''Palaemon affinis'' is a

species In biology, a species is the basic unit of Taxonomy (biology), 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 ...

shrimp Shrimp are crustaceans (a form of shellfish) with elongated bodies and a primarily swimming mode of locomotion – most commonly Caridea and Dendrobranchiata of the decapod order, although some crustaceans outside of this order are refer ...

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 commer ...

. 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 els ...

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 List of islands of New Zealand, smaller islands. It is the ...

Taxonomy

''Palaemon affinis'' was first described in 1837 by

Henri Milne-Edwards Henri Milne-Edwards (23 October 1800 – 29 July 1885) was an eminent French zoologist. Biography Henri Milne-Edwards was the 27th child of William Edwards, an English planter and colonel of the militia in Jamaica and Elisabeth Vaux, a Frenchw ...

as ''Palaemon affinis'' and ''Palaemon quoianus''. In 1876, ''P. affinis'' was placed in the ''Leander''

subgenus In biology, a subgenus (plural: subgenera) is a taxonomic rank directly below genus. In the International Code of Zoological Nomenclature, a subgeneric name can be used independently or included in a species name, in parentheses, placed betw ...

(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 A carnivore , or meat-eater (Latin, ''caro'', genitive ''carnis'', meaning meat or "flesh" and ''vorare'' meaning "to devour"), is an animal or plant whose food and energy requirements derive from animal tissues (mainly muscle, fat and other ...

. 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 descri ...

, 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 ...

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. ...

bivalves Bivalvia (), in previous centuries referred to as the Lamellibranchiata and Pelecypoda, is a class of marine and freshwater molluscs that have laterally compressed bodies enclosed by a shell consisting of two hinged parts. As a group, biv ...

and plant material.

References

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