Terrestrial-crustacean
Guides
Armadillidiidae
pill bugs, roly polies, pill woodlice, slaters, potato bugs, curly bugs, doodle bugs, Butchy-Boys
Armadillidiidae is a family of terrestrial isopod crustaceans distinguished by their ability to roll into a complete ball (conglobation) when disturbed. This defensive behavior, shared with unrelated pill millipedes and some other arthropods, has made them commonly known as pill bugs or roly polies. The family contains approximately 18 recognized genera and shows highest diversity in Mediterranean karstic regions, with some species having achieved widespread global distribution through human activity.
Armadillidium
pill woodlice, leg pebbles, pill bugs, roly-poly, potato bugs
Armadillidium is a genus of terrestrial crustaceans commonly known as pill bugs or roly-polies, distinguished by their ability to roll into a ball when disturbed (conglobation). The genus contains approximately 189 recognized species, most endemic to Mediterranean regions. These detritivores inhabit moist environments and play important roles in decomposition. The most widespread species, A. vulgare, has been introduced globally and serves as a soil bioindicator.
Armadillidium nasatum
Nosy Pill Woodlouse
Armadillidium nasatum is a large woodlouse species native to Western Europe, particularly Britain, that has been introduced to North America and other regions. It reaches up to 21 mm in length and is distinguished from congeners by a rectangular protrusion ("nose") at the apex of the head and a rounded tail tip with incurved sides. Unlike some relatives, it does not form a complete ball when enrolled. The species exhibits synanthropic tendencies and prefers drier habitats than most woodlice.
Armadilloniscus
Driftclingers
Armadilloniscus is a genus of terrestrial isopods (woodlice) in the family Detonidae, first described by Uljanin in 1875. The genus contains at least 30 described species, commonly referred to as driftclingers. These organisms are part of the diverse crustacean fauna found in various terrestrial and coastal environments.
Atlantoscia floridana
Florida Fast Woodlouse
Atlantoscia floridana is a terrestrial isopod (woodlouse) in the family Philosciidae. The species has been documented in North America, South America, and Africa, indicating a broad transatlantic distribution. It is known to be relatively fragile compared to other woodlice but naturally high in calcium content. In captive settings, it shows preferences for specific humidity gradients.
Cubaris
Reclined Pill Woodlice
Cubaris is a genus of woodlice (terrestrial isopods) in the family Armadillidae, established in 1833 with Cubaris murina as the type species. The genus contains more than 100 described species, though it has become a wastebasket taxon with many species placed in it that do not fit the original description. Species in this genus are capable of conglobation (rolling into a ball) and have been widely used in ecotoxicity testing due to their sensitive behavioral responses to soil contaminants. Several Cubaris species, particularly undescribed forms such as "Rubber Ducky," have become popular in the pet trade.
Cylisticus
Cylisticus is a genus of woodlice (terrestrial isopods) in the family Cylisticidae, containing at least 70 described species. These soil-dwelling crustaceans are found in tropical and temperate regions, where they inhabit the upper soil layers. At least one species, C. convexus, has been studied as a tropical soil decomposer with limited vertical dispersal ability. The genus is part of the diverse oniscidean fauna contributing to litter breakdown and nutrient cycling.
Diplocheta
Rock Slaters
Diplocheta is an infraorder of terrestrial isopods commonly known as rock slaters. Members of this group are adapted to coastal and intertidal environments, showing morphological specializations for life in these habitats. The group was established by Vandel in 1957 and includes the family Ligiidae. These isopods represent an evolutionary transition between fully marine and fully terrestrial lifestyles.
Floridoscia
Floridoscia is a genus of terrestrial isopods (woodlice) in the family Philosciidae, described in 1984 by Schultz and Johnson. As members of the suborder Oniscidea, these crustaceans are fully adapted to land. The genus is endemic to Florida and contains species restricted to this region.
Floridoscia fusca
Florida Rufous Woodlouse
Floridoscia fusca is a terrestrial isopod species in the family Philosciidae, commonly known as the Florida Rufous Woodlouse. It is native to North America and belongs to the suborder Oniscidea, which encompasses the majority of terrestrial isopods. The species was described by Schultz and Johnson in 1984.
Holoverticata
Woodlice and Pillbugs
Holoverticata is an infraorder of isopod crustaceans encompassing the familiar terrestrial woodlice and pillbugs. Members of this group are distinguished by their dorsoventrally flattened bodies, seven pairs of walking legs, and ability to occupy moist terrestrial habitats. The group includes species capable of conglobation (rolling into a ball) as well as those that remain flattened. This infraorder represents the most successful lineage of crustaceans to colonize land.
Isopoda
isopods, woodlice, pillbugs, sowbugs, sea slaters, gribbles
Isopoda is an ancient order of crustaceans encompassing over 10,000 described species across marine, freshwater, and terrestrial habitats. Members are characterized by dorsoventrally flattened bodies, seven pairs of similar walking legs (giving the group its name from Greek iso- "equal" and pod- "foot"), and two pairs of antennae. The order exhibits exceptional morphological diversity, ranging from minute interstitial forms to giant deep-sea species exceeding 30 cm in length. Isopods lack a carapace, instead possessing overlapping dorsal plates that provide flexibility and protection. Females brood eggs in a specialized marsupium formed by oostegites under the thorax.
Ligidium kofoidi
Kofoid's Rockslater
Ligidium kofoidi is a species of woodlouse in the family Ligiidae, described by Maloney in 1930. It is a small to medium-sized terrestrial isopod found in North America. The species is rarely documented, with only a handful of observations recorded. As a member of the genus Ligidium, it inhabits moist terrestrial environments and belongs to a group commonly known as rockslaters.
Littorophiloscia vittata
Eastern Saltmarsh Woodlouse
Littorophiloscia vittata is a woodlouse species in the family Halophilosciidae, native to the east coast of North America. It inhabits saltmarsh environments, typically found under boards and debris. The species was first described by Thomas Say in 1818. As a member of the suborder Oniscidea, it belongs to the diverse group of terrestrial isopods commonly known as woodlice or pill bugs.
Miktoniscus spinosus
Eastern Mikto
Miktoniscus spinosus is a small terrestrial isopod in the family Trichoniscidae, commonly known as the Eastern Mikto. It belongs to the suborder Oniscidea, which encompasses the familiar woodlice and pill bugs. The species is native to the eastern United States, with documented presence in New England. As a member of the Synocheta, it represents one of the more derived lineages of terrestrial isopods.
Nagurus
Nagurus is a genus of terrestrial isopods in the family Trachelipodidae, established by Holthuis in 1949. These woodlice are found in tropical and subtropical regions, with records from northern Europe and Southeast Asia suggesting either introduced populations or broader native distribution than currently documented. The genus comprises small to medium-sized isopods adapted to life on land.
Oniscus asellus
common woodlouse, common shiny woodlouse, European sowbug
Oniscus asellus is a large terrestrial isopod native to Western and Northern Europe, and one of the most widespread woodlouse species in the British Isles. It reaches up to 16 mm in length and inhabits diverse moist environments, including rotting wood, gardens, and human structures. The species exhibits biphasic moulting, consuming its shed exoskeleton, and has been documented to fragment weathered polystyrene plastic into microplastics. Two subspecies are recognized: the widespread O. a. asellus and the smaller, more colorful O. a. occidentalis in western France and southeastern Britain.
Peracarida
Amphipods, Isopods, and Allies
Peracarida is a superorder of malacostracan crustaceans comprising approximately 12,000 species across 13 orders. The group is defined by the presence of a marsupium (brood pouch) formed by oostegites—flattened plates on the basalmost leg segments of females. Members occupy marine, freshwater, and terrestrial habitats, ranging from minute interstitial forms to the giant isopod Bathynomus giganteus (76 cm) and giant amphipod Alicella gigantea (34 cm). The earliest known peracaridian, Oxyuropoda ligioides, dates to the Late Devonian (~360 mya).
Porcellio spinicornis
Brickwork Woodlouse
Porcellio spinicornis is a medium-sized terrestrial isopod in the family Porcellionidae, native to Europe and introduced to North America. It is distinguished by prominent spiny frontal lateral lobes, the feature referenced in its species name. The species is nocturnal and detritivorous, feeding on dead plant material. It exhibits direct development with eggs and juveniles carried in a fluid-filled marsupium until the first juvenile stage.
Porcellionides floria
Flowery Blue Isopod
Porcellionides floria is a species of terrestrial isopod (woodlouse) in the family Porcellionidae, first described by Garthwaite and Sassaman in 1985. The species has been recorded in North America and Mexico, with 89 observations documented on iNaturalist as of the source date. Like other members of its family, it is a detritivorous crustacean adapted to life on land.
Proporcellio vulcanius
Proporcellio vulcanius is a terrestrial isopod in the family Porcellionidae, described by Verhoeff in 1908. The species belongs to a genus characterized by reduced pleopodal lungs and adaptation to drier microhabitats compared to many woodlice. Records indicate presence across parts of Europe and northern Asia. The specific epithet 'vulcanius' suggests possible association with volcanic or warm habitats, though this has not been formally verified.
Rhyscotus
armadillo woodlice
Rhyscotus is a genus of armadillo woodlice in the family Rhyscotidae, first described by Gustav Budde-Lund in 1885. The genus contains twelve recognized species distributed across multiple continents. Members of this genus are terrestrial isopods adapted to life on land.
Venezillo pisum
Venezillo pisum is a species of terrestrial isopod in the family Armadillidae, first described by Budde-Lund in 1885. The specific epithet 'pisum' (Latin for 'pea') likely refers to some aspect of its appearance or behavior, though the original description's reasoning is not preserved in available sources. As a member of the Oniscidea (woodlice and pill bugs), it is a detritivore inhabiting moist terrestrial environments. The species has been recorded in North America, though it may represent an introduced population given its original description from European material.