Pleustidae is a family of

cosmopolitan Cosmopolitan may refer to: Internationalism * World citizen, one who eschews traditional geopolitical divisions derived from national citizenship * Cosmopolitanism, the idea that all of humanity belongs to a single moral community * Cosmopolitan ...

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 ...

belonging to the order

Amphipoda 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 ...

. Generally, members of this family are

benthic The benthic zone is the ecological region at the lowest level of a body of water such as an ocean, lake, or stream, including the sediment surface and some sub-surface layers. The name comes from the Ancient Greek word (), meaning "the depths". ...

carnivores. They are characterized by tooth-like projections on their dorsal plates, as well as specialized gnathopods for grabbing prey.

Description

Pleustid amphipods typically measure between . They can possess strong colorations, from solid black and white to spotted and mottled sandy colors. Sometimes, they are brightly colored, which is hypothesized to be an example of

aposematism Aposematism is the Advertising in biology, advertising by an animal, whether terrestrial or marine, to potential predation, predators that it is not worth attacking or eating. This unprofitability may consist of any defenses which make the pr ...

. Carinated, tooth-like projections of the dorsal surface of the

pereon The anatomy of a decapod consists of 20 body segments grouped into two main body parts: the cephalothorax and the pleon (abdomen). Each segment – often called a somite – may possess one pair of appendages, although in various groups these ma ...

and

pleon The anatomy of a decapod consists of 20 body segments grouped into two main body parts: the cephalothorax and the pleon (abdomen). Each segment – often called a somite – may possess one pair of appendages, although in various groups these ma ...

segments are common in this family. Another important diagnostic characteristic is the shape of the lower lip, where the outer lobes are tilted at an odd angle and the inner lobes are broad. Other characteristics of the family include the second urosome segment being smaller than the first and third segments, the

rostrum Rostrum may refer to: * Any kind of a platform for a speaker: **dais **pulpit ** podium * Rostrum (anatomy), a beak, or anatomical structure resembling a beak, as in the mouthparts of many sucking insects * Rostrum (ship), a form of bow on naval ...

typically curving downwards, the first pair of antennae typically having a highly reduced accessory

flagellum A flagellum (; : flagella) (Latin for 'whip' or 'scourge') is a hair-like appendage that protrudes from certain plant and animal sperm cells, from fungal spores ( zoospores), and from a wide range of microorganisms to provide motility. Many pr ...

, the second pair of gnathopods being larger than the first, and the presence of a short

telson The telson () is the hindmost division of the body of an arthropod. Depending on the definition, the telson is either considered to be the final segment (biology), segment of the arthropod body, or an additional division that is not a true segm ...

. This family may be difficult to distinguish from members of the superfamily Eusiroidea, as they share many common characteristics, including pointed heads and appendages of similar shapes.

Distribution

Species of Pleustids have been described from across the globe, including

Antarctica Antarctica () is Earth's southernmost and least-populated continent. Situated almost entirely south of the Antarctic Circle and surrounded by the Southern Ocean (also known as the Antarctic Ocean), it contains the geographic South Pole. ...

. Many of the described species come from the west coast of

North America North America is a continent in the Northern Hemisphere, Northern and Western Hemisphere, Western hemispheres. North America is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the southeast by South Ameri ...

Reproduction

Members of the family Pleustidae may possess some degree of

sexual dimorphism Sexual dimorphism is the condition where sexes of the same species exhibit different Morphology (biology), morphological characteristics, including characteristics not directly involved in reproduction. The condition occurs in most dioecy, di ...

, though these differences are small. Females may be slightly larger than males, have smaller eyes, and have numerous differences of the various

appendages An appendage (or outgrowth) is an external body part or natural prolongation that protrudes from an organism's body such as an arm or a leg. Protrusions from single-celled bacteria and archaea are known as cell-surface appendages or surface app ...

. Unlike in family

Phoxocephalidae Phoxocephalidae is a family of small, shrimp-like crustaceans in the suborder Gammaridea described by Georg Ossian Sars in 1891. It contains '' Cocoharpinia iliffei'', a critically endangered species on the IUCN Red List The International U ...

, Pleustid amphipods do not aggregate in swarms to reproduce.

Genera

The family contains 36 genera in 12 subfamilies: * Subfamily Atylopsinae **'' Atylopsis'' **'' Myzotarsa'' * Subfamily Austropleustinae **'' Austropleustes'' **'' Tepidopleustes'' * Subfamily Dactylopleustinae **'' Dactylopleustes'' * Subfamily Eosymtinae **'' Cognateosymtes'' **'' Eosymtes'' * Subfamily Mesopleustinae **'' Mesopleustes'' * Subfamily Neopleustinae **'' Hendrycksopleustes'' **'' Neopleustes'' **'' Pleustostenus'' **'' Shoemakeroides'' * Subfamily Parapleustinae **'' Chromopleustes'' **'' Commensipleustes'' **'' Gnathopleustes'' **'' Incisocalliope'' **'' Micropleustes'' **'' Parapleustes'' **'' Trachypleustes'' * Subfamily Pleusirinae **'' Pleusirus'' * Subfamily Pleustinae **'' Pleustes'' **'' Thorlaksonius'' * Subfamily Pleustoidinae **'' Pleustoides'' * Subfamily Pleusymtinae **'' Anomalosymtes'' **'' Budnikopleustes'' **'' Heteropleustes'' **'' Holopleustes'' **'' Kamptopleustes'' **'' Pleustomesus'' **'' Pleusymtes'' **'' Rhinopleustes'' **'' Vinogradovopleustes'' * Subfamily Stenopleustinae **'' Arctopleustes'' **'' Domicola'' **'' Gracilipleustes'' **'' Stenopleustes''

References

{{Authority control Amphipod families