Jump to content

Recommended Posts

anastasis008

Hey, a question I have always wanted to ask is about dinosaur relatives, more specifically what do we mean when we refer to two dinosaurs as cousins ? Do we mean that a kind of dinosaur(for example baryonyx ) lived in an environment but at one point a group got separated by land and this group got to live in another part of the world so that group resulted in adapting to another environment and becoming a different dinosaur (for example spinosaurus ) or do we mean that a dinosaur is an ancestor of another dinosaur (again for example baryonyx evolved into spinosaurus)?

This may seem like a really basic question to ask but I haven't really been able to find an answer so if someone answered it would be great.

Share this post


Link to post
Share on other sites
Troodon

I'm sure there are many interpretations of "cousins" but I like to refer to Dinosaurs in the same family group.  In your example its all Spinosauridae dinosaurs 

 

Screenshot_20190715-054545.thumb.jpg.a364221d0f5b56ff6cc6f22ed13f93bb.jpg

Share this post


Link to post
Share on other sites
FossilNerd

I’ve always heard the term “cousins” being used loosely to say that the animals are related to each other on the evolutionary tree. To use an extant analogy. Dogs are cousins to the wolf. Meaning they are descended from them. You could say the same for any other member of the canidae family. Foxes, jackals, and coyotes, for example.

 

Your first example is of how evolution and adaptation can occur.  Groups can spilt from each other and adapt to their different environment. They can evolve separately over time, but are still related and could be termed as “cousins”. 

 

In your second example of baryonyx being a descendant of spinosaurus. I think it is the same answer. They could be labeled as cousins because they are related in the evolutionary tree (in the same family Spinosauridae). If something else is also in the same family it too could be labeled as a cousin. 

Edited by FossilNerd
Clarification.

Share this post


Link to post
Share on other sites
Troodon

FYI Spinosaurus is not a direct decendent of Baryonyx.   Baryonyx is a Baryonychinae whille Spinosaurus is a Spinosaurinae.  They are counsins:D

Share this post


Link to post
Share on other sites
anastasis008
4 hours ago, Troodon said:

I'm sure there are many interpretations of "cousins" but I like to refer to Dinosaurs in the same family group.  In your example its all Spinosauridae dinosaurs 

 

Screenshot_20190715-054545.thumb.jpg.a364221d0f5b56ff6cc6f22ed13f93bb.jpg

Yes but by cousins we mean that they descended from eatch other or were the same animal living in different areas?

Share this post


Link to post
Share on other sites
anastasis008
4 hours ago, FossilNerd said:

I’ve always heard the term “cousins” being used loosely to say that the animals are directly related to each other on the evolutionary tree. To use an extant analogy. Dogs are cousins to the wolf. Meaning they are descended directly from them. You could say the same for any other member of the canidae family. Foxes, jackals, and coyotes, for example.

 

Your first example is of how evolution and adaptation can occur.  Groups can spilt from each other and adapt to their different environment. They can evolve separately over time, but are still related and could be termed as “cousins”. 

 

In your second example of baryonyx being a direct descendant of spinosaurus. I think it is the same answer. They could be labeled as cousins because they are related in the evolutionary tree. If something else also evolved from baryonyx it too could be labeled as a cousin. 

Ok that's a clearer image thank you for your time and clear explanation!

Share this post


Link to post
Share on other sites
Troodon
1 hour ago, anastasis008 said:

Yes but by cousins we mean that they descended from eatch other or were the same animal living in different areas?

It depends how far back you want to look.  Descendents can be from different areas before the continents split apart.   For example Ceratosaurus from the Morrison formation of North America are related to the Ceratosaurus in Portugal and Tanzania.  

Share this post


Link to post
Share on other sites
jpc

'cousins' is a term that really has no set-in-stone definition in taxonomy.  It has a very definite definition if we are talking about human relations within a person's family.  Cousins are the children of your aunt and uncle.  I would argue that dogs and wolves are NOT cousins because one is a direct descendant of the other.  On the other hand wolves and foxes are cousins.  Again these things are open to interpretation. 

Share this post


Link to post
Share on other sites
ynot
On 7/15/2019 at 10:47 AM, anastasis008 said:

Yes but by cousins we mean that they descended from eatch other or were the same animal living in different areas?

I always interpreted it as meaning that the two species had a common ancestor. (Chimps and humans.)

 

On 7/15/2019 at 12:01 PM, jpc said:

  I would argue that dogs and wolves are NOT cousins because one is a direct descendant of the other. 

Todays domestic dog is believed to have originated from a wild dog that inhabits the far east (asia) and not from wolfs.

Although in recent years wolf DNA has been added to the mix.

Share this post


Link to post
Share on other sites
Mark Kmiecik

I thought it meant two species that were able to interbreed and produce offspring whether sterile or not. Makes me wonder how many species of fossils were actually sterile hybrids, dead ends, so to speak.

Share this post


Link to post
Share on other sites
DPS Ammonite
10 minutes ago, Mark Kmiecik said:

I thought it meant two species that were able to interbreed and produce offspring whether sterile or not. Makes me wonder how many species of fossils were actually sterile hybrids, dead ends, so to speak.

One sterile individual does not a species make. No species were sterile otherwise they could not have formed a population group called a species. It is possible that low fertility of a species that originated as a hybrid might have doomed the species.

 

It is possible that a species does not reproduce sexually but by other means such as cloning. (Think trees such as aspen.) However, if you cannot reproduce sexually you are usually doomed.

Share this post


Link to post
Share on other sites
Mark Kmiecik
23 minutes ago, DPS Ammonite said:

One sterile individual does not a species make. No species were sterile otherwise they could not have formed a group called a species. It is possible that low fertility of a species that originated as a hybrid might have doomed the species.

The Tiger Muskie is a usually-sterile hybrid of the true Muskie and the Northern Pike. It occurs in the wild, not as frequently as either of the parent species but enough to be found pretty much everywhere both parent species are found in the same body of water. If it and it's parent species had become extinct it would probably be considered a separate species because of the differences between it and the parent species. So what I'm saying is how would we know that one species of dinosaur is not the hybrid offspring of two other species that interbred for millions of years? How would we know?

 

It makes me want to re-think the T. Rex / Nano / ?  debate. Is one or the other the hybrid offspring of one or the other plus something we have not yet discovered or vice versa? How would we know? Or would we call it a different species because it had shorter legs or . . . .

Share this post


Link to post
Share on other sites
DPS Ammonite

A sterile hybrid is not a species. As you mentioned, you could theoretically find a fossil that was sterile hybrid that was the result of repeated matings between two species. The hybrid would not be considered a new species. I have never heard of any papers that were written that described a fossil sterile hybrid. I do not think that we could recognize them as such. 

Share this post


Link to post
Share on other sites
Mark Kmiecik
1 minute ago, DPS Ammonite said:

A sterile hybrid is not a species.

In extant species, true. But in extinct species if it differs enough from both parents, how would we determine that it was a sterile hybrid of those two?

Share this post


Link to post
Share on other sites
DPS Ammonite

I doubt that you could determine that a different looking fossil was a sterile hybrid. If you could, the different fossil could not be considered a new species.

Share this post


Link to post
Share on other sites
Mark Kmiecik

 

2 minutes ago, DPS Ammonite said:

I doubt that you could determine that a different looking fossil was a sterile hybrid. If you could, the different fossil could not be considered a new species.

That's what I've been saying. Since we can't tell if it was a sterile hybrid we assign it to a separate species.

Share this post


Link to post
Share on other sites
DPS Ammonite
Just now, Mark Kmiecik said:

 

That's what I've been saying. Since we can't tell if it was a sterile hybrid we assign it to a separate species.

I agree that it would be assigned a separate species since we could not know if it is fertile or not.

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now


  • Recently Browsing   0 members

    No registered users viewing this page.

×