Dr. Carl Maia, played by Antonio Moreno, is a character in the film Creature from the Black Lagoon.
Dr. Maia finds a fossilized hand of an amphibious humanoid. While ordering his assistants to stay behind, he immediately leaves to visit Dr. David Reed. The two of them join with Dr. Mark Williams on a expedition. The also bring along Kay Lawrence and Edwin Thompson.
They charter the Rita, captained by Lucas, as they troll through the Amazon searching for more evidence of the fossil. Before long the Gill-Man takes notice of Kay who is swimming in his lagoon and he follows Rita, killing those aboard one by one in order to get to Kay.
Eventually Kay is taken by the creature to a subterranean cave where Maia, Reed and Williams confront the creature and rescue Kay.