I am trying to understand better the etymon of the first part of the word haruspex.
The Wiktionary entry and other sources mention «haru- (“intestines”)», but there seems to be no Latin word *haru or the like (apart from derivate words such as haruspex, hariolor etc.). Wiktionary and Lewis-Short mention older roots, from Faliscan, Sanskrit, Proto-Indoeuropean etc., while Lewis's Elementary Latin Dictionary tantalisingly records “HAR-”, but I can't find other references to this root as such in that book.
Are there more modern, more complete explanation of the haru- root?