Boat rotifer
Euchlanis dilatata
The boat rotifer is a widespread freshwater rotifer characterized by its transparent, boat-shaped dorsal lorica. It primarily inhabits the littoral zones of stagnant or slow-moving water bodies, often found among aquatic vegetation. The species moves by swimming with its ciliated corona and plays a significant role in the nutrient cycling of aquatic ecosystems.
Details
Identification
Boat-shaped dorsal lorica, flat ventral plate, two strong toes on the foot, incudate type mastax.
Social behavior
Usually solitary, but can occur in high densities when food supply is abundant.
Diet
Feeds on unicellular green algae, diatoms, bacteria, and organic decay products.
Hunting strategy
Filter feeder; creates a water current with its corona to direct food particles to the mouth.
Spawning substrate
Aquatic plants or detritus particles.
Overwintering
Formation of resting eggs (latent eggs) that overwinter in the sediment.
Ecology
Ecological role
Important primary consumer transferring energy from algae and bacteria to higher trophic levels.
Natural predators
Predatory rotifers (e.g., Asplanchna), small crustaceans, and larval fish.
Competitor species
Other planktonic rotifers such as Brachionus species.
Ecosystem service
Contributes to the self-purification of water bodies by consuming bacteria and organic suspended matter.
Threats
Heavy chemical pollution of water bodies, excessive eutrophication, and habitat loss due to drainage.
Scientific profile
Profile
Distinguishing features
Characteristic deep, U- or V-shaped notch at the posterior end of the dorsal plate. Two strong, sword-shaped toes. The mastax is of the malleate type. Clear differentiation between dorsal and ventral plates by a lateral groove.
Reproduction
Heterogony: Obligately parthenogenetic for most of the year (amictic females). Under stress or seasonal cues, mictic females appear, producing resting eggs after fertilization.
Role in food web
Important primary consumer in the littoral zone; transforms microbial biomass and algae into energy available for higher trophic levels.
Protection & threats
Status not on standard scale
Main threats
Loss of littoral macrophyte beds due to shoreline construction, herbicide use, and severe eutrophication (algal blooms).