薄皮蚤屬
薄皮蚤属（学名：）为薄皮蚤科动物唯一的一個属。過往本屬只有透明薄皮蚤（学名：）一個物种，直至2009年本屬的第二個物種被發現。這兩個物種在對比其他雙甲下綱物種來說比較大，近乎透明及透光，是一類捕食性物種。本屬物種最長可長至，有兩枝可用，作游泳的觸角，以及一隻複眼。腿可用作捕捉碰巧路過的橈足亞綱物種。
透明薄皮蚤見於北半球溫帶的湖泊中，很可能是枝角目物種當中唯一曾被報章報導過的已描述生物；而"L. richardi"現時只見於俄罗斯遠東地區的黑龙江流域，儘管日本認為在其國內分佈的物種亦是"L. richardi"。 For most of the year, "Leptodora" reproduces 单性生殖, 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.
薄皮蚤屬物種的成體是北美洲原生浮游枝角目物種當中體型最大的；至於到底有多大，各種報告間不盡相同，但雌性成體普遍可長至長，部分報告聲稱可長至長。這些動物的身體約有98%是透明的，以避免被魚類獵食。 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 is small and only covers the .
胸節的六對附肢形成一個「餵哺籃」，用以捕捉獵物。 The second 觸角 are used for swimming, while the first antennae are 痕跡器官 in females but elongated in males, where they are used in 有性生殖. There is a single large 複眼 which takes up much of the animal's head. It comprises around 500 s, which are spherically arranged, and the whole eye is movable by up to 10° in any direction.
透明薄皮蚤廣泛分佈於北半球溫帶的湖泊中，見於北美洲、亚洲、欧洲及非洲。在北美洲，其分佈範圍南至德克萨斯州及俄克拉荷馬州；在中国大陆分佈於浙江、江苏、安徽、江西、湖北、吉林、黑龙江、云南、内蒙古等地，主要栖息于大中型湖泊的敞水区、也出现在沿岸以及小型湖泊与积水较深的池塘中。在欧洲、北非部分地區、阿拉伯半岛北部及亚洲喜马拉雅山脉以北地區亦有分佈。
透明薄皮蚤是一種貪婪的捕食者，能夠控制其偏愛獵物的數量，一般都是溞属（"Daphnia"）、', ', ', ', ""及剑水蚤属（"Cyclops"）等各屬物種的幼體。 It seems to encounter its prey by chance, with contact initiating a 反射 (生理学), in which the 腹 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 白鮭屬, perch, and 歐白魚.
In 琵琶湖, 日本, "L. kindtii" is 寄生 by the 线虫动物门 "Raphidascaris biwakoensis", a parasite of 鱼.
Female "Leptodora" produce a brood of eggs through 单性生殖 every 12 hours. These eggs hatch into a 幼体l stage about long. There are six further 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 有性生殖. The resulting eggs sink to the bottom where they 越冬, hatching the following year as -like larvae.
"Leptodora" is so distinct from other cladocerans that some authors have suggested grouping all other cladocerans into a 演化支 called "Eucladocera", with "Leptodora" as its 姐妹群. It is now believed, however, that "Leptodora" is sister to , 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 (鳃s) on its legs, the reduction of the carapace, and the fact that the winter eggs hatch as nauplii.
"Leptodora kindtii" is "probably the only cladoceran ever described in a newspaper". The German microscopist organised a 學術研討會 in 不来梅 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 "". However, this description was ignored by the scientific community, and described the species in 1861 with the name "Leptodora hyalina". The 異名 was not noticed until Simon Albrecht Poppe informed Lilljeborg of it in 1889, and Lilljeborg corrected the error in his 1900 專著.
2009年，Korovchinsky首度為本屬的第二個物種"Leptodora richardii"作出描述：這個物種採樣自黑龙江盆地的湖泊，包括博隆湖。
現時下列組合均被視為透明薄皮蚤（"Leptodora kindtii"）的異名：
The name "Leptodora" is from the 希腊语 words ' and ', collectively meaning thin-skinned. The 种加词 "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 国际动物命名法规. The epithet "hyalina", used by Lilljeborg, is from the Greek "", and means .