Strange Growth On Female Guppy

[m.shaugh]

I recently acquired a few new guppies from a friend of mine who selectively bred her fish for certain traits for 11 generations. Yesterday after I acclimated/introduced my new fish to my guppy tank I noticed a strange growth on one of my new females. It seems to be cartilaginous/bony and maybe moving under voluntary control? Has anyone every seen anything like this? Should I be concerned? She is acting normal... eating, socializing, etc.  Thanks!!

 

[eaglesaquarium]

Is it possible to get a slightly higher res photo.

 

[Antinerf]

Side note: Isn't a dark spot in that area indicative of pregnancy?