Invertebrates: cone snails, jellyfish, and sea urchins

Welcome back to evolution of venom, Today’s blog topic, we will be covering the cone snail, jellyfish and sea urchins and how they use their venom.

Cone snails are marine gastropods belong to the family Conidae that prey on worms, molluscs and fish. Cone snails hunt by using their siphon to track prey, they use their proboscis to shoot a radula tooth to inject venom in the prey. They prey is immediate paralysed, allowing the snail to swallow the prey whole (Dutertre et al, 2014). Below is a diagram of a cone snail and how they hunt fish.

Anatomy of a cone snail and their hunting strategy by Ocean’s treasure  

Jellyfish are soft-bodied invertebrates that belong to the phylum Cnidaria, they mostly feed on small fish and prawns. Jellyfish float in the water and rely on their venomous tentacles to catch prey or defend themselves from other predators (Warrell, 2015). The tentacles have over a million sting capsules that when they come into contact with prey, they release small harpoons into the prey and bring it closer to them to eat (Junghanss & Bodio, 2006). Below is a diagram of a box sea jelly.

Anatomy of a box sea jelly by Ocean’s treasure 

Sea urchins are spiny echinoderms that belong to the class Echinoidea. Their shells are round and spiny, with the spines and tube feet helping them move across the ocean floor. Sea urchins mostly feed on algae, but will feed on slow moving animals. Their venom comes from their spines that when threatened or step on, the spines become embedded in the skin, causing extreme pain (Warrell, 2015). Below is a diagram of a sea urchin.

Anatomy of a sea urchin by Ocean’s treasure 

 

Next week blog, we will be covering bee’s, wasps, centipedes and moths that use venom. Below the articles used in this week blog for more reading at their venom.

 

Article references

Dutertre, S., Jin, A., Alewood, P. & Lewis, R. 2014, "Intraspecific variations in Conus geographus defence-evoked venom and estimation of the human lethal dose", TOXICON, vol. 91, pp. 135-144

 

Dutertre, S., Jin, A., Vetter, I., Hamilton, B., Sunagar, K., Lavergne, V., Dutertre, V., Fry, B., Antunes, A., Venter, D., Alewood, P. & Lewis, R. 2014, "Evolution of separate predation- and defence-evoked venoms in carnivorous cone snails", NATURE COMMUNICATIONS, vol. 5, no. 3521, pp. 3521-9

 

Warrell, D.A. 2015;2016;, "Venomous animals", Medicine, vol. 44, no. 2, pp. 120-124

 

Junghanss, T. & Bodio, M. 2006, "Medically Important Venomous Animals: Biology, Prevention, First Aid, and Clinical Management", Clinical Infectious Diseases, vol. 43, no. 10, pp. 1309-1317

 

Picture references

http://otlibrary.com/conus-snail/

http://otlibrary.com/box-sea-jelly/

http://otlibrary.com/sea-urchin/