Simocephalus mixtus
Sars, 1903
Simocephalus mixtus is a cladoceran crustacean in the Daphniidae, first described by Sars in 1903. It is a filter-feeder found in tropical and sub-tropical aquatic systems, capable of consuming both green and cyanobacteria. The exhibits temperature-dependent feeding , with measurable variation in filtration rates across 20–30°C. Its ability to consume Microcystis, albeit at lower rates than preferred algal foods, suggests potential utility in biomanipulation of cyanobacterial blooms.

Pronunciation
How to pronounce Simocephalus mixtus: //ˌsɪmoʊˈsɛfələs ˈmɪkstəs//
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Images
Habitat
Tropical and sub-tropical aquatic systems, including wetlands.
Distribution
Afrotropical, Nearctic, Neotropical, Oriental (Indomalaya), and Palearctic regions based on GBIF records.
Diet
filter-feeder; consumes Chlorella vulgaris (green ) and Microcystis sp. (cyanobacteria), with significantly lower ingestion rates on Microcystis compared to C. vulgaris.
Behavior
Feeding and filtration rates vary with temperature (20, 25, 30°C) and food concentration (0.2–2.0 × 10⁶ mL⁻¹).
Ecological Role
Potential agent for top-down biomanipulation of cyanobacterial blooms in tropical and sub-tropical aquatic systems, contingent on control of fish pressure.
Human Relevance
Proposed for use in managing cyanobacterial blooms through biomanipulation, though large- application requires further investigation.
Sources and further reading
- BugGuide
- GBIF taxonomy match
- iNaturalist taxon
- NCBI Taxonomy
- Catalogue of Life
- Look Out, Franklin's Bumble Bee, They're Coming for You! | Bug Squad
- Bug Eric: Spider Sunday: Labyrinth Spiders
- Effect of temperature, food quality and quantity on the feeding behavior of Simocephalus mixtus and Hyalella azteca: implications for biomanipulation