I think the original Lithuanian family name was Rentauskas. (Traditionally, that means women in the family would go by Rentauskaite if the weren't married, or a woman who married a Rentauskas would be Rentauskiene.) By the time they settle in the US,it's just Rentauskas. But our branch of the family spelled it Rantauskas (don't know why),and one of my grandpa's brothers used Rentel. And sometimes you see it as Rentowski or Rantowski, the Polish spelling I think. Lithuanian names are difficult to track down. I'll send you an invite to view my family tree on Ancestry and you can see if the names
on it are familiar.