This is technically an answer (it's a contemporary source), but...

The Yalkut Reuven here is quoting directly from שלשלת הקבלה. The original source can be found here (bottom third of the page). The problem is that the if you look at the beginning of the paragraph, it's prefacing with the follow disclaimer:

"האומות אומרים"

That is, שלשלת הקבלה is bringing myth/stories from "external sources", and if you read further, it looks like just a collection of weird things he's heard from various sources.

Example:

"בגלילות סיטיאה יש אנשים שאין להם אלא עין אחת במצח"

Note also that the general reputation of שלשלת הקבלה is problematic.

This is technically an answer (it's a contemporary source), but...

The Yalkut Reuven here is quoting directly from שלשלת הקבלה. The original source can be found here (bottom third of the page). The problem is that the if you look at the beginning of the paragraph, it's prefaced with the follow disclaimer:

"האומות אומרים"

That is, שלשלת הקבלה is bringing myth/stories from "external sources", and if you read further, it looks like just a collection of weird things he's heard from various sources.

Example:

"בגלילות סיטיאה יש אנשים שאין להם אלא עין אחת במצח"

Note also that the general reputation of שלשלת הקבלה is problematic.