''Leptodora'' is a genus containing two
species
In biology, a species is the basic unit of 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 the appropriate s ...
of large, nearly
transparent
Transparency, transparence or transparent most often refer to:
* Transparency (optics), the physical property of allowing the transmission of light through a material
They may also refer to:
Literal uses
* Transparency (photography), a still, ...
predatory
Predation is a biological interaction where one organism, the predator, kills and eats another organism, its prey. It is one of a family of common feeding behaviours that includes parasitism and micropredation (which usually do not kill th ...
water flea
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 ...
s. They grow up to long, with two large
antennae used for swimming and a single
compound eye
A compound eye is a visual organ found in arthropods such as insects and crustaceans. It may consist of thousands of ommatidia, which are tiny independent photoreception units that consist of a cornea, lens, and photoreceptor cells which disti ...
. The legs are used to catch
copepods that it comes into contact with by chance. ''Leptodora kindtii'' is found in temperate lakes across the
Northern Hemisphere and is probably the only cladoceran ever
described in a
newspaper
A newspaper is a Periodical literature, periodical publication containing written News, information about current events and is often typed in black ink with a white or gray background.
Newspapers can cover a wide variety of fields such as p ...
; ''L. richardi'' is only known from eastern
Russia
Russia (, , ), or the Russian Federation, is a transcontinental country spanning Eastern Europe and Northern Asia. It is the largest country in the world, with its internationally recognised territory covering , and encompassing one-eig ...
. For most of the year, ''Leptodora'' reproduces
parthenogenetically, with males only appearing late in the season, to produce winter eggs which hatch the following spring. ''Leptodora'' is the only genus in its family, the Leptodoridae, and suborder, Haplopoda.
Description
Adults of ''Leptodora'' are the largest
plankton
Plankton are the diverse collection of organisms found in water (or air) that are unable to propel themselves against a current (or wind). The individual organisms constituting plankton are called plankters. In the ocean, they provide a crucia ...
ic cladocerans native to North America; reports vary concerning the largest size, but adult females typically grow to long, but with some reports of females up to .
They are about 98% transparent,
as a defense against predation by
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 ...
. Lilljeborg notes:
The female is transparent to such a high degree, literally "as clear as water", that her presence is often only given away by her movements. In bright sunlight, the shadow is normally seen before the animal itself.
The male is similarly transparent.
The abdomen is elongated, but the
carapace is small and only covers the
brood pouch.
The six pairs of
thoracic
The thorax or chest is a part of the anatomy of humans, mammals, and other tetrapod animals located between the neck and the abdomen. In insects, crustaceans, and the extinct trilobites, the thorax is one of the three main divisions of the crea ...
appendages form a "feeding basket" which is used to capture prey. The second
antennae are used for swimming, while the first antennae are
rudimentary in females but elongated in males, where they are used in
sexual reproduction
Sexual reproduction is a type of reproduction that involves a complex life cycle in which a gamete ( haploid reproductive cells, such as a sperm or egg cell) with a single set of chromosomes combines with another gamete to produce a zygote th ...
.
There is a single large
compound eye
A compound eye is a visual organ found in arthropods such as insects and crustaceans. It may consist of thousands of ommatidia, which are tiny independent photoreception units that consist of a cornea, lens, and photoreceptor cells which disti ...
which takes up much of the animal's head.
It comprises around 500
facet
Facets () are flat faces on geometric shapes. The organization of naturally occurring facets was key to early developments in crystallography, since they reflect the underlying symmetry of the crystal structure. Gemstones commonly have facets cut ...
s, which are spherically arranged, and the whole eye is movable by up to 10° in any direction.
Distribution
''Leptodora kindtii'' is widespread in northern temperate lakes. In
North America, it occurs as far south as
Texas
Texas (, ; Spanish: ''Texas'', ''Tejas'') is a state in the South Central region of the United States. At 268,596 square miles (695,662 km2), and with more than 29.1 million residents in 2020, it is the second-largest U.S. state by ...
and
Oklahoma. It is also found across
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 subcontinent of Eurasia and it is located entirel ...
, in parts of
North Africa
North Africa, or Northern Africa is a region encompassing the northern portion of the African continent. There is no singularly accepted scope for the region, and it is sometimes defined as stretching from the Atlantic shores of Mauritania in ...
, northern
Arabia
The Arabian Peninsula, (; ar, شِبْهُ الْجَزِيرَةِ الْعَرَبِيَّة, , "Arabian Peninsula" or , , "Island of the Arabs") or Arabia, is a peninsula of Western Asia, situated northeast of Africa on the Arabian Plat ...
, and in
Asia
Asia (, ) is one of the world's most notable geographical regions, which is either considered a continent in its own right or a subcontinent of Eurasia, which shares the continental landmass of Afro-Eurasia with Africa. Asia covers an are ...
(north of the
Himalaya
The Himalayas, or Himalaya (; ; ), is a mountain range in Asia, separating the plains of the Indian subcontinent from the Tibetan Plateau. The range has some of the planet's highest peaks, including the very highest, Mount Everest. Over 100 ...
).
Ecology and behaviour
![Daphnia pulex](https://upload.wikimedia.org/wikipedia/commons/4/4e/Daphnia_pulex.png)
''Leptodora kindtii'' is a voracious predator and is capable of controlling numbers of its preferred prey items,
which are generally juveniles of ''
Daphnia
''Daphnia'' is a genus of small planktonic crustaceans, in length. ''Daphnia'' are members of the order Anomopoda, and are one of the several small aquatic crustaceans commonly called water fleas because their saltatory swimming style resembl ...
'', ''
Bosmina
''Bosmina'' is a genus in the order Cladocera, the water fleas. Its members can be distinguished from those of '' Bosminopsis'' (the only other genus in the family Bosminidae) by the separation of the antennae; in ''Bosminopsis'', the antennae ...
'', ''
Ceriodaphnia'', ''
Diaphanosoma
''Diaphanosoma'' is a genus of ''Sididae''.
The genus was described in 1850 by Fischer.
It has cosmopolitan distribution.
Species:
* ''Diaphanosoma amurensis'' Korovchinsky & Sheveleva, 2009
* ''Diaphanosoma australiensis'' Korovchinsky, 1981 ...
'', ''
Diaptomus
''Diaptomus'' is a genus of copepods with a single eye spot. It is superficially similar in size and appearance to ''Cyclops''. However it has characteristically very long first antennae that exceed the body length. In addition, the females car ...
'', ''
Polyphemus
Polyphemus (; grc-gre, Πολύφημος, Polyphēmos, ; la, Polyphēmus ) is the one-eyed giant son of Poseidon and Thoosa in Greek mythology, one of the Cyclopes described in Homer's ''Odyssey''. His name means "abounding in songs and leg ...
'' and ''
Cyclops''.
It seems to encounter its prey by chance, with contact initiating a
reflex, in which the
abdomen
The abdomen (colloquially called the belly, tummy, midriff, tucky or stomach) is the part of the body between the thorax (chest) and pelvis, in humans and in other vertebrates. The abdomen is the front part of the abdominal segment of the to ...
is brought forward to close the feeding basket. In many cases, the prey escapes this haphazard response. Juvenile ''Daphnia'' are slower than adults to respond to the predator's attack, and are therefore more likely to be caught.
The most important predators of ''Leptodora'' are fishes, including
whitefish,
perch
Perch is a common name for fish of the genus ''Perca'', freshwater gamefish belonging to the family Percidae. The perch, of which three species occur in different geographical areas, lend their name to a large order of vertebrates: the Per ...
,
ziege
''Pelecus cultratus'', commonly known as the ziege, sichel, sabre carp or sabrefish, is a cyprinid fish species from Eastern Europe and adjacent Asian regions, the only one in its genus, inhabiting the lower reaches of rivers and brackish waters ...
and
bleak
Bleak may refer to:
Fish
* Species of the genus '' Alburnus''
* '' Alburnoides bipunctatus'', also known as the schneider
Music
* "Bleak", a song by Opeth from '' Blackwater Park''
* "Bleak", a song by Soulfly from '' Dark Ages''
Other uses
* B ...
.
In
Lake Biwa
is the largest freshwater lake in Japan, located entirely within Shiga Prefecture (west-central Honshu), northeast of the former capital city of Kyoto. Lake Biwa is an ancient lake, over 4 million years old. It is estimated to be the 13th ol ...
,
Japan, ''L. kindtii'' is
parasitised by the
nematode ''
Raphidascaris biwakoensis'', a parasite of
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 ...
.
Life cycle
Female ''Leptodora'' produce a brood of eggs through
parthenogenesis
Parthenogenesis (; from the Greek grc, παρθένος, translit=parthénos, lit=virgin, label=none + grc, γένεσις, translit=génesis, lit=creation, label=none) is a natural form of asexual reproduction in which growth and developmen ...
every 12 hours.
These eggs hatch into a
larva
A larva (; plural larvae ) is a distinct juvenile form many animals undergo before metamorphosis into adults. Animals with indirect development such as insects, amphibians, or cnidarians typically have a larval phase of their life cycle.
...
l stage about long. There are six further
instar
An instar (, from the Latin '' īnstar'', "form", "likeness") is a developmental stage of arthropods, such as insects, between each moult (''ecdysis''), until sexual maturity is reached. Arthropods must shed the exoskeleton in order to grow or ...
s before the adult form is reached with a length of .
The time taken to reach adulthood is temperature dependent, but takes between 3 and 6 days.
For most of the year, reproduction is parthenogenetic, with eggs being produced by females without males being present in the population.
In the autumn, parthenogenetically produced males begin to appear;
males and females then
reproduce sexually. The resulting eggs sink to the bottom where they
overwinter
Overwintering is the process by which some organisms pass through or wait out the winter season, or pass through that period of the year when "winter" conditions (cold or sub-zero temperatures, ice, snow, limited food supplies) make normal acti ...
,
hatching the following year as
nauplius-like larvae.
Related taxa
''Leptodora'' is so distinct from other cladocerans that some authors have suggested grouping all other cladocerans into a
clade called "Eucladocera", with ''Leptodora'' as its
sister group. It is now believed, however, that ''Leptodora'' is sister to
Onychopoda
Onychopoda are a specialised order of branchiopod crustaceans, belonging to the superorder Cladocera.
The order Onychopoda is "one of the most morphologically distinctive groups of cladocerans". They have only four pairs of legs, compared to fiv ...
, being the only genus in the family Leptodoridae and the subclass Haplopoda.
Features which separate it from other families include its large size, the lack of branchial appendages (
gill
A gill () is a respiratory organ that many aquatic organisms use to extract dissolved oxygen from water and to excrete carbon dioxide. The gills of some species, such as hermit crabs, have adapted to allow respiration on land provided they are ...
s) on its legs, the reduction of the carapace, and the fact that the winter eggs hatch as nauplii.
Taxonomic history
![Water trench, Bremen 09](https://upload.wikimedia.org/wikipedia/commons/5/52/Water_trench%2C_Bremen_09.JPG)
''Leptodora kindtii'' is "probably the only cladoceran ever described in a newspaper".
The German microscopist
Gustav Woldemar Focke
Gustav Woldemar Focke (24 January 1810, Bremen – 1 June 1877, Bremen) was a German physician and naturalist. He was a nephew of naturalist Gottfried Reinhold Treviranus.
He studied medicine at the University of Heidelberg, receiving his d ...
organised a
scientific meeting
An academic conference or scientific conference (also congress, symposium, workshop, or meeting) is an event for researchers (not necessarily academics) to present and discuss their scholarly work. Together with academic or scientific journals a ...
in
Bremen in 1844 together with the pharmacist Georg Christian Kindt. He studied the fauna of the ditches surrounding the city (the ') and displayed live specimens at the meeting. During the meeting, he also published a description of the species in the ' on Sunday September 22, 1844, placing the species in the genus ''
Polyphemus
Polyphemus (; grc-gre, Πολύφημος, Polyphēmos, ; la, Polyphēmus ) is the one-eyed giant son of Poseidon and Thoosa in Greek mythology, one of the Cyclopes described in Homer's ''Odyssey''. His name means "abounding in songs and leg ...
''.
However, this description was ignored by the scientific community, and
Wilhelm Lilljeborg described the species in 1861 with the name ''Leptodora hyalina''. The
synonymy
A synonym is a word, morpheme, or phrase that means exactly or nearly the same as another word, morpheme, or phrase in a given language. For example, in the English language, the words ''begin'', ''start'', ''commence'', and ''initiate'' are all ...
was not noticed until Simon Albrecht Poppe informed Lilljeborg of it in 1889,
and Lilljeborg corrected the error in his 1900
monograph.
In 2009, a second species, ''Leptodora richardii'', was described from individuals collected from lakes in the
Amur River basin, including
Lake Bolon.
Synonyms
Synonyms of ''Leptodora kindtii'' include:
*''Polyphemus kindti''
Focke, 1844
*''Hyalosoma dux''
Wagner, 1868
*''Leptodora angusta''
Sars, 1890
*''Leptodora hyalina''
Lilljeborg, 1861
*''Leptodora pellucida''
Joseph, 1882
Etymology
The name ''Leptodora'' is from the
Greek
Greek may refer to:
Greece
Anything of, from, or related to Greece, a country in Southern Europe:
*Greeks, an ethnic group.
*Greek language, a branch of the Indo-European language family.
**Proto-Greek language, the assumed last common ancestor ...
words ' and ', collectively meaning thin-skinned.
The
specific epithet ''kindtii'' is presumed to refer to G. C. Kindt, who worked closely with Focke.
The alternative spelling ''kindti'' is sometimes encountered,
but is no longer considered correct under the
International Code of Zoological Nomenclature
The International Code of Zoological Nomenclature (ICZN) is a widely accepted convention in zoology that rules the formal scientific naming of organisms treated as animals. It is also informally known as the ICZN Code, for its publisher, the ...
.
The epithet ''hyalina'', used by Lilljeborg, is from the Greek ', and means
glassy.
External links
*
*
*
*
References
{{Taxonbar, from=Q30636
Cladocera
Branchiopoda genera
Taxa named by Wilhelm Lilljeborg