There are things like skin color and musculature, but what I meant by outer shell was more of a full representation of the specimen with his flesh and all. So skeletal structure and body posture would apply to the classification. I can recognize a human from an ape with no problem. I can even recognize a severed human head from a severed ape head, what I may not be able to classify is a human skull and an ape skull.
JM
The art of reconstructing the "flesh" of skeletal remains has advanced light years in the past few decades. Nowadays, computers are fed the data and can reconstruct not only the appearance, but the stance of the individual (if hip/thigh are available).
"There are things like skin color"
There is a greater difference between the skin color of an African and an Irishman than there is between the skin color of either and a chimp. In fact, there are human beings whose skin color would match that of a chimps.
"and musculature,"
Musculature (and body posture) is mostly based on the skeleton.
"what I may not be able to classify is a human skull and an ape skull."
Specialized forensic scientists can determine what a human's face looks like based only on their skull. By studying how muscles attach to the bones, they can make very accurate guesses as to what the facial structure would look like. Someone who is an expert at looking at the skulls of different animals would have absolutely no problem telling the difference between a human skull and a chimp skull.
So, what exactly is the major difference between a chimp and a human that cannot be seen from a skeleton?