And we might as well include official descriptions of these UPenn videos too:
When one visualizes the Roman Republic, the first image that usually comes to mind is that of a male aristocrat whose portrait bears the signs of advanced age: incised lines on or around the forehead, eyes, and mouth, and short, closely cropped hair that is often receding. On occasion there is no hair at all, and the irregularly shaped heads frequently feature large ears, thick lips, and sharply aquiline noses. Why did the Romans choose such an unusual type, and how long did it remain in vogue? In this lecture, Dr. C. Brian Rose, Curator-in-Charge, Mediterranean Section, answers these and other questions about Roman portraits, and presents new archaeological evidence from the northern Galilee that bears on the date of the type’s creation.