Taxa named by Arnold Edward Ortmann

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 47 extinct species, making it the second-largest family of marine hermit crabs, after the Paguridae.

Procambarus is a genus of crayfish in the family Cambaridae, all native to North and Central America. It includes a number of troglobitic species, and the marbled crayfish (marmorkrebs), which is parthenogenetic. Originally described as a subgenus for four species, it now contains around 161 species.

Menippidae is a family of crabs of the order Decapoda.

Cambarellus is a genus of small freshwater crayfish in the family Cambaridae. The 19 species are found in Mexico (subgenus Cambarellus) and the Gulf States of the United States (subgenus Pandicambarus). Among the Mexican species, C. areolatus, C. patzcuarensis, and C. prolixus are considered seriously threatened by the IUCN, and C. alvarezi is already extinct. C. chihuahuae was also believed to be extinct until rediscovered in 2012. C. alvarezi and four undescribed, extinct Cambarellus species were restricted to desert spring systems in southwestern Nuevo León; each one shared its habitat with

Atelecyclidae is a family of crabs belonging to the superfamily Cancroidea, and currently contains eight genera of which two are extinct. However, the genera other than Atelecyclus and Pseudocorystes do not belong in the Cancroidea, and are to be removed from the family. Atelecyclus † Levicyclus † Palaeotrichia Peltarion Podocatactes Pseudocorystes Protopeltarion Trichopeltarion

Cheiragonidae is a small family of crabs, sometimes called helmet crabs, placed in its own superfamily, Cheriagonoidea. It comprises three extant species, Erimacrus isenbeckii, Telmessus acutidens and Telmessus cheiragonus; there are no yet evidences of Cheiragonidae in the fossil record. Many of these crabs were formerly treated as members of the Atelecyclidae.

The Processidae are a family of shrimp, comprising 65 species in five genera, and the only family in the superfamily Processoidea. They are small, nocturnal animals, mostly living in shallow seas, particularly on grass flats. The first pereiopods are usually asymmetrical, with a claw on one, but not the other (Ambidexter forming the exception to this rule). The rostrum is generally a simple projection from the front of the carapace, with two teeth, one at the tip, and one further back.

species of mollusc

Dynomenidae is a family of crabs in the superfamily Dromioidea mostly found in Madagascar. There are nineteen genera in this family: five extant and fourteen known from fossils:

species of crustacean

thumb|Harpactoxanthopsis quadrilobata fossil, Middle Eocene, Venetia Region, northern Italy

genus of crustaceans

Chirostyloidea is an anomuran superfamily with squat lobster-like representatives. It comprises the three families Chirostylidae, Eumunididae and Kiwaidae. Although representatives of Chirostyloidea are superficially similar to galatheoid squat lobsters, they are more closely related to Lomisoidea and Aegloidea together forming the clade Australopoda. No fossils can be confidently assigned to the Chirostyloidea, although Pristinaspina may belong either in the family Kiwaidae or Chirostylidae.

species of crustacean

species of mollusc

species of crustacean

species of crustacean

species of crustacean

Faxonius is a genus of freshwater crayfish in the family Cambaridae. There are more than 90 described species in Faxonius. It includes the rusty crayfish, an invasive species in North America, and three species, F. virilis, F. immunis, and F. limosus, that are invasive to Europe.

species of crab

species of king crab