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Cranium Skull of B. The upper and lower molars and second to fourth premolars are double-rooted and high-crowned. The head of Basilosaurus did not have room for a melon like modern toothed whales, and the brain was smaller in comparison, as well. They are not believed to have had the social capabilities of modern whales.
Fahlke and others concluded that the skull of Basilosaurus is asymmetrical like in modern toothed whales, and not, as previously assumed, symmetrical like in baleen whales and artiodactyls closely related to cetaceans. In modern toothed whales, this asymmetry is associated with high-frequency sound production and echolocation, neither of which is thought to be present in Basilosaurus.
This cranial basilosaurus facts to write about probably evolved in protocetids and basilosaurids together with directional underwater hearing and the sound-receiving apparatus in the mandible the auditory fat pad and the pan bone thin portion of mandible.
In the basilosaur skull, the inner and middle ear are enclosed by a dense tympanic bulla.
The synapomorphic cetacean air sinus system is partially present in basilosaurids, including the pterygoid, peribullary, maxillary, and frontal sinuses.
The periotic bone, which surrounds the inner ear, is partially isolated. The mandibular canal is large and laterally flanked by a thin bony wall, the pan bone or acoustic fenestra. These features enabled basilosaurs to hear directionally in water. The ear of basilosaurids is more derived than those in earlier archaeocetes, such as remingtonocetids and protocetids, in the acoustic isolation provided by the air-filled sinuses inserted between the ear and the skull.
The basilosaurid ear did, however, have a large external auditory meatus, strongly reduced in modern cetaceans, but though this was probably functional, it can have been of little use under water. Recent studies revealed that Basilosaurus isis had a power bone crushing bite, exerting over 3, to 4, pounds per square inch, arguably the strongest bite force of any mammal, in order to crack open the skulls of young Dorudonwhich were its preferred prey based on the bite marks found on the skulls of the Dorudon.
Eric Snively, Robert Welsh and Julia Fahlke, the authors of the article speculate the Basilosaurus isis was an active predator rather than a scavenger. Spine Restoration of a group A complete Basilosaurus skeleton was found inand several attempts have been made to reconstruct the vertebral column from partial skeletons.
Kellogg estimated a total of 58 vertebrae, based on two partial and nonoverlapping skeletons of B. More complete fossils uncovered in Egypt in the s allowed a more accurate estimation: The vertebral formula of B. Basilosaurus has an anguilliform eel-like body shape because of the elongation of the centra of the thoracic through anterior caudal vertebrae.
In life, these vertebrae were filled with marrow, and because of the enlarged size, made them buoyant. From this it can be deduced that Basilosaurus swam predominantly in two dimensions at the sea surface, in contrast to the smaller Dorudonwhich was probably a diving, three-dimensional swimmer.
The skeletal anatomy of the tail suggests that a small fluke was probably present, which would have aided only vertical motion. The limited size of the limb and the absence of an articulation with the sacral vertebrae, makes a locomotory function unlikely. Analysis has shown that the reduced limbs could rapidly adduct between only two positions.
Gingerich theorized that Basilosaurus may also have moved in a very odd, horizontal anguilliform fashion to some degree, something completely unknown in modern cetaceans.
The vertebrae appear to have been hollow, and likely also fluid-filled. This would imply that Basilosaurus typically functioned in only two dimensions at the ocean surface, compared with the three-dimensional habits of most other cetaceans.
Judging from the relatively weak axial musculature and the thick bones in the limbs, Basilosaurus is not believed to have been capable of sustained swimming or deep diving, or terrestrial locomotion.
Feeding The cheek teeth of Basilosaurus retain a complex morphology and functional occlusion. Heavy wear on the teeth reveals that food was first chewed then swallowed.Please write down any comments, questions, or concerns below this sentence. Dunkleosteus77 (talk) , 10 May (UTC) A concern is the article size, per WP:SIZE.
Basilosaurus cetoides belonged to an extinct group of whales known as the Archaeoceti that lived 40 to 34 million years ago. It grew 40 to 65 feet in length, and was the largest known animal of its day.
Write these statements down in a notebook and collect them. Underline assumptions, write them down and test them to see if they are valid.
Another problem, which adds to the student’s frustration, is the overuse of scientific jargon and unpronounceable words, burying him in a sea of confusion.
The only memorial in the world which glorifies a pest - the Mexican Boll Weevil is located in Enterprise, Alabama. Dothan Alabama is the Peanut Capital of the World.
Fifty percent of all the peanuts produced in the U.S. are grown within miles of Dothan. Basilosaurus did have small hind limbs (certainly too small for walking), and Teaching Evolution says “they were thought to be non-functional.” But they were probably used for grasping during copulation, according to even other evolutionists.
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