River Bluffcatch vs delayed Aggression

GG Poker - $0.05 Ante $0.02 NL - Holdem - 8 players
Hand converted by PokerTracker 4

MP: 196.6 BB
MP+1: 102 BB
CO: 186.2 BB
BTN: 230.6 BB
SB: 330 BB
BB: 200 BB
UTG: 196.4 BB
Hero (UTG+1): 393.2 BB

8 players post ante of 0.4 BB, SB posts SB 0.4 BB, BB posts BB 1 BB

Pre Flop: (pot: 4.6 BB) Hero has Q♣ J♣

fold, Hero raises to 4 BB, fold, fold, CO calls 4 BB, BTN raises to 12.4 BB, fold, fold, Hero calls 8.4 BB, CO calls 8.4 BB

Flop: (41.8 BB, 3 players) 6♠ 7♠ Q♠
Hero checks, CO checks, BTN checks

Turn: (41.8 BB, 3 players) 4♦
Hero checks, CO checks, BTN bets 21 BB, Hero calls 21 BB, fold

River: (83.8 BB, 2 players) 8♣
Hero checks, BTN bets 71.2 BB, Hero ?

Villain is unknown. What do you think of this spot -- over- or underbluffed? I guess that I would rather hold a spade in my hand like TsTx or JsJx, however, these are only a few combos. Holding a Q seems also fine and with that I am at the top of my range (but that is not a reason for calling at the micros). There are a lot of combos in villains value range like some 5x, sets and slowplayed flushs, however, also a lot of possible bluff combos like busted spade draws or some random garbage like JThh. Thing is, the limit is not known for its extensive bluffs. Call or fold?