New Chinese pterosaur, [i]Hamipterus[/i] - nesting site with eggs!

[Patrx]

http://www.sci-news.com/paleontology/science-hamipterus-tianshanensis-pterosaur-eggs-china-01973.html

[tyrantqueen]

Cool find. On the subject of eggs: why is it that pterosaurs, unlike crocodilians and dinosaurs, hatched from leathery, soft shelled eggs, much like squamates and certain species of turtles? Since they're archosaurs, you would expect them to share the same kind of hard eggshell as their dinosaur and crocodile cousins.  Do you think that the soft shelled egg condition was posessed by early reptile ancestors, and pterosaurs (for whatever reason) retained that particular quirk? Maybe the hard eggshell developed on another, later branch of the evolutionary tree to pterosaurs. I've also noticed that most reptiles that lay softshell eggs are ones that do not practice any kind of parental care.

I hope it's not a stupid question.

[Patrx]

Actually, I was wondering that myself! I hadn't known until know that pterosaur eggshells were soft.

[stoneage]

Cool find. On the subject of eggs: why is it that pterosaurs, unlike crocodilians and dinosaurs, hatched from leathery, soft shelled eggs, much like squamates and certain species of turtles? Since they're archosaurs, you would expect them to share the same kind of hard eggshell as their dinosaur and crocodile cousins.  Do you think that the soft shelled egg condition was posessed by early reptile ancestors, and pterosaurs (for whatever reason) retained that particular quirk? Maybe the hard eggshell developed on another, later branch of the evolutionary tree to pterosaurs. I've also noticed that most reptiles that lay softshell eggs are ones that do not practice any kind of parental care.

I hope it's not a stupid question.

It seems to me that where you have many Pterosaurs of different sizes along with eggs it is likely there was parental care.  I mean it sounds like a nesting site where they are socially co-existing.  It doesn't sound like Turtles where they lay their eggs and leave.

[Patrx]

Cool find. On the subject of eggs: why is it that pterosaurs, unlike crocodilians and dinosaurs, hatched from leathery, soft shelled eggs, much like squamates and certain species of turtles? Since they're archosaurs, you would expect them to share the same kind of hard eggshell as their dinosaur and crocodile cousins.  Do you think that the soft shelled egg condition was posessed by early reptile ancestors, and pterosaurs (for whatever reason) retained that particular quirk? Maybe the hard eggshell developed on another, later branch of the evolutionary tree to pterosaurs. I've also noticed that most reptiles that lay softshell eggs are ones that do not practice any kind of parental care.

I hope it's not a stupid question.

It seems to me that where you have many Pterosaurs of different sizes along with eggs it is likely there was parental care.  I mean it sounds like a nesting site where they are socially co-existing.  It doesn't sound like Turtles where they lay their eggs and leave.

That's the odd thing. It seems like soft eggshells are more common with animals that produce a lot of offspring but don't invest parental care (I think this is called "r" strategy?) Yet, this colony suggests a nesting site, not just a laying site, because both adult female and adult male specimens are present. That would suggest fewer offspring but more parental care, which (I think) is known as "K" strategy. Other archosaurs, like crocodilians and dinosaurs, which produce hard eggshells, are closer to "K" strategists.

[tyrantqueen]

Cool find. On the subject of eggs: why is it that pterosaurs, unlike crocodilians and dinosaurs, hatched from leathery, soft shelled eggs, much like squamates and certain species of turtles? Since they're archosaurs, you would expect them to share the same kind of hard eggshell as their dinosaur and crocodile cousins.  Do you think that the soft shelled egg condition was posessed by early reptile ancestors, and pterosaurs (for whatever reason) retained that particular quirk? Maybe the hard eggshell developed on another, later branch of the evolutionary tree to pterosaurs. I've also noticed that most reptiles that lay softshell eggs are ones that do not practice any kind of parental care.

I hope it's not a stupid question.

It seems to me that where you have many Pterosaurs of different sizes along with eggs it is likely there was parental care.  I mean it sounds like a nesting site where they are socially co-existing.  It doesn't sound like Turtles where they lay their eggs and leave.

I don't think pterosaurs cared for their young, certainly not in the manner that mammals and birds do. In Mark Witton's book, Pterosaurs from Deep Time, he suggested that baby pterosaurs were able to fly as soon as they were hatched (the bones in the wing were fully elongated and formed, and in proportion to the rest of their body), and were left to fend for themselves.

[brandem]

http://www.sci-news.com/paleontology/science-hamipterus-tianshanensis-pterosaur-eggs-china-01973.html

I'm more interested that the paleaoartist decided to take the image of this creature in a romance novel cover direction.

[stoneage]

Cool find. On the subject of eggs: why is it that pterosaurs, unlike crocodilians and dinosaurs, hatched from leathery, soft shelled eggs, much like squamates and certain species of turtles? Since they're archosaurs, you would expect them to share the same kind of hard eggshell as their dinosaur and crocodile cousins.  Do you think that the soft shelled egg condition was posessed by early reptile ancestors, and pterosaurs (for whatever reason) retained that particular quirk? Maybe the hard eggshell developed on another, later branch of the evolutionary tree to pterosaurs. I've also noticed that most reptiles that lay softshell eggs are ones that do not practice any kind of parental care.

I hope it's not a stupid question.

It seems to me that where you have many Pterosaurs of different sizes along with eggs it is likely there was parental care.  I mean it sounds like a nesting site where they are socially co-existing.  It doesn't sound like Turtles where they lay their eggs and leave.

I don't think pterosaurs cared for their young, certainly not in the manner that mammals and birds do. In Mark Witton's book, Pterosaurs from Deep Time, he suggested that baby pterosaurs were able to fly as soon as they were hatched (the bones in the wing were fully elongated and formed, and in proportion to the rest of their body), and were left to fend for themselves.

Witton's theories are still considered controversial.  Even he has illustrations in his book of nest guarding.  http://scienceblogs.com/tetrapodzoology/wp-content/blogs.dir/471/files/2012/05/i-aeec512af92a1a462d3d1b8b2c7e191e-Witton-azhdarchid-hatchlings-May-2011.jpg 

[tyrantqueen]

Cool find. On the subject of eggs: why is it that pterosaurs, unlike crocodilians and dinosaurs, hatched from leathery, soft shelled eggs, much like squamates and certain species of turtles? Since they're archosaurs, you would expect them to share the same kind of hard eggshell as their dinosaur and crocodile cousins.  Do you think that the soft shelled egg condition was posessed by early reptile ancestors, and pterosaurs (for whatever reason) retained that particular quirk? Maybe the hard eggshell developed on another, later branch of the evolutionary tree to pterosaurs. I've also noticed that most reptiles that lay softshell eggs are ones that do not practice any kind of parental care.

I hope it's not a stupid question.

It seems to me that where you have many Pterosaurs of different sizes along with eggs it is likely there was parental care.  I mean it sounds like a nesting site where they are socially co-existing.  It doesn't sound like Turtles where they lay their eggs and leave.

I don't think pterosaurs cared for their young, certainly not in the manner that mammals and birds do. In Mark Witton's book, Pterosaurs from Deep Time, he suggested that baby pterosaurs were able to fly as soon as they were hatched (the bones in the wing were fully elongated and formed, and in proportion to the rest of their body), and were left to fend for themselves.

Witton's theories are still considered controversial.  Even he has illustrations in his book of nest guarding.  http://scienceblogs.com/tetrapodzoology/wp-content/blogs.dir/471/files/2012/05/i-aeec512af92a1a462d3d1b8b2c7e191e-Witton-azhdarchid-hatchlings-May-2011.jpg

That doesn't necessarily mean that they engaged in parental care. They might simply have watched over the hatchlings as they left the "nest".

Also, I made a mistake. It wasn't Witton's book, it was actually David Unwin's. But actually, in Witton's own book (which I also own), even he states he does not think pterosaurs would have engaged in anything beyond nest guarding.

[Dinoguy2]

Cool find. On the subject of eggs: why is it that pterosaurs, unlike crocodilians and dinosaurs, hatched from leathery, soft shelled eggs, much like squamates and certain species of turtles? Since they're archosaurs, you would expect them to share the same kind of hard eggshell as their dinosaur and crocodile cousins.  Do you think that the soft shelled egg condition was posessed by early reptile ancestors, and pterosaurs (for whatever reason) retained that particular quirk? Maybe the hard eggshell developed on another, later branch of the evolutionary tree to pterosaurs. I've also noticed that most reptiles that lay softshell eggs are ones that do not practice any kind of parental care.

I hope it's not a stupid question.

It seems to me that where you have many Pterosaurs of different sizes along with eggs it is likely there was parental care.  I mean it sounds like a nesting site where they are socially co-existing.  It doesn't sound like Turtles where they lay their eggs and leave.

That's the odd thing. It seems like soft eggshells are more common with animals that produce a lot of offspring but don't invest parental care (I think this is called "r" strategy?) Yet, this colony suggests a nesting site, not just a laying site, because both adult female and adult male specimens are present. That would suggest fewer offspring but more parental care, which (I think) is known as "K" strategy. Other archosaurs, like crocodilians and dinosaurs, which produce hard eggshells, are closer to "K" strategists.

I don't think different sizes suggest social behavior. We see in dinosaurs that sexual maturity was reached long before full size, in some cases even before half size. Younger pterosaurs would be smaller and would be able to breed. Older pterosaurs could be up to twice as big and still breeding. If they all congregated together to breed and lay eggs, we'd expect many different size ranges due to age, sex, and even simple individual size variation between animals of the same age.

To test this hypothesis we would look for a large number of bones from young juveniles too young for sexual maturity at the same site, which AFAIK are not there. Just small adults and large adults.

Important to remember that pterosaurs were not birds, did not grow like birds and did not have bird-like life histories. Except for a few like maybe Pteranodon, which does seem to have grown to maturity in under a year, but still no evidence of parental care (but also no evidence of young juveniles at all).

[Scipionyx]

Cool find. On the subject of eggs: why is it that pterosaurs, unlike crocodilians and dinosaurs, hatched from leathery, soft shelled eggs, much like squamates and certain species of turtles? Since they're archosaurs, you would expect them to share the same kind of hard eggshell as their dinosaur and crocodile cousins.  Do you think that the soft shelled egg condition was posessed by early reptile ancestors, and pterosaurs (for whatever reason) retained that particular quirk? Maybe the hard eggshell developed on another, later branch of the evolutionary tree to pterosaurs. I've also noticed that most reptiles that lay softshell eggs are ones that do not practice any kind of parental care.

I hope it's not a stupid question.

It seems to me that where you have many Pterosaurs of different sizes along with eggs it is likely there was parental care.  I mean it sounds like a nesting site where they are socially co-existing.  It doesn't sound like Turtles where they lay their eggs and leave.

That's the odd thing. It seems like soft eggshells are more common with animals that produce a lot of offspring but don't invest parental care (I think this is called "r" strategy?) Yet, this colony suggests a nesting site, not just a laying site, because both adult female and adult male specimens are present. That would suggest fewer offspring but more parental care, which (I think) is known as "K" strategy. Other archosaurs, like crocodilians and dinosaurs, which produce hard eggshells, are closer to "K" strategists.

Perhaps this is a nesting colony akin to the ones hypothesized for sauropods: lots of individuals laying lots of eggs in one place.
Also, if most animals that use the "r" strategy (if that is what it is called) have soft shelled eggs, that might mean that there is something about soft-shelled eggs that makes them better for that strategy, and perhaps caused pterosaurs to evolve eggs like that.