50328
The largest is the near-threatened " Melanosuchus niger " , the " jacaré-açu " or large or black caiman of the Amazon River basin .
 black caiman, Amazon River
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: media, plant, vehicle, astronomical object, time, disease, animal, location, person, organization, mythical figure, food, biology, geographical phenomenon, instrument, event 
Text: {0} 
Answer:
 black caiman, Amazon River