Purple shore crab

Purple shore crab
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Arthropoda
Class:	Malacostraca
Order:	Decapoda
Suborder:	Pleocyemata
Infraorder:	Brachyura
Family:	Varunidae
Genus:	Hemigrapsus
Species:	H. nudus
Binomial name
Hemigrapsus nudus (Dana, 1851)
Synonyms
Grapsus marmoratus White, 1847 Pseudograpsus nudus Dana, 1851 Heterograpsus nudus (Dana, 1851) Heterograpsus marmoratus Milne-Edwards, 1853 Brachynotus nudus

The purple shore crab (Hemigrapsus nudus or the naked shore crab^[1]) is a common crab of the family Varunidae that is indigenous to the west coast of United States, Canada, and Mexico. H. nudus was first described in 1847 by Adam White, and in 1851, James Dwight Dana formally classified the species. H. nudus is a small, amphibious crab that is similar physically and behaviorally to Pachygrapsus crassipes and Hemigrapsus oregonensis. The purple shore crab is generally a dark purple color with olive green, red, and white spots. Mating season for H. nudus begins in mid-winter and larval crabs undergo 5 zoeal stages and a juvenile stage. Adult crabs mainly feed on algae but will occasionally scavenge other animals. H. nudus prefers inter-tidal and sub-tidal zones, and it can oftentimes be found sheltering under rocks or other debris. H. nudus demonstrates complex compensatory mechanisms to counteract fluctuating salinity and water oxygen concentrations, permitting it to live in a variety of different environments.