HOME | DD
labgnome — Forget KT Hesperornids
by-nc-nd
Published: 2009-07-23 21:48:56 +0000 UTC; Views: 1291; Favourites: 19; Downloads: 26
Redirect to original
Description
Evolved hesperornid cetacean analogues, for and for their dinosaurid's world from some discussion. In the place of mammalian cetaceans, streamlined fully aquatic descendants of hesperornis. The front wings have completely atrophied and in some species the teeth have been replaces by a sieve to filter plankton and krill. Again, sideways some more.Related content
Comments: 20
because birds must lay eggs,and they must lay them on land even pouches for eggs woldnt work because pressure would destroy the eggs) how they reproduce?
👍: 0 ⏩: 1
I initially expect they have full live birth. I haven't been able find anything of fossil Hesperornid reproduction so I don't know if, or what kind of eggs they laid.
Considering that many marine reptiles had live birth, I think it would be a plausible evolution for them.
👍: 0 ⏩: 1
Hesperornids are birds,birds have hard shelled eggs,which are very unlikely to de-evolve,even the jurassic marine crocodiles (all archosaurs,with possible expection of pterosaurs) had/have hard shelled eggs, Thalattosuchids,had to lay eggs outside water
In fact,the embryo gets all calcium from the egg shell.I suppose birds are not able to be ovoviviparous either because there needs to be gas-exchange between the embryo inside egg and enviroment,which would the mothers body prevent
so just because other animals managed to get this ability,it does not means that all animals which live in similar enviroment can get this abillity
👍: 0 ⏩: 1
Well we know about modern birds. We also don;t know about the exact type of eggs laid by theropods, or the relationship between hesperornids and modern birds.
👍: 0 ⏩: 1
all non-avian dinosaurs had eggs similar to eggs of avian dinosaurs
👍: 0 ⏩: 1
From what I understand that's still debated. Also I see no reason that it would have to "go backwards" either.
👍: 0 ⏩: 1
Perhaps they could lay their eggs in lagoons. Or they could have eggs that float which they would guard until the young hatched...
👍: 0 ⏩: 1
That doesn't strike me as realistic solution.
👍: 0 ⏩: 1
Would these hesperonids have penguin-like feathers, or have more cetacean-like skin and blubber? Or something else?
👍: 0 ⏩: 1
I'm thinking that by this point in their evolution that the feathers are either absent or reduced to small hair-like structures for improved hydrodynamics. All species have a thick layer of blubber, like whales.
👍: 0 ⏩: 0
interesting design here, they achieve locomotion b moving similarily to the way a whale does, correct?
oh, and there is a way to flip these 9immages... once you scan them, doubble click on the image, and there should be editing tools...
👍: 0 ⏩: 1
Oh I know that, however I was at my local library and only had 30 minutes to scan and upload everything. Sideways was better than nothing.
Their locomotion became more and more "whale-like" as their legs shortened, and they were more and more completely aquatic. Eventually the legs themselves were completely internalized and the feet evolved into flippers then a fluke.
The idea is that they eventually out-competed the mosasaurs and were sufficiently successful in their niches to prevent the rise of cetaceans, or some other mammalian analogue in this timeline.
👍: 0 ⏩: 1
I see... and so, have you thought to design any plancton-like organisms that the larger beasts feed on? or have they not chanced so much in this alternate timeline?
👍: 0 ⏩: 1
Currently I'm assuming they are similar or analogous enough to those in our own timeline that they are essentially the same. Most algae and crustacean groups as we know them had evolved by the end of the Cretaceous so the differences should be fairly minor.
👍: 0 ⏩: 1
you speak the truth, I however tend to forget these things...
of course, there are the rare occaions when a new species of crab larvea mutates and gains the ability to mate while in the larval stage, so I figured there may be some...
👍: 0 ⏩: 1
That's true, however if the major groups survived with the KT impact, then in it's absence they should be even less changed, or at least that was my line of thinking. I'm currently toying with ideas for mammals and birds, especially smaller ones. However some interesting ideas have made their way forward.
👍: 0 ⏩: 0
Alternate hesperornids = instant win, especially when converging on cetaceans. I like the way you've completely eliminated the wings and streamlined them into a zeuglodon-like form. Very nice!
👍: 0 ⏩: 1
Thanks, they were probably my favorite concept out of them all.
I tried to be as straight-forward in the evolutionary adaptations as possible. The body-design is pretty much the same in all the species with most of the specialization being in the beaks, like many modern bird groups.
The general idea I had was that the wings would eventually completely atrophy and be absorbed into the body, like the hind limbs of whales, whereas the hind legs would eventually evolve into flippers and ultimately a fluke, the whole while the body becoming more flexible and serpentine. From there they diversified form a common ancestor according to habitat and feeding habits. Eventually they wold fill ecological niches form filter-feeding plankton eaters to apex predators and lots of others in between.
👍: 0 ⏩: 0
You've got some neat concepts there, mate.
I liked them so much that I made this: [link] . Check it out!
👍: 0 ⏩: 0