Carter and Rosas, however, rejected the subspecific division in 1997, noting the classification had only been validated once, in 1968, and the P. b. paraguensis type specimen was very similar to P. b. brasiliensis.
Porén, Carter e Rosas rexeitaron esta subdivisión en subespecies en 1997, indicando que a clasificación só fora validada unha vez, en 1968, e o espécime tipo de P. b. paraguensis era moi similar a P. b. brasiliensis.