The ‘dinosaur renaissance’ of the late 1960s and 70s saw the flabby-bodied, tail-dragging behemoths of earlier decades be replaced by sprightly, athletic animals with big, bulging limb muscles, erect tails, and dashing patterns and colour schemes.
Fast forward to the early decades of the 21st century. As ridiculous as it would have seemed to the palaeontologists and palaeoartists of the 1980s and before, feathered non-bird dinosaurs are now “commonplace”
The old, chunky, tail-dragging dinosaurs of the 1950s and before are dead, but the shrink-wrapped, sparse-feathered ones of the 1980s should be, too.
Articulated skeletons, trackways, and the way bones fit together show that dinosaurs generally walked and ran with horizontal bodies and tails that were approximately parallel to the ground. Tail-tips might have drooped or dangled, but tails only really sloped downwards in horned dinosaurs, and to a degree in therizinosaurs and brachiosaur-like sauropods.
The idea that bird-like non-avialan coelurosaurs were feathered has been popular in some circles since the late 1980s at least. That’s right, feathered (non-avialan) dinosaurs are not a new thing, but were ‘normal’ and oft-illustrated by a whole generation of people interested in the life appearance of dinosaurs. Bakker, Hallett and Paul were all illustrating feathered theropods throughout the late 1970s and 80s but it was Paul’s 1988 book Predatory Dinosaurs of the World (Paul 1988) that launched the idea into mainstream dinofandom (see also Paul 1987). Paul’s arguments were pretty sensible: they basically hinged on the fact that non-bird maniraptorans like Velociraptor are extremely similar in form and anatomical detail to indisputably feathered Archaeopteryx. While quite a few palaeontologists agreed that the notion of a feathery Velociraptor was at least plausible, what I remember from the 1980s and early 90s is those palaeontologists who declared this idea unlikely and overly speculative. Nope, it’s scales scales scales until proven otherwise, they said. Of course, it turns out that Paul and those other palaeoartists were actually right all along.
Needless to say, there’s a ton more than could be said about dinosaur life appearance. What I’ve done here is merely overview, in very brief fashion, some of the more easily summarised subject areas. What do people do when they need up-to-date information on these sorts of issues? That’s not an easy question to answer. The only competent and comprehensive review of dinosaur life appearance is Paul’s 1987 book chapter (Paul 1987), and it’s now woefully out of date.
Your other recourse is to scour through the vast primary literature, or to team up with a friendly expert (and don’t go assuming that palaeontologists are necessarily useful on this sort of stuff. Those who work on phylogenetics, diversity across time, histology and so on are often not up to speed on soft tissue anatomy. Exhibit A: all those execrable and hopelessly inaccurate dinosaur images published in books that were supposedly authenticated by august working scientists). So, what’s needed? The answer: a grand new illustrated work that provides a comprehensive guide to the life appearance of fossil dinosaurs. The good news: plans to produce just such a project are underway right now. Watch this space…