Rafael Gutierrez-Galvan, 29, and his wife Deyanira Garza, 28, face charges of selling protected wildlife under the Big Cat Public Safety Act.
It is the first breach of the new law, which came into force in December 2022 and limits the breeding, selling and possession of big cats including jaguars.
Federal officials said Gutierrez-Galvan and Garza violated the act after selling a margay cub and attempting to later sell a jaguar.
The sale of the jaguar cub was supposed to take place on Tuesday. Gutierrez-Galvan had reportedly asked Garza to bring a case of cash from their home to the location.
However, officers found the cash after pulling Garza over in a traffic stop before she arrived at the sale location.
Authorities said Gutierrez-Galvan had sold a margay cub for $7,500 to the same man in a sports store car park in Alamo the previous month.
Neither Gutierrez-Galvan nor Garza has a license to buy, sell, trade or transport exotic animals.
They were taken into custody and made their first court appearances on Wednesday. If convicted, they could face up to five years in federal prison and a possible fine of up to $20,000.
Authorities said both animals have been recovered.
