.5/1 77 on ATx Flop Bet the Turn or River?

[somapopper]

PokerStars 0.50/1.00 Hold'em (9 handed) Hand History Converter Tool from FlopTurnRiver.com (Format: 2+2 Forums)

Preflop: Hero is UTG with 7[img]/images/graemlins/heart.gif[/img], 7[img]/images/graemlins/club.gif[/img]. MP3 posts a blind of $0.50. CO posts a blind of $0.50.
<font color="#CC3333">Hero raises</font>, <font color="#666666">4 folds</font>, CO (poster) calls, <font color="#666666">3 folds</font>.

Flop: (6.50 SB) A[img]/images/graemlins/club.gif[/img], T[img]/images/graemlins/club.gif[/img], 4[img]/images/graemlins/diamond.gif[/img] <font color="#0000FF">(2 players)</font>
<font color="#CC3333">Hero bets</font>, CO calls.

Turn: (4.25 BB) A[img]/images/graemlins/spade.gif[/img] <font color="#0000FF">(2 players)</font>
Hero checks, CO checks.

River: (4.25 BB) 2[img]/images/graemlins/diamond.gif[/img] <font color="#0000FF">(2 players)</font>
Hero checks?

Final Pot: 4.25 BB

CO's first hand at the table.

If CO bet the turn I would have called planning to C/C any river.

Does anybody bet the turn or once that gets checked through the river?