Hermit crabs are anomuran decapod crustaceans of the superfamily Paguroidea that have adapted to occupy empty scavenged mollusc shells to protect their fragile exoskeletons. There are over 800 species of hermit crab, most of which possess an asymmetric abdomen concealed by a snug-fitting shell. Hermit crabs' soft (non-calcified) abdominal exoskeleton means they must occupy shelter produced by other organisms or risk being defenseless.
Raninidae is a family of unusual crabs, sometimes known as "frog crabs", on account of their frog-like appearance. They are taken by most scientists to be quite primitive among the true crabs. They closely resemble the (unrelated) mole crabs, due to parallel evolution or convergent evolution. In both groups, the claws are modified into tools for digging, and the body is a rounded shape that is easy to bury in sand. Unlike most other true crabs, the abdomens of raninids are not curled under the cephalothorax.
The Diogenidae are a family of hermit crabs, sometimes known as "left-handed hermit crabs" because in contrast to most other hermit crabs, its left chela (claw) is enlarged instead of the right. It comprises 429 extant species, and a further 46 extinct species, making it the second-largest family of marine hermit crabs, after the Paguridae.
The Paguridae are a family of hermit crabs of the order Decapoda. The king crabs, Lithodoidea, are now widely understood to be derived from deep within the Paguridae, with some authors placing their ancestors within the genus Pagurus.
Etyiidae is a prehistoric family of dromiacean crabs only known from Cretaceous and a few Paleocene fossils.
Albuneidae is a little-known family of specialized burrowing sand crabs. There are 50 extant species as well as nine fossil species that have been described. Fossil specimens have been described from the Cretaceous, Miocene and Oligocene.
Albunea is a genus of mole crab within the Albuneidae. Little is known about this group's biology. A. groeningi is named after Matt Groening, creator of The Simpsons.
Corystidae is a family of crabs, in its own superfamily, Corystoidea. It includes what was once thought to be the oldest Eubrachyuran fossil, Hebertides jurassica, thought to be dating from the Bathonian ; the species was subsequently reinterpreted as being Cenozoic in age. Corystidae contains ten extant and five extinct species in eight genera:
Ciliopagurus is a genus of hermit crabs, of the family Diogenidae, which are sometimes referred to as the "left-handed hermit crabs", because in contrast to most other hermit crabs, the left chela (claw) is enlarged instead of the right. They are found in the Indo-Pacific region and in the eastern Atlantic Ocean.
The Pylojacquesidae are a small family of hermit crabs, comprising only two monotypic genera. The family was erected in 2001, after two specimens at Museum für Naturkunde at the Humboldt University of Berlin were recognised as being quite distinct from other described hermit crabs. The family members differ from other hermit crabs in that their mandibles are chitinous and toothed.
The Galatheoidea are a superfamily of decapod crustaceans comprising the porcelain crabs and some squat lobsters. Squat lobsters within the three families of the superfamily Chirostyloidea are not closely related to the squat lobsters within the Galatheoidea. The fossil record of the superfamily extends back to the Middle Jurassic genus Palaeomunidopsis.
Mesoparapylocheles is an extinct hermit crab genus which existed during the Mesozoic in what is now Europe. It was described by René H.B. Fraaije, Adiël A. Klompmaker and Pedro Artal in 2012. The type species is Mesoparapylocheles michaeljacksoni from the Albian or Cenomanian of Spain; which was named after the singer Michael Jackson. Genus also includes other species from the Late Jurassic (Kimmeridgian) of Germany and from the Late Jurassic (Tithonian) of Austria.
Mesoparapylocheles michaeljacksoni is an extinct hermit crab species that existed during the Albian or Cenomanian in what is now Spain. It is the type species of the genus Mesoparapylocheles. It was described by René H.B. Fraaije, Adiël A. Klompmaker and Pedro Artal in 2012, and was named after the singer Michael Jackson as it was discovered on June 25, 2009, the day Jackson died.
Cretatrizocheles olazagutiensis is an extinct hermit crab which existed during the Albian or Cenomanian of what is now Spain. It was described by René H.B. Fraaije, Adiël A. Klompmaker and Pedro Artal in 2012, and is the only species in the genus Cretatrizocheles.
This list of fossil arthropods described in 2015 is a list of new taxa of trilobites, fossil insects, crustaceans, arachnids and other fossil arthropods of every kind that have been described during the year 2015. The list only includes taxa at the level of genus or species.
Parapylocheles scorpio is a species of hermit crab in the family Parapylochelidae. It lives at depths from 200 to 925 meters in the Indo-West Pacific, in Indonesia and the Philippines, although it may live in water as shallow as 100 meters, in wood fragments, tusk shells, and pieces of bamboo. It is the only member in its genus, with another genus in its family with one species in it being extinct, Mesoparapylocheles michaeljacksoni.
Necrocarcinidae is an extinct family of Late Jurassic and Cretaceous crabs. It comprises 40 species grouped in seven genera.
2020 in arthropod paleontology is a list of new arthropod fossil taxa, including arachnids, crustaceans, insects, trilobites, and other arthropods that were announced or described, as well as other significant arthropod paleontological discoveries and events which occurred in 2020.
Pirimelinae is a subfamily of crabs belonging to the family Carcinidae in the order Decapoda. It previously was treated as a family.
Xylopagurus is a genus of hermit crabs within the family Xylopaguridae. There are currently 4 species assigned to the genus.
