These air bubbles are produced by a specialized organ called the propodium. This species lives its life upside down attached to air bubbles that it made itself, forming a self-made float. It is thought that Janthina globosa was used as a source of purple dye for clothes in ancient times. pallida (Record of the Australian Museum, 2017, 160-161). globosa most likely evolved from the species J. Many other species fall in the genera Janthina. The oldest fossil of the Janthina genera was found on Santa Maria Island in the Atlantic, but the earliest record of Janthina globosa specifically is unclear, despite its long fossil record (Record of the Australian Museum, 2017, 142). Janthina globosa was first captured in 1822 off the Gulf of Antalya in the Northeastern part of the Mediterranean Sea (Teker S, Gökoğlu M, Julian D. Maximum recorded depth is 13 metres (43 ft). Strandings of this species and others of its genera are also due to wave and current movements (F. If conditions permit it, these snails can be found outside these latitudes. 2002).įour other species that fall in the genera Janthina can be found in the Mediterranean Sea (along with Janthina globosa) but they are also found between these latitudes: 50°N and 40°S. This makes the population size of Velella a good predictor of Janthina globosa location and population size (Deudero S, Pinnegar J, Polunin N. Since Velella is their preferred prey, Janthina globosa will appear in places it is not normally found if there is a large amount of Velella prey to consume. Janthina globosa seems to prefer larger Velella over smaller bodied Velella due to the availability of more soft tissue to eat as compared to the smaller members of that species. Unlike many other marine animals, Janthina globosa’s diet does not change too much as it matures. Janthina globosa are able to tolerate the poison excreted from Velella’s nematocysts, making them an easy target for predation by Janthina globosa. Velella has stinging nematocysts that they use to defend themselves and to capture prey. Although scientists have observed that Velella is its favored prey option, upon gut analysis it seems that Janthina globosa will eat just about anything, even exhibiting cannibalistic behaviors by eating members of its own species. Its most popular prey, based on scientific observation, seems to be Velella (Wilson and Wilson, 1956, 301). Although Janthina globosa seems like a harmless snail, it is an incredibly successful predator. It secretes a purple dye (the same dye that gives it its purple color) to paralyze its prey, allowing it to eat its target without much of a fight. ![]() It and many other members of the Janthina genera have an epipodium that is thought to help with balance in the water (Wilson and Wilson, 1956, 301). ![]() Its unique purple color serves to camouflage itself in its environment and also serves as an efficient means of obtaining food, making it a better predator. Protected by its hard outer shell, Janthina globosa has a soft body with forked cephalic tentacles on its belly, used for many different things like locomotion and receiving sensory input. Inside its shell lives the organism itself. Janthina globosa has a glossy shell, characterized by four symmetrical spirals evenly spaced on its shell. Females normally grow to larger sizes than males, making it easy to distinguish between the sexes. Janthina globosa, commonly referred to as the violet snail, is a neustonic organism characterized by its thin, fragile purple shell and large size The maximum recorded shell length is 38.5 mm.
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