Leptodora is a genus containing two species of large, nearly transparent Predation . They grow up to long, with two large antennae used for swimming and a single compound eye. The legs are used to catch that it comes into contact with by chance. Leptodora kindtii is found in temperate lakes across the Northern Hemisphere and is probably the only water flea species ever described in a newspaper; L. richardi is only known from eastern Russia. For most of the year, Leptodora reproduces parthenogenesis, 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
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.
Lilljeborg notes:
Das Weibchen ist in so hohem Grade durchsichtig, in wahrem Sinne »wasserhell», dass oft nur die Bewegungen ihr Dasein in dem Wasser verrathen. Bei auffallendem Sonnenlicht wird gewöhnlich der Schatten früher als das Thier selbst entdeckt.
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 thorax form a "feeding basket" which is used to capture prey.
Distribution
Leptodora kindtii is widespread in northern temperate lakes. In
North America, 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).
Ecology and behaviour
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 Coregonus, European perch, ziege and Common Bleak.
In Lake Biwa, Japan, L. kindtii is parasitism by the nematode Raphidascaris biwakoensis, a parasite of fish.
Life cycle
Female
Leptodora produce a brood of eggs through
parthenogenesis every 12 hours.
These eggs hatch into a
stage about long. There are six further
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
overwintering,
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, 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 (
) 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 microscopist Gustav Woldemar Focke organised a scientific meeting in
Bremen in 1844 together with the pharmacist Georg Christian Kindt. He studied the fauna of the ditches surrounding the city (the
Bremer Stadtgraben) and displayed live specimens at the meeting. During the meeting, he also published a description of the species in the
Weser-Zeitung 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.
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 language words
leptos and
dora, 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
ὕαλος, and means
hyaline.
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