correct comma use?

Hi,

I saw this complex? sentence in hela's post named 'Past form of the verbs "lie/lay"'. Do you think it is correct to use a comma for what seems to be two clauses?

But the skeleton was too large to be human, the bones of the legs were exceptionally long and as we uncovered more of it, we culd see that the creature had a thin, curved neck like a swan, but much longer and more powerful.

I have heard something like a comma can be used to connect short but very related clauses like this:

I ran toward the store, he ran the other way.