400 NL Very confusing river. What does his river bet mean?

[dirtytricks]

Villain is tag 20/15 no other reads. Im also TAG. No history between us.

Full Tilt Poker, $2/$4 NL Hold'em Cash Game, 4 Players
LeggoPoker Hand History Converter

UTG: $666
BTN: $388
Hero (SB): $478.90
BB: $414.50

Pre-Flop: T[img]/images/graemlins/diamond.gif[/img] T[img]/images/graemlins/club.gif[/img] dealt to Hero (SB)
<font color="red">UTG raises to $14</font>, BTN folds, <font color="red">Hero raises to $52</font>, BB folds, UTG calls $38

Flop: ($108) 5[img]/images/graemlins/diamond.gif[/img] 6[img]/images/graemlins/heart.gif[/img] 8[img]/images/graemlins/club.gif[/img] (2 Players)
<font color="red">Hero bets $77</font>, UTG calls $77

Turn: ($262) 4[img]/images/graemlins/diamond.gif[/img] (2 Players)
Hero checks, UTG checks

River: ($262) A[img]/images/graemlins/club.gif[/img] (2 Players)
Hero checks, <font color="red">UTG bets $174</font>, Hero folds?

[dirtytricks]

bump