Field Guide to Venomous and Medically Important Invertebrates ...

Figure 235. The ―false box jellyfish‖ (Chiropsalmus quadrigatus). This species should not be
confused with the other, more dangerous, box jellyfish (Chironex fleckeri). Photo: K. Gillet.
The pink jellyfish, Pelagia noctiluca, is distributed worldwide and cases of severe cutaneous
envenomation by this species are a common but periodic occurrence. This species has cyclic
population dynamics and it appears in abundance about every 10 to 12 years. During these
proliferations, swarms of medusae congregate near beaches resulting in significant numbers of
envenomations. The stings usually produce minor cutaneous reactions such as reddened,
inflamed, and itchy eruptions, but some produce lesions are more dramatic and may present as a
burn-like response. Many stinging victims have post inflammatory pigmentation that may last
several months but this condition eventually resolves spontaneously.
Figure 236. Pink jellyfish (Pelagia noctiluca). Photo: George Reclos.
The thimble jellyfish, Linuche unguiculata, is a small (~0.78 inch or 20 mm diameter) species
widely distributed in the Caribbean. They have a distinct appearance and appear dark brown
internally. Thimble jellyfish often occur in swarms of several thousand specimens, but isolated
individuals are occasionally seen as well. They are distributed throughout the Caribbean and
where they breed throughout the summer although populations tend to peak in May. Initial
contact with thimble jellyfish is generally noted by a sensation of contact followed by mild
irritation. Within a few days, the stings develop into an itchy, reddened rash on exposed areas of
the body. Symptoms generally self-resolve and itching can be aided with antihistamines.
Figure 237. Thimble jellyfish (Linuche unguiculata). Photo: Jim Christensen.