The staff of the Maritime Aquarium at Norwalk is mourning the death of its Asian water monitor lizard, more commonly known as its black dragon. The 7-foot lizard died overnight Monday. “We’re always saddened by the death of any animal at the Aquarium, but the black dragon was appreciated as a very special creature by staff as well as by our guests,” said Barrett Christie, the Aquarium’s director of Animal Husbandry. Cause of death is unknown. A necropsy will be performed at the Connecticut Veterinary Medical Diagnostic Laboratory at UConn.