On 12/10/23 2:27 PM, erik simpson wrote:
> On Sunday, December 10, 2023 at 11:10:03 AM UTC-8, Sight Reader wrote:
>> Whaddya guys think? Is buzz over a sort of “non-avian cormorant” premature?
>>
>> https://www.smithsonianmag.com/science-nature/worlds-first-swimming-dinosaur-discovered-in-mongolia-180981217/
> Maybe someone with much better anatomical insight than I could see the "cormorant-like" resemblance,
> but the actual article describing it (https://www.nature.com/articles/s42003-022-04119-9) describes it as
> "A non-avian dinosaur with a streamlined body exhibits potential adaptations for swimming" is amore subdued
> buzz.

Unfortunately, any material that might show if the legs had any swimming
adaptations is missing. I'm assuming that the tail was sufficiently
inflexible not to be used, as would be expected in a maniraptoran.

On 12/10/23 15:14, John Harshman wrote:
> On 12/10/23 2:27 PM, erik simpson wrote:
>> On Sunday, December 10, 2023 at 11:10:03 AM UTC-8, Sight Reader wrote:
>>> Whaddya guys think? Is buzz over a sort of “non-avian cormorant”
>>> premature?
>>>
>>> https://www.smithsonianmag.com/science-nature/worlds-first-swimming-dinosaur-discovered-in-mongolia-180981217/
>> Maybe someone with much better anatomical insight than I could see the
>> "cormorant-like" resemblance,
>> but the actual article describing it
>> (https://www.nature.com/articles/s42003-022-04119-9) describes it as
>> "A non-avian dinosaur with a streamlined body exhibits potential
>> adaptations for swimming" is amore subdued
>> buzz.
>
> Unfortunately, any material that might show if the legs had any swimming
> adaptations is missing. I'm assuming that the tail was sufficiently
> inflexible not to be used, as would be expected in a maniraptoran.

So basic question. How large was an Allosaurus or Tyrannosaurus
when they first hatched? Do you clearly know what young large
Theropoda looked like? Are some maniraptorans improperly
classified as a different species from say Allosaurus when in
fact they were simply younger forms of larger Theropoda?

On 12/12/23 3:15 PM, Trolidan7 wrote:
> On 12/10/23 15:14, John Harshman wrote:
>> On 12/10/23 2:27 PM, erik simpson wrote:
>>> On Sunday, December 10, 2023 at 11:10:03 AM UTC-8, Sight Reader wrote:
>>>> Whaddya guys think? Is buzz over a sort of “non-avian cormorant”
>>>> premature?
>>>>
>>>> https://www.smithsonianmag.com/science-nature/worlds-first-swimming-dinosaur-discovered-in-mongolia-180981217/
>>> Maybe someone with much better anatomical insight than I could see
>>> the "cormorant-like" resemblance,
>>> but the actual article describing it
>>> (https://www.nature.com/articles/s42003-022-04119-9) describes it as
>>> "A non-avian dinosaur with a streamlined body exhibits potential
>>> adaptations for swimming" is amore subdued
>>> buzz.
>>
>> Unfortunately, any material that might show if the legs had any
>> swimming adaptations is missing. I'm assuming that the tail was
>> sufficiently inflexible not to be used, as would be expected in a
>> maniraptoran.
>
> So basic question.  How large was an Allosaurus or Tyrannosaurus
> when they first hatched?  Do you clearly know what young large
> Theropoda looked like?  Are some maniraptorans improperly
> classified as a different species from say Allosaurus when in
> fact they were simply younger forms of larger Theropoda?
>
Baby dinosaurs were generally a tiny fraction of adult size, judging
from known eggs. But juveniles can be distinguished from adults.
Apophyses should be unfused or cartilaginous (likely missing), and bone
near the ends of long bones should show signals of growth. But there
have been juveniles confused with adults of smaller species in the past,
for example Nanotyrannus.

On 12/12/23 16:19, John Harshman wrote:
> On 12/12/23 3:15 PM, Trolidan7 wrote:
>> On 12/10/23 15:14, John Harshman wrote:
>>> On 12/10/23 2:27 PM, erik simpson wrote:
>>>> On Sunday, December 10, 2023 at 11:10:03 AM UTC-8, Sight Reader wrote:
>>>>> Whaddya guys think? Is buzz over a sort of “non-avian cormorant”
>>>>> premature?
>>>>>
>>>>> https://www.smithsonianmag.com/science-nature/worlds-first-swimming-dinosaur-discovered-in-mongolia-180981217/
>>>> Maybe someone with much better anatomical insight than I could see
>>>> the "cormorant-like" resemblance,
>>>> but the actual article describing it
>>>> (https://www.nature.com/articles/s42003-022-04119-9) describes it as
>>>> "A non-avian dinosaur with a streamlined body exhibits potential
>>>> adaptations for swimming" is amore subdued
>>>> buzz.
>>>
>>> Unfortunately, any material that might show if the legs had any
>>> swimming adaptations is missing. I'm assuming that the tail was
>>> sufficiently inflexible not to be used, as would be expected in a
>>> maniraptoran.
>>
>> So basic question.  How large was an Allosaurus or Tyrannosaurus
>> when they first hatched?  Do you clearly know what young large
>> Theropoda looked like?  Are some maniraptorans improperly
>> classified as a different species from say Allosaurus when in
>> fact they were simply younger forms of larger Theropoda?
>>
> Baby dinosaurs were generally a tiny fraction of adult size, judging
> from known eggs. But juveniles can be distinguished from adults.
> Apophyses should be unfused or cartilaginous (likely missing), and bone
> near the ends of long bones should show signals of growth. But there
> have been juveniles confused with adults of smaller species in the past,
> for example Nanotyrannus.

You know if you have a lot of R selection and nearly
no parental investment, with the adults laying a large
number of small eggs, then the juveniles could hatch
and then start hunting smaller animals or eating smaller
amounts of plant material moderately quickly. That
could result in a vast number of small animals in comparison
with those that are large enough to start laying eggs and
mate.

They would just hunt smaller animals or eat less tough plants.
Many would die as juveniles before reaching larger sizes.

I once remember reading that some species of crocodilians
might not undergo senescence, rather they keep growing larger
until the environment can no longer support them, and then
they starve. With a lot of R selection, you could have
animals of larger possible size have much more animals
grow in niches for smaller organisms before reproducing
at the larger size. Of course if you can clearly tell that
would rule out a lot of maniraptora being juveniles of
larger theropods.