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On Plausibility; mulling on the nature of criticism
Topic Started: Aug 19 2017, 03:37 PM (629 Views)
LittleLazyLass
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kusanagi
Aug 29 2017, 09:16 PM
Homo type behaviours and morphology might not be inevitable, but intelligence and encephalisation are repeated trends in the Tertiary. Some people seem in denial of the fact brain size has increased in several mammal and bird lineages.
It's also gone and not increased that much in several others, nevermind in squamtes, testudines, crocodilians, amphibians, fish, and most invertebrates.
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kusanagi
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I "obsess" over certain criticisms of Russell's Dinosauroid, because they are as ideological in nature as the Dinosauroid itself: but ppl don't see it. Though they are just as guilty of bias, or stenonychosaur feathers would scarcely matter, si?

1. Plausibility of an organism are not the same thing as its narrative
2. Broad designs such as bipedalism, are not the same as mere details like feathers or not

The fact elephants, cetaceans and mammalian land carnivores can converge upon hominin intelligence and social behaviours, shows sophonts or sapiens just require the evolution of intelligence in a context of increased social complexity and extended parental care. The problem is, the dexterity required DOES seem to require some kind of arboreal ancestry. Such as a simian or perhaps something like the raccoons.

In any case faulty assumptions are five in spec bio, and must be forgiveable when they were years ago, prior to present knowledge such as feathered archosaurs of the Chinese Yixian biota. In retrospect feathered theropods were an open question, as were the early stages in the origin of feathers that were first revealed by a Yixian compsognathid. Unlike something such as dinosaur endothermy which was demonstrated by any sane standard, by comparative anatomy as applied to known fossil data.
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kusanagi
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Squamates do have particularly intelligent forms because varanids are as intelligent as rodents, and sebecid endocasts show they were less intelligent than modern eusuchians. These trends towards brain evolution are broader than people think on land and are thought in some way to be related to the angiospermisation of land plant communities starting in the Cretaceous.
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kusanagi
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A second trend besides repeated Tertiary evolution of intelligence, is that less intelligent (or perhaps, more accurately less social) animals like hyaenodonts and entelodonts go extinct; there is no evidence for pack hunting even in deinonychosaurs, that are predicted sociable for dinosaurs. It is absent among marsupials but it evolved several times even within a single clade such as canidae, once in hyenas, and even once in cats; similar social structures are evolved in some ailuroids and small, terrestrial herpestoids. Sociability was a key factor in the success of the carnivores from the mid Tertiary on with parallels in things like horses and primates.

So saying a deinonychosaurid would not necessarily have become more intelligent because fish and turtles didn't, is not really an argument. Stenonychosaur mammalian analogs (canids) did, and the spotted hyena which is convergent upon the canids, is one of the smartest mammals. Yes, troodontids would have gotten smarter if they survived; the dromaeosaur ambush predators maybe not, although lions show it would not be impossible for them to become sociable to defend their kills, which drives intelligence.

Is this not plausible inferred from Tertiary trends among mammals and ground birds?

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Imagine a mid Tertiary co-evolution of social dromaeosaurs - their last post-Eocene survivors - as sociable kill protectors in an arms race against faster and smarter troodontid kleptoparasites, and the social troodontids in the Miocene replace the last dromaeosaurs in the large predator niche. Abelisauroids on the southern continents would lag behind even were they subject to parallel evolutionary pressures. The similarly small brained tyrannosauromorphs are gone more or less by the end of the Eocene, maybe straggling longer, but their ambush predation and small brains do them no favours in a changing world. Unenlagids as pennaraptors do have similar potential as their cousins from the northern continents, maybe as smart as the small cathartids and seagulls. However both abelisauroids and unenlagines in the Miocene of South America would somehow falter like the borhyaenoids and phorusrhacids of our timeline; predatory, dry land crocodile allies would falter and perhaps disappear at the same time.

Alvarezsaurs died out with the reforestation and archaic ornithomimids persisted as browsers till the mid Tertiary when they switched to grazing. The more intelligent and bird-like caenagnathiforms are however the dominant herbivores with social behaviours equivalent to that seen in hooved mammals such as horses. Therizinosauroids like our world's elephants survived despite their slowness by a mixture of sheer bulk and intensified social interactions, making them among the smartest animals in the world. Sauropods and ornithischians mostly constitute an archaic fauna that was gone by the end of the Eocene on northern continents, with a few stragglers and even temporary successes of the Oligocene. Their upper limits of intelligence are things like geese in our timeline: like abelisauroids they lag behind, as ornithischians like wombatid/hystricid analogs persisting even in northern ecosystems, or the sauropod herds still reigning over Australia and Madagascar. When Tethys no longer isolated Africa as an island continent only the most vigorous of Gondwana-type clades left Africa, and her sauropod fauna was not among them. Sauropods became limited to South America and the Congolian region of mainland Africa, of former Sahulland and of Madagascar. Their main competition were the Holarctic therizinosaurs, and their juveniles were subject to predation pressures from new predators entering South America and mainland Africa.

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Rodlox
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kusanagi
Aug 30 2017, 06:44 AM
The problem is, the dexterity required DOES seem to require some kind of arboreal ancestry. Such as a simian or perhaps something like the raccoons.
please don't tell the elephants that. you'd hurt their feelings - and then they'd refuse to use their fine motor skills ever again.
(ditto the octopus)
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Empyreon
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Are you plausible?

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ah, but accurate now, or accurate then? were Troodonts seen as feathered *back when Dinoman was designed* ?

Precisely. While it is true that paleontologists began finding fossil evidence for feathers on dinosaurs has been proposed for more than a hundred years, the concept held little influence until the 1960's. Even in the 80's (when this was published, and when I was first learning about dinosaurs) there was precious little fossil evidence for feathers, and the extent of their presences among clades was largely unknown. Sure, there was Archaeopteryx and similar fossils, but the generally accepted view of most dinosaurs was pretty naked, and sometimes scaly. Besides, whether it's called, Stenonychosaurus, Troodon or "dinosaur holotype for which we have a few fragmented fossils so far", discounting the project based on integument (or lack thereof) seems superficial (see what I did there?).
Edited by Empyreon, Aug 30 2017, 11:55 AM.
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Dragonthunders
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Except that he did. Fifty two pages explaining not only the rationale behind the dinosauroid features, but the rationale behind the species of origin.

Wait, he wrote a whole article explaining about it or is part of something else?

Quote:
 
I "obsess" over certain criticisms of Russell's Dinosauroid, because they are as ideological in nature as the Dinosauroid itself: but ppl don't see it. Though they are just as guilty of bias, or stenonychosaur feathers would scarcely matter, si?

But the discussion has been around in the plausible of the design, not of how it would obtain intelligence or high cognitive abilities or the chances to obtain them, unless I'm missing something.

I really felt that the discussion had split into two different points, one discussing the plausibility of the dinoman design in relation to its ancestral form, and you about the intelligence, the consistency of this through groups and to what degree tend to converge to ours, which is interesting, but feels out of the topic.
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Empyreon
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Are you plausible?

Dragonthunders
 
Wait, he wrote a whole article explaining about it or is part of something else?

Here it is!
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HangingThief
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Rodlox
Aug 30 2017, 11:39 AM
kusanagi
Aug 30 2017, 06:44 AM
The problem is, the dexterity required DOES seem to require some kind of arboreal ancestry. Such as a simian or perhaps something like the raccoons.
please don't tell the elephants that. you'd hurt their feelings - and then they'd refuse to use their fine motor skills ever again.
(ditto the octopus)
I believe the advanced dexterity of primate hands has just as much or more to do with grabbing bugs than being arboreal.
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Rodlox
Aug 29 2017, 11:09 PM
ah, but accurate now, or accurate then? were Troodonts seen as feathered *back when Dinoman was designed* ?
Well, there were a few depictions of feathery troodontids back in the 80s (Gregory S. Paul's drawings come to mind) but obviously the depiction Russel chose to go with was not such a depiction.
Again though the point is that he was basing his speculation on an inaccurate depiction, which would necessarily lead to an inaccurate speculation even if one accepted every one of his assumptions about what sapient beings "should" be like or if one came up with some justification for making a humanoid dinosaur (whether that be a long chain of evolutionary coincidences, or alien space bats, or whatever).
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kusanagi
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Dragonthunders: the intelligence of an animal is - as a function of the brain - just another aspect of its physiology that needs to be explained to figure out the probaility of it evolving in any situation; if it is not predestined it does not appear randomly either. Whilst discussing intelligence and its origins or anything else in to much depth runs a risk of going off the topic I have two last observations to make on the subject, before I move on.

1. Scans of phorusrhacid skulls show them to have well developed problem solving skills similar to woodpeckers, hornbills, passerines and psittacines. For phylogenetic context molecular trees and the morphological dataset of Mayr and Clark reveal cariamae to be higher land birds themselves (Mayr and Clark find them to be cuculiformes), whilst Livezey and Zusi found them to be Grui, instead. As kleptoparasitism is associated in large carnivores and hominins with the evolution of problem solving intelligence, this may offer a window onto the ecology of phorusrhacids. If this isn't relevant to the possible evolution of intelligence is an animal such as Stenonychosaurus - what is?

2. Today at small body sizes metatherians no not have small brains per body weight when they are compared to eutherians (although a notable exception is the peramelomorpha). Small dasyurids (Antechinus and Smithinopsis) are not smaller brained than placentals of a similar size, although this does not hold for thylacines or the Tasmanian devil are when they are compared to placental carnivores of a similar weight: thus the trends affecting sociability and intelligence in clade Carnivora were not affecting large dasyuromorphs to the same degree. Macropodids (like the bandicoots) are particularly small brained although kangaroos do happen to have the most complex brain surfaces of any marsupials, whereas the petauroids, burramyoids and Tarsipes all are comparable to the lower end of extant primate encephalisation. Now remembering that primate brain size increased in three lineages independantly, this does not mean these marsupials are especially large brained or especially smart by placental standards. Rather it apears that australidelphians (at least) were not as strongly affected by the broad evolutionary trends leading recurrently to exceptional intelligence and sociability among the primates, so no marsupial monkeys evolved, nor any true pouched wolves or spotted hyenas for that matter. Statements that afrotheres or xenarthrans have a lower EQ on average than marsupials are red herrings when the problem is why marsupials never produced anything smart as an elephant though the brain evolution does show increases to some degree. Was the constraint ecological, or is their potential capped by something else such as their life history? Some marsupials such as Petropseudes display extended care of juveniles but nothing like the extensive social networks seen in some primates and cetaceans exists in a marsupial, nor does even simple tool use like the use of stones by sea otters in spite of the number of species with ecological and functional similarities to basal primates, graviportal tethytheres etc. Was this a constraint of phylogenetic origin, or is it an ecological one relating to the oddness of Australia?

https://www.ncbi.nlm.nih.gov/pubmed/18230970
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2941275/

Rodlox: elephants have nothing like the dexterity of hominins for the purposes of intensive object manipulation (two hands, effectively three in many ethnohistorical hunter gatherers) and our hands have not the slightest adaptation to tool use: the hands of a macaque or a baboon would do just as fine, the precision grip came first. Elephant trunks have their own evolutionary history from tapir-like proto-trunks, though I guess adaptations to browsing may be funtionally identical to those of arborealism. Incirrate octopi are obviously not arboreal although they do clamber and grasp substrates (i doubt how dextrous the tentacles of squid and such like are, as a comparison). I am not sure how relevant the tentacles of cephalopods are to the evolution of hands in tetrapods, as their overall function is different ie. most of the fine control over octopus tentacles relates to gripping and pulling with suckers, rather than the form of manipulation as seen in human hands or (yes) the fingered elephant trunks.
Edited by kusanagi, Aug 30 2017, 08:49 PM.
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kusanagi
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HangingThief: I am unsure but whilst this makes sense at the more general level, it makes less sense for the hand morphology seen in catarrhines or raccoons, pronograde animals that use their hands when they are climbing as well as foraging and grasping food items.
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IIGSY
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Seeing as how the normally simple minded mollusks produced the cephalopods, how plausible is a lineage of very intelligent arthropods? Arthropods seem more intelligent than mollusks on average, so it's definitely within the realm of possibility.
Edited by IIGSY, Aug 30 2017, 08:09 PM.
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kusanagi
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Arthropod brains might constrict their guts if they got too large, so there might be a constraint. Hymenopterans are at the upper end of arthropod encephalisation, but I don't know how closely their brains correspond to those of vertebrates. Sorry I can't help more.
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kusanagi
Aug 30 2017, 08:31 PM
Arthropod brains might constrict their guts if they got too large, so there might be a constraint. Hymenopterans are at the upper end of arthropod encephalisation, but I don't know how closely their brains correspond to those of vertebrates. Sorry I can't help more.
Do mollusks have any advantages over arthropods in this regard?
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Nematozoic: After a mass extinction of ultimate proportions, a single species of nematode is the only surviving animal.
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