if dinosaurs still ruled the earth... - Historum

**oshron** · December 20th, 2009, 11:51 PM

hey

im doing YET MORE RESEARCH, though this time for a speculative zoology project on another board in which the asteroid that caused the extinction of the dinosaurs misses earth and dinosaurs continue to evolve for over sixty-five million more years. im still working out the kinks in the actual bestiary (thats still being covered on the other board), but i was curious as to what you all think would happen with possible sentient dinosaurs in this world. we've pretty much devised on the other board that two independent lineages of sentient dinosaur arise seperately on two continents: one descended from troodonts in north america that later spreads to south america as well, and one descended from unenlagiines that originates in africa and later spreads throughout eurasia and possibly into the british isles, madagascar, and oceania.

know that these animals would probably appear around the same time that humans did in earth's fossil record (PLEASE do not bring up religion for this; this IS speculation after all), approximately 2 million years ago or so. the justification of them appearing then instead of much earlier is because the most intelligent dinosaurs in the cretaceous were about as smart as a modern magpie (which is smart for a bird, but not so much as primates), and 65 million years may allow them to develop hominid-like intelligence, and therefore mastery over fire and stone/obsidian tools and maybe even the domestication of animals

**plutoboyz** · December 21st, 2009, 01:37 AM

1. Earth will be less crowded.
2. Our civilization will be thousand years more backward. probably we are still in medieval ages
3. Cavalry units won't ride horse.
4. Historum won't exist.

**Rasta** · December 21st, 2009, 07:00 AM

Quote:

Originally Posted by plutoboyz

1. Earth will be less crowded.
2. Our civilization will be thousand years more backward. probably we are still in medieval ages
3. Cavalry units won't ride horse.
4. Historum won't exist.

I doubt that humans would even exist.

**Rasta** · December 21st, 2009, 07:08 AM

Quote:

Originally Posted by oshron

hey

im doing YET MORE RESEARCH, though this time for a speculative zoology project on another board in which the asteroid that caused the extinction of the dinosaurs misses earth and dinosaurs continue to evolve for over sixty-five million more years. im still working out the kinks in the actual bestiary (thats still being covered on the other board), but i was curious as to what you all think would happen with possible sentient dinosaurs in this world. we've pretty much devised on the other board that two independent lineages of sentient dinosaur arise seperately on two continents: one descended from troodonts in north america that later spreads to south america as well, and one descended from unenlagiines that originates in africa and later spreads throughout eurasia and possibly into the british isles, madagascar, and oceania.

know that these animals would probably appear around the same time that humans did in earth's fossil record (PLEASE do not bring up religion for this; this IS speculation after all), approximately 2 million years ago or so. the justification of them appearing then instead of much earlier is because the most intelligent dinosaurs in the cretaceous were about as smart as a modern magpie (which is smart for a bird, but not so much as primates), and 65 million years may allow them to develop hominid-like intelligence, and therefore mastery over fire and stone/obsidian tools and maybe even the domestication of animals

This is an interesting question. If the dinosaurs never went extinct, we would never see the rise of the mammals. Many creatures that exist today, simply would not. It is interesting to speculate if sapiance is a logical "end result" of evolution, or simply an accident. Even if dinosaurs were not killed by an impact, I suspect many of the large dinosaurs would die off in the ice age and the subsequent climate change like we see with the megafauna.

**Cicero** · December 21st, 2009, 08:03 AM

And rest your brain with Gary Larson's personal, cartoon theory of dinosaur extinction.

http://images.google.com/imgres?imgu...a%3DN%26um%3D1

They would become too clever for their own good and become extinct.

**Rasta** · December 21st, 2009, 08:10 AM

Quote:

They would become too clever for their own good and become extinct.

Kinda like us.

**Rasta** · December 21st, 2009, 10:03 AM

Another thing to question: What are the qualities that could allow sapience to develop? Based on our understanding of sapience, we are the only creatures to ever develop it. Obviously, our closest relatives, Pan troglodytes (chimps), never developed sapience, so it is hard to pin down what caused us to develop it and not them.

**oshron** · December 21st, 2009, 10:32 AM

chimps are actually pretty smart and have developed legit tool manufacture; not just picking up a stick and using it, actually sharpening it to hunt(yes, chimps DO hunt, but thats another thing entirely)

it was concluded that terrestrial primates would never evolve at all because there are already too many dinosaurs on the ground, though they still evolve in trees, mostly as lemurs(interestingly, madagascar lacks lemurs in this alternative evolution). it IS possible that terrestrial primates would appear in certain isolated environments, possibly ones like madagascar or the deep congo, but these would be few and far between

it was also concluded that mammals would still rise to prominence in SOME parts of the world. for instance, during an ice age, mammals would likely rise to prominence in northern latitudes not because of fur and warm-bloodedness, but because they do not dig nest and lay their eggs in the permafrost like their alt-evo contemporaries, the sauropods and abelisaurs, would, though tyrannosaurs, dromaeosaurs(raptors), and ceratopsians would likely still be around there. also note that ceratopids--horned ceratopsians like triceratops--die out in the oligocene in this alt-evo, but hornless ceratopsians descended from dinos like protoceratops and become grazing herd animals. back to the mammals, there likely wouldnt be anything like what we classically imagine as prehistoric mammals, like no mammoths or sabertooths---

yknow what? im just gonna post what was concluded on the other board:

Quote:

1. any animals that were alive after the Turonian stage can have descendants in the Cenozoic
2. azhdarchids were not the only pterosaurs around at the end of the Cretaceous
3. anurognathids are valid
4. pterosaurs and birds coexist because birds only diversified in small forms while pterosaurs occupied many lifestyles as they grew
5. birds were mostly sparrow-sized in the late Cretaceous
6. hypsilophodonts may have been burrowers, but were extremely rare at the end of the Cretaceous
7. plesiosaurs didn’t really compete against mosasaurs and would therefore probably survive longer than any other group
8. whales may evolve to compete with mosasaurs over ammonites, which are the main food source for mosasaurs
9. ichthyosaurs are extinct
10. some dolphins may evolve to exploit ammonites and this may in turn hurt mosasaurs
11. whales would have trouble evolving from their basal ambulocetid forms into fully marine basilosaurids due to competition from mosasaurs in most parts of the world, but could potentially become dominant in cold waters where mosasaurs were not present
12. sauropterygians aside from mosasaurs occurred in cold waters
13. plesiosaurs could survive in virtually any aquatic environment
14. aside from whales, other potential marine mammals are: cimolestans (which produced otter-like forms), monotremates, gondwanotheres (closely related to multituberculates), mesonychians (which also produced otter-like forms), and relatives of Castorcauda, though only one of these could be the dominant clade
15. gharials produced marine forms in the Cenozoic
16. champsosaurs and crocodiles could also produce strictly marine forms
17. ambulocetid-type whales gave birth on land, whereas marine reptiles (aside from crocodiles, turtles, and sea birds) could not
18. plesiosaurs gave birth to live young instead of laying eggs, but it is unknown whether or not they did that on land or in the sea
19. crocodiles, turtles, and sea birds are the only marine reptiles that definitively laid eggs instead of having live young
20. crocodilians could possibly produce metriorhynchid or “false ichthyosaur” forms that are completely marine and give birth to live young
21. crocodilians would probably head for the seas because there are several parts of the ocean unexploited by mosasaurs and other sea monsters, but could also appear in other parts of the ocean alongside mosasaurs
22. relict populations of some animals may be present in Australia and Africa because there are almost no fossils from those places during the Late Cretaceous
23. Madagascar was already separated from Africa at this time, so it is likely that the fauna of Africa and Madagascar were radically different
24. Madagascar and India were connect during the Cretaceous and could therefore have similar life forms that then spread outwards (ex: rahonavids, only known from Madagascar, would probably exist in India as well and spread to Eurasia from there)
25. terrestrial primates are not to be expected; just arboreal prosimians
26. sapient dinosaurs are beaked and bird-like and are descended from two independent lineages: troodonts in the Americas and unenlagiines in Africa; the troodonts spread through the Americas while the unenlagiines originate in Africa and then spread outwards to Eurasia and even Oceania, and the two could intermingle during the Pleistocene when the Bering Land Bridge is formed
27. gondwanatheres are considered multituberculates, being a sister clade to true multies (cimolodonts)
28. a supposed bat tooth found in Argentina actually belongs to a relative of Volaticotherium, and teeth from a related mammal were found in Morocco; since Volaticotherium was a gliding mammal, and these two are from the Late Cretaceous in separate continents, it is possible that they could have developed flight during the Cretaceous
29. monotremes and placental mammals are ultraviolet blind, but marsupials are not, so some basal mammals like multies could see ultraviolet. Mammals cannot produce other pigments other than melanin, but monkeys have colorful faces due to the structure of the skin, and a species of kangaroo produces and oil that gives it a purplish color. Thus, there could be colorful multies and other non-placental mammals with colorful naked skin patches
30. squids and other cephalopods are still present and could very well produce forms that are not around today, such as baleen squids(unlikely), manta-squids, lamprey-like species, and weird ammonite-like ones

And for the timeline we’ve devised:

PALEOCENE – EOCENE
1. the world continued as it was in the Late Cretaceous until the Thermal Maximum 55.8 mya
2. thermal maximum: global temperatures rise dramatically, producing a tropical climate
3. thermal maximum: rainforests expand in a fairly short space of time and dinosaurs are forced to adapt to the new conditions as well as to the collision of India with Asia, which caused a faunal interchange
4. pachycephalosaurs and the last stegosaurs (in India) die out during the Paleocene due to the Thermal Maximum
5. sauropods were unable to adapt to the rainforests due to toe-less feet and are restricted to polar forests by the Eocene
6. ceratopsids are thrown into decline by the rainforests and die out in the Oligocene, but smaller ceratopsians survive
7. hadrosaurs are the only herbivores to experience total success, thriving on all continents except for Africa
8. smaller ornithopods are common in southern continents, with thescelosaurs expanding shortly into Asia
9. ankylosaurs are barely affected by the thermal maximum
10. the collision of Europe and Asia allowed large descendants of Pyroraptor to invade the other northern landmasses
11. Indian abelisaurs are able to adapt well to the rainforests, throwing tyrannosaurs into deline
12. tyrannosaurs lose their dominance due to less adaptation, and only survive in smaller dilong-like forms
13. noasaurs dominate Africa
14. Australia is inhabited by the last living allosaurs
15. ornithomimids, troodonts, and alvarezsaurs diversify
16. therizinosaurs are restricted to bear-sized rainforest forms and huge polar forms
17. ground-dwelling dromaeosaurs become larger while smaller ones diversify as tree-climbers
18. rahonavids give rise to a new group of animals expanding outwards from India into Laurasia
19. birds suffer, but come back strong with the descendants of Enantiornis, Apsaravis, and in paleognathes and fowl; the descendants of Ichthyornis and Pseudodontornis diversify after pteranodonts die out, while hesperornids are reduced to small freshwater forms, some of which can still fly
20. pteranodont pterosaurs are extinct
21. larger terrestrial azhdarchids are restricted to polar forests and coastal zones as a result of grasslands being replaced by forests, and produce a new lineage of pterosaurs, whose ancestor Eunemicolopterus was surprisingly small with a wingspan of one meter
22. anurognathids and possibly ctenochasmatoids reappear in the fossil record
23. mammals change little aside from the appearance of primates, cimolestans, mesonychians, and hyaenodonts; volaticotheres reappear in the fossil record as bat-like fliers, while aquatic mammals are also present
24. champsosaurs are common in America but are reduced to small lizard-like forms in Eurasia
25. crocodiles are common everywhere in both salt and fresh water
26. mosasaurs are common while plesiosaurs are restricted to few marine forms and plenty of freshwater ones

OLIGOCENE
1. after the Thermal Maximum ends, the rainforests recede to the tropics, but the climate is still fairly warm and grasslands do not expand yet, with temperate and mixed forests as the dominant ecosystem (similar to the Cretaceous)
2. sauropods and therizinosaurs return as the dominant herbivores in the northern continents
3. hadrosaurs are still common, with lambeosaurs dominant in Asia and hadrosaurines in America; hadrosaurs of unclear lineage are present in South America and Australia
4. protoceratopsids produce large forms, but few were as large as the ceratopsids
5. small ornithopods fall into decline; the last Laurasian forms die out due to competition from ornithomimids, avimimids, protoceratopsids, and even mammals (they were already very rare during the Cretaceous) and they only manage to survive in the south
6. ankylosaurs stay virtually the same
7. a poorly understood lineage of ornithischians descended from heterodontosaurs achieve dominance in Africa
8. Eurasian abelisaurs begin to lose their dominance to dromaeosaurs and tyrannosaurs, with the latter regaining their former large sizes
9. oviraptorosaurs barely change since the cretaceous, though they reach Africa, South America, and Australia presumably because of semi-aquatic forms due to their mollusk diet
10. troodonts stay mostly the same
11. because of the Cretaceous land bridge between North and South America, troodonts, dromaeosaurs, microraptors, and oviraptors are all present in South America, causing the decline of the local abelisaurs and unenlagiines
12. Africa has its own native noasaurs and unenlagiines
13. azhdarchids make a comeback, with flightless forms taking over African niches filled by small theropods elsewhere
14. smaller pterosaurs, including the small flying forms descended from Eunemicolopterus, change little
15. afrothere mammals expand into many new forms, ranging from small tenrecs to capybara-like forms (note that hyaenodonts may actually be afrotheres, so there are also cat-sized mammalian predators)
16. multituberculates produce beaver-sized forms
17. mesonychians become fox-like opportunists
18. metatherians have mustelid and possum-like forms pratically everywhere while cimolestan diversity decreases somewhat
19. volaticotheres stay virtually the same, while aquatic mammals of an aforementioned group(but including gondwanatheres) occur in marine environments for the first time
20. plesiosaurs come back strong while mosasaurs are thrown into decline, having been strongly affected by the Thermal Maximum, and the roles of the Eocene are reversed, with plesiosaurs becoming more dominant while mosasaurs disappear somewhat
21. hesperornids experience a magnificent comeback while auk- and loon-like penguins have the southern hemisphere as their stronghold
22. dyrosaur crocodiles die out while champsosaurs go to the sea for the first time; filter-feeding crocodiles are to be expected
23. sphenodonts are in better conditions, as tuataras are present in both Australia and South America

MIOCENE
1. Africa collides with Eurasia and total chaos ensues
2. the last Eurasian hadrosaurs are replaced by the African ornithischians, which also effectively replace many ceratopsians
3. therizinosaurs and sauropods invade Africa, and flightless pterosaurs invade Eurasia, taking over ornithomimid niches
4. large troodontids die out, but smaller ones remain
5. abelisaurs are now represented by one or two titanic genera, with smaller niches gone to dromaeosaurs, noasaurs, and tyrannosaurs
6. large protoceratopsids produce a lineage of grazers, which is remarkable since they were mostly browsers
7. ankylosaurs are restricted to a single genus in Eurasia
8. hadrosaurs still dominate South America and Australia, which are now vast grasslands
9. the last South American abelisaurs die out, allowing unenlagiines, dromaeosaurs, and oviraptors to become the dominant predators there
10. troodonts diversify to omnivore niches
11. microraptors occur in American forests but are wiped out elsewhere by arboreal mammals
12. meridiunglates take over small ornithischian niches
13. animals of unknown origin take over the niche of South American sauropods, which no longer exist there
14. the fauna of Australia barely change

PLIOCENE
1. the climate gets colder, and Antarctica is totally frozen-over for the first time, and tundras appear in the arctic
2. chorstoderes, monitors, several bird clades, small pterosaurs, sauropods, ankylosaurs, and primates vanish from Europe due to the climate change
3. eastern Asian is not as affected by the climate change, so most of the aforementioned animals are still present there
4. Eurasia’s metatherian mammals occur in both shrew- and mustelid-like forms
5. cimolestans are represented as treeshrew-like squirrel analogues, and primates are lemur-like animals (surprisingly, Madagascar has no lemurs, with plesiadaptiformes diversifying instead)
6. hyaenodonts and mesonychians are the foxes, cats, and civets of this world
7. the last abelisaurs die out, and noasaurs are mostly restricted to large tropical forms with a few exceptionally large forms in central Eurasia
8. dromaeosaurs and tyrannosaurs reign supreme as predators in the cold zones, with some species venturing into Africa as jackal- or hyena-like generalists and in at least one leopard-like form
9. sauropods and ceratopsians occur mostly in Africa and southern Eurasia, but the occasional dryings of the Mediterranean allowed them to produce smaller forms native to the sea’s islands
10. the African ornithischians establish themselves in the colder zones of the continent
11. avimimids completely take over omnivorous niches formerly occupied by ornithomimids and flightless pterosaurs over those of the old oviraptors
12. flying pterosaurs occur as gigantic azhdarchids soaring over all other landmasses and as smaller eunemicolopterids in the world’s rainforests as small frugivores and omnivores, perhaps with some ground hornbill-like forms, and some anurognathids flying around at dusk or dawn as nightjar analogues
13. mosasaurs mostly disappear from the sea, now restricted to the tropics
14. gharials are restricted and choristoderes are reduced to freshwater forms in Asia and America, respectively
15. sea birds and polycotylids manage to adapt to the colder waters just fine, and aquatic mammals become bigger than ever
16. South America is struct by an asteroid, and its fauna was still recovering when the Isthmus of Panama was formed
17. troodontids and meridiungulates not only survive but achieve success partially due to the colder climates, and the latter has less competition in the colder zones of Laurasia
18. other American species fall into decline: native dromaeosaurs and hadrosaurs are reduced to smaller species or to larger elephantine ones, respectively
19. Australia’s fauna hasn’t changed much except for the extinction of the top predator, a type of allosaur, which was replaced by unenlagiines and crocodilians; hadrosaurs, basal ceratopsians, and large mammals, and flightless birds are among Australia’s denizens

the reason that the plesitocene isnt really covered here is because there arent expected to be many changes from the pliocene to the pleistocene. this would be the last era covered

**Rasta** · December 21st, 2009, 10:46 AM

Quote:

the reason that the plesitocene isnt really covered here is because there arent expected to be many changes from the pliocene to the pleistocene. this would be the last era covered

Cool. Thanks for posting that. It's a lot of info to digest. . .

**oshron** · December 21st, 2009, 10:56 AM

lol, yeah, i know