Would like an ID on an amphipod-like critter

[musty baby]

I got some pictures for a friend (Diablitaroja on RC but not on very often) of these animals from her tank. They appear to max out at about 5/16 of an inch long and burrow about an inch down into her sand bed. She's got boatloads of them. Any help on an ID would be great (simply to satisfy our curiosity)!

From the top

From the side (sorry for the glare, for some reason I didn't think to pull out my handy dandy homemade paper light diffuser)

Belly shot w/ eggs

And with an amphipod to show relative size.

 

[iamwhatiam52]

The sand against my glass has several burrows with what seems to be the same critter.
Never had a problem.

 

[musty baby]

Yep, no problem here either. Just curious as to what they are.

 

[LeslieH]

They are tanaids. Do a search under Tanaidacea for more information.

 

[musty baby]

I was hoping you'd come to my rescue! Thanks!