''Neomysis integer'' is a species of
opossum shrimp
Mysida is an order of small, shrimp-like crustaceans in the malacostracan superorder Peracarida. Their common name opossum shrimps stems from the presence of a brood pouch or "marsupium" in females. The fact that the larvae are reared in this ...
found in shallow marine bays and
estuaries
An estuary is a partially enclosed coastal body of brackish water with one or more rivers or streams flowing into it, and with a free connection to the open sea. Estuaries form a transition zone between river environments and maritime environment ...
of
Europe
Europe is a large peninsula conventionally considered a continent in its own right because of its great physical size and the weight of its history and traditions. Europe is also considered a Continent#Subcontinents, subcontinent of Eurasia ...
, with a transparent greenish or brownish body and a large
cephalothorax
The cephalothorax, also called prosoma in some groups, is a tagma of various arthropods, comprising the head and the thorax fused together, as distinct from the abdomen behind. (The terms ''prosoma'' and ''opisthosoma'' are equivalent to ''cepha ...
. It is found in very shallow water in both high and low-salinity habitats. It is a filter feeder and the female broods her eggs in a
brood pouch beneath her cephalothorax.
Description
''Neomysis integer'' is a slender opossum shrimp growing to a maximum length of about . The head has a pair of large, stalked eyes and two pairs of
antennae, both of which are
biramous (branched into two parts). The exopod (the outermost branch) of the second antenna forms an elongated scale with bristles round its edges and extends forward into a sharp point. The thorax has eight segments each bearing a pair of biramous limbs, the outer branches of which have a feathery appearance. The head and first six segments of the thorax are covered by a protective
carapace
A carapace is a Dorsum (biology), dorsal (upper) section of the exoskeleton or shell in a number of animal groups, including arthropods, such as crustaceans and arachnids, as well as vertebrates, such as turtles and tortoises. In turtles and tor ...
which extends forward in a triangular plate with a depressed centre between the eyes. The abdomen bears short limbs and the last segment bears larger, flattened biramous limbs which form a tail fan. The
telson
The telson () is the posterior-most division of the body of an arthropod. Depending on the definition, the telson is either considered to be the final segment of the arthropod body, or an additional division that is not a true segment on accou ...
(the last abdominal segment between the tail fan) is not forked, a fact emphasised by the
specific name Specific name may refer to:
* in Database management systems, a system-assigned name that is unique within a particular database
In taxonomy, either of these two meanings, each with its own set of rules:
* Specific name (botany), the two-part (bino ...
''"integer"''. This opossum shrimp is semi-transparent, sometimes with a brownish tinge.
[
]
Distribution and habitat
''Neomysis integer'' is native to the northeastern Atlantic Ocean, its range extending from the Baltic Sea and North Sea to the Mediterranean. It is found just above the seabed in very shallow waters in coastal and estuarine habitats at a wide range of salinities and is able to adapt to changing salinity levels.[ It is often the commonest mysid shrimp in the low-salinity upper parts of estuaries.][ It is also present in lakes in ]Frisia
Frisia is a cross-border cultural region in Northwestern Europe. Stretching along the Wadden Sea, it encompasses the north of the Netherlands and parts of northwestern Germany. The region is traditionally inhabited by the Frisians, a West Ger ...
that were originally linked to the sea but became isolated when the Afsluitdijk causeway was constructed in 1933. Over the succeeding years, the sea water gradually turned to freshwater and ''Neomysis integer'' was the only opossum shrimp that survived.
Biology
These opossum shrimps are frequently found in large numbers and filter small food particles out of the water, occasionally consuming larger prey. The diet consists largely of detritus, but water fleas
The Diplostraca or Cladocera, commonly known as water fleas, are a superorder of small crustaceans that feed on microscopic chunks of organic matter (excluding some predatory forms).
Over 1000 species have been recognised so far, with many more ...
and 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 are also consumed. Opossum shrimps themselves often fall prey to fish
Fish are aquatic, craniate, gill-bearing animals that lack limbs with digits. Included in this definition are the living hagfish, lampreys, and cartilaginous and bony fish as well as various extinct related groups. Approximately 95% of li ...
. In the Frisian Lakes these include the European perch (''Perca fluviatilis''), the European smelt (''Osmerus eperlanus''), the ruffe (''Gymnocephalus cernua''), young pike-perch
''Sander'' (formerly known as ''Stizostedion'') is a genus of predatory ray-finned fish in the Family (biology), family Percidae, which also includes the perches, Gymnocephalus, ruffes, and Darter (fish), darters. They are also known as "pike-pe ...
(''Sander lucioperca'') and sometimes the European eel
The European eel (''Anguilla anguilla'') is a species of eel, a snake-like, catadromous fish. They are normally around and rarely reach more than , but can reach a length of up to in exceptional cases.
Eels have been important sources of fo ...
(''Anguilla anguilla'').[ The females have a brood pouch under their thorax in which eggs and young develop.]
References
{{Taxonbar, from=Q3858315
Mysida
Crustaceans described in 1814