The arrest of Costillia is the latest high-profile arrest in President Felipe Calderón's crackdown on organised crime, and the government said it would reveal more details about the capture early on Thursday. Such figures are often paraded in front of the media, handcuffed and dressed in flak jackets.
A government security source said Costilla was detained in Tampico in north-east Mexico, where the cartel was active, without putting up a fight. The US state department had a reward of up to $5-million for Costilla's capture.
No other details were immediately available.
Last week, Mexico's navy captured senior Gulf cartel member Mario Cardenas, alias "Fatso," also in the north-east state of Tamaulipas where Costilla was caught.
The cartel's power has waned during a feud with the brutal Zetas gang, which acted as enforcers for the Gulf cartel before breaking with their employers. That conflict has caused some of the most sickening killings of the drug war.
There have been more than 55 000 drug-related deaths during Calderón's six-year offensive against cartels, and incoming president Enrique Peña Nieto has vowed to quickly reduce the number of beheadings and mass executions.
Peña Nieto takes office on December 1. – Reuters