''Palaemon affinis'' is a

species In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate s ...

of shrimp of the

family Family (from la, familia) is a group of people related either by consanguinity (by recognized birth) or affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its members and of society. Idea ...

Palaemonidae Palaemonidae is a family of shrimp in the order Decapoda. Many species are carnivores that eat small invertebrates, and can be found in any aquatic habitat except the deep sea. One significant genus is ''Macrobrachium'', which contains commercia ...

. Early authors used the name ''Palaemon affinis'' for specimens now known to belong to a variety of species, but ''P. affinis'' is now known to be

endemic Endemism is the state of a species being found in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also found else ...

to the waters of

New Zealand New Zealand ( mi, Aotearoa ) is an island country in the southwestern Pacific Ocean. It consists of two main landmasses—the North Island () and the South Island ()—and over 700 smaller islands. It is the sixth-largest island count ...

Taxonomy

''Palaemon affinis'' was first described in 1837 by Henri Milne-Edwards as ''Palaemon affinis'' and ''Palaemon quoianus''. In 1876, ''P. affinis'' was placed in the ''Leander'' subgenus (which is a subgenus of '' Palaemon''). In 1954, ''P. affinis'' was moved to the ''Palaemon'' subgenus and ''P. quoianus'' was recognized as a synonym for ''P. affinis''.

Distribution and habitat

Although previously thought to be present in many other countries, the species is now only known to occur in New Zealand. However, it has been noted that some specimens in the subantarctic islands and Australia may also be ''Palaemon affinis''. It has been suggested that prey abundance is the main factor controlling the distribution of ''P. affinis''. ''P. affinis'' occurs along shores in rocky intertidal zones and in estuaries. The shrimp is very tolerant of salinity changes and can survive in water with a salinity of 5-43%

Diet

The species is mostly carnivorous. Based on examination of stomach contents, they appear to primarily feed upon

amphipods Amphipoda is an order of malacostracan crustaceans with no carapace and generally with laterally compressed bodies. Amphipods range in size from and are mostly detritivores or scavengers. There are more than 9,900 amphipod species so far describ ...

, but may also eat

polychaete Polychaeta () is a paraphyletic class of generally marine annelid worms, commonly called bristle worms or polychaetes (). Each body segment has a pair of fleshy protrusions called parapodia that bear many bristles, called chaetae, which are made ...

gastropods The gastropods (), commonly known as snails and slugs, belong to a large taxonomic class of invertebrates within the phylum Mollusca called Gastropoda (). This class comprises snails and slugs from saltwater, from freshwater, and from land. The ...

, bivalves and plant material.

References

{{Taxonbar, from=Q7126385 Palaemonidae Marine crustaceans of New Zealand Crustaceans described in 1837 Taxa named by Henri Milne-Edwards