December 2024
Phronima sp. Latreille, 1802 MBCN 26670
Phronima is a genus of planktonic amphipod crustaceans that mostly live between 40 and 100 meters in depth, although during daylight hours, they typically descend to deeper waters.
They are omnivorous animals, although it is common to observe females (which are larger than males) hunting tunicates and salps, from which they feed and also use their gelatinous parts to build “houses” in the shape of a barrel. These structures are used for laying eggs, and once they hatch, the females protect the larvae until they reach adulthood.
The barrel is so important to Phronima females that it is often possible to see more than one occupying the same barrel.
Moreover, they spend so much time inside that they have developed a pair of eyes specially adapted to look through the opening of the barrel with great visual acuity, allowing them to detect the contrast of their small prey against the blue background of the sea.
The specimen in the museum, which is likely either P. sedentaria or P. atlantica, is not inside its barrel, even though it is a female specimen.
- Origin: Balearic Sea
- Age: Current
