Freethought & Rationalism Archive

MrDarwin · 03-13-2002, 12:10 PM

Paleontologists have discovered a new mammal from the Jurassic of South America:

<a href="http://www.washingtonpost.com/wp-dyn/articles/A21940-2002Mar13.html" target="_blank">Paleontologists Find Jurassic Fossil</a>

Anybody want to lay bets on how long before the creationsts pick up on this and start twisting it to their own agenda? ("See, this just shows that mammals and dinosaurs lived together, so it proves the earth is only 6000 years old and there really was a global flood!")

[ March 13, 2002: Message edited by: MrDarwin ]

DarkBronzePlant · 03-13-2002, 01:11 PM

I don't think the notion that mammals lived alongside dinosaurs is anything new...

Corwin · 03-13-2002, 01:14 PM

It isn't.... but when has that ever stopped them before?

Valentine Pontifex · 03-13-2002, 03:28 PM

Quote:

Originally posted by MrDarwin:
Paleontologists have discovered a new mammal from the Jurassic of South America:

<a href="http://www.washingtonpost.com/wp-dyn/articles/A21940-2002Mar13.html" target="_blank">Paleontologists Find Jurassic Fossil</a>

Anybody want to lay bets on how long before the creationsts pick up on this and start twisting it to their own agenda? ("See, this just shows that mammals and dinosaurs lived together, so it proves the earth is only 6000 years old and there really was a global flood!")

I am not sure how seriously I can take this one. The researchers suggested that mammals evolved twice? That would leave two possiblities: 1) Darwinian evolution is wrong or 2) mammals are an invalid taxa.

I suspect that they are full of it.

theyeti · 03-13-2002, 04:24 PM

Quote:

Originally posted by LordValentine:

I am not sure how seriously I can take this one. The researchers suggested that mammals evolved twice? That would leave two possiblities: 1) Darwinian evolution is wrong or 2) mammals are an invalid taxa.

I suspect that they are full of it.

I don't think the article claims that mammals evolved twice. Only that the ones in the Southren hemisphere did some evolving after they split from the rest. Here's the sentence that sounds confusing:

"Researchers said it suggests that mammals developed independently in the Southern Hemisphere."

Nothing else in the article seems to indicate that this is independent evolution; rather, these are early members of the monotreme lineage, from whom the platapus and echinda, both endemic to the Southren hemispere, evolved. Still, it would be good if someone could check out the Nature article and give us the scoop.

theyeti

MrDarwin · 03-13-2002, 04:28 PM

I agree that the sentence is rather ambiguous. Bear in mind that you're not reading the research article itself, but rather a story written by a reporter (probably with a minimal background in biology), compiled from a press release that itself was almost certainly not written by one of the researchers.

Oolon Colluphid · 03-14-2002, 12:13 AM

It seems to me that, till these "researchers" and "palaeontologists" can be identified and their work seen in print, we may as well ignore this 'find'. A Google search for Asfaltomylos patagonicus turns up nothing at all. So far, this discovery is hearsay.

Cheers, Oolon

Per Ahlberg · 03-14-2002, 03:45 AM

It's in today's Nature:

Rauhut, O.W.M., Martin, T., Ortiz-Jaureguizar, E. & Puerta, P., 2002: A Jurassic mammal from South America. Nature 416, 165-168.

The 'convergence' story is not as dramatic as the news reports claim (surprise surprise!). Essentially, the new beast, Asfaltomylus patagonicus, belongs to a recently recognised group of Mesozoic mammals from Gondwana that developed a particular kind of dentition ("tribosphenic dentition") in parallel with the placentals + marsupials that were evolving in the Northern Hemisphere. Interestingly, this Gondwana group (now called Australosphenida, as opposed to the Tribosphenida of the Northern Hemisphere) seems to be the ancestral stock of the monotremes (duckbilled platypuses and echidnas). So the split between the monotremes on the one hand, and the placentals + marsupials on the other, goes back at least to the Middle Jurassic.

Per

Oolon Colluphid · 03-14-2002, 03:58 AM

Brilliant, Per! Many thanks!

Here's the abstract, though it only really repeats what Per has just said:

Quote:

The Jurassic period is an important stage in early mammalian evolution, as it saw the first diversification of this group, leading to the stem lineages of monotremes and modern therian mammals. However, the fossil record of Jurassic mammals is extremely poor, particularly in the southern continents. Jurassic mammals from Gondwanaland are so far only known from Tanzania and Madagascar, and from trackway evidence from Argentina. Here we report a Jurassic mammal represented by a dentary, which is the first, to our knowledge, from South America. The tiny fossil from the Middle to Late Jurassic of Patagonia is a representative of the recently termed Australosphenida, a group of mammals from Gondwanaland that evolved tribosphenic molars convergently to the Northern Hemisphere Tribosphenida, and probably gave rise to the monotremes. Together with other mammalian evidence from the Southern Hemisphere, the discovery of this new mammal indicates that the Australosphenida had diversified and were widespread in Gondwanaland well before the end of the Jurassic, and that mammalian faunas from the Southern Hemisphere already showed a marked distinction from their northern counterparts by the Middle to Late Jurassic.

Oh for a Nature subscription!

(My birthday's in September, so you've all got time to save up...

)

Cheers, Oolon

Coragyps · 03-14-2002, 06:03 AM

Why does Asfaltomylus sound to me like fancy Texas-speak for a 'possum that's been flattened on the pavement?

[ March 14, 2002: Message edited by: Coragyps ]

03-13-2002, 12:10 PM	#1
MrDarwin Veteran Member Join Date: May 2001 Location: Washington, DC Posts: 4,140	New Jurassic mammal Paleontologists have discovered a new mammal from the Jurassic of South America: <a href="http://www.washingtonpost.com/wp-dyn/articles/A21940-2002Mar13.html" target="_blank">Paleontologists Find Jurassic Fossil</a> Anybody want to lay bets on how long before the creationsts pick up on this and start twisting it to their own agenda? ("See, this just shows that mammals and dinosaurs lived together, so it proves the earth is only 6000 years old and there really was a global flood!") [ March 13, 2002: Message edited by: MrDarwin ]</p>

03-14-2002, 06:03 AM	#10
Coragyps Veteran Join Date: Aug 2001 Location: Snyder,Texas,USA Posts: 4,411	Why does Asfaltomylus sound to me like fancy Texas-speak for a 'possum that's been flattened on the pavement? [ March 14, 2002: Message edited by: Coragyps ]</p>

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03-13-2002, 01:11 PM	#2
DarkBronzePlant Veteran Member Join Date: Jun 2001 Location: San Francisco, CA USA Posts: 3,568	I don't think the notion that mammals lived alongside dinosaurs is anything new...

03-13-2002, 01:14 PM	#3
Corwin Veteran Member Join Date: Jan 2002 Posts: 4,369	It isn't.... but when has that ever stopped them before?

03-13-2002, 04:28 PM	#6
MrDarwin Veteran Member Join Date: May 2001 Location: Washington, DC Posts: 4,140	I agree that the sentence is rather ambiguous. Bear in mind that you're not reading the research article itself, but rather a story written by a reporter (probably with a minimal background in biology), compiled from a press release that itself was almost certainly not written by one of the researchers.

03-14-2002, 12:13 AM	#7
Oolon Colluphid Contributor Join Date: Sep 2000 Location: Alibi: ego ipse hinc extermino Posts: 12,591	It seems to me that, till these "researchers" and "palaeontologists" can be identified and their work seen in print, we may as well ignore this 'find'. A Google search for Asfaltomylos patagonicus turns up nothing at all. So far, this discovery is hearsay. Cheers, Oolon

03-14-2002, 03:45 AM	#8
Per Ahlberg Senior Member Join Date: Feb 2002 Posts: 582	It's in today's Nature: Rauhut, O.W.M., Martin, T., Ortiz-Jaureguizar, E. & Puerta, P., 2002: A Jurassic mammal from South America. Nature 416, 165-168. The 'convergence' story is not as dramatic as the news reports claim (surprise surprise!). Essentially, the new beast, Asfaltomylus patagonicus, belongs to a recently recognised group of Mesozoic mammals from Gondwana that developed a particular kind of dentition ("tribosphenic dentition") in parallel with the placentals + marsupials that were evolving in the Northern Hemisphere. Interestingly, this Gondwana group (now called Australosphenida, as opposed to the Tribosphenida of the Northern Hemisphere) seems to be the ancestral stock of the monotremes (duckbilled platypuses and echidnas). So the split between the monotremes on the one hand, and the placentals + marsupials on the other, goes back at least to the Middle Jurassic. Per

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