Vampire squid taxonomy: A cautionary tale for deep-sea science
In 2024, marine biologists announced the discovery of a second living vampire squid species from the South China Sea. Two years later, that discovery has been retracted. The specimen was not a new species after all. This episode, detailed in the Bulletin of Marine Science, illustrates the self-correcting nature of taxonomy and the challenges of studying deep-sea creatures.
What is the vampire squid?
The vampire squid (Vampyroteuthis infernalis) is neither a true squid nor an octopus. It is the only surviving member of the ancient cephalopod order Vampyromorphida. Discovered in 1898 by German zoologist Carl Chun during the Valdivia Expedition, it lives in low-oxygen depths below 550 meters. Its name means 'vampire squid from hell,' but it feeds on marine snow, not blood. When threatened, it inverts its arms into a protective pineapple shape and releases bioluminescent mucus.
The 2024 discovery in the South China Sea
In September 2016, researchers from the South China Sea Institute of Oceanology collected a vampire squid specimen at depths of 800 to 1,000 meters. They noted a pointed tail, a broader lower beak, and light-emitting organs positioned differently than in known specimens. Genetic analysis of mitochondrial COI and nuclear rDNA sequences suggested it belonged to a distinct monophyletic group. In 2024, they named it Vampyroteuthis pseudoinfernalis, sparking excitement about undiscovered deep-sea biodiversity.
Why the 2026 correction matters
A team led by Smithsonian expert Michael Vecchione re-examined the evidence. They found that the distinctive traits, such as beak shape and photophore spacing, varied naturally across vampire squid life stages. Soft-bodied cephalopods often deform when captured and brought to the surface. Re-analysis of phylogenetic trees with additional genetic markers showed no support for a separate species. The 2024 claim was corrected, and V. pseudoinfernalis is now listed as a junior synonym of V. infernalis.
What this tells us about deep-sea research
This case highlights several challenges. Initial descriptions often rely on few specimens. Soft-bodied creatures are easily damaged in nets. Single-gene sequencing can be misleading. The deep ocean remains poorly sampled. As one researcher noted, 'Studying creatures near the surface is considerably easier.' The correction does not erase the original record but updates it under the Principle of Priority.
FAQ: Vampire squid taxonomy
Is there still only one living vampire squid species?
Yes. Vampyroteuthis infernalis remains the only living species of the order Vampyromorphida.
Could another new species be found?
Possibly. The deep ocean is vast and largely unexplored. Future expeditions may yet reveal additional species.
Why did the 2024 study get it wrong?
Limited sample size, physical deformation during capture, and reliance on single-gene sequencing led to an incorrect species designation.