Question: What was the other name for the extinct tiger subspecies, which inhabited the sparse forests and riverine corridors west and south of the Caspian Sea, from Turkey, Mesopotamia, Iran and the Caucasus, that has a project reestablishing populations of the Siberian tiger by introducing them as replacements to the extinct tiger? 
Sentence (from "Siberian Tiger Introduction Project"): The Siberian Tiger Introduction Project involves reestablishing populations of the Siberian tiger ("Panthera tigris altaica)", also known as the Amur tiger, in their former range and also expanding their range by introducing them as replacements of their genetically similar relative, the extinct Caspian tiger ("Panthera tigris virgata") which inhabited Central and Western Asia.
Relevant evidence: Yes