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A Speculative Dinosaur Project; What if dinos never died out?
Topic Started: Nov 8 2009, 11:28 AM (3,387 Views)
T.rex09
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What if all non-avian dinosaurs didn't die out? After Dougal Dixon's famous book The New Dinosaurs: An Alternate Evolution many different people have asked that question. I will try to answer it.

Anybody who wants to is welcome to join. I'm a pretty crappy artist so I will probably need the assistance of 1 or 2 artists.
Timelines will be available if you guys request.
"Church if I die you can have my orange juice."-Red vs Blue
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Carlos
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*sigh* Were did the annoucements for things like, I don't know, dinosaur eating mammals, went wrong!?

Anyway, as I've mentioned many times there are some late Cretaceous volaticotheres appearently, such as Argentoconodon and some other shit I forgot the name that comes from Morocco. Because only teeth/jaws are known, and because we know that Volaticotherium itself was a gliding mammal from the Jurassic/Cretaceous boundary, its natural to assume these late Cretaceous mammals could maybe had developed flight. Thus, no bats, but flying volaticotheres
Lemuria:
http://s1.zetaboards.com/Conceptual_Evolution/topic/5724950/

Terra Alternativa:
http://s1.zetaboards.com/Conceptual_Evolution/forum/460637/

My Patreon:

https://www.patreon.com/Carliro

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Holben
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Well, dinosaurs wouldn't have had much chance of eating our ancestors anyway.

Flying volicatheres? Interesting. But sadly no bats.
Time flows like a river. Which is to say, downhill. We can tell this because everything is going downhill rapidly. It would seem prudent to be somewhere else when we reach the sea.

"It is the old wound my king. It has never healed."
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Venatosaurus
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Many mammals in the presence of dinosaurs would not be confined to the night time. It is known from various fossils, that mammals, during the Mesozoic, came in a variety of sizes, shapes, and niches, and not restricted to tiny, night-time insectivores ;)



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Carlos
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I gave up explaining about Mesozoic's fauna. Appearently the stupid outdated cliches are too deeply rooted on the mind of most people, so I gave up spreading knowledge
Lemuria:
http://s1.zetaboards.com/Conceptual_Evolution/topic/5724950/

Terra Alternativa:
http://s1.zetaboards.com/Conceptual_Evolution/forum/460637/

My Patreon:

https://www.patreon.com/Carliro

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Holben
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Please update us.
Time flows like a river. Which is to say, downhill. We can tell this because everything is going downhill rapidly. It would seem prudent to be somewhere else when we reach the sea.

"It is the old wound my king. It has never healed."
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Venatosaurus
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There is such a thing as reading a book or checking the internet ;) We can't seriously be expected to answer every little question man



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Carlos
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I know, but at least I wish the general knowledge was updated at least by 2000's standards, not stuck on the 90's
Lemuria:
http://s1.zetaboards.com/Conceptual_Evolution/topic/5724950/

Terra Alternativa:
http://s1.zetaboards.com/Conceptual_Evolution/forum/460637/

My Patreon:

https://www.patreon.com/Carliro

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Holben
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Ah well. I don't want to be stuck in the 90s, so i'm going to find some dinosaur common myths page or something like that.
Time flows like a river. Which is to say, downhill. We can tell this because everything is going downhill rapidly. It would seem prudent to be somewhere else when we reach the sea.

"It is the old wound my king. It has never healed."
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ATEK Azul
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That might be media and book wrighters faults because in the U.S.A. most books are using outdated references and the news only shows very few acheavements inh paleontology most of which either cover Dinosaurs from China or Ice Age Mammoth remains.
I am dyslexic, please ignore the typo's!
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Venatosaurus
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Or repetitively cover Tyrannosaurus rex !



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Holben
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Well, here's a small bit of misinformation. I knew most of this anyway.
Some of it is outdated however.

Quote:
 
Bad Language – Dinosaur Success
Let’s begin by analysing the common, throw-away pronouncement that dinosaurs were one of – or simply "the" – most successful group of animals, ever. They ruled the earth for ~165 Ma (million years). Often, this will be followed up with the comparison that humans have only been around for ~0.2 Ma. These assertions are typical of the dinosaur phenomenon: they contain sufficient elements of truth to sound authoritative, but the language is so sloppy that the statements have no precise meaning, and the conclusion is a non sequitur.

First of all, what is a dinosaur in this context? Most well-versed kids and a few adults will know that the dinosaurs comprise two orders: the Ornithischia and Saurischia. Accepting for the moment that both orders arose from a common ancestor, i.e. that the Dinosauria is a natural group (a clade), then it has the rank of superorder. So this is the first bit of imprecision to clear up: Any statements about dinosaurs being around for 165 Ma, then, apply to the orders or to the entire superorder.

(For comparison, stem group representatives of the order to which we humans belong, Primates, date from the earliest Tertiary, approximately 65 Ma. The oldest known true primates occur about 55 Ma, near the Paleocene/Eocene boundary. On the other hand, the order Euselachii, which includes the sharks, has been around since the Late Devonian: at least 360 Ma.)

Did individual species of dinosaur exist for an unusually long time? Did T. rex stalk the earth for a hundred million years? No; nothing like it. Not even ten. Most individual species of dinosaurs were extant for two to three million years. Certainly, that is still a lot longer than mankind’s couple of hundred thousand years ... but, then, we’re not dead yet.
Moreover, there are many other groups of animals and plants which have endured far longer. A small brachiopod, the genus Lingula, springs to mind. This animal has endured virtually unchanged since the Cambrian: 500 Ma or so. The fern genus, Osmunda, has been around since the Triassic, when there lived a species virtually identical to the extant O. claytoniana (Phipps et al. 1998). But Lingula and Osmunda have never ruled the world whereas dinosaurs did. Or, more precisely, ruled the land, because dinosaurs never made it into the oceans. The large Jurassic and Cretaceous marine beasts, the mosasaurs and so on, were not dinosaurs.
Species Lifetime
The famous Tyrannosaurus rex roamed the earth for approximately 3 million years, from 67 Ma to 65 Ma (Horner & Lessem 1993, p. 149).

And then, what does it mean "to rule the land"? Do we mean to attain the greatest diversity? Well, if we do, then the insects rule the land, and have done since time immemorial. So, no, we can’t mean that. What about biomass, then? Raw tonnage. Oh darn: in that case bacteria take the honours, and always have done. Well, surely the dinosaurs at least beat up our ancestors, right? Possibly, though since our ancestors were predominantly mouse-sized, it seems unlikely T. rex (or even Compsognathus) would have really found much value in persecuting them.
So, in the end, maybe we just have to say that dinosaurs were big, spectacular beasts which, as a group, lived on the earth for around 165 Ma. Having chipped away the hyperbole, that is the claim we are left with. It is true, as far as we know, and it is "scientific" in the sense that it makes no claim beyond that which the evidence will support.
And isn’t that enough?
Dinosaurs as Large Animals

Introduction and Definitions

Possibly the most celebrated feature of dinosaurs, at least as far as the lay public is concerned, is their large size. If one judged from the hype alone, you might think all dinosaurs were very large, that dinosaurs accounted for all large animals during Mesozoic, that they were the only really large creatures ever to live upon the planet, and that nothing comparable lives today.

But, no: many dinosaurs were rather small, and many other creatures – living in the Mesozoic and subsequently – were larger than most dinosaurs.
Before proceeding further, we should clarify what we mean by "large." Three possibilities suggest themselves:
Length, which can be measured easily and objectively from any complete skeleton. For example: "The largest head of any dinosaur belongs to the ceratopsian Torosaurus with a massive 2 m long skull" (Carpenter 2002).
Height, which may require some interpretation of the animals’ life posture, though such reconstructions are likely to be relatively accurate.
Weight, the estimation of which is more difficult and quite subjective, though some anatomical clues (the size of muscle attachment scars, the size and strength of bones) provide a general indication. At the present state of the art, weight estimates determined by various techniques can easily vary by a factor of three or more. For example, published weight estimates for Diplodocus carnegei range from 5.8 to 18.5 tonnes (Norell et al. 1995, p. 24).

Small Dinosaurs
The smallest reliably known dinosaur is Compsognathus longus, known from the Lower Jurassic (including the famous Solnhofen Limestone) of western Europe, which attained an adult length of only 70 cm, including the tail.

Not much larger is another very small dinosaur, Heterodontosaurus, also Lower Jurassic, known from South African fossils.

Large Non-Dinosaurs
One of the larger Mesozoic animals was a euryapsid reptile, the pliosaur Liopleurodon (Class Reptilia, Subclass Sauropterygia, Order Plesiosauria, Superfamily Plesiosauroidea), of BBC "Walking with Dinosaurs" fame. If the uppermost estimates of this creature's size - about 25 metres long - are to be believed, then this reptile was the equal of a large dinosaur such as Apatosaurus.
Excerpt from BBC site:

Crocodiles are quite close relatives of the dinosaurs, having evolved from the archosaur ancestors in the Triassic period. Crocodiles have changed very little since then, nearly all being armour-plated, semi-aquatic predators.

Other pliosaurs - Kronosaurus queenslandicus - 9 to 10 metres according to Wikipedia http://en.wikipedia.org/wiki/Kronosaurus

and the as yet unnamed taxon from Svalbard - 15 metres; see

http://www.nhm.uio.no/pliosaurus/english/index.html and http://www.sciencedaily.com/releases/2008/02/080229101002.htm

Sereno’s crocodile - Sarcosuchus or something similar?

An even larger crocodylian ...

By the Cretaceous period crocodiles had become very abundant and widespread. One of the most remarkable of the Cretaceous crocodiles comes from the Rio Grande in Texas. Named Deinosuchus ("terrible crocodile"), this is the largest crocodile so far found. Its skull is 2m in length and if this creature had the proportions of a typical crocodile then it may have attained a length of 15m and weighed around 2 tonnes. Deinosuchus was sufficiently large and heavy to have preyed on sizeable dinosaurs, catching them by stealth as they waded into lakes and rivers to drink.

Toward the end of the Age of Dinosaurs, during a time known as the Late Cretaceous, a new type of giant predator appeared along the southern coasts of North America. It was a huge species of crocodylian and is called Deinosuchus.

Neither a crocodile nor an alligator, it was an ancestor of both modern groups, but it reached weights of many tons and it had some features unique to the species. Average-sized individuals were bigger than the carnivorous dinosaurs with which they cohabited; the largest specimens were the size of a T-rex. This is the biography of these giant beasts, including the long history of their discovery, research about their makeup, and the first published evidence about their prey. Generations of people have stared at the 6-foot reconstructed skull at the American Museum of Natural History in New York, not realising that the only real bones in the specimen were bits of snout and lower jaw. New fossils and research show that the actual animal was quite different from the reconstruction, and now we can reliably assemble the skull and the remainder of the animal. The book also deals with the ancient life and geology of the coastal areas where Deinosuchus thrived, including its competitors and its prey, which likely included carnivorous dinosaurs among its numbers. Since Deinosuchus is found on eastern and western sides of the Great Inland Sea that split North America, it must have crossed this vast seaway during the Late Cretaceous. How and why the crocodylian crossed the seaway is the focus of a key chapter in the book. There is also detailed discussion of the methods used to determine the size of these giant animals, how we can date the fossils and describe their living environments, and why we can be sure who at whom 80 million years ago.


Subclass Sauropterygia
The Sauropterygia were marine predators of the Mesozoic, which includes the Triassic near shore orders, Nothosauria and Pachypleurosauria, and the post-Triassic, fully marine, Plesiosauria which comprises the short-necked pliosaurs and the longer-necked plesiosaurs.

Five genera of Callovian (Middle Jurassic, ~150 Ma) pliosaurs are currently recognised. There are three short-snouted genera: Liopleurodon, Simolestes, and the newest genus Pachycostasaurus.


Tertiary mega-mammals
modern blue whales (Balaenoptera musculus)

The Guinness Book of Records lists the largest blue whale ever measured as a 110 foot female taken off South Georgia (Southern Ocean). Although there is a degree of uncertainty about this measurement, there is, however, an undisputed 103 foot female on record.

convert to metres – around 30

Dinosaur Growth
Refer Gramling 2005 and Sander & Klein 2005

Conclusion
Nevertheless, dinosaurs definitely do include some of the largest representatives of any group known. For example, at 14 m, Tyrannosaurus and Gigantosaurus are the largest ever terrestrial carnivores (Carpenter 2002).

Seismosaurus is probably the longest dinosaur known to date, though only incomplete remains have been found. the animal was probably at least 40 metres, and possibly as long as 50 metres. The animal was certainly extremely heavy, also; possibly even heavier than the current record-holder, Brachiosaurus. Weight estimates for Brachiosaurus range from 31 to 87 tons.

Warm Blooded ... or Maybe Not?
Introduction and Definitions
Various sources would have one believe this question is effectively decided one way or the other whereas, in fact, the evidence either way is far from compelling.

But first, what does it mean to be “warm blooded?”

More properly, we should be discussing endothermy (= homeothermy, homoiothermy), the ability of an animal to maintain a constant internal body temperature despite changes in the temperature of its external environment. Mammals and birds are homeotherms. They maintain their bodies at a constant, usually elevated, temperature by conserving heat generated as a result of metabolic activity, particularly in organs such as muscles and the liver. (Adapted from The New Penguin Dictionary of Science, 1998.)

Size Matters?
The co-existence of equally large marine reptiles – Liopleurodon was a euryapsid reptile (Class Reptilia, Order Plesiosauroidea) about 25 metres long; the size of a large dinosaur such as Apatosaurus. That Liopleurodon was certainly cold-blooded, makes it quite clear that it was not necessary for large, Late Mesozoic animals to be warm-blooded, but it doesn’t necessarily mean they weren’t either.

Dinosaurs as Active Animals
One of the articles of faith held by the warm-blooded lobby is that dinosaurs – particularly the very large species – were extremely active, fast and agile creatures. If true, it would probably strengthen the case for endothermy. However, recent research does not always support the fast/agile hypothesis:

"The fastest gait and speed of the largest theropod (carnivorous) dinosaurs, such as Tyrannosaurus, is controversial. Some studies contend that Tyrannosaurus was limited to walking, or at best an 11 m s-1 top speed, whereas others argue for at least 20 m s-1 running speeds. We demonstrate a method of gauging running ability by estimating the minimum mass of extensor (supportive) muscle needed for fast running. The model’s predictions are validated for living alligators and chickens. Applying the method to small dinosaurs corroborates other studies by showing that they could have been competent runners. However, models show that in order to run quickly, an adult Tyrannosaurus would have needed an unreasonably large mass of extensor muscle, even with generous assumptions. Therefore, it is doubtful that Tyrannosaurus and other huge dinosaurs (~6,000 kg) were capable runners or could reach high speeds." (Hutchinson and Garcia 2002, p. 1018; read more ).
Norell et al. 1995 (p. 34) concludes that, like many other aspects of dinosaur lore, "the speeds of dinosaurs have been subject to fantastic claims. Such claims are difficult to test, and the only available evidence (that determined from footprints combined with models based on living animals) suggests that, while larger dinosaurs may have been capable of running, they were predominantly slow-footed and unable to attain the speeds of even a moderately fast human runner."
The Fossil Heart Debate
Comparative anatomists since the time of Richard Owen have observed that birds and crocodilians have a four-chambered heart and have speculated that such a heart was present in extinct archosaurs as well. Until recently, no direct evidence of the cardiovascular system had been reported in any archosaur fossil. Fisher et al., however, using computerized tomography (CT) scanning, reported the discovery of a four-chambered heart with a single systemic aorta within the chest region of a dinosaur fossil dating from the Cretaceous. Even more surprising, the specimen reportedly was collected from channel sandstones of the Hell Creek Formation, a fluvial setting that rarely preserves soft tissues. Examination by one of us (Rowe) of the specimen in the North Carolina State Museum of Natural Science and examination of the CT imagery, however, lead us to conclude that the object is not a fossilized heart but an ironstone concretion. Such concretions are commonly found in Upper Cretaceous fluvial sediments of the North American western interior, often in association with dinosaur bones.

Response: Rowe et al. speculate that the object that we interpreted as a heart is an ordinary ironstone concretion. A casual inspection of its structure, however, indicates that it is a sandstone concretion, and its occurrence and our more extensive examinations support our original interpretation. ...

CT imaging has allowed identification of structures embedded within the chest concretion that are consistent with the shape, volume, position, and orientation of the more muscular portions of a heart (ventricles and aortic arch). It is logical to suspect that the structures formed the nucleus for the peculiar concretion that surrounds them. Permineralization of the structures is not implied, because organic residues may have initiated the mineralization of cements within the concretion. Time scales of months to tens of years--not millions of years, as Rowe et al. maintain--are common for many types of concretions.

The concretions submitted to museum curators are usually simple shapes (they are often suspected of being fossil eggs) and are seldom subjected to CT scanning to the same extent as the concretion studied by Fisher et al. No tubular structure associated with two contiguous ovoid structures has ever been reported within a concretion in such intimate association with a dinosaur skeleton before. Identification of the object as a fossil dinosaur heart need not assume structural identity with a crocodile heart or the preservation of relatively thin-walled structures. We continue to pursue our investigations of this unusual fossil.

Endothermy as an Apomorphy
established in the Triassic? surely not?
closest relatives - crocodilians - definitely not homeothermic



Personally, i think dinosaurs or maybe just theropods must have been warm- or lukewarm-blooded, but there are some who disagree.
Time flows like a river. Which is to say, downhill. We can tell this because everything is going downhill rapidly. It would seem prudent to be somewhere else when we reach the sea.

"It is the old wound my king. It has never healed."
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Carlos
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...

Next time, just ask me or any people I might give the links of if you have any doubts
Lemuria:
http://s1.zetaboards.com/Conceptual_Evolution/topic/5724950/

Terra Alternativa:
http://s1.zetaboards.com/Conceptual_Evolution/forum/460637/

My Patreon:

https://www.patreon.com/Carliro

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Holben
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Heeheehee.
That's how i get round people.

Anyway, is Trex09 keeping anklyosaurs?
Time flows like a river. Which is to say, downhill. We can tell this because everything is going downhill rapidly. It would seem prudent to be somewhere else when we reach the sea.

"It is the old wound my king. It has never healed."
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Carlos
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If he's basing this project on the earlier versions of Spec, I guess so
Lemuria:
http://s1.zetaboards.com/Conceptual_Evolution/topic/5724950/

Terra Alternativa:
http://s1.zetaboards.com/Conceptual_Evolution/forum/460637/

My Patreon:

https://www.patreon.com/Carliro

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Holben
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Good.
Time flows like a river. Which is to say, downhill. We can tell this because everything is going downhill rapidly. It would seem prudent to be somewhere else when we reach the sea.

"It is the old wound my king. It has never healed."
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