There is a slight discrepancy, but here is an estimate of taxes for the route in question via ITA:

USDA APHIS Fee (XA)
$3.96
US Immigration Fee (XY)
$7.00
US Customs Fee (YC)
$5.50
US International Arrival Tax (US)
$18.00
Argentina Custom And Immigration Services Tax International (QO)
$10.00
Argentina Airport Tax International (XR)
$49.00
Argentina Security Tax International (TQ)
$10.00
US September 11th Security Fee (AY)
$5.60

This totals to $109.06

I'm not sure where the ~$20 discrepancy lies. Furthermore, I think AA provides a similar breakdown of taxes when you're making the reservation.