Cladoceran
Guides
Bosmina freyi
Bosmina freyi is a small cladoceran crustacean in the family Bosminidae, described by De Melo and Hebert in 1994. It inhabits freshwater environments, with documented populations in tropical eutrophic reservoirs. Research has examined morphological plasticity in this species, particularly variation in body size, mucron length, and antennule morphology in response to environmental conditions.
Bythotrephes longimanus
Spiny Water Flea, Spiny Waterflea
Bythotrephes longimanus is a predatory planktonic cladoceran crustacean native to northern Europe and Asia that has become a significant invasive species in North America since its introduction to the Great Lakes in the 1980s. Adults reach up to 15 mm in length, with females growing substantially larger than males. The species exhibits cyclic parthenogenesis and produces distinctive morphological forms depending on reproductive mode and season. Its invasion has caused substantial ecological disruption through direct predation on native zooplankton and non-lethal effects that alter prey behavior and population dynamics.
Ctenopoda
Ctenopoda is an order of small crustaceans within the superorder Diplostraca, comprising three families: Holopediidae, Pseudopenilidae, and Sididae. Members are commonly known as water fleas and are predominantly freshwater inhabitants, though the genus Penilia is marine. The order is characterized by specialized swimming antennae and a body plan that reflects functional separation between locomotion and feeding appendages. Ctenopoda species have been documented across diverse aquatic habitats including lakes, reservoirs, wetlands, and coastal marine systems, with some species introduced to areas outside their native ranges by human activity.
Haplopoda
Haplopoda is an infraorder of branchiopod crustaceans within the order Diplostraca. It contains the single extant family Leptodoridae, represented by the genus Leptodora, commonly known as the water flea Leptodora kindtii. This group is notable for being among the largest predatory cladocerans. The infraorder is now treated as a synonym of Onychopoda in many modern classifications.
Holopedium gibberum
Holopedium gibberum is a planktonic cladoceran distinguished by a large gelatinous mantle that encloses the body. The species exhibits pronounced phenotypic plasticity in mantle size as an inducible defense against invertebrate predators, particularly Chaoborus larvae. Populations show strong sensitivity to fish predation pressure, with distribution patterns reflecting avoidance of high-predation environments. The species demonstrates seasonal population dynamics tied to food availability and predation regimes, with reproductive investment varying in response to environmental stressors.
Holopedium glacialis
A small freshwater cladoceran crustacean in the family Holopediidae. The species was described in 2007 from Nearctic material and is distinguished from congeners by genetic and morphological characteristics. Like other members of the genus, it possesses a distinctive gelatinous mantle that encloses the body.
Leptodoridae
Leptodoridae is a monotypic family of large predatory water fleas containing the single genus Leptodora. Members are among the largest cladocerans, reaching up to 18 mm in length. They are transparent, pelagic predators found in temperate lakes. The family is distinguished by its unique body plan and reduced carapace, representing a distinct lineage within the order Diplostraca.
Onychopoda
Onychopoda is a specialized order of predatory branchiopod crustaceans within the superorder Cladocera, distinguished by having only four pairs of legs (compared to five or six in related orders) and segmented raptorial appendages used for grasping prey. The order comprises three families (Cercopagididae, Podonidae, Polyphemidae), ten genera, and approximately 33 described species. Most species are endemic to the Ponto-Caspian basin, though some occur in freshwater and marine habitats worldwide. Onychopoda exhibits one of the most distinctive morphological and ecological radiations among cladocerans, having evolved predation as a novel feeding strategy and colonized habitats across a broad salinity range.
Picripleuroxus denticulatus
Picripleuroxus denticulatus is a species of small freshwater crustacean in the family Chydoridae, commonly known as water fleas or chydorid cladocerans. The species was described by Birge in 1879 and is distributed across multiple continents including the NeArctic, PalaeArctic, and AfroTropical regions. Records indicate presence in Brazil across multiple states. As a member of the Chydoridae, it inhabits freshwater environments where it contributes to aquatic food webs.
Podon
Podon is a genus of marine cladocerans in the family Podonidae, characterized by onychopod morphology. The genus includes at least four described species: P. intermedius, P. leuckarti, P. leuckartii, and P. schmackeri. Members are euryhaline and eurythermal, inhabiting estuarine and coastal marine waters. Populations exhibit strong seasonal dynamics, with spring and fall peaks and summer disappearance in temperate regions.
Simocephalus serrulatus
Simocephalus serrulatus is a freshwater cladoceran crustacean in the family Daphniidae. It is a cosmopolitan zooplankton species found across multiple continents including Australasian, Afrotropical, Nearctic, and Neotropical regions. The species has been used in ecotoxicological studies, particularly research on per- and polyfluoroalkyl substances (PFAS) tolerance and population-level variation in life history traits.