Ask a Vertebrate Paleontologist and Marine Mammal Biologist Questions!


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BigNorseWolf wrote:
Why does phylogeny matter? I see the more esoteric type biologists arguing over it all the time but... why?

Evolution is the backbone of biology. To reference a well known quote: "Nothing in Biology Makes Sense Except in the Light of Evolution"

To understand how things evolve...you need to know what they are related to and what the common ancestors of groups were. This means that you need to know the the evolutionary tree for a group (the phylogeny) before you can figure out anything.

A good example are snakes. There is a lot of debate over how and where snakes evolved. Everyone agrees they are lizards, but what lizards are most closely related to them, and how fossil snakes fit into the picture, influences how we think snakes got all their features that make them "snaky". If you think the oldest snakes are all terrestrial burrowing animals, than snake limb reduction and other features were probably a consequence of adaptation to living underground. If you think they are close relative to the ancestors of mosasaurs, this would suggest that the common ancestor of snakes was aquatic, and that limb loss is related to convergence on an eel-like form. Phylogenies provide us with ways of testing these ideas.

In my own work, I have used phylogenies to determine where fur seals and sea lions evolved and how they spread through the world oceans, how seals simplified their teeth and lost the ability to chew, and how the ability to echolocate evolved alongside the ability the hear at high frequencies. I can't really imagine any of my studies as being possible without the use of some sort of phylogeny at some stage of the research.


Pathfinder Adventure Path, Lost Omens, Starfinder Adventure Path, Starfinder Roleplaying Game Subscriber

What's your favorite extinct marine mammal?


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Cole Deschain wrote:
What's your favorite extinct marine mammal?

Probably the giant fossil walrus Pontolis, which was the size of a elephant seal but has a long skull more typical of what you would see in a leopard seal. A scary combination.

Scarab Sages

MMCJawa wrote:
KarlBob wrote:

Great thread! Thanks for sharing your knowledge with us.

What are your thoughts about the ReptileEvolution.com controversy?

David Peters is an utter crank and doesn't know the first thing about evolutionary trees or how to construct and interpret them. I actually have been recently checking his blog because in the last few weeks he has started adding whales to his large reptile tree and has been reporting amazing (read = crazy) results, like dolphins and baleen whales not being related, or that dolphins are related to tenrecs.

I didn't know he had started in on whales and dolphins now. That's a big jump from 'There's something wrong with our pterosaurs'.

Speaking of pterosaurs, I like the way he draws their wings. Whether he's right or not, there's something satisfying to me in the idea that their wings folded up neatly when not in use.

Edit: I just followed his link to pterosaur.net. Despite his claims to the contrary, to me their wing drawings don't look that much different than his.

I hope that his use of Photoshop-style digital fossil manipulation doesn't prejudice the rest of the paleontology community against it too much. Trying to rearrange bones from a photo of a fossil that you've never seen in person seems less than ideal, but it makes sense to me that simultaneously examining the physical fossil and reassembling the bones in 3D with Photoshop or CAD-style modeling software might reveal some things that aren't obvious from the fossil itself.


KarlBob wrote:

I didn't know he had started in on whales and dolphins now. That's a big jump from 'There's something wrong with our pterosaurs'.

Speaking of pterosaurs, I like the way he draws their wings. Whether he's right or not, there's something satisfying to me in the idea that their wings folded up neatly when not in use.

Edit: I just followed his link to pterosaur.net. Despite his claims to the contrary, to me their wing drawings don't look that much different than his.

I hope that his use of Photoshop-style digital fossil manipulation doesn't prejudice the rest of the paleontology community against it too much. Trying to rearrange bones from a photo of a fossil that you've never seen in person seems less than ideal, but it makes sense to me that simultaneously examining the physical fossil and reassembling the bones in 3D with Photoshop or CAD-style modeling software might reveal some things that aren't obvious from the fossil itself.

From what I understand, his ideas of wing shape are based solely on the photoshop technique, and are not really something supported by available evidence

As for his technique, people do regularly use UV lighting or CT scanning to identify or clarify features hard to see in the fossil. The problem with the photoshop method is that, without viewing the fossils in person, you can't determine if the "feature" being identified isn't some random artificial scratch or other feature introduced by prep, or simply image artifacts from pixelation or lighting issues. Without side by side comparisons of fossil and image, the method is worthless. David Peters doesn't do this...the images he analyzed are often random pictures from books and scientific papers. He routinely has trouble telling apart real versus fake features by using these images and these methods.


I've read that Moeritherium (sp?) is no longer considered the basal ancestor of elephants and their relatives. Which animal is now considered to be such?

Also, one of my favorite extinct elephant relative is the Stegotetrabelodon, a four tusked beast who's upper and lower tusks seem to be about the same size. It's probably related to gomphotheres, but what possible use could two sets of identical tusks be? And it seemed to have lived in arid areas, as well. It confuses me.


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DungeonmasterCal wrote:

I've read that Moeritherium (sp?) is no longer considered the basal ancestor of elephants and their relatives. Which animal is now considered to be such?

Also, one of my favorite extinct elephant relative is the Stegotetrabelodon, a four tusked beast who's upper and lower tusks seem to be about the same size. It's probably related to gomphotheres, but what possible use could two sets of identical tusks be? And it seemed to have lived in arid areas, as well. It confuses me.

Not sure where you heard about Moeritherium, but as far as I know it's still considered an elephant, and an early diverging member of that lineage. It probably wasn't a direct ancestor of the modern species (IIRC, ancestors of the Mastodont lineage were present at the same time this species lived). And there were earlier elephants certainly. But it is still an early relative of elephant.

No idea on the possible use of 4 sets of tusks...it's possibly something more related to male to male combat than foraging. But yeah it's interesting just how many weird patterns of tusk development occurred in elephants (I have a soft spot for Platybelodon myself


I guess I wasn't clear. I figured Moeritherium was still considered part of the elephant lineage, but I thought it had been removed as the direct ancestor of them. And yeah, Platybelodons are pretty cool... lol
Now there is something I didn't know, and that's mastodon ancestors emerged at roughly the same time. I guess I'm so far behind on my hobby now after all these years I still remember it being a much later offshoot.

Thanks for the info!


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Incidentally, I once met Chris Brochu when he lectured when Sue the T Rex toured America. During the Q&A, which was in a packed auditorium, no one asked any questions except for the occasional kid. None of the adults did. Except me. I bet I asked over a dozen questions. I know he got a little tired of just me but he realized I was extremely interested in what he had to say. His specialty is crocodiliforms, and actually got into a discussion about them them after the lecture. He asked me if I was a paleontologist myself because I knew so much already about what he was talking about, and I told him, "No, just a nerd." He laughed and then went into the Monty Python Cheese Shop sketch. We both had a huge laugh over that and he said nerdism should be a class for paleontology.


DungeonmasterCal wrote:

I guess I wasn't clear. I figured Moeritherium was still considered part of the elephant lineage, but I thought it had been removed as the direct ancestor of them. And yeah, Platybelodons are pretty cool... lol

Now there is something I didn't know, and that's mastodon ancestors emerged at roughly the same time. I guess I'm so far behind on my hobby now after all these years I still remember it being a much later offshoot.

Thanks for the info!

Well I would have to go and look up a recent phylogeny of the group to be sure. But in general using phylogenies we can only get at "close to the common ancestor", and its very difficult to actually prove direct descent. Anyway when I am back with some place with better journal access I will take a look


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DungeonmasterCal wrote:
Incidentally, I once met Chris Brochu when he lectured when Sue the T Rex toured America. During the Q&A, which was in a packed auditorium, no one asked any questions except for the occasional kid. None of the adults did. Except me. I bet I asked over a dozen questions. I know he got a little tired of just me but he realized I was extremely interested in what he had to say. His specialty is crocodiliforms, and actually got into a discussion about them them after the lecture. He asked me if I was a paleontologist myself because I knew so much already about what he was talking about, and I told him, "No, just a nerd." He laughed and then went into the Monty Python Cheese Shop sketch. We both had a huge laugh over that and he said nerdism should be a class for paleontology.

I've met Brochu a few times...he is a great guy and does some excellent work, especially since he is one of the few folks actually paying attention to post Cretaceous crocs. Gives great talks as well!


So spinosaurus's hind legs. I've heard some back and forth opinions. Did it have short weenie-dog legs, typical non-avian theropod length legs, or something in between?

Shadow Lodge

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Why are Monotremes classified as mammals while many of those cool haired Mesozoic mammal cousin critters like docodonta are not.

Does come down to Monotremes no being extinct when the early classification was being made?

Would life on earth be better off if homo sapiens were extinct?


Threeshades wrote:
So spinosaurus's hind legs. I've heard some back and forth opinions. Did it have short weenie-dog legs, typical non-avian theropod length legs, or something in between?

I'm not answering for MMCJawa, but the latest reconstruction I've seen shows it having somewhat weaker hind legs that would make it difficult to walk upright without support from it's longer forelimbs, so it may have spent more time in the water.


Kerney wrote:

Why are Monotremes classified as mammals while many of those cool haired Mesozoic mammal cousin critters like docodonta are not.

Does come down to Monotremes no being extinct when the early classification was being made?

Would life on earth be better off if homo sapiens were extinct?

I'd not heard of docodonts. I had to look them up. Interesting.


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Do you ever have to deal with insane arguments with people who fund your research?

I wish the above was not based on something I moderated at work recently.


Kerney wrote:

Why are Monotremes classified as mammals while many of those cool haired Mesozoic mammal cousin critters like docodonta are not.

Does come down to Monotremes no being extinct when the early classification was being made?

Would life on earth be better off if homo sapiens were extinct?

Basically Mammalia is currently defined as a "crown group", which effectively means the common ancestor of all living mammals and their descendants. This puts several groups of hairy critters outside of Mammalia proper, but rather in more expansive groups such as Mammaliaformes. So yeah, it's pretty much based on what is alive today, and if Monotremata had died out millions of years ago, than platypuses and echidnas would not be considered mammals.

There of course have been other definitions of mammals, including definitions based on ear and jaw anatomy, but these appear to be less popular now.

As for life on earth be better without humanity? Starlings, House Sparrows, and rats would probably disagree. Certainly cows, dogs and cats have benefited from humans. But we would have a far greater diversity of of animals alive today had modern humans not evolved.


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DungeonmasterCal wrote:
Threeshades wrote:
So spinosaurus's hind legs. I've heard some back and forth opinions. Did it have short weenie-dog legs, typical non-avian theropod length legs, or something in between?
I'm not answering for MMCJawa, but the latest reconstruction I've seen shows it having somewhat weaker hind legs that would make it difficult to walk upright without support from it's longer forelimbs, so it may have spent more time in the water.

I'm not actually super convinced that Spinosaurs had hind limbs all that shorter than typical theropods, nor do I think its quadrupedal in locomotion. The most recent big study to suggest that based it's finding not on a single specimen, but rather a composite of multiple individuals. It could be they are correct, but I think more data is needed.

Don't get me wrong...Spinosaurs are really bizarre animals, I just don't know if they are quite THAT bizarre.


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MagusJanus wrote:

Do you ever have to deal with insane arguments with people who fund your research?

I wish the above was not based on something I moderated at work recently.

With funding no...generally speaking funding requests go through committees formed of other scientists, and for smaller grants when I was a student I received no feedback, while more recently the bigger grants I have applied for have all liked my grant applications.

The bigger frustration being getting high praise for a grant which I invested numerous late nights into making perfect, only to still not get funded, simply because there wasn't enough money in the pot to fund all the well-received grants (this has happened twice now to me).


MMCJawa wrote:
MagusJanus wrote:

Do you ever have to deal with insane arguments with people who fund your research?

I wish the above was not based on something I moderated at work recently.

With funding no...generally speaking funding requests go through committees formed of other scientists, and for smaller grants when I was a student I received no feedback, while more recently the bigger grants I have applied for have all liked my grant applications.

The bigger frustration being getting high praise for a grant which I invested numerous late nights into making perfect, only to still not get funded, simply because there wasn't enough money in the pot to fund all the well-received grants (this has happened twice now to me).

Ouch. I always hate it when that happens. I've always been glad I never was in a position to make that choice.

Shadow Lodge

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If you had to drop hungry prehistoric carnivores at one of the following events, which carnivore would you choose.

A crowded mall, an NFL playoff game, or the Trump inauguration?


Any or all of them. I don't go to malls, I don't watch football, and I loathe Trump. So none of it would affect me, at least. I can't speak for MMCJawa.


What do you have against invertebrates.

Scarab Sages

I had a discussion with a friend recently and we had a disagreement over which group is closer related to the dinosaurs "The Plesiosaurs" or "The Crocodiles"

I assume it's the Plesiosaurs, and that the reason he's thinking the crocodiles being crocs and birds usually are refereed to as animals that's been around since the time of the dinosaurs.


Bill, Brain Collector wrote:
What do you have against invertebrates.

Maybe they're all spineless and cowardly?


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DungeonmasterCal wrote:
Bill, Brain Collector wrote:
What do you have against invertebrates.
Maybe they're all spineless and cowardly?

Crawdadly?


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what do you have against invertebrates?

Dip


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Do you know any invertebrate biologists, and if so do they have difficulty standing or sitting upright?


Only if they have a hard carapace to help hold them up. Worms would just flop over.


I did some digging (heh, digging...paleontology..) and I couldn't find anything that related plesiosaurs to dinosaurs. It seems they developed from totally different ancestral types. MMCJAWA may laugh in my face and shout "He's wrong!" from the rooftops, and I wouldn't blame him, being only an armchair paleontologist anyway. But if I had to guess I'd say they were not related.


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Kerney wrote:

If you had to drop hungry prehistoric carnivores at one of the following events, which carnivore would you choose.

A crowded mall, an NFL playoff game, or the Trump inauguration?

Wow I totally missed these earlier questions...my apologies to all.

I don't think I would be prone to dropping prehistoric carnivores at any events (since they would probably just end up panicked and eventually shot). Although the first think that popped to mind was Ambulocetus, which wouldn't admittedly be the most dangerous thing on land.


Bill, Brain Collector wrote:
What do you have against invertebrates.

with the exception of wasps, which I have a bit of an irrational fear about at times, I don't have anything personal against them. I just am not super interested in invertebrates.


Azullius Koujou wrote:

I had a discussion with a friend recently and we had a disagreement over which group is closer related to the dinosaurs "The Plesiosaurs" or "The Crocodiles"

I assume it's the Plesiosaurs, and that the reason he's thinking the crocodiles being crocs and birds usually are refereed to as animals that's been around since the time of the dinosaurs.

Crocs and dinosaurs are archosaurs, and thus are more closely related to each other than plesiosaurs. Plesiosaurs are Sauropterygians, which are a clade that branched off the reptile tree at an earlier time than archosaurs.


What's your top five favorite dinosaurs.

Favorite campy dinosaur movie, or movies. The sixties and seventies are practically riddled with them.


captain yesterday wrote:

What's your top five favorite dinosaurs.

Favorite campy dinosaur movie, or movies. The sixties and seventies are practically riddled with them.

Spinosaurus, Therizinosaurus, Scansoriopteryx, Edmontonia, Oviraptor, in no particular order and subject to day to day variation.

Favorite campy Dinosaur movie? Maybe 1 Million B.C. or Caveman? The recent 10,000 B.C. gets some credit if only because the Terror Birds in it were awesome, but the rest of that movie sucked.


My favorite is Planet Of The Dinosaurs. Probably one of the most hilarious movies I saw as a kid. :-)


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Valley of the Gwange.


If we could bring back extinct species, should we? if so, under what circumstances?


^If we could bring back the ones we made extinct, we should (except for dangerous pathogens/parasites, so things like Smallpox, Guinea Worm, and Polio are out). Problem is: I don't trust us to do it right -- we'd instead make an even worse mess (the Jurassic Park series got that right, even though it isn't dealing with species we made extinct).


It's a wooly mammoth, they eat plants. Whats the worst that could happen!

*watches someone mix in some hippo dna and all hell breaks loose*


They gonna eat all r posies...


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BigNorseWolf wrote:
If we could bring back extinct species, should we? if so, under what circumstances?

I see de-extinction as being just another part of conservation efforts. So yes, I think we should try to bring back extinct species, but obviously should prioritize based on the potential of recreating wild populations. A Bluebuck Would be comparatively easy to bring back, because it went extinct from direct hunting and the habitat is still there to put it back into the wild. And its reintroduction is not going to race to much local protest because its not a predator.

Somethings are also likely also to be just really difficult. Ground Sloths would be problematic, because there are no modern sloths large enough to bring an embryo to term. Chinese River Dolphins, if you could bring them back, have no where to go, since the Yangtze is still very much a disaster. And good luck convincing anyone right now about the merits of bringing back Short-faced bears or Saber-toothed cats.

FYI, I really don't think we will have, at least in the next century so, the ability to actually bring back dinosaurs or anything much older than 10,000 years in age. So basically Holocene and Ice Age critters. I don't think any of these really carry much in the way of environmental risk.


UnArcaneElection wrote:

^If we could bring back the ones we made extinct, we should (except for dangerous pathogens/parasites, so things like Smallpox, Guinea Worm, and Polio are out). Problem is: I don't trust us to do it right -- we'd instead make an even worse mess (the Jurassic Park series got that right, even though it isn't dealing with species we made extinct).

I dunno...the Jurassic Park series was often pretty silly in how it portrayed science and the movies often treated dinosaurs more as monsters (especially Jurassic World) than actual animals. I think most of the arguments put forward on why its a bad idea also apply to modern zoos, yet lions are not constantly eating the guests.

De-extinction efforts would be focused on animals that overlapped with man in time, if not always in location, and shouldn't cause much of any concerns. The bigger question is whether there is a place to put these animals if we bring them back. Many areas don't have enough enforcement to keep the populations healthy, and many habitats still suffer under the conditions that caused the extinctions in the first place (environmental degradation, invasive species, climate change, etc).


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Sabertooth tigers ftw!!! You convinced me already! Just imagine the cat shows we could have! And eventually, sabertoothed housecats!!!


If you could ride a dinosaur, which one.

Liberty's Edge

Sissyl wrote:
Sabertooth tigers ftw!!! You convinced me already! Just imagine the cat shows we could have! And eventually, sabertoothed housecats!!!

Yeah, if you start down the de-extinction route you are also inherently opening the door to dispersal of new designer species... which is then likely going to generate far greater interest because you can tailor make a life form to fit a particular goal.


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I hardly think ethics have anything to do with science...


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captain yesterday wrote:
If you could ride a dinosaur, which one.

Probably a sauropod since I assume it would be a smooth ride and it wouldn't try to eat me


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CBDunkerson wrote:
Sissyl wrote:
Sabertooth tigers ftw!!! You convinced me already! Just imagine the cat shows we could have! And eventually, sabertoothed housecats!!!
Yeah, if you start down the de-extinction route you are also inherently opening the door to dispersal of new designer species... which is then likely going to generate far greater interest because you can tailor make a life form to fit a particular goal.

We don't need to bring back extinct animal to create designer lifeforms. Hell...what is a Pug or Persian cat if not a designer lifeform.


MMCJawa wrote:
UnArcaneElection wrote:

^If we could bring back the ones we made extinct, we should (except for dangerous pathogens/parasites, so things like Smallpox, Guinea Worm, and Polio are out). Problem is: I don't trust us to do it right -- we'd instead make an even worse mess (the Jurassic Park series got that right, even though it isn't dealing with species we made extinct).

I dunno...the Jurassic Park series was often pretty silly in how it portrayed science and the movies often treated dinosaurs more as monsters (especially Jurassic World) than actual animals. I think most of the arguments put forward on why its a bad idea also apply to modern zoos, yet lions are not constantly eating the guests.

{. . .}

I didn't say they weren't silly about the science (indeed, they are), but that they got the Humans messing things up part right (especially for greed and pride).

Sissyl wrote:
Sabertooth tigers ftw!!! You convinced me already! Just imagine the cat shows we could have! And eventually, sabertoothed housecats!!!

Now see what I mean?

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