Assuming many influences and common traditions, what was the particular essence of Roman mythology as opposed to Greek, Etruscan, or Latin mythology?

Question

Assuming many influences and common traditions, what was the particular essence of Roman mythology as opposed to Greek, Etruscan, or Latin mythology?

Accepted Answer

The answer to this question depends very much on the period of Roman history being considered. It is possible to speak of the different mythological emphases among the Archaic Romans, followed by those of the Republican Romans and finally, those of the Imperial Romans.

Roman Mythology

Latins, Etruscans, and Archaic Rome

Assuming many influences and common traditions, what was the particular essence of Roman mythology as opposed to Greek, Etruscan, or Latin mythology?