Leptodora
Encyclopedia
Leptodora is a genus containing two species
of large, nearly transparent
predatory
water fleas. They grow up to 21 mm (0.826771653543307 in) long, with two large antennae
used for swimming and a single compound eye. The legs are used to catch other copepod
s 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
; L. richardi is only known from eastern Russia
. 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 subclass, Haplopoda.
ic cladocerans; reports vary concerning the largest size, but adult females typically grow to 12 mm (0.47244094488189 in) long, but with some reports of females up to 21 mm (0.826771653543307 in). They are about 98% transparent, as a defense against predation by fish
. Lilljeborg notes:
The male is similarly transparent. The abdomen is elongated but the carapace
is small and only covers the brood pouch
.
The five pairs of thoracic
appendage
s 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
. There is a single large compound eye which takes up much of the animal's head. It comprises around 500 facet
s, which are spherically arranged, and the whole eye is movable by up to 10° in any direction.
, it occurs as far south as Texas
and Oklahoma
. It is also found across Europe
, in parts of North Africa
, northern Arabia, and in Asia
(north of the Himalaya).
Leptodora kindtii is a voracious predator and is capable of controlling numbers of its preferred prey items, which are generally juveniles of Daphnia
, Bosmina
, Ceriodaphnia, Diaphanosoma, Diaptomus
, Polyphemus and Cyclops
. It seems to encounter its prey by chance, with contact initiating a reflex
, in which the abdomen
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
, ziege
and bleak.
In Lake Biwa
, Japan
, L. kindtii is parasitised
by the nematode
Raphidascaris biwakoensis, a parasite of fish
.
every 12 hours. These eggs hatch into a larva
l stage about 2 millimetre (0.078740157480315 in) long. There are six further instar
s before the adult form is reached with a length of 6 millimetre (0.236220472440945 in). 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, hatching the following year as nauplius-like larvae.
called "Eucladocera", with Leptodora as its sister group. It is now believed, however, that Leptodora is sister to Onychopoda
, 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
s) on its legs, the reduction of the carapace, and the fact that the winter eggs hatch as nauplii.
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. However, this description was ignored by the scientific community, and Wilhelm Lilljeborg
described the species in 1861 with the name Leptodora hyalina. The synonymy
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
.
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 epithet hyalina, used by Lilljeborg, is from the Greek , and means glassy
.
Species
In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...
of large, nearly transparent
Transparency and translucency
In the field of optics, transparency is the physical property of allowing light to pass through a material; translucency only allows light to pass through diffusely. The opposite property is opacity...
predatory
Predation
In ecology, predation describes a biological interaction where a predator feeds on its prey . Predators may or may not kill their prey prior to feeding on them, but the act of predation always results in the death of its prey and the eventual absorption of the prey's tissue through consumption...
water fleas. They grow up to 21 mm (0.826771653543307 in) long, with two large antennae
Antenna (biology)
Antennae in biology have historically been paired appendages used for sensing in arthropods. More recently, the term has also been applied to cilium structures present in most cell types of eukaryotes....
used for swimming and a single compound eye. The legs are used to catch other copepod
Copepod
Copepods are a group of small crustaceans found in the sea and nearly every freshwater habitat. Some species are planktonic , some are benthic , and some continental species may live in limno-terrestrial habitats and other wet terrestrial places, such as swamps, under leaf fall in wet forests,...
s that it comes into contact with by chance. Leptodora kindtii is found in temperate lakes across the Northern Hemisphere
Northern Hemisphere
The Northern Hemisphere is the half of a planet that is north of its equator—the word hemisphere literally means “half sphere”. It is also that half of the celestial sphere north of the celestial equator...
and is probably the only cladoceran ever described
Alpha taxonomy
Alpha taxonomy is the discipline concerned with finding, describing and naming species of living or fossil organisms. This field is supported by institutions holding collections of these organisms, with relevant data, carefully curated: such institutes include natural history museums, herbaria and...
in a newspaper
Newspaper
A newspaper is a scheduled publication containing news of current events, informative articles, diverse features and advertising. It usually is printed on relatively inexpensive, low-grade paper such as newsprint. By 2007, there were 6580 daily newspapers in the world selling 395 million copies a...
; L. richardi is only known from eastern Russia
Russia
Russia or , officially known as both Russia and the Russian Federation , is a country in northern Eurasia. It is a federal semi-presidential republic, comprising 83 federal subjects...
. For most of the year, Leptodora reproduces parthenogenetically
Parthenogenesis
Parthenogenesis is a form of asexual reproduction found in females, where growth and development of embryos occur without fertilization by a male...
, 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 subclass, Haplopoda.
Description
Adult Leptodora are the largest planktonPlankton
Plankton are any drifting organisms that inhabit the pelagic zone of oceans, seas, or bodies of fresh water. That is, plankton are defined by their ecological niche rather than phylogenetic or taxonomic classification...
ic cladocerans; reports vary concerning the largest size, but adult females typically grow to 12 mm (0.47244094488189 in) long, but with some reports of females up to 21 mm (0.826771653543307 in). They are about 98% transparent, as a defense against predation by fish
Fish
Fish are a paraphyletic group of organisms that consist of all gill-bearing aquatic vertebrate 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...
. 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
Carapace
A carapace is a dorsal 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 tortoises, the underside is called the plastron.-Crustaceans:In crustaceans, the...
is small and only covers the brood pouch
Brood pouch (Peracarida)
The marsupium or brood pouch, is a characteristic feature of Peracarida, including the orders Amphipoda, Isopoda and Cumacea. It is an egg chamber formed by oostegites, which are appendices which are attached to the coxae of the first pereiopods...
.
The five pairs of thoracic
Thorax
The thorax is a division of an animal's body that lies between the head and the abdomen.-In tetrapods:...
appendage
Appendage
In invertebrate biology, an appendage is an external body part, or natural prolongation, that protrudes from an organism's body . It is a general term that covers any of the homologous body parts that may extend from a body segment...
s form a "feeding basket" which is used to capture prey. The second antennae
Antenna (biology)
Antennae in biology have historically been paired appendages used for sensing in arthropods. More recently, the term has also been applied to cilium structures present in most cell types of eukaryotes....
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
Sexual reproduction is the creation of a new organism by combining the genetic material of two organisms. There are two main processes during sexual reproduction; they are: meiosis, involving the halving of the number of chromosomes; and fertilization, involving the fusion of two gametes and the...
. There is a single large compound eye which takes up much of the animal's head. It comprises around 500 facet
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...
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 AmericaNorth America
North America is a continent wholly within the Northern Hemisphere and almost wholly within the Western Hemisphere. It is also considered a northern subcontinent of the Americas...
, it occurs as far south as Texas
Texas
Texas is the second largest U.S. state by both area and population, and the largest state by area in the contiguous United States.The name, based on the Caddo word "Tejas" meaning "friends" or "allies", was applied by the Spanish to the Caddo themselves and to the region of their settlement in...
and Oklahoma
Oklahoma
Oklahoma is a state located in the South Central region of the United States of America. With an estimated 3,751,351 residents as of the 2010 census and a land area of 68,667 square miles , Oklahoma is the 28th most populous and 20th-largest state...
. It is also found across Europe
Europe
Europe is, by convention, one of the world's seven continents. Comprising the westernmost peninsula of Eurasia, Europe is generally 'divided' from Asia to its east by the watershed divides of the Ural and Caucasus Mountains, the Ural River, the Caspian and Black Seas, and the waterways connecting...
, in parts of North Africa
North Africa
North Africa or Northern Africa is the northernmost region of the African continent, linked by the Sahara to Sub-Saharan Africa. Geopolitically, the United Nations definition of Northern Africa includes eight countries or territories; Algeria, Egypt, Libya, Morocco, South Sudan, Sudan, Tunisia, and...
, northern Arabia, and in Asia
Asia
Asia is the world's largest and most populous continent, located primarily in the eastern and northern hemispheres. It covers 8.7% of the Earth's total surface area and with approximately 3.879 billion people, it hosts 60% of the world's current human population...
(north of the Himalaya).
Ecology and behaviour
Daphnia
Daphnia are small, planktonic crustaceans, between 0.2 and 5 mm in length. Daphnia are members of the order Cladocera, and are one of the several small aquatic crustaceans commonly called water fleas because of their saltatory swimming style...
, Bosmina
Bosmina
Bosmina is a genus in the order Cladocera. Its members can be distinguished from those of Bosminopsis by the separation of the antennae; in Bosminopsis, the antennae are fused at their bases....
, Ceriodaphnia, Diaphanosoma, Diaptomus
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 carry the eggs in a single sac rather than the twin sacs seen in...
, Polyphemus and Cyclops
Cyclops (genus)
Cyclops is one of the most common genera of freshwater copepods, comprising over 400 species . The name Cyclops comes from the Cyclops of Greek mythology which shares the quality of having a single large eye, which may be either red or black in Cyclops.Cyclops individuals may range from...
. It seems to encounter its prey by chance, with contact initiating a reflex
Reflex
A reflex action, also known as a reflex, is an involuntary and nearly instantaneous movement in response to a stimulus. A true reflex is a behavior which is mediated via the reflex arc; this does not apply to casual uses of the term 'reflex'.-See also:...
, in which the abdomen
Abdomen
In vertebrates such as mammals the abdomen constitutes the part of the body between the thorax and pelvis. The region enclosed by the abdomen is termed the abdominal cavity...
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
Coregonus
Coregonus is a diverse genus of fish in the salmon family . The type species is the common whitefish . The Coregonus species are known as whitefishes...
, perch
European perch
The European perch, Perca fluviatilis, is a predatory species of perch found in Europe and Asia. In some areas it is known as the redfin perch or English perch, and it is often known simply as perch. The species is a popular quarry for anglers and has been widely introduced beyond its native area,...
, ziege
Ziege
The ziege or sabre carp, Pelecus cultratus, is a species of ray-finned fish in the Cyprinidae family, and the only species of its genus....
and bleak.
In Lake Biwa
Lake Biwa
is the largest freshwater lake in Japan, located in Shiga Prefecture , northeast of the former capital city of Kyoto. Because of its proximity to the ancient capital, references to Lake Biwa appear frequently in Japanese literature, particularly in poetry and in historical accounts of battles.-...
, Japan
Japan
Japan is an island nation in East Asia. Located in the Pacific Ocean, it lies to the east of the Sea of Japan, China, North Korea, South Korea and Russia, stretching from the Sea of Okhotsk in the north to the East China Sea and Taiwan in the south...
, L. kindtii is parasitised
Parasitism
Parasitism is a type of symbiotic relationship between organisms of different species where one organism, the parasite, benefits at the expense of the other, the host. Traditionally parasite referred to organisms with lifestages that needed more than one host . These are now called macroparasites...
by the nematode
Nematode
The nematodes or roundworms are the most diverse phylum of pseudocoelomates, and one of the most diverse of all animals. Nematode species are very difficult to distinguish; over 28,000 have been described, of which over 16,000 are parasitic. It has been estimated that the total number of nematode...
Raphidascaris biwakoensis, a parasite of fish
Fish
Fish are a paraphyletic group of organisms that consist of all gill-bearing aquatic vertebrate 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...
.
Life cycle
Female Leptodora produce a brood of eggs through parthenogenesisParthenogenesis
Parthenogenesis is a form of asexual reproduction found in females, where growth and development of embryos occur without fertilization by a male...
every 12 hours. These eggs hatch into a larva
Larva
A larva 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 2 millimetre (0.078740157480315 in) long. There are six further instar
Instar
An instar is a developmental stage of arthropods, such as insects, between each molt , until sexual maturity is reached. Arthropods must shed the exoskeleton in order to grow or assume a new form. Differences between instars can often be seen in altered body proportions, colors, patterns, or...
s before the adult form is reached with a length of 6 millimetre (0.236220472440945 in). 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
Sexual reproduction
Sexual reproduction is the creation of a new organism by combining the genetic material of two organisms. There are two main processes during sexual reproduction; they are: meiosis, involving the halving of the number of chromosomes; and fertilization, involving the fusion of two gametes and the...
. The resulting eggs sink to the bottom where they overwinter, 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 cladeClade
A clade is a group consisting of a species and all its descendants. In the terms of biological systematics, a clade is a single "branch" on the "tree of life". The idea that such a "natural group" of organisms should be grouped together and given a taxonomic name is central to biological...
called "Eucladocera", with Leptodora as its sister group. It is now believed, however, that Leptodora is sister to Onychopoda
Onychopoda
Onychopoda are a specialised suborder of branchiopod crustaceans, belonging to the order Cladocera.The suborder Onychopoda is "one of the most morphologically distinctive groups of cladocerans". They have only four pairs of legs, compared to five or six pairs in Ctenopoda and Anomopoda...
, 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
Gill
A gill is a respiratory organ found in many aquatic organisms that extracts dissolved oxygen from water, afterward excreting carbon dioxide. The gills of some species such as hermit crabs have adapted to allow respiration on land provided they are kept moist...
s) on its legs, the reduction of the carapace, and the fact that the winter eggs hatch as nauplii.
Taxonomic history
Leptodora kindtii is "probably the only cladoceran ever described in a newspaper". The German amateur microscopist Gustav Woldemar Focke organised a scientific meeting in BremenBremen
The City Municipality of Bremen is a Hanseatic city in northwestern Germany. A commercial and industrial city with a major port on the river Weser, Bremen is part of the Bremen-Oldenburg metropolitan area . Bremen is the second most populous city in North Germany and tenth in Germany.Bremen is...
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. However, this description was ignored by the scientific community, and Wilhelm Lilljeborg
Wilhelm Lilljeborg
Wilhelm Lilljeborg was a Swedish zoologist. He is particularly known for his work on the Cladocera of Sweden, and on the Balaenoptera. Lilljeborg was a member of the Royal Swedish Academy of Sciences from 1861.-References:...
described the species in 1861 with the name Leptodora hyalina. The synonymy
Synonym (taxonomy)
In scientific nomenclature, a synonym is a scientific name that is or was used for a taxon of organisms that also goes by a different scientific name. For example, Linnaeus was the first to give a scientific name to the Norway spruce, which he called Pinus abies...
was not noticed until Simon Albrecht Poppe informed Lilljeborg of it in 1889, and Lilljeborg corrected the error in his 1900 monograph
Monograph
A monograph is a work of writing upon a single subject, usually by a single author.It is often a scholarly essay or learned treatise, and may be released in the manner of a book or journal article. It is by definition a single document that forms a complete text in itself...
.
In 2009, a second species, Leptodora richardii, was described from individuals collected from lakes in the Amur River basin, including Lake Bolon
Lake Bolon
Lake Bolon is a large freshwater lake in the Khabarovsk Krai, Russia. It has an area of 338 km², it is 70 km long and 20 km wide. Maximum depth is about 4 m. It is located on the broad west-bank flood plain of the Amur River about 80 km south of Komsomolsk and drains into the...
.
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 GreekGreek language
Greek is an independent branch of the Indo-European family of languages. Native to the southern Balkans, it has the longest documented history of any Indo-European language, spanning 34 centuries of written records. Its writing system has been the Greek alphabet for the majority of its history;...
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
International Code of Zoological Nomenclature
The International Code of Zoological Nomenclature is a widely accepted convention in zoology that rules the formal scientific naming of organisms treated as animals...
. The epithet hyalina, used by Lilljeborg, is from the Greek , and means glassy
Hyaline
The term hyaline denotes a substance with a glass-like appearance.-Histopathology:In histopathological medical usage, a hyaline substance appears glassy and pink after being stained with haematoxylin and eosin — usually it is an acellular, proteinaceous material...
.