Deadly Organism of the Fortnight: Pterois volitans.

This fortnight’s selection is an absolutely beautiful animal that happens to be extremely deadly, funnily enough.
It is a marine reef fish that is native to waters of the Indian and Pacific Oceans, but one that is also found in the Atlantic as an invasive species following accidental introduction.

Pterois volitans.

The species is commonly known as the Lionfish, and it is deadly because of spines that deliver venom. These spines are attached to glands and the whole bit is covered by an integumentary sheath that bears the same striking colouration that the rest of the body does. There are 13 dorsal spines, 3 anal spines & 2 pelvic spines.

Anatomy of dorsal venom-delivering spines in P.volitans

The illustration is taken from this paper, which unfortunately is behind a paywall, but if you can you may want to read the paper.

Now, if we were to focus on the venom per se for a little while, one would find that the venom is primarily cardiotoxic, i.e, it has both inotropic effects (weakening the force of contraction) and chronotropic effects (slowing down the heart rate) by virtue of acting on adrinergic and cholinergic neurons, and also by triggering the release of nitric oxide. You may find a reference that elaborates upon the exact mechanisms here.

cDNA analysis of the venom genes has been carried out, and it reveals that Pterois spp venom is very similar to stonefish venom, you can find more on that here

Talking of the venom, there was also a mention of a non-proteinaceous toxin in the literature, but given that toxin peptides have already been sequenced and studied using cDNA analysis, I’m not quite sure how important/correct that report was (See here for a reference)

They’re apparently popular aquarium fish. Yeah, right.

That is all from me insofar this article is concerned.


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