Hymenocaris
Encyclopedia
Hymenocaris is a genus
of Cambrian
crustacean
s. Some species originally assigned to Hymenocaris were later transferred to Canadaspis
, such as Canadaspis perfecta (Hymenocaris perfecta), leaving only Hymenocaris vermicauda. Differences between Hymenocaris and Canadaspis have been used to justify erecting a separate family
, Hymenocarididae and order
, Hymenostraca for Hymenocaris, although it is also sometimes placed in the family Canadaspididae and the order Canadaspidida.
Genus
In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...
of Cambrian
Cambrian
The Cambrian is the first geological period of the Paleozoic Era, lasting from Mya ; it is succeeded by the Ordovician. Its subdivisions, and indeed its base, are somewhat in flux. The period was established by Adam Sedgwick, who named it after Cambria, the Latin name for Wales, where Britain's...
crustacean
Crustacean
Crustaceans form a very large group of arthropods, usually treated as a subphylum, which includes such familiar animals as crabs, lobsters, crayfish, shrimp, krill and barnacles. The 50,000 described species range in size from Stygotantulus stocki at , to the Japanese spider crab with a leg span...
s. Some species originally assigned to Hymenocaris were later transferred to Canadaspis
Canadaspis
Canadaspis was a Cambrian genus of crustacean or euarthropod, a benthic feeder that moved mainly by walking and possibly used its biramous appendages to stir mud in search of food...
, such as Canadaspis perfecta (Hymenocaris perfecta), leaving only Hymenocaris vermicauda. Differences between Hymenocaris and Canadaspis have been used to justify erecting a separate family
Family (biology)
In biological classification, family is* a taxonomic rank. Other well-known ranks are life, domain, kingdom, phylum, class, order, genus, and species, with family fitting between order and genus. As for the other well-known ranks, there is the option of an immediately lower rank, indicated by the...
, Hymenocarididae and order
Order (biology)
In scientific classification used in biology, the order is# a taxonomic rank used in the classification of organisms. Other well-known ranks are life, domain, kingdom, phylum, class, family, genus, and species, with order fitting in between class and family...
, Hymenostraca for Hymenocaris, although it is also sometimes placed in the family Canadaspididae and the order Canadaspidida.