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? 

Context paragraphs:
Bali tiger: The Bali tiger ("Panthera tigris balica") is an extinct tiger subspecies that lived in the Indonesian island of Bali.

Siberian tiger: The Siberian tiger ("Panthera tigris altaica"), also called Amur tiger, is a tiger subspecies inhabiting mainly the Sikhote Alin mountain region with a small population in southwest Primorye Province in the Russian Far East.  The Siberian tiger once ranged throughout all of Korea, north-eastern China, Russian Far East, and eastern Mongolia.  In 2005, there were 331–393 adult and subadult Siberian tigers in this region, with a breeding adult population of about 250 individuals.  The population had been stable for more than a decade due to intensive conservation efforts, but partial surveys conducted after 2005 indicate that the Russian tiger population was declining.  An initial census held in 2015 indicated that the Siberian tiger population had increased to 480–540 individuals in the Russian Far East, including 100 cubs.  This was followed up by a more detailed census which revealed there was a total population of 562 wild Siberian tigers in Russia.

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.  Currently, the Siberian tiger inhabits the cold mountains of the Russian Far East and northern China.

Trinil tiger: The Trinil tiger ("Panthera tigris trinilensis") is an extinct tiger subspecies dating from about 1.2 million years ago that was found at the locality of Trinil, Java, Indonesia.  The fossil remains are now stored in the Dubois Collection of the National Museum of Natural History in Leiden, the Netherlands.  Although these fossils have been found on Java, the Trinil tiger is probably not a direct ancestor of the Javan tiger.  The Trinil tiger probably became extinct 50,000 years ago.  The Bali tiger was also not closely related to the Trinil because of their time differences.

Wanhsien tiger: The Wanhsien tiger ("Panthera tigris acutidens"), is an extinct subspecies of tiger that lived in Asia from the late Pliocene until the middle Pleistocene.  They were driven to extinction in the islands of Indonesia by another tiger subspecies, the Trinil tiger ("P. t. trinilensis") and in Asia by yet another subspecies, the South China tiger ("P. t. amoyensis")

Panthera tigris sudanensis: The Panthera tigris sudanensis is a claimed subspecies of tiger, not scientifically recognised, allegedly living in Africa.  It was described in 1951 by Paul E. P. Deraniyagala, based on a fur he saw in a Cairo bazaar.  When he asked the seller for information, Deraniyagala was told the animal was shot in the Sudan.  As Mazák wrote in 1980, it was either a joke or the seller felt obliged to be polite and answer any question, whether with truth or an invention.  Deraniyagala took a picture of the specimen's fur, which, when published, made the scientists say, according to the pattern of stripes, it was most likely a fur of the Caspian tiger ("Panthera tigris virgata") and the fur must have been smuggled from Iran or Turkey.  At that time, the Caspian tiger was nearly extinct.  If a photo were enough for a scientific description, "Panthera tigris sudanensis" would now be one of the Caspian tiger's synonyms; as Mazák wrote, "the situation is half-humorous, half-ironic."  Tigers are not known to have ever inhabited Africa.

Geography of Azerbaijan: Azerbaijan is situated in the Caucasus region of Eurasia.  Three physical features dominate Azerbaijan: the Caspian Sea, whose shoreline forms a natural boundary to the east; the Greater Caucasus mountain range to the north; and the extensive flatlands at the country's center.  About the size of Portugal or the state of Maine, Azerbaijan has a total land area of approximately 86,600 square kilometers, less than 1% of the land area of the former Soviet Union.  Of the three Transcaucasian states, Azerbaijan has the greatest land area.  Special administrative subdivisions are the Nakhchivan Autonomous Republic, which is separated from the rest of Azerbaijan by a strip of Armenian territory, and the Nagorno-Karabakh Autonomous Region, entirely within Azerbaijan.  (The status of Nagorno-Karabakh was under negotiation in 1994.)  Located in the region of the southern Caucasus Mountains, Azerbaijan borders the Caspian Sea to the east, Georgia and Russia to the north, Iran to the south, and Armenia to the southwest and west.  A small part of Nakhchivan also borders Turkey to the northwest.  The capital of Azerbaijan is the ancient city of Baku, which has the largest and best harbor on the Caspian Sea and has long been the center of the republic's oil industry.

Caspian red deer: The Caspian red deer ("Cervus elaphus maral"), is one of the easternmost subspecies of red deer that is native to areas between the Black Sea and Caspian Sea such as Crimea, Asia Minor, the Caucasus Mountains region bordering Europe and Asia, and along the Caspian Sea region in Iran.  The Caspian red deer is sometimes referred to as maral, noble deer, or eastern red deer.

Caspian tiger: The Caspian tiger ("Panthera tigris virgata") is an 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, through Central Asia to the Takla Makan desert of Xinjiang in China, until the end of the 20th century.  Depending on the region, it was also called Hyrcanian tiger, Turanian tiger, Persian tiger, and "Babre Mazandaran" (Persian: ‎ ‎ , Tiger of Mazandaran).  It was one of the largest big cats to have ever lived and was described as being intermediate in size between Siberian and Bengal tigers.

Alborz: Alborz (   Persian: البرز‎ ‎ ), also spelled as Alburz, Elburz or Elborz, is a mountain range in northern Iran that stretches from the border of Azerbaijan along the western and entire southern coast of the Caspian Sea and finally runs northeast and merges into the Aladagh Mountains in the northern parts of Khorasan.  This mountain range is divided into Western, Central, and Eastern Alborz Mountains.  The Western Alborz Range (usually called the Talish Mountains) runs south-southeastward almost along the western coast of the Caspian Sea.  The Central Alborz (the Alborz Mountains in the strictest sense) runs from west to east along the entire southern coast of the Caspian Sea, while the Eastern Alborz runs in a northeasterly direction towards the northern parts of the Khorasan region southeast of the Caspian Sea.  Mount Damavand, the highest mountain in Iran, is located in the Central Alborz Mountains.

Supporting paragraphs: Siberian Tiger Introduction Project Caspian tiger
Answer: Hyrcanian tiger