Overview of Freshwater Invertebrates of North America
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Transcript of Overview of Freshwater Invertebrates of North America
Overview of Freshwater Invertebrates of North America
• 10,000-15,000 species in temperate North America
• all major invertebrate phyla accept Echinodermata have freshwater representatives
Protozoa• ubiquitous
• important consumers of bacteria & cyanobacteria, algae, and other protozoans
• prey for oligochaetes, chironomids, rotifers, etc.
• do not tolerate anoxic conditions
Porifera • 25 species freshwater sponges in North
America
• one family (Spongillidae)
• symbiotic algae
• Gemmules
• restricted to waters containing silica
Cnidaria • Hydrozoa only; 20 species
• e.g. taxa:• Hydra (polyp)• Chlorohydra (polyp); contains Chlorella an
endosymbiotic algae• Craspedacusta (medusoid)
Platyhelminthes• class Turbellaria (Planarians)
• > 200 species
• mostly benthic scavengers
Rotifera “wheel animals”• 2500 species described
• free living herbivores & predators
• Corona
• muscular pharynx & mastix
Mollusca• class Gastropoda (350 species);
snails & limpets
• class Bivalvia (250 species); clams & mussels
Annelida• classes Oligochaeta & Hirudinea
Arthropoda• subphylum Chelicerata
• class Acari (water mites)
• subphylum Uniramia• class Insecta- 10 orders have aquatic
representatives
Arthropoda• subphylum Crustacea
• class Malacostraca- crayfish & shrimps, isopods, & amphipods
• class Ostracoda- "seed shrimps“
• class Brachiopoda- fairy shrimps, tadpole shrimps & cladocerans (e.g. Daphnia)
• class Copapoda- important zooplanktors
Order Hemiptera• “true bugs”
• piercing-sucking mouth parts
Order Diptera• flies, gnats, and
mosquitoes
• complete metamorphosis
• important disease vectors
Order Odonata- dragonflies & damselflies
• ~650 North American species
• aquatic nymphs; mostly fresh water
• flying adults
• common families:• Gomphidae• Aeshnidae• Corduliidae
Anisoptera vs. Zygoptera
Ephemeroptera- mayflies• rocky-bottom 2nd &
3rd order streams
• most with three caudal filaments
Order Trichoptera- caddis flies
• nymphs construct nets and cases
• cool lotic waters
Order Plecoptera- stone flies• inhabitants of
clean, cool water
• good bioindicators
• adults live 1-4 weeks
Order Megaloptera- dobson flies• also called
hellgrammites
• predaceous larvae
• common families:• Corydalidae• Sialidae
Chelicerata (water mites)
Order Isopoda• pill bugs, sow bugs
• aquatic and terrestrial forms
• dorsoventrally flattened body