two ideas which are: a notable preservation bias called the Lazarus effect may exist; or an inaccurate determination of when vampire squids originally settled in the deep oceans. The Lazarus effect may result from the scarcity of post-Cretaceous research regions or from the reduced abundance and distribution of vampire squids. In any case, even while the search regions remain the same, it is more difficult to locate and analyze them.

In 2024 a second species of Vampyroteuthis was proposed, Vampyroteuthis