A’living fossil, ‘the vampire squid populates the deep waters of all the world’s ocean basins at depths from 500 to 3,000 m.

The types is a soft-bodied, passive animal, about the size, shape, and color of a football.

It has a dark red body, big blue eyes, and a cloak-like web that extends in between its 8 arms.

When threatened, the squid turns inside out, exposing rows of wicked-looking ‘cirri.’

While other squid recreate simultaneously late in their lives, the vampire squid reveals proof of several reproductive cycles.

“Modern cephalopods (coleoids)– consisting of squids, octopuses, and cuttlefish– divided more than 300 million years back into 2 significant family trees: the ten-armed Decapodiformes (squids and cuttlefish) and the eight-armed Octopodiformes (octopuses and the vampire squid),” stated Shimane University biologist Masa-aki Yoshida and associates.

“Despite its name, the vampire squid has 8 arms like an octopus however shares crucial genomic functions with squids and cuttlefish.”

“It inhabits an intermediate position in between these 2 family trees– a connection that its genome exposes for the very first time at the chromosomal level.”

“Although it comes from the octopus family tree, it keeps components of a more ancestral, squid-like chromosomal company, offering brand-new insight into early cephalopod development.”

In brand-new research study, the authors sequenced the genome of the vampire squid from a private gathered in the West Pacific Ocean.

“At over 11 billion base sets, the vampire squid genome is approximately 4 times bigger than the human genome, making it the biggest cephalopod genome ever examined,” they stated.

“Despite this size, its chromosomes reveal a remarkably saved structure.”

“Because of this, Vampyroteuthis is thought about a ‘genomic living fossil’– a contemporary agent of an ancient family tree that maintains essential functions of its evolutionary past.”

The scientists discovered that it has actually maintained parts of a decapodiform-like karyotype while contemporary octopuses went through substantial chromosomal blends and rearrangements throughout advancement.

This saved genomic architecture offers brand-new ideas to how cephalopod family trees diverged.

“The vampire squid sits right at the user interface in between octopuses and squids,” stated Dr. Oleg Simakov, a scientist at the University of Vienna.

“Its genome exposes deep evolutionary tricks on how 2 noticeably various family trees might emerge from a shared forefather.”

By comparing the vampire squid with other sequenced types, consisting of the pelagic octopus Argonauta hiansthe researchers had the ability to trace the instructions of chromosomal modifications over evolutionary time.

“The genome series of Argonauta hians (paper nautilus), a ‘unusual’ pelagic octopus whose women secondarily got a shell-like calcified structure, was likewise provided for the very first time in our research study,” they stated.

“The analysis recommends that early coleoids had a squid-like chromosomal company, which later on merged and compressed into the contemporary octopus genome– a procedure called fusion-with-mixing.”

“These irreparable rearrangements most likely drove crucial morphological developments such as the expertise of arms and the loss of external shells.”

“Although it is categorized as an octopus, the vampire squid keeps a hereditary heritage that precedes both family trees,” included Dr. Emese Tóth, a scientist at the University of Vienna.

“It offers us a direct check out the earliest phases of cephalopod development.”

“Our research study offers the clearest hereditary proof yet that the typical forefather of octopuses and squids was more squid-like than formerly believed.”

“It highlights that massive chromosomal reorganization, instead of the development of brand-new genes, was the primary motorist behind the amazing variety of modern-day cephalopods.”

The outcomes were released on November 21, 2025 in the journal iScience

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Masa-aki Yoshida et al2025. Huge genome of the vampire squid exposes the obtained state of modern-day octopod karyotypes. iScience 28 (11 ): 113832; doi: 10.1016/ j.isci.2025.113832