Bootlace Worm Crowned Invertebrate of the Year 2026

The marine ribbon worm *Lineus longissimus*, commonly called the bootlace worm, was highlighted as the “Invertebrate of the Year 2026.” Observers documented an individual washed ashore after a storm at St Andrews that measured approximately 55 metres, far exceeding the species’ typical length of about 15 metres. Even at its maximum, the worm remains only 5–10 mm wide. Its body is highly elastic, allowing it to stretch considerably when disturbed.

The Guardian

Swedish naturalist Olaus Magnus first noted the worm’s toxic slime in 1555, but the chemical nature of the secretion was not fully described until 2018 by Swedish scientists. The toxins, termed alpha-nemertides, function to paralyse and kill crustacean prey such as crabs. Laboratory work has shown that the same compounds are lethal to cockroaches while having minimal effects on mammals.

The Guardian

Bootlace worms belong to the phylum Nemertea, which comprises more than 1,250 described species occupying habitats from intertidal zones to deep-sea environments. *L. longissimus* is a voracious predator, capable of swallowing soft-bodied annelid worms whole. The species’ striking length and potent slime illustrate the broader ecological significance of nemerteans, a group that remains relatively obscure despite its diversity.

The Guardian

Researchers suggest that the alpha-nemertide toxins could serve as templates for new insecticidal agents, given their efficacy against insects and low toxicity to mammals. The discovery underscores the potential for marine invertebrates to yield novel bioactive compounds, a field that may still hold many undiscovered chemicals and medicines. —reflects growing interest in exploring such understudied organisms for practical applications.

The Guardian