A new fossil species supports an early origin for toothed whale echolocation

  title={A new fossil species supports an early origin for toothed whale echolocation},
  author={Jonathan H Geisler and Matthew W Colbert and James L. Carew},
Odontocetes (toothed whales, dolphins and porpoises) hunt and navigate through dark and turbid aquatic environments using echolocation; a key adaptation that relies on the same principles as sonar. Among echolocating vertebrates, odontocetes are unique in producing high-frequency vocalizations at the phonic lips, a constriction in the nasal passages just beneath the blowhole, and then using air sinuses and the melon to modulate their transmission. All extant odontocetes seem to echolocate… 

Evidence for convergent evolution of ultrasonic hearing in toothed whales (Cetacea: Odontoceti)

This discovery implies that either the lineage leading to this Olympicetus-like taxon lost the ability to hear ultrasonic sound, or adaptations for ultrasonic hearing evolved twice, once in xenorophids and again on the stem of the odontocete crown group.

The Origin of High-Frequency Hearing in Whales

Convergent evolution in toothed whale cochleae

Support is added for cochlear morphology being used to predict the ecology of extinct cetaceans after it was found that the extreme acoustic environment of the deep ocean likely constrains co chlear shape, causing the coChlear morphology of sperm and beaked whales to converge.

A toothless dwarf dolphin (Odontoceti: Xenorophidae) points to explosive feeding diversification of modern whales (Neoceti)

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Separate evolutionary regimes are reconstructed for odontocetes living in acoustically complex environments, suggesting that these niches impose strong selective pressure on echolocation ability and thus increased cranial asymmetry.

The bony labyrinth of toothed whales reflects both phylogeny and habitat preferences

The investigation of more than 20 species of extinct and modern odontocetes shows that the semi-circular canals are not very informative, in contrast to baleen whales, while the cochlea alone bears a strong signal.

Evolution of orbit size in toothed whales (Artiodactyla: Odontoceti)

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Evolution of cranial telescoping in echolocating whales (Cetacea: Odontoceti)

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Gigantism Precedes Filter Feeding in Baleen Whale Evolution

Macroevolution of Toothed Whales Exceptional Relative Brain Size

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A phylogenetic blueprint for a modern whale.

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The morphological data presented here substantiate and extend the unified “phonic lips” hypothesis of sound generation in toothed whales suggested by Cranford et al. (J Morphol 1996;228:223–285).

The Cetacean Ear: Form, Frequency, and Evolution

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A virtually complete skull found in Late Oligocene beds on the Mangyshlak Peninsula of the Republic of Kazakhstan in the 1960s is the first specimen of Patriocetus known from the eastern Paratethys region, extending the range of this genus approximately 4,000 km eastward from the type locality of the genus at Linz.

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