On Sunday, October 10, 2021 at 9:37:21 AM UTC-7, daud....@gmail.com wrote:
> On Saturday, October 9, 2021 at 9:26:05 PM UTC-4, John Harshman wrote:
> > On 10/9/21 5:15 PM, Daud Deden wrote:
> > > On Saturday, October 9, 2021 at 6:10:40 PM UTC-4, John Harshman wrote:
> > >> On 10/9/21 9:46 AM, Daud Deden wrote:
> > >>> On Saturday, October 9, 2021 at 9:31:03 AM UTC-4, John Harshman wrote:
> > >>>> On 10/8/21 9:55 PM, Daud Deden wrote:
> > >>>>> On Saturday, October 9, 2021 at 12:35:28 AM UTC-4, erik simpson wrote:
> > >>>>>> On Friday, October 8, 2021 at 8:41:01 PM UTC-7, daud....@gmail.com wrote:
> > >>>>>>> Erik! Help! This theropod could possibly have been a genetic precursor to modern ducks?
> > >>>>>>> Was it a biped with long boney tail and teethy jaws with protruding chin? Could ducks have then lost/shrunk the tail, teeth and chin bone when they adopted arboreal upright tensional perching with hind limb tendon locking, in parallel with pterosaurs, avians and hominoids?
> > >>>>>>>
> > >>>>>>> Chins are found in species which habitually lift to drink water above the surface, humans and gibbons by scooping, and elephants by trunk-suction. Ducks have to lift their water-filled mouths vertically to drink, they can't drink it straight from the surface like a cat. They lack kansaignathus chins because they lost their dentition for weight-saving flight, like pterosaurs, while hominoids became flat-faced. Humans developed dense-boned chins only after becoming obligate orthograde striding ground bipedalists, no other hominids developed chins. Kansaignathus sogdianas SHOULD HAVE NO CHIN PROMINENCE unless it lifted water above surface level during drinking.
> > >>>>>>>
> > >>>>>>> Thoughts?
> > >>>>>>>
> > >>>>>>> DD
> > >>>>>>> -
> > >>>>>>>> The 2021 paper was one of those now you see it, now you don't. Unfortunately, I missed
> > >>>>>>>> the chance to download the PDF. You could yourself, I imagine. The abstract:
> > >>>>>>>>
> > >>>>>>>> "A new dromaeosaurid theropod dinosaur, Kansaignathus sogdianus gen. et sp. nov., is described based on a dentary from the Yalovach Formation (Santonian) at Kansai locality in northern Fergana Valley (Tajikistan) collected by Paleontological Institute of the Academy of Sciences of the USSR in 1963–1964. Dentary has 12 tooth alveoli and not downturned anterior end. There is a chin prominence. Dorsal margin is concave and ventral margin is convex. There are two rows of vascular foramina on the labial side and irregular intermediate foramina in the anterior part of a dentary. The interdental plates are not discernable. Kansaignathus is one of the most basal members of the subfamily Velociraptorinae. It fills the gap in the fossil record of the Velociraptorinae between the Early Cretaceous Deinonychus and more derived Campanian–Maastrichtian velociraptorines of Asia and North America."
> > >>>>>>>>
> > >>>>>>>> In other words, a single bone. Do you think it sheds light on whatever point you've been
> > >>>>>>>> hinting at? Or do you think they're using this specimen to investigate a different point? I doubt
> > >>>>>>>> you're in a position to answer that question, based on your unfamiliarity with trees.
> > >>>>>> Unless phylogentic indications are spectacularly wrong, no, it's not even a stem duck.
> > >>>>>
> > >>>>> No, I know it was not a duck, a stem duck or a root duck. But could the bone have come from an ancient reptile ancestor of ducks, long before anything duck-like was alive?
> > >>>> No. Again, ducks do not have separate ancestry from other birds.
> > >>>
> > >>> But that is not at issue. I'm specifying ducks only because I personally witnessed my muscovy duck drink water by lifting its head, I don't know if all birds do that, so I limited the question to ducks.
> > >>>
> > >>> What is at issue is that ducks/birds might have descended from a reptile ancestor which had to lift its head (2" - 20"+) above the water surface in order to drink (like ducks have to).
> > >>>
> > >>> Modern animals which have chins do this, modern animals that don't have chins do not typically do this (except ducks/birds which lost teeth and perhaps boney chin due to strong selection for aerodynamic lightening).
> > >>>
> > >>> The
> > >>>> sister group of ducks is screamers. The sister group of ducks and
> > >>>> screamers is galliforms. The sister group of ducks, screamers, and
> > >>>> galliformes is Neoaves. The sister group of ducks, screamers,
> > >>>> galliforms, and Neoaves is Paleognathae. And all these are nested within
> > >>>> various additional clades of birds. The fossil in question can't be
> > >>>> ancestral to ducks unless it's ancestral to all modern birds.
> > >>>
> > >>> No argument there. But did the LCA of all modern birds likely have a *very general resemblance* to today's waterfowl? Or did it look like a canary, an eagle, a moa, all very different from typical waterfowl?
> > >>>
> > >>> (I recall mentioning my surprise when I noticed unexpected similarities in a pigeon and a mallard, which I had never even imagined before.)
> > >>>
> > >>>>> Its placement
> > >>>>>> amoung dromaeosaurids might move around if more of the skeleton were known, and it might not
> > >>>>>> even be a dromaeosaurid at all (although I defer to the judgement of authors in that regard).
> > >>>>> So we don't know.
> > >>>>>
> > >>>> Don't be confused about what we do or don't know. We may not know just
> > >>>> what that fossil is, but we know much about what it isn't. It isn't a
> > >>>> mammal. It isn't a fish.
> > >>>
> > >>> Agree.
> > >>>
> > >>> And it isn't a duck ancestor.
> > >>>
> > >>> Palognathae ancestor?
> > >>>
> > >> Most birds have to lift their heads to drink, but I'm wondering if you
> > >> mean the same thing I do by that. There are a few exceptions. Pigeons,
> > >> if I recall. And sandgrouse?
> > >
> > > https://www.birdsoutsidemywindow.org/2010/07/09/anatomy-how-birds-drink/
> > > Doves & pigeons can drink with beak lowered. Nectarivores can too. Sandgrouse lift but do not tilt back their heads while drinking.
> > > Do all long-necked avians (eg. waterfowl, ostriches) lift water above the surface to drink?
> > > Did all long-necked dinosaurs lift water and tilt head before drinking?
> > What do you mean by "long-necked"? Almost all birds do it. We don't know
> > about the behavior of extinct species.
> > > No, it's not a paleognath ancestor either;
> > >> again, birds are monophyletic, Neornithes is monophyletic, and so are
> > >> several groups in between.
> > >
> > > I don't know the latest proper technical name that includes all modern avians. But I meant to compare all living birds to the long-necked bipedal dinosaur.with the prominent chin.
> I meant 'a chin prominence'.
> > The term is either Neornithes or Aves, depending on who's talking.
> > > There is no room for this theropod jaw to be
> > >> ancestral to any group of birds separately, and of course it's unlikely
> > >> to be the ancestor of anything.
> > >
> > > The jury is still out on that claim, imo.
> > Your opinion, I'm afraid, is not informed.
> I don't think this one is either, despite the name: eagle-nosed shovel-chinned duck-billed dinosaur, found where I went on a Rio Grande river expedition in '79.
> https://www.livescience.com/65937-shovel-chinned-dinosaur.html aquilarhinus palimentum
>
> Dilophosaurus had a chin but not a (human-like) mental protuberance: "The dentary bone (the front part of the mandible where most of the teeth there were attached) had an up-curved rather than pointed chin. The chin had a large foramen at the tip, and a row of small foramina ran in rough parallel with the upper edge of the dentary". https://en.m.wikipedia.org/wiki/Dilophosaurus
>
> Dinosaurs don't seem to have had chins comparable to elephants, some hylobatids & humans.

Most if not all dinosaurs (including birds) didn't and don't closely resemble elephants, hylobatids or humans.
What are you trying to get at? Given the length of time separating "us" (synapsids) from "them" (diapsids) it
might be more surprising that they resemble us as much as they do. At least one now-departed eccentric saw
deep connections between ankylosaurs and armadillos.