic analysis of the petrosal in therian mammals. Journal of Vertebrate Paleontology, 10:183–205.Google Scholar
Wible, J. R., and Hopson, J. A. 1993. Basicranial evidence for early mammal phylogeny, p. 45–62. In Szalay, F. S., Novacek, M. J., and McKenna, M. C. (eds.), Mammal Phylogeny—Mesozoic differentiation, multituberculates, monotremes, early therians and marsupials, Volume 1. Springer-Verlag, New York.Google Scholar
Yamada, M., and Yoshizaki, F. 1959. Osseous labyrinth of Cetacea. The Scientific Reports of the Whale Research Institute (Tokyo), 14:291–304.Google Scholar
Zeller, U. 1985. The morphogenesis of the fenestra rotunda in mammals. Fortschritte der Zoologie, 30:153–157.Google Scholar
Zhou, X., Zhai, R., Gingerich, P. D., and Chen, L. 1995. Skull of a new mesonychid (Mammalia, Mesonychia) from the Late Paleocene of China. Journal of Vertebrate Paleontology, 15:387–400.Google Scholar