Slipper lobster
Family of achelate crustaceans with distinctive flattened antennae.
Slipper lobsters make up the family Scyllaridae, a group of roughly 90 species of achelate crustaceans within the decapod clade Reptantia. They inhabit warm oceans and seas worldwide. Despite their name, they are not true lobsters; their closest relatives are spiny lobsters and furry lobsters. Their most distinctive feature is their enlarged second antennae, which extend forward from the head as broad, flattened plates. Every species of slipper lobster is edible, and a few—like the Moreton Bay bug and the Balmain bug (Ibacus peronii)—are commercially valuable.
The head has six segments and the thorax eight, all covered by a thick carapace. The abdomen consists of six segments, each bearing a pair of pleopods. The thoracic appendages function either as walking legs or as maxillipeds. The head segments carry mouthparts and two pairs of antennae. The first pair, or antennules, are mounted on long, flexible stalks and are used for sensing the surroundings. The second pair are the most noticeable feature: they are expanded and flattened into large plates that project horizontally forward. Slipper lobsters vary greatly in size. The smallest species, the Mediterranean *Scyllarus pygmaeus*, reaches a maximum total length of 55 mm (2.2 in) and is usually under 40 mm (1.6 in). The largest, *Scyllarides haanii*, can grow up to 50 cm (20 in) long.
These animals are typically bottom-dwellers on continental shelves, living at depths down to 500 m (1,600 ft). Their diet includes a range of molluscs—such as limpets, mussels, and oysters—as well as crustaceans, polychaetes, and echinoderms. They grow slowly and can live to a considerable age. Unlike many other decapod crustaceans, they lack the giant neurons needed for tail-flip escapes, so they rely on other defenses, such as burying themselves in the substrate or depending on their heavily armored exoskeleton. Their main predators are bony fish; in the Mediterranean, the grey triggerfish is the most significant predator of *Scyllarides latus*.
After hatching, young slipper lobsters go through about ten instars as phyllosoma larvae—leaf-shaped, planktonic zoeae. These stages last most of a year, after which the larva molts into a brief "nisto" stage that lasts a few weeks. Little is known about the transition from this stage to adulthood, after which they continue growing through a series of molts.
Though fished wherever they are found, slipper lobsters have not been as heavily targeted as spiny lobsters or true lobsters. Fishing methods depend on the species' habitat. Those preferring soft substrates, like *Thenus* and *Ibacus*, are often caught by trawling. Species that favor crevices, caves, and reefs—including *Scyllarides*, *Arctides*, and *Parribacus*—are usually taken by scuba divers. In 1991, the global catch was reported at 2,100 tonnes. More recently, annual production has been around 5,000 tonnes, with the majority coming from *Thenus orientalis* in Asia.
The family Scyllaridae goes by many common names. "Slipper lobster" is the most widespread, followed by "shovel-nosed lobster" and "locust lobster." "Spanish lobster" is used for *Arctides*, "mitten lobster" for *Parribacus*, and "fan lobster" for *Evibacus* and *Ibacus*. In Australia, several species are called "bugs"—for instance, the Balmain bug (*Ibacus peronii*) and the Moreton Bay bug (*Thenus orientalis*). Other Australian names include bay lobster, blind lobster, flapjack, flat lobster, flying saucer, gulf lobster, mudbug, sandbug, shovel-nose bug, shovelnose lobster, crayfish, slipper bug, and squagga. Rarer terms are flathead lobster (for *Thenus orientalis*) and bulldozer lobster. In Greece, they are sometimes known as *Kolochtypes*, which roughly translates to "bum hitter." Twenty-two genera are recognized, most of which were established in 2002 by Lipke Holthuis for species previously placed under *Scyllarus*.
The fossil record of slipper lobsters extends back 100–120 million years—considerably less than that of their closest relatives, the spiny lobsters. An earlier significant fossil is *Cancrinos claviger*, described from Upper Jurassic sediments at least 142 million years old. This species may represent either an ancestor of modern slipper lobsters or the sister group to the family Scyllaridae sensu stricto.
- field
- Crustacean biology
- known_for
- Enlarged, flattened antennae; edible species of commercial importance
- species_count
- About 90
- largest_species
- Scyllarides haanii, up to 50 cm
- smallest_species
- Scyllarus pygmaeus, up to 55 mm
Lore & Background
Slipper lobsters have six segments in their heads and eight segments in the thorax, collectively covered in a thick carapace. The six abdominal segments each bear a pair of pleopods, while thoracic appendages are walking legs or maxillipeds. Their most conspicuous feature is the second pair of antennae, expanded and flattened into large plates extending horizontally forward from the head. They lack the giant neurones that allow other decapod crustaceans to perform tailflips, relying instead on burial in substrate and a heavily armoured exoskeleton to escape predators. After hatching, young slipper lobsters pass through around ten instars as phyllosoma larvae—leaf-like, planktonic zoeae—lasting the greater part of a year. The larva then moults into a 'nisto' stage that lasts a few weeks. Almost nothing is known about the transition from this stage to adults, which continue to grow through a series of moults.
Reader's Guide
Slipper lobsters are bottom-dwelling crustaceans found on continental shelves worldwide, inhabiting depths of up to several hundred meters. They are slow-growing and long-lived, feeding on a varied diet that includes molluscs such as limpets, mussels, and oysters, as well as other crustaceans, polychaete worms, and echinoderms. Unlike many other decapods, they lack the giant neurons needed for rapid tailflips to escape predators; instead, they rely on burying themselves in the substrate and their heavily armoured exoskeleton for protection. Their most significant predators are bony fish—for instance, the grey triggerfish is a major threat to the Mediterranean species *Scyllarides latus*. After hatching, young slipper lobsters go through about ten larval stages as leaf-like, planktonic phyllosoma larvae over nearly a year, then moult into a brief nisto stage before transitioning to adulthood—a process that remains poorly understood. Commercially, slipper lobsters are fished wherever they occur, though less intensively than spiny or true lobsters. Fishing methods depend on habitat: species on soft substrates, like those in the genera *Thenus* and *Ibacus*, are often caught by trawling, while those inhabiting crevices, caves, and reefs (such as *Scyllarides*, *Arctides*, and *Parribacus*) are typically harvested by scuba divers. The global catch is dominated by *Thenus orientalis* in Asia. Slipper lobsters are known by many common names, including “shovel-nosed lobster,” “locust lobster,” and in Australia, “bugs” such as the Balmain bug and Moreton Bay bug. Their fossil record extends back 100–120 million years, less than that of their spiny lobster relatives, with the Jurassic fossil *Cancrinos claviger* possibly representing an ancestor or sister group to the modern family.
Did You Know?
- Slipper lobsters lack the giant neurones that allow other decapod crustaceans to perform tailflips.
- The smallest species, Scyllarus pygmaeus, grows to a maximum total length of 55 mm.
- The largest species, Scyllarides haanii, may reach 50 cm in length.
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