Titanus Gojira

Godzilla and Dagon(Also known as Raijin, Species 5146_ADAM, or Godzilla-type creature.) are one of the only known species of Titanus Gojira that appeared in human eyes yet, or having records of their existence. Godzilla was first seen in 1954, while Dagon was first seen by the Phoenicians, while they made their way to Japanese islands in 11th Century BC., and believing that is their God, Dagon. After the defeat of Dagon from Muto Prime, it went ashore land and dies in the Philippines, leaving the skeleton to be discovered in 1999. It was also told that Dagon was far older than Godzilla, in age, according to Ishiro Serizawa, in 1999, when he went to see its skeleton in Godzilla(2014).

It is possible there might be more Titanus Gojira in the monsterverse, lurking below the Hollow Earth, likely hibernating or etc.