Scientists find missing link between whale and its closest relative, the hippo

UC Berkeley News ^ | 24 January 2005 | Robert Sanders, Media Relations

[PatrickHenry]

A group of four-footed mammals that flourished worldwide for 40 million years and then died out in the ice ages is the missing link between the whale and its not-so-obvious nearest relative, the hippopotamus.

The conclusion by University of California, Berkeley, post-doctoral fellow Jean-Renaud Boisserie and his French colleagues finally puts to rest the long-standing notion that the hippo is actually related to the pig or to its close relative, the South American peccary. In doing so, the finding reconciles the fossil record with the 20-year-old claim that molecular evidence points to the whale as the closest relative of the hippo.

"The problem with hippos is, if you look at the general shape of the animal it could be related to horses, as the ancient Greeks thought, or pigs, as modern scientists thought, while molecular phylogeny shows a close relationship with whales," said Boisserie. "But cetaceans – whales, porpoises and dolphins – don't look anything like hippos. There is a 40-million-year gap between fossils of early cetaceans and early hippos."

In a paper appearing this week in the Online Early Edition of the Proceedings of the National Academy of Sciences, Boisserie and colleagues Michel Brunet and Fabrice Lihoreau fill in this gap by proposing that whales and hippos had a common water-loving ancestor 50 to 60 million years ago that evolved and split into two groups: the early cetaceans, which eventually spurned land altogether and became totally aquatic; and a large and diverse group of four-legged beasts called anthracotheres. The pig-like anthracotheres, which blossomed over a 40-million-year period into at least 37 distinct genera on all continents except Oceania and South America, died out less than 2 and a half million years ago, leaving only one descendent: the hippopotamus.

This proposal places whales squarely within the large group of cloven-hoofed mammals (even-toed ungulates) known collectively as the Artiodactyla – the group that includes cows, pigs, sheep, antelopes, camels, giraffes and most of the large land animals. Rather than separating whales from the rest of the mammals, the new study supports a 1997 proposal to place the legless whales and dolphins together with the cloven-hoofed mammals in a group named Cetartiodactyla.

"Our study shows that these groups are not as unrelated as thought by morphologists," Boisserie said, referring to scientists who classify organisms based on their physical characteristics or morphology. "Cetaceans are artiodactyls, but very derived artiodactyls."

The origin of hippos has been debated vociferously for nearly 200 years, ever since the animals were rediscovered by pioneering French paleontologist Georges Cuvier and others. Their conclusion that hippos are closely related to pigs and peccaries was based primarily on their interpretation of the ridges on the molars of these species, Boisserie said.

"In this particular case, you can't really rely on the dentition, however," Boisserie said. "Teeth are the best preserved and most numerous fossils, and analysis of teeth is very important in paleontology, but they are subject to lots of environmental processes and can quickly adapt to the outside world. So, most characteristics are not dependable indications of relationships between major groups of mammals. Teeth are not as reliable as people thought."

As scientists found more fossils of early hippos and anthracotheres, a competing hypothesis roiled the waters: that hippos are descendents of the anthracotheres.

All this was thrown into disarray in 1985 when UC Berkeley's Vincent Sarich, a pioneer of the field of molecular evolution and now a professor emeritus of anthropology, analyzed blood proteins and saw a close relationship between hippos and whales. A subsequent analysis of mitochondrial, nuclear and ribosomal DNA only solidified this relationship.

Though most biologists now agree that whales and hippos are first cousins, they continue to clash over how whales and hippos are related, and where they belong within the even-toed ungulates, the artiodactyls. A major roadblock to linking whales with hippos was the lack of any fossils that appeared intermediate between the two. In fact, it was a bit embarrassing for paleontologists because the claimed link between the two would mean that one of the major radiations of mammals – the one that led to cetaceans, which represent the most successful re-adaptation to life in water – had an origin deeply nested within the artiodactyls, and that morphologists had failed to recognize it.

This new analysis finally brings the fossil evidence into accord with the molecular data, showing that whales and hippos indeed are one another's closest relatives.

"This work provides another important step for the reconciliation between molecular- and morphology-based phylogenies, and indicates new tracks for research on emergence of cetaceans," Boisserie said.

Boisserie became a hippo specialist while digging with Brunet for early human ancestors in the African republic of Chad. Most hominid fossils earlier than about 2 million years ago are found in association with hippo fossils, implying that they lived in the same biotopes and that hippos later became a source of food for our distant ancestors. Hippos first developed in Africa 16 million years ago and exploded in number around 8 million years ago, Boisserie said.

Now a post-doctoral fellow in the Human Evolution Research Center run by integrative biology professor Tim White at UC Berkeley, Boisserie decided to attempt a resolution of the conflict between the molecular data and the fossil record. New whale fossils discovered in Pakistan in 2001, some of which have limb characteristics similar to artiodactyls, drew a more certain link between whales and artiodactyls. Boisserie and his colleagues conducted a phylogenetic analysis of new and previous hippo, whale and anthracothere fossils and were able to argue persuasively that anthracotheres are the missing link between hippos and cetaceans.

While the common ancestor of cetaceans and anthracotheres probably wasn't fully aquatic, it likely lived around water, he said. And while many anthracotheres appear to have been adapted to life in water, all of the youngest fossils of anthracotheres, hippos and cetaceans are aquatic or semi-aquatic.

"Our study is the most complete to date, including lots of different taxa and a lot of new characteristics," Boisserie said. "Our results are very robust and a good alternative to our findings is still to be formulated."

Brunet is associated with the Laboratoire de Géobiologie, Biochronologie et Paléontologie Humaine at the Université de Poitiers and with the Collège de France in Paris. Lihoreau is a post-doctoral fellow in the Département de Paléontologie of the Université de N'Djaména in Chad.

The work was supported in part by the Mission Paléoanthropologique Franco-Tchadienne, which is co-directed by Brunet and Patrick Vignaud of the Université de Poitiers, and in part by funds to Boisserie from the Fondation Fyssen, the French Ministère des Affaires Etrangères and the National Science Foundation's Revealing Hominid Origins Initiative, which is co-directed by Tim White and Clark Howell of UC Berkeley.

[AnotherCreationist]

Indeed, little do you know how little you know. Little do you know how little scientists know, too, for that matter. Red Skelton, like the rest of us, was mortal.

First, I'd like to address the claim made via someone else's quotation that we must ignore the fossil evidence of "apparent whale ancestors." We do not ignore them. We challenge the unprovable assertions made, such as that they are "apparent" whale ancestors at all.

Next, I'll address some of the articles you've bombed the message board with:

SINE Evolution, Missing Data, and the Origin of Whales
- This paper assumes that common ancestors exist. It ignores the possibility that similarities can exist
without common ancestry (as is possible if all were designed by one Creator.) And as can be expected, it ignores the possibility that a worldwide curse (caused by sin) could affect many organisms in exactly the same way.

Phylogenetic relationships among cetartiodactyls based on insertions of short and long interpersed elements: Hippopotamuses are the closest extant relatives of whales
- The same is true for this paper, and while the subject may be different, the assumptions about evolution are identical to those found in the last paper.

Evidence from Milk Casein Genes that Cetaceans are Close Relatives of Hippopotamid Artiodactyls
- Again, we see the same problem. This article uses different characteristics to claim common ancestry, but it
assumes that the common characteristics observed are a result of inheritance, and not common design.

Analyses of mitochondrial genomes strongly support a hippopotamus±whale clade
- This article, again, exhibits the same assumptions. Moreover, the title is extremely helpful in placing this
"proof" in proper context: "strongly support" means "remains consistent with." It does not mean "unquestionable proof."

A new, diminutive Eocene whale from Kachchh (Gujarat, India) and its implications for locomotor evolution of cetaceans
- This article was more interesting than the last few. Fortunately, it included a picture of the skeleton of
the creature it was discussion, which helped show the dearth of information they are working from. In short, it
seems quite possible that a new species is seen here (although, if the remains were better preserved, it is also
possible that this organism would turn out to be something more familiar) but it does nothing to prove or even
support evolution unless evolution is assumed.

A new Eocene archaeocete (Mammalia, Cetacea) from India and the time of origin of whales
- This article is no longer posted, but it appears to be similar to the last one.

Mysticete (Baleen Whale) Relationships Based upon the Sequence of the Common Cetacean DNA Satellite1
- This article makes conclusions that creatures are related because of similarities. As I've already stated,
this does not prove anything except that the creatures have similarities.

The Mitochondrial Genome of the Sperm Whale and a New Molecular Reference for Estimating Eutherian Divergence Dates
- This article is no longer posted.

Limbs in whales and limblessness in other vertebrates: mechanisms of evolutionary and developmental transformation and loss
- This article is one of the more interesting thus far. Its flaw is that it assumes whales and dolphins and such
ever had limbs. It discusses limb-loss in snakes and tries to compare limb-loss in other vertebrates to it, coming
up with theoretical mechanisms for this to occur. Interestingly, the Bible does deal with snake limb-loss. How about that?

Eocene evolution of whale hearing
- Could not access this site.

Novel Phylogeny of Whales Revisited but Not Revised
- This article was thankfully short, but again, sought to draw inferences of common ancestry (and proximity of
such ancestry) from similarities between the creatures. Again, I restate that this is also consistent with
common design.

Land-to-sea transition in early whales: evolution of Eocene Archaeoceti (Cetacea) in relation to skeletal proportions and locomotion of living semiaquatic mammals
- This article is no longer posted.

Subordinal artiodactyl relationships in the light of phylogenetic analysis of 12 mitochondrial protein-coding genes
- A couple of interesting things going on here, neither of which you'll want to hear about. First, conclusions
are again drawn based on similarities between the species that do not necessarily follow. But more interestingly,
the study supports the findings of some studies, but does not support the findings of other studies. Could this
be because this entire branch of science is analyzing data under false presumptions, such as that similarities
in different organisms will show common ancestry?

New Morphological Evidence for the Phylogeny of Artiodactyla, Cetacea, and Mesonychidae
- So as to avoid repeating myself, I will say that this paper is making the same mistakes most of the others were.
Interestingly, it is also inconsistent with other "evolution" studies based on different methods. That's always fun for a creationist to see.

Cetacean Systematics
- With this link, it becomes obvious that you know nothing about the articles you have posted. This is a schedule of presentations at a conference, with abstracts of each included. Nice. No actual information is given. And with this, I will no longer review your articles. The amount of time to point out the same problem(s)over and over again is not worth it.

Just because you can find information about why evolutionists think the way they do does not mean that the
conclusions are correct. You can find an equally overwhelming amount of "scientific" information about how
Jewish people and Black people, among others, are less evolved than the Master German Race. Of course, you won't
appreciate the Nazi reference. Few evolutionists do, because it reveals one of the major moral problems with the
theory, when followed to its logical conclusion.

For kicks, I will attempt to offer you an explanation that explains "ALL the mountains of available evidence."
God created everything. Man sinned, thus incurring punishment, and the world became cursed. Indeed, the effects of this curse remain far reaching, and probably impossible to fully understand (remember what Red Skelton said? The whole point of his little adage was that we don't know everything, and can't possibly know everything.) 1656 years later, God flooded the entire earth, killing millions of organisms and leaving the fossil record that we interpret based on the little we know today, overwhelmingly to our detriment.

You can deny creation all you want, and you can subscribe to all the inventive ways others use to "prove" their anti-creation views, but you cannot change reality. You will die, and you will either be reconciled to your creator or not. Your beliefs do not threaten me, nor those like me. Based on your hostile posting, however, I suspect that our views threaten you. I wonder why that is, considering that you appear to believe we all evolved from nothing, and will become nothing again. If you're correct, then who cares? What is the point? Rather than sit here and argue about it, you should go enjoy the limited time you have left to exist. Or you can continue to ponder why and how we exist, and pray that the Lord opens your heart to the truth.

[Quark2005]

Little do you know how little scientists know, too, for that matter.

Crank.

Quit while you're not so far behind.