Speleonectes tulumensis: First Known Venomous Crustacean

Marine biologists reporting in the journal Molecular Biology and Evolution say that they have identified the world’s first venomous crustacean – a rare remipede called Speleonectes tulumensis.

Speleonectes tulumensis. Image credit: University of Bonn.

Speleonectes tulumensis. Image credit: University of Bonn.

Remipedes are a group of blind, aquatic and cave-dwelling crustaceans first described in 1981. They occur only in underwater caves in Central America, the Caribbean, the Canary Islands, and western Australia.

These crustaceans bear a certain resemblance to terrestrial centipedes. They have long, segmented bodies, with most segments equipped with swimming legs.

For few decades remipedes were known only from 300-million-year-old fossils. Since 80s, scientists have discovered more than 20 living remipede species. They suggest that insects evolved from crustaceans and that remipedes are more closely related to insects than any other crustacean.

Venom delivery system of Speleonectes tulumensis and its 3D reconstruction, shown in purple: cep – cephalon; dc – ductus; gl – gland; t – tentorium; rv – reservoir; mxu – maxillule; phx – pharynx. Image credit: von Reumont BM et al.

Venom delivery system of Speleonectes tulumensis and its 3D reconstruction, shown in purple: cep – cephalon; dc – ductus; gl – gland; t – tentorium; rv – reservoir; mxu – maxillule; phx – pharynx. Image credit: von Reumont BM et al.

The team, led by Dr Ronald Jenner from Natural History Museum in London, UK, analyzed the venom delivery apparatus of Speleonectes tulumensis and found a paralyzing neurotoxin and other chemicals.

According to the biologists, the Speleonectes tulumensis‘ neurotoxin is very similar to neurotoxins in spider venom.

“This venom is clearly a great adaptation for these blind cave-dwellers that live in nutrient-poor underwater caves,” Dr Jenner said in the interview with the press-office at Natural History Museum.

“Not one of the approximately 70,000 described species of crustaceans was known, until now, to be venomous.”

He added there are other candidates for venomous crustaceans – few species of remipede and a fish parasite known to pierce the skin of fish and cause them to hemorrhage.

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Bibliographic information: von Reumont BM et al. The first venomous crustacean revealed by transcriptomics and functional morphology: remipede venom glands express a unique toxin cocktail dominated by enzymes and a neurotoxin. Molecular Biology and Evolution, published online October 16, 2013; doi: 10.1093/molbev/mst199