Why were Earthly dinosaurs on the spaceship? Because, in the Whoverse the Earth hosts another humanoid race besides Homo sapiens. There is also a lizard-like race called the Silurians or Homo reptilia, currently hibernating deep underground. But millions of years ago the Silurians had a technologically advanced societ among the dinosaurs. When the asteroid that caused the extinction of the dinosaurs was on a collision course with Earth, the Silurians filled a spaceship with dinosaurs and plants to rescue them. Thus dinosaurs on a spaceship.
Of course I don't watch Doctor Who for serious science, so it's no surprise when scientific inaccuracies appear. But Brain Switek has pointed out that the dinosaur designers for the episode missed an opportunity to make the deadly raptors that stalk the TARDIS crew more colorful. As he put it:
... the unidentified “raptors” suffered the curse of the bunny hands and insufficient feathery coats. Filmmakers seem reluctant to drape feathers over dromaeosaurids, but, for any effects artists who may be reading, we know that these dinosaurs had exquisite plumage covering almost their entire body. If you’re going to have raptors, they should be intricately feathery. [...] You may want to laugh at a Deinonychus all puffed up, but that will be the last sound you ever make before it starts to eat you.I would go further than that. It was recently found that a distant cousin of Tyrannosaurus rex called Yutyrannus huali was covered with a downy coat of 6-8 inch long feathers over most of its body. That has lead to speculation that T. rex might have been feathered as well.
Analysis of the fossilized feathers of the much smaller Sinosauropteryx lead to the discovery that the more than 120 million year old feathers contain melanosome cells that store either red or black pigments. The pattern of those pigment cells in the fossils suggest that Sinosauropteryx may have been striped, at least along its tail.
So I'd propose putting those two findings together with a bit of artistic license, giving even the great T. rex on the spaceship colorfully patterned plumage. I think that would have looked awesome and have had the right mix of terror wrapped in whimsy to suit a Doctor Who episode.
Apparently the idea of feathered dinosaurs apparently is quite upsetting to young-earth creationists, who don't like the way it supports the hypothesis that modern birds evolved from dinosaurs. Fiction that depicts prehistoric animals based on the most up-to-date fossil evidence not only has cool-looking creatures, but also helps promote science in general.
More feathered dinosaurs please!
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Top image: Sinocalliopteryx gigas as a stealth hunter feeding on the dromaeosaur Sinornithosaurus. Illustration by Cheung Chungtat. From Xing L, Bell PR, Persons WS IV, Ji S, Miyashita T, et al. (2012) Abdominal Contents from Two Large Early Cretaceous Compsognathids (Dinosauria: Theropoda) Demonstrate Feeding on Confuciusornithids and Dromaeosaurids. PLoS ONE 7(8): e44012. doi:10.1371/journal.pone.0044012.g008. This file is licensed under the Creative Commons Attribution 2.5 Generic license.
Bottom image: Cover of Analog Science Fact & Fiction February 1961. It illustrates "The Weakling" by Everett B. Cole, in which there are great "saurians" used as pack animals, meat and pets on an alternate (or future?) Earth. The story is heavily dependent on "psionics" and mind control as a plot device, if you like that sort of thing. The cover and story are available through Project Gutenburg, and are out of copyright.