Monday, September 27, 2010

September 27, 2010 : Basilosaurus (Extinct)


Basilosaurus ("King Lizard") is a genus of cetacean that lived from 40 to 34 million years ago Its fossilized remains were first discovered in the southern United States (Louisiana), and were initially believed to be some sort of reptilian sea monster, hence the suffix -"saurus", but later it was found that was not the case. Fossils from at least two other species of this taxon have been found in Egypt and Pakistan.
in the Late Eocene.Basilosaurus averaged about 18 meters (60 ft) in length, and is believed to have been the largest animal to have lived in its time. It displayed an unparalleled degree of elongation compared with modern whales. Their very small vestigial hind limbs have also been a matter of interest for paleontologists. The species is the state fossil of Mississippi and Alabama in the United States.

During the early 19th century in the American South, Basilosaurus cetoides fossils were so common (as well as large) that they were regularly used as furniture. Vertebrae were sent to the American Philosophical Society by a Judge Bly of Arkansas and Judge John Creagh of Clarke County, Alabama. Both fossils ended up in the hands of the anatomist Dr. Richard Harlan, who requested more examples from Creagh. With some reservation, Harlan speculated that the fossils belonged to a (50 m [166 ft] long) marine reptile, for which he suggested the name Basilosaurus, meaning “King reptile”.

When the British anatomist Sir Richard Owen studied the spine, mandibular fragments, arms, and ribs (more recently found) he proclaimed them to be mammalian. Owen proposed renaming the find to Zeuglodon cetoides (“whale-like yoke teeth”), which is now a junior synonym; though the latter is considered by many to be a more fitting name, the first-published name always takes precedence. The name Zeuglodon refers to the double rooted teeth typical of marine mammals.

In 1845, “Dr.” Albert Koch heard stories of giant bones in Alabama, and went down to cobble together a full skeleton. He eventually created a huge 114-foot (35 m) skeleton of a “sea serpent” he called "Hydrarchos", which he displayed in New York City, and later Europe. It was eventually shown to have come from 5 different individuals, some of which were not Basilosaurus. The remains were eventually destroyed in the Great Chicago Fire.

Fossil finds of another species, Basilosaurus isis, have been found in the aptly named Valley of the Whales in Egypt. The fossils were very well preserved, hind limbs included, and were rather numerous. Paleontologist Philip Gingerich, who organized several expeditions to the valley, speculated that Egyptian crocodile worship may have been inspired by the huge skeletons that lay there. Fossil remains of another species, Basilosaurus drazindai, have been found in Pakistan. Another fossilized species named Basiloterus husseini was its closest known relative, but was not as large or elongated.

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