STL Science Center

STL Science Center

28 April 2012

Tiny Terrors

Image from Ji & Ji
Sinosauropteryx is one of those skeletons that has been found almost complete, which immediately tells paleontologists a lot about their body size and shape as well as providing immediate clues to their behavior and interactions with the habitat, which we thankfully know something about due to studies of the soil containing the remains and paleobotany. At any rate, the fact that the skeleton is as comprehensive as it is has, as mentioned yesterday, yielded additionally fantastic treasures in that it shows evidence of very basal feathering characteristics and has the remnants of pigmentation characteristics that paleontologists can use to determine, fairly accurately we all hope, the color of this tiny dinosaur. Tiny is a relative term, but if you remember, yesterday we discussed how this dinosaur was about half tail and as tall as a Jack Russell Terrier, so it was indeed tiny in dinosaur terms for the typical Cretaceous fauna of China at the time of its existence.

©Julius Csotonyi
The diet, speaking of its size, would have been restricted to things it could actually catch or safely scavenge. Scavenging may be looked down at in some circles for whatever reason, but no surviving meal to meal predator looks a gift horse in the mouth, and certainly not when you are the size of a lap dog! The diet, though, was probably strongly rooted in insects, the occasionally unguarded dinosaur egg or carcass, lizards, small mammals, perhaps even hatchlings. I have yet to read any of the studies done on the Sinosauropteryx, but it is my belief that animals of this size are more than likely to be heavily opportunistic hunters and willing to stomach a variety of foods. The ideal place for them to hunt down these foods would indeed, as portrayed by Csotonyi, be in the dense undergrowth of the forest where, if the coloration of the feathering filaments is correct, the reds and light bands on the tail would blend in with the browns and ruddy colors of the forest floor's low sunlight needing ferns.

©Australian Museum
Ill. James Reece
The banding is pretty universally accepted by paleontologists as being the correct coloration of the animal as far as current science can ascertain from studying the feathering filaments that were present with the skeleton and have pigmentation chemicals found within their fossils. That being said, the illustration by James Reece for the Australian Museum is not necessarily incorrect. There is no way, that I know of at present, to conclude that Sinosauropteryx remained the same color for all of its life, for seasons of the year, or even that they were not sexually dimorphic with the females lacking the banding (or the males lacking the banding since I have not looked into which the pigmented skeleton is yet). In the undergrowth of the forest any of the three scenarios is plausible and Reece's fawn coloration is a pattern seen throughout deep woodland animal's histories especially amongst the young of several species currently; this includes deer, tapirs, quoll, and even woodpeckers. It is simple camouflage at its best to be honest, and it makes a great deal of sense for an underbrush predator to have coloring like this at some point in its life or for one sex to be colored this way also.

This illustration is the one in the bunch that I have found that I do not readily adopt as plausible. The only reason for this is the lack of feathering to the entirety of the body. We know for a fact that there were basal filament based feathers on this skeleton of this animal. In fact, it here appears to be covered in more of a hair than a downy feathering or even a filament feathering. We know, we think, for a fact what the coloration of this animal was. Now, despite not following the coloration of the feathers, we can live with the Jurassic Park V. antirrhopus coloring scheme, the only feathering we see on this body is at the tip of the tail. This is a decidedly lizard like representation of an animal that seemed to be leaning much more toward birds, and we would like to see that more in the illustration. It's good in terms of overall shape, but it just does not convey an image of a paranoid, quick, underbrush predator that reacts quickly and with speed.

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