Controversies in Evolution: ‘Jurassic beaver’ unearthed in China

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‘Jurassic beaver’ unearthed in China: Fossil overturns ideas about mammals’ lowly status in dinosaur era

Another evolutionary Icon ‘bites the dust’

For years, the mammals living in the era of dinosaurs have been thought of as tiny shrewlike creatures scurrying through the underbrush. Now the discovery of a furry aquatic creature with seallike teeth and a flat tail like a beaver has demolished that image.

Ji Q., Luo Z.-X., Yuan C.-X.& Tabrum A. R. . Science, 311. 1123 - 1127 (2006).

See also Jurrassic Beaver swims into view Nature News, Michael Hopkin

22 Comments

Another evolutionary Icon ‘bites the dust’

Leave it to beaver.

The linked MS-NBC article didn’t say whether it was placental, monotreme or marsupial. I guess I’ll have to dig it out of Science.

If that’s not a porn film title in the making, I don’t know what is.

It is neither monotreme, multituberculate, marsupial, or placental. It’s a docodont: a mid-Mesozoic group of mammaliaforms (the larger clade of mammals and their closest relatives).

About the only other time docodonts have made it into the news was the discovery of the burrowing Fruitafossor last year.

Scratch that last comment: Fruitafossor was actually a true mammal, nested between monotremes and their extinct kin on one branch, and triconodonts, multis, marsupials, and placentals on the other. Sorry about that.

Leave it to beaver.

Must . . resist . . urge . . to make… joke . …

Must … resist . … .

Arrrggghhhh!!!!!!!!!!

I wonder if creationists will claim that this is yet another so-called living fossil which will disprove evolution ?

They’ll probably just classify it as another “kind” of beaver !

I prefer the news link to New Scientist. The Nature article has this irritating nonsense:

mistaken Wrote:

The evolutionary history of mammals is a long and complex one. The earliest mammals evolved from primitive terrestrial reptiles called therapsids, which lived some 200 million years ago.

No, synapsids and sauropsids were separate lines.

Ever notice how much of this stuff comes out of China.

The Commie atheists have a real handle on fossil making.

Google it.

Note that several 2004 and 2005 studies have redated the sediments at Daohugaou where the fossils were recovered to the Lower Cretaceous, not the Middle Jurassic.

“Jacob” wrote:

Ever notice how much of this stuff comes out of China.

Ever notice how much this stuff comes from one type of fossil bed, a lake bottom environment? So called lagerstätten, or lake-beds, are ideal preserves of a low-oxygen slow-deposition region where accumulated detritus can be resolved into crepe-thin layers of sandstone and limestone and shale. These regions are IDEAL for preserving fine details in animals, and are known at the Quercy site in France (not a commie country), Messel and Solnhofen in Germany (also, not a commie country), the London Clay in England (commies!!!), the Green River beds in Wyoming, USA (Is the USA a commie country?), and places in Russia, Denmark, the eastern US seaboard such as at Newark, New Jersey, and so forth. So quit whining.

The Commie atheists have a real handle on fossil making.

Indeed they are so busy faking these fossils that they forgot such finds have been known in other countries for centuries. The fossil beds in China are both more extensive, and less-developed, than in other countries, and there are tons of villages spending old-time hard work mining and quarrying to make roofing slates and housing materials and thus, as in Solnhofen, coming across these fossils more readily than the scientists at the other sites, who work on their own, and never fake fossils. The last faked fossil in the West was, if I recall correctly, either Creationists hoaxes at Paluxy, and the Piltdown forgery, which was falsified – not by creationists disproving evolution – but by scientists who had accepted it for 50 years before making a detailed study to find the fakery involved … and may have implicated famed author Sr Arthur Conan Doyle, a “christian” and an “occultist”.

So who’s doing the harm here? When we, as scientists, find falsification, lies, and corruption in our institutions and our collections, we are as avid to be rid of these problems and expose them as any one else, and will be the first to do so, as history has shown for centuries, and will continue to do. So far, creation apologetics has FAILED to provide evidence that has not been quacked or misinterpreted out of context.

This fossil itself shows the detail of variability in many early non-mammals, long before they became true mammals, and expands our knowledge, not decreases it. This should be embraced, not rejected. Creationists seem almost rabid to proclaim questions on where our “transitional fossils” are, and when we point to animals like Castorocauda, or Archaeopteryx, they wave their arms, or call them “beavers” and “birds”, and decided to stop listening. The truth is, should anyone decide to hear it, is that nearly all animals are “transitional” between ancestors and descendants, and this is true of fossils back to time immemorial.

I was under the impression that “therapsid” always referred to a kind of synapsid reptile and was distinct from “pelycosaur” another kind of synapsid (think dimetrodon). Perhaps the confusion here is the similarity to the term “theropod” which always refers to a diapsid (except when it refers to Lenny).

Ever notice how much of this stuff comes out of China.

The Commie atheists have a real handle on fossil making.

Ever notice how much of this stuff comes out of ignorant hit-and-run IDiots who have nothing of substance to say.

The creationists have a real handle on unsubstantiated claim-making.

Google it.

Okay, this is marginally off topic, but we are talking about primative mammals. I have a question that has intrigued me for years and have never found the answer in a comparative physiology text.

What form does nitrogenous waste excretion take in monotremes?

This is an important evolutionary question, plus it bugs the heck out of me that I don’t know.

The last faked fossil in the West was, if I recall correctly, either Creationists hoaxes at Paluxy, and the Piltdown forgery

Well, there was also Archaeoraptor, but this wasn’t really a fake — it was just two different fossils that had been artificially fitted together by the finder to inflate the price (one a Microraptor, and the other a previously unknown avian now named Yanornis).

What form does nitrogenous waste excretion take in monotremes?

I’m not entirely sure if this answers your question, but monotreme means one-holed, referring to the use of a single orifice for excrement (both urinary and digestive tract) and reproduction. In other words, they have a cloaca.

re: Monotremes Mr. Vicklund - Wow! What a poor design! Why would anyone put an amusement park and a waste treatment facility in the same location? It must be The Unintelligent Designer.

Kevin, I didn’t ask the question well. Do they excrete uric acid or urea? There that’s clearer!

Kevin, I didn’t ask the question well. Do they excrete uric acid or urea? There that’s clearer!

Going through my Functional Anatomy of the Vertebrates text, I found no reference to differences between the three major mammal groups in regards to kidney functions. There is a great deal of variance in nephron structure between species but the excretion of nitrogenous waste is always referred to as urea. Some variance in concentration depending on habitat/niche though.

Vandalhooch

The reason I ask is that birds secrete uric acid. The explanation usually given is that being egg-layers birds require a nitrogenous waste that isn’t water soluble. Since monotremes are egg-layers I wonder how, if they produce urea, they manage to not poison their developing young.

Posted by J-Dog on February 24, 2006 09:04 AM

“re: Monotremes Mr. Vicklund - Wow! What a poor design! Why would anyone put an amusement park and a waste treatment facility in the same location? It must be The Unintelligent Designer.”

The single external entry/exit condition is inherited from their reptile-like ancestors and is shared with many modern reptiles and birds. Call it an unholy alliance.

this is the worst web page i’ve ever been to.

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This page contains a single entry by PvM published on February 23, 2006 2:55 PM.

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