Posted on 12/20/2007 6:50:22 AM PST by Red Badger
This undated handout artist rendering provided by Northeastern Ohio Universities Colleges of Medicine and Pharmacy (NEOUCOM) shows The 48 million year old ungulate Indohyus from India. Indohyus is a close relative of whales, and the structure of its bones and chemistry of its teeth indicate that it spent much time in water. In this reconstruction, it is seen diving in a stream, much like the modern African Mousedeer does when in danger. (AP Photo/NEOUCOM)
(AP) -- The gigantic ocean-dwelling whale may have evolved from a land animal the size of a small raccoon, new research suggests.
What might be the missing evolutionary link between whales and land animals is an odd animal that looks like a long-tailed deer without antlers or an overgrown long-legged rat, fossils indicate.
The creature is called Indohyus, and recently unearthed fossils reveal some crucial evolutionary similarities between it and water-dwelling cetaceans, such as whales, dolphins and porpoises.
For years, the hippo has been the leading candidate for the closest land relative because of its similar DNA and whale-like features. So some scientists were skeptical of the new hypothesis by an Ohio anatomy professor whose work was being published Thursday in the journal Nature.
Still, some researchers have been troubled that hippos seem to have lived in the wrong part of the world and popped up too recently to be a whale ancestor.
Newer fossils point to the deer-like Indohyus. The animal is a "missing link" to the sister species to ancient whales, said Hans Thewissen, an anatomy professor at Northeastern Ohio Universities College of Medicine.
"As a zoo animal, it looks nothing like a whale," Thewissen said. But, he added, when it comes to anatomical features, the Indohyus "is quite strikingly like one."
Thewissen, who earlier published papers on fossils of what he called the first amphibious whale and the skeleton of the oldest known whale, studied hundreds of Indohyus bones unearthed from mudstone in the Kashmir region of India. From that cache of bones he created a composite skeleton of a 48 million-year-old creature.
The key finding connecting Indohyus to the whale is its thickened ear bone, something only seen in cetaceans. An examination of its teeth showed that the land-dwelling creature spent lots of time in the water and may have fed there, like hippos and whales. Also, the specific positioning and shape of certain molars connects Indohyus to the earliest whales, which are about 50 million years old, Thewissen said.
"The earliest whales didn't look like whales at all," Thewissen said. "It looked like a cross between a pig and a dog." They lost their legs and ability to walk on land about 40 million years ago, he said.
And the Indohyus? "A tiny little deer maybe the size of a raccoon and no antlers," Thewissen said. He said it most resembles the current African mousedeer, which has a rat-like nose and "when danger approaches, it jumps in the water and hides."
India and Pakistan were the general region where early whales lived. That matches with the Indohyus but not the early African hippos, Thewissen said. While modern-day cetaceans are known to be smart, early whales and Indohyus had small brains, the researcher said.
Other scientists were intrigued, but far from convinced, especially since the case for hippos has looked good, they said.
"While this new hypothesis for the origin of whales is compelling, it will require further testing, especially since other recent studies have suggested both hippos and Raoellids were involved in whale ancestry," San Diego State University biology professor Annalisa Berta said in an e-mail. Raoellids are the larger grouping of species that include the Indohyus.
Kenneth Rose, a professor of functional anatomy and evolution at Johns Hopkins University, said Thewissen didn't provide enough evidence to merit his conclusions. He also questioned the use of the composite skeleton. The ear bone thickness, the key trait that Thewissen used, was difficult to judge and seemed based on a single specimen, Rose said. Much of the work is based on teeth, and overall the remains preserved from this family of species are poorly preserved, he said.
Thewissen said there are problems with not enough well preserved fossils, but he said what's left makes a strong case for Indohyus as the closest land ancestor - with hippos as the closest living land relative.
Then, you missed the two that “gradually” became whales.
These people sure have vivid imaginations.
I was thinking "wharf rat". I've seen 'em in New Orleans so big they could barely squeeze into a storm drain.
There are old trolls and there are droll trolls, but there are very few old droll trolls
This abstract knowledge will never be useful!
“ the specific positioning and shape of certain molars connects Indohyus to the earliest whales, which are about 50 million years old,”
The time and money spent learning this could be utilized in much better ways!
But I thought the whales descended from a common ancestor of the hippo?
Only the branch that concludes with Michael Moore, Ted Kennedy, Helen Thomas and Rosie O’Donuts.......
That would explain the legend of the “turdy-point-buck”
I believe that leftwing moonbats are not actually descended from moonbats. It is a controversy, but perhaps this deer/hippo/whale thing has contributed to the human genome and offers an alternate possibility. It is possible given how little evolutionists actually know and how far out their theories go. I mean, so what if the hippo developed too late to become a whale, they do share a few characteristics. By that reasoning it is possible that Kennedy and O'Donnell do have whale/hippo ancestry.
Ha Ha Ha Ha! Good one.
Things would have to be damned bad for me to look at a nutria and think "Mmmm... dinner!" And I'm about half-Cajun.
About ten years ago, Chef Paul Prudhomme tried to generate interest in using nutria meat. I think he even had it on the menu at K-Paul's for a while. Blech.
However, given their reproductive rate, we might be able to turn them into some sort of alternative motor fuel. ;-)
GGG ping
Other scientists were intrigued, but far from convinced, especially since the case for hippos has looked good, they said. "While this new hypothesis for the origin of whales is compelling, it will require further testing, especially since other recent studies have suggested both hippos and Raoellids were involved in whale ancestry," San Diego State University biology professor Annalisa Berta said in an e-mail. Raoellids are the larger grouping of species that include the Indohyus. Kenneth Rose, a professor of functional anatomy and evolution at Johns Hopkins University, said Thewissen didn't provide enough evidence to merit his conclusions. He also questioned the use of the composite skeleton. The ear bone thickness, the key trait that Thewissen used, was difficult to judge and seemed based on a single specimen, Rose said.Thanks Fractal Trader.
In his Origin of Species, Darwin notes a case of a black bear swimming for hours with its mouth agape, catching aquatic insects much as a whale might feed. "I can see no difficulty in a race of bears being rendered, by natural selection, more aquatic in their structure and habits, with larger and larger mouths, till a creature was produced as monstrous as a whale," he speculated. The ridicule and attacks engendered by this passage grew to such a pitch that Darwin pared it down and then deleted it altogether in later editions. [The Whale's Tale, Richard Monastersky, Science News, November 6, 1999, Vol. 156 No. 19 p. 296]
| Pakicetus Fossil range: Early Eocene |
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| Pakicetus inachus Gingerich & Russell, 1981 |
Reconstruction of Pakicetus
Pakicetus is a genus of extinct cetaceans found in the early Eocene (55.8 ± 0.2 - 33.9 ± 0.1 Ma) of Pakistan, hence their name. The strata where the fossils were found was then part of the coast of the Tethys Sea.
The first fossil, a lone skull, was thought to be a mesonychid, but Gingerich and Russell recognized it as an early cetacean from characteristic features of the inner ear, found only in cetaceans: the large auditory bulla is formed from the ectotympanic bone only. This suggests that it is a transitional species between extinct land mammals and modern cetaceans.
Complete skeletons were discovered in 2001, revealing that Pakicetus was primarily a land animal, about the size of a wolf, and very similar in form to the related mesonychids.
Nutria’s not half bad.
You forgot the sarcasm tag.
“the specific positioning and shape of certain molars”
Whales have teeth?
“the specific positioning and shape of certain molars connects Indohyus to the earliest whales, which are about 50 million years old,”
I guess they had teeth early on. But,,,,who cares!
“Don’t become an archeologist, little girl. You’ll just spend your days brushing the teeth of old monsters.” (scientist to Lisa Simpson)
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