''Palaemon affinis'' is a

species A species () is often defined as the largest group of organisms in which any two individuals of the appropriate sexes or mating types can produce fertile offspring, typically by sexual reproduction. It is the basic unit of Taxonomy (biology), ...

shrimp A shrimp (: shrimp (American English, US) or shrimps (British English, UK)) is a crustacean with an elongated body and a primarily Aquatic locomotion, swimming mode of locomotion – typically Decapods belonging to the Caridea or Dendrobranchi ...

of the

family Family (from ) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). It forms the basis for social order. Ideally, families offer predictabili ...

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 commerci ...

. 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 only 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 foun ...

to the waters of

New Zealand New Zealand () is an island country in the southwestern Pacific Ocean. It consists of two main landmasses—the North Island () and the South Island ()—and List of islands of New Zealand, over 600 smaller islands. It is the List of isla ...

Taxonomy

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

Henri Milne-Edwards Henri Milne-Edwards (23 October 1800 – 29 July 1885) was a 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 Frenchwoman. Hen ...

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

subgenus In biology, a subgenus ( 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 between the ge ...

(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 The sub-Antarctic zone is a physiographic region in the Southern Hemisphere, located immediately north of the Antarctic region. This translates roughly to a latitude of between 46° and 60° south of the Equator. The subantarctic region inc ...

and

Australia Australia, officially the Commonwealth of Australia, is a country comprising mainland Australia, the mainland of the Australia (continent), Australian continent, the island of Tasmania and list of islands of Australia, numerous smaller isl ...

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 nutrition and energy requirements are met by consumption of animal tissues (mainly mu ...

. Based on examination of stomach contents, they appear to primarily feed upon

amphipods Amphipoda () is an order (biology), 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 10,700 amphip ...

, but may also eat

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

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

bivalves Bivalvia () or bivalves, in previous centuries referred to as the Lamellibranchiata and Pelecypoda, is a class of aquatic molluscs (marine and freshwater) that have laterally compressed soft bodies enclosed by a calcified exoskeleton consis ...

and plant material.

References

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