''Longipedia'' is a genus of marine

copepod Copepods (; meaning "oar-feet") are a group of small crustaceans found in nearly every freshwater and saltwater habitat (ecology), habitat. Some species are planktonic (inhabiting sea waters), some are benthos, benthic (living on the ocean floor) ...

s of the family

Longipediidae Longipediidae is a family of copepods Copepods (; meaning "oar-feet") are a group of small crustaceans found in nearly every freshwater and saltwater habitat. Some species are planktonic (inhabiting sea waters), some are benthic (living on the ...

, order

Canuelloida Polyarthra is an order of copepods belonging to the class Copepoda Copepods (; meaning "oar-feet") are a group of small crustaceans found in nearly every freshwater and saltwater habitat. Some species are planktonic (inhabiting sea waters), so ...

. The genus ''Longipedia'' comprises 23 accepted species and is distributed worldwide. The Longipediidae generally are long and missile shaped, with segmented bodies covered by hard

chitin Chitin ( C8 H13 O5 N)n ( ) is a long-chain polymer of ''N''-acetylglucosamine, an amide derivative of glucose. Chitin is probably the second most abundant polysaccharide in nature (behind only cellulose); an estimated 1 billion tons of chit ...

. ''Longipedia'' utilize thoracopods to move, pulling themselves through the water. Distinctive features of ''Longipedia'' species are an elongated P2

endopod The arthropod leg is a form of jointed appendage of arthropods, usually used for walking. Many of the terms used for arthropod leg segments (called podomeres) are of Latin origin, and may be confused with terms for bones: ''coxa'' (meaning hip, plur ...

; and a tooth on the P2 endopod third segment. Identification and differentiation between ''Longipedia'' species can be difficult due to morphological similarities among species.

Phylogeny

Until recently the family Longipediidae was classified in the section Polyarthra of

Harpacticoida Harpacticoida is an order of copepods, in the subphylum Crustacea. This order comprises 463 genera and about 3,000 species; its members are benthic copepods found throughout the world in the marine environment (most families) and in fresh water ...

. Recent genetic analysis has reclassified that section as a separate order, the Canuelloida. The morphological differences of the Polyarthra from the other Harpacticoids have also been identified as a reason for separation of Polyarthra from the other Harpacticoids. The new order, Canuelloida, includes the families of Longipediidae and Canuellidae.

Distribution

The Longipediidae are located throughout the world in brackish and marine waters. Most frequently they have been identified in shallow marine habitats with sandy or muddy sediments. They have also been identified on

macroalgae Seaweed, or macroalgae, refers to thousands of species of macroscopic, multicellular, marine algae. The term includes some types of ''Rhodophyta'' (red), ''Phaeophyta'' (brown) and ''Chlorophyta'' (green) macroalgae. Seaweed species such as k ...

, in

seagrass beds A seagrass meadow or seagrass bed is an underwater ecosystem formed by seagrasses. Seagrasses are marine (saltwater) plants found in shallow coastal waters and in the brackish waters of estuaries. Seagrasses are flowering plants with stems and ...

and in marine plankton. Recently a new species of ''Longipedia'' has been identified in samples from a Caribbean

mesophotic coral reef A Mesophotic coral reef or mesophotic coral ecosystem (MCE), originally from the Latin word ''meso'' (meaning middle) and ''photic'' (meaning light), is characterised by the presence of both light-dependent coral and algae, and organisms that can b ...

. This species is unusual because the depth at which it was found is not typical of other ''Longipedia'' species, suggesting that the range of habitats supporting Longipediidae may be greater than previously understood.

Growth and development

Like other copepods, ''Longipedia'' larvae have a

plankton Plankton are the diverse collection of organisms found in Hydrosphere, water (or atmosphere, air) that are unable to propel themselves against a Ocean current, current (or wind). The individual organisms constituting plankton are called plankt ...

ic naupliar larval stage, and through molting go through six stages to become copepodites. Once larva metamorphose to the copepodite form, they continue to

molt In biology, moulting (British English), or molting (American English), also known as sloughing, shedding, or in many invertebrates, ecdysis, is the manner in which an animal routinely casts off a part of its body (often, but not always, an outer ...

in five stages, adding complexity and size over time. As nauplius, planktonic ''Longipedia'' have good swimming abilities. As copepodites, they remain close to a substratum.

Habitat and behavior

''Longipedia'' species 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 ancient Greek, βένθος (bénthos), meaning "t ...

or hyperbenthic

filter feeder Filter feeders are a sub-group of suspension feeding animals that feed by straining suspended matter and food particles from water, typically by passing the water over a specialized filtering structure. Some animals that use this method of feedin ...

s. In the

Mediterranean The Mediterranean Sea is a sea connected to the Atlantic Ocean, surrounded by the Mediterranean Basin and almost completely enclosed by land: on the north by Western and Southern Europe and Anatolia, on the south by North Africa, and on the e ...

, various ''Longipedia'' species were identified as

detrital Detritus (; adj. ''detrital'' ) is particles of rock derived from pre-existing rock through weathering and erosion.Essentials of Geology, 3rd Ed, Stephen Marshak, p G-7 A fragment of detritus is called a clast.Essentials of Geology, 3rd Ed, Stephen ...

feeders, while others were identified as phytophile. ''Longipedia'' species are preyed upon by small fish and corals. In

seagrass Seagrasses are the only flowering plants which grow in marine environments. There are about 60 species of fully marine seagrasses which belong to four families (Posidoniaceae, Zosteraceae, Hydrocharitaceae and Cymodoceaceae), all in the orde ...

beds they are more abundant in the

intertidal The intertidal zone, also known as the foreshore, is the area above water level at low tide and underwater at high tide (in other words, the area within the tidal range). This area can include several types of Marine habitat, habitats with var ...

zone, in the top few centimeters of substrate. In Costa Rica, ''Longipedia'' were found on the Caribbean coastline. In the mesophotic reef, the newly discovered species was collected with coral, but the sample also included substrate, so the specific habitat of the species and role in the ecosystem was not identifiable. In a study analyzing sediments and stomach contents of small fish in the North Sea, it has been noted that a species of ''Longipedia'' constituted the majority of the biomass in the sediments during the summer months. This increase was attributed to the increase in

phytoplankton Phytoplankton () are the autotrophic (self-feeding) components of the plankton community and a key part of ocean and freshwater ecosystems. The name comes from the Greek words (), meaning 'plant', and (), meaning 'wanderer' or 'drifter'. Ph ...

in sediment following the

spring bloom The spring bloom is a strong increase in phytoplankton abundance (i.e. stock) that typically occurs in the early spring and lasts until late spring or early summer. This seasonal event is characteristic of temperate North Atlantic, sub-polar, and ...

, providing ample food to the copepods, and the copepod breeding activities.

References

{{taxonbar, from=Q10569193 Copepods