Who is Jabez?

I was reading in 1 Chronicles today. There seems to be a whole lot of genealogy listing in the first half of the book. I'm only to chapter 5 and it's still all about soandso's descendants and their descendants, etc. It is laying out the genealogy to David, I believe, but sometimes it gets to be tedious. It is kind of cool to see who turns into what group of people who you hear about fighting with Israel and Judah later on (ex. Canaan was the father of Sidon his firstborn, and of the Hittites, Jebusites, Amorites, Girgashites, Hivites, Arkites...).

Anyway, so I read three plus chapters of the sons of various people and in chapter four verses nine and ten it says: Jabez was more honorable than his brothers. His mother had named him Jabez, saying, "I gave birth to him in pain." Jabez cried out to the God of Israel, "Oh, that you would bless me and enlarge my territory! Let your hand be with me, and keep me from harm so that I will be free from pain." And God granted his request.

Then verse 11 goes right back to people and their sons. I, of course, was wondering, Where did this come from? And who is Jabez? None of the people before are named Jabez to indicate what family he's related to except that the title of the chapter is "Other Clans of Judah". So where do these two verses come from? They seem very out of place and a little confusing.


So this post is more of a question. Does anyone have greater understanding of this passage and could answer my questions? Who is Jabez and why is this random story in the middle of all of the genealogy?