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Penguins Probably Lived Alongside Dinosaurs

Started by suspsy, February 24, 2017, 11:29:55 AM

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ZoPteryx

#20
This is a very cool discovery!  I wonder at what point crown-penguins became totally flightless.  I had always assumed it was due to their isolation in Gondwana (maybe Zealandia specifically?) sometime after the K/Pg event, with few enemies they could afford to specialize.  But now I'm thinking it was actually a response to the K/Pg extinction, lack of food and a sudden disappearance of competition drove them into the water further.  The thermal insulating properties of water would have also been advantageous during the impact winter.


Gwangi

Quote from: Sinornis on February 28, 2017, 09:25:59 PM
If they made extinct penguin figures that looked like the attached photo, I'm a customer! While they are at it, and I think I mentioned this before, they should consider some Green River and Messel birds. Presbyornis would be a great collector figure.

A little off topic, I'd like to see a another attempt at a Hesperornis figure and one of Ichthyornis.

http://avianmusing.blogspot.com/

1. Pinguinus impennis 2. Waimanu manneringi 3. Pachydyptes ponderosus 4. Icadyptes salasi 5. Inkayacu paracasensis 6. Anthropornis nordenskjoeldi



Pinguinus impennis is of course, not a penguin.

Sinornis

Quote from: Gwangi on March 02, 2017, 01:54:19 AM
Quote from: Sinornis on February 28, 2017, 09:25:59 PM
If they made extinct penguin figures that looked like the attached photo, I'm a customer! While they are at it, and I think I mentioned this before, they should consider some Green River and Messel birds. Presbyornis would be a great collector figure.

A little off topic, I'd like to see a another attempt at a Hesperornis figure and one of Ichthyornis.

http://avianmusing.blogspot.com/

1. Pinguinus impennis 2. Waimanu manneringi 3. Pachydyptes ponderosus 4. Icadyptes salasi 5. Inkayacu paracasensis 6. Anthropornis nordenskjoeldi



Pinguinus impennis is of course, not a penguin.

You are absolutely correct (and neither is the Homo sapien!!) thank you for pointing that out.
I also forgot to credit the image;
http://thagomizers.tumblr.com/post/49440768652/prehistorics-penguins-1great-auk-pinguinus

Dinoguy2

#23
Quote from: Halichoeres on February 25, 2017, 09:43:30 PM
Quote from: GasmaskMax on February 25, 2017, 08:56:52 PM
I had no idea penguins were that old. So wouldn't that put them on the more primitive end of the bird spectrum, or is my knowledge of extinct birds just as lacking as I already know it is?

Evolutionary biologists try to avoid using the word primitive to refer to anything currently alive, because an extant organism has, by definition, been evolving just as long as everything else now alive and carries a mix of both primitive and derived features. Traditionally penguins have been thought to be one of the first groups to diverge from other birds, but molecular phylogenies now find them deeply nested within a clade of other aquatic birds. Their closest relatives are probably the group containing albatrosses and petrels.

I think it's fine to call something primitive if it physically resembles the ancestral state of its group. So coelacanths might in many ways be considered primitive. Tinamous are primitive ratites because they're probably close to what the ancestors of ostriches and kiwi looked like. Even though ostriches and tinamou have been evolving for the same amount of time, ostriches have become much more different looking during that time. But penguins definitely aren't, they're extremely specialized compared to the first neornithes. So while the lineage is older than previously thought, that just means they evolved extremely rapidly or are even older than we now think.
The Carnegie Collection Dinosaur Archive - http://www.dinosaurmountain.net

Halichoeres

#24
Quote from: Dinoguy2 on March 04, 2017, 07:59:13 PM
Quote from: Halichoeres on February 25, 2017, 09:43:30 PM
Quote from: GasmaskMax on February 25, 2017, 08:56:52 PM
I had no idea penguins were that old. So wouldn't that put them on the more primitive end of the bird spectrum, or is my knowledge of extinct birds just as lacking as I already know it is?

Evolutionary biologists try to avoid using the word primitive to refer to anything currently alive, because an extant organism has, by definition, been evolving just as long as everything else now alive and carries a mix of both primitive and derived features. Traditionally penguins have been thought to be one of the first groups to diverge from other birds, but molecular phylogenies now find them deeply nested within a clade of other aquatic birds. Their closest relatives are probably the group containing albatrosses and petrels.

I think it's fine to call something primitive if it physically resembles the ancestral state of its group. So coelacanths might in many ways be considered primitive. Tinamous are primitive ratites because they're probably close to what the ancestors of ostriches and kiwi looked like. Even though ostriches and tinamou have been evolving for the same amount of time, ostriches have become much more different looking during that time. But penguins definitely aren't, they're extremely specialized compared to the first neornithes. So while the lineage is older than previously thought, that just means they evolved extremely rapidly or are even older than we now think.

I think it misleads people into assuming low-diversity branches of the phylogeny represent the primitive condition for all traits, which is never completely true and usually not even mostly true. The phylogenetic position of acoel flatworms, tunicates, and hagfishes was always assumed to be more basal, for example, because of secondary losses of synapomorphies associated with their actual clades. The modern gombessa resembles in many ways coelacanths that were around in the Cretaceous, but it definitely cannot be used as a proxy for the ancestor of all sarcopterygians, for example. To describe it as primitive leads researchers in fields like developmental genetics, to say nothing of the general public, astray as to how evolution actually works (namely, on every branch at all times, relentlessly). In particular, it leads one to believe that all of its character states in the putatively primitive taxon can be assumed to be the same as the ancestral state until proven otherwise, which is an insupportable assumption. The extreme case is the hilarious question, "if humans came from monkeys, why are there still monkeys?" That's the product of the same kind of thinking that calls anything now living "primitive."

It is fine to call a particular trait primitive, if you have evidence to suggest that the common ancestor of [Arbitrary Clade] had that trait, but I can't agree that it's fine to call any extant taxon primitive.

For more on this, see: http://botanyprofessor.blogspot.com/2014/07/whats-so-primitive-about-amborella.html

[edited to correct a typo]
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BlueKrono

Is a "gombessa" the West Indian coelacanth? Where does that name come from? It's not even on the Wikipedia page.
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Halichoeres

Quote from: BlueKrono on March 06, 2017, 03:09:34 PM
Is a "gombessa" the West Indian coelacanth? Where does that name come from? It's not even on the Wikipedia page.

Yup, it's the name that South Africans used for it before Marjorie Courtenay-Latimer happened upon it.
In the kingdom of the blind, better take public transit. Well, in the kingdom of the sighted, too, really--almost everyone is a terrible driver.

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Derek.McManus

Are there any estimates of the current coelacanth population? Just curious?

Halichoeres

Quote from: Derek.McManus on March 06, 2017, 09:02:36 PM
Are there any estimates of the current coelacanth population? Just curious?

The Comoros species is assessed as critically endangered (http://www.iucnredlist.org/details/full/11375/0), but I don't know if there's a reliable specific estimate of the total population. They're hard to sample, as you might imagine for something that went undetected for so long.
The Sulawesi species is estimated at around 10,000 (http://www.iucnredlist.org/details/135484/0), but that's also very provisional.

Fisheries biologists joke that counting fish is just like counting trees, except you can't see them and they move.
In the kingdom of the blind, better take public transit. Well, in the kingdom of the sighted, too, really--almost everyone is a terrible driver.

My attempt to find the best toy of every species

My trade/sale/wishlist thread

Sometimes I draw pictures

Dinoguy2

#29
On the other hand, I'd say you can definitely call Anchiornis or Archaeopteryx primitive birds. The fact that they bounce around the big three paravian clades so much is direct evidence that their morphology is incredibly close to the common ancestor of those groups. I disagree that primitive implies "this is exactly what the common ancestor looks like". That's the fallacy created when you call Archaeopteryx the ancestor of birds. Calling something primitive is not to say every trait is primitive, just that in general, subjective terms, this is sort of what the common ancestor of clade x would have looked like based on current evidence. If it's "primitiveness" turns out to be due to secondary losses, then of course we should stop saying that about it.

QuoteTo describe it as primitive leads researchers in fields like developmental genetics, to say nothing of the general public, astray as to how evolution actually works (namely, on every branch at all times, relentlessly).
But absolutely NOT at the same rate, or in a way that is externally/morphologically visible.
The Carnegie Collection Dinosaur Archive - http://www.dinosaurmountain.net

Halichoeres

Quote from: Dinoguy2 on March 19, 2017, 10:15:50 AM
On the other hand, I'd say you can definitely call Anchiornis or Archaeopteryx primitive birds. The fact that they bounce around the big three paravian clades so much is direct evidence that their morphology is incredibly close to the common ancestor of those groups. I disagree that primitive implies "this is exactly what the common ancestor looks like". That's the fallacy created when you call Archaeopteryx the ancestor of birds. Calling something primitive is not to say every trait is primitive, just that in general, subjective terms, this is sort of what the common ancestor of clade x would have looked like based on current evidence. If it's "primitiveness" turns out to be due to secondary losses, then of course we should stop saying that about it.

I have no objection to calling something like Archaeopteryx that is actually a short branch or a few short branches away from the actual common ancestor of birds a primitive bird or primitive bird relative. But for example, this paper (http://www.sciencedirect.com/science/article/pii/S0016648005003801) calls an extant bichir "primitive," and this other paper (https://academic.oup.com/endo/article-lookup/doi/10.1210/en.2007-0547) calls lancelets primitive. We don't know enough about the history of either polypterids or cephalochordates to call either "primitive." The implication is that they are somehow less evolved than their sister groups, for no reason other than that their sister groups contain a larger number of species and they each have long naked stems. This is a misapprehension. They have been evolving in different directions, and there isn't any particular reason a priori to suspect that they have evolved less.


Quote from: Dinoguy2 on March 19, 2017, 10:15:50 AM
QuoteTo describe it as primitive leads researchers in fields like developmental genetics, to say nothing of the general public, astray as to how evolution actually works (namely, on every branch at all times, relentlessly).
But absolutely NOT at the same rate, or in a way that is externally/morphologically visible.

Yes, obviously, rates of molecular and morphological evolution are heterogeneous, and I take your point that one lineage might have undergo a larger quantity of morphologically obvious evolution. I'm only claiming that it's a problematic, misleading phrasing, as shown by the papers I linked to above, and therefore best avoided when referring to extant taxa.
In the kingdom of the blind, better take public transit. Well, in the kingdom of the sighted, too, really--almost everyone is a terrible driver.

My attempt to find the best toy of every species

My trade/sale/wishlist thread

Sometimes I draw pictures

You can support the Dinosaur Toy Forum by making dino-purchases through these links to Ebay and Amazon. Disclaimer: these and other links to Ebay.com and Amazon.com on the Dinosaur Toy Forum are often affiliate links, so when you make purchases through them we may make a commission.