Halocaridina

Taxobox
name = "Halocaridina"

---

image_caption= Ovigerous okinaōpaeokinaula
regnum = Animalia
phylum = Arthropoda
subphylum = Crustacea
classis = Malacostraca
ordo = Decapoda
subordo = Pleocyemata
infraordo = Caridea
familia = Atyidae
genus = "Halocaridina"
species = "H. rubra"
binomial = "Halocaridina rubra"
binomial_authority = Holthuis, 1963

"Halocaridina rubra" is a small red shrimp of the family Atyidae, with the common Hawaiian name okinaōpaeokinaula (meaning "red shrimp").

It is a small red shrimp, rarely longer than 1½ cm in length, typically found in brackish water pools near the sea shore, sometimes in large numbers. Such pools are referred to as anchialine pools (from the Greek "anchialos" = near the sea).

okinaŌpaeokinaula are herbivorous and detritivorous shrimp occupying both hypogeal (subterranean) and epigeal (surface) anchialine waters. They are endemic to the Hawaiian islands, and most commonly found in anchialine pools in fresh lava substrates on Hawaiokinai and Maui Island, but have been found in limestone karst pools and hypogeal habitats in limestone on older islands, such as Ookinaahu.

Typical food of okinaōpaeokinaula is algal and bacterial mats on the surface of rocks and other substrates in anchialine pools. Chelipeds are adapted for scraping and filtering of algal-bacterial layers.Serrated setae scrape the substrate surface, and filamentous setae collect the loosened food materials. The latter can also act as filters, although filter feeding is only observed in pools with dense phytoplankton blooms.

The grazing activity of this shrimp is essential in maintaining the integrity of the crust, an actively growing matrix of plants, bacteria, diatoms, protozoans, and underlying siliceous and carbonate materials.

"Halocaridina" is well adapted to the epigeal-hypogeal habitat in the pools. It reproduces in the subterranean portion of the habitat.

Its habitat is unique and sparsely represented on five of the eight high Hawaiian Islands.

Recent popularity of okinaōpaeokinaula as a low-maintenance pet in Hawaiokinai and elsewhere has brought this otherwise obscure decapod crustacean into popular consciousness. A long-lived species, okinaōpaeokinaula have been known to live for as long as 20 years in captivity. Sexes are difficult to distinguish, but gravid females carry clusters of red/maroon eggs under their pleopods, and early larvae are planktonic filter-feeders.

References

*cite journal |quotes=no |author=J. H. Bailey-Brock & R. E. Brock |year=1993 |title=Feeding, reproduction, and sense organs of the Hawaiian anchialine shrimp "Halocaridina rubra" (Atyidae) |journal=Pacific Science |volume=47 |issue=4 |pages=338–355
*Santos, S.R. (2006) Patterns of genetic connectivity among anchialine habitats: a case study of the endemic Hawaiian shrimp Halocaridina rubra on the island of Hawaii. Mol Ecol, 15, 2699-2718.
*Ivey, J.L. and Santos, S.R. (2007) The complete mitochondrial genome of the Hawaiian anchialine shrimp Halocaridina rubra Holthuis, 1963 (Crustacea: Decapoda: Atyidae). Gene, 394, 35-44.