Arthropods~ Some smaller freshwater types with links to Micscape resources

Arthropods are characterised by jointed limbs and include major groups like the crustacea, insects, spiders and mites. They have many segments, a tough outer skeleton and many modified limbs. There are many microscopic and macroscopic types that occur in freshwater. Notes: There are several other groups with limb-like structures that aren't arthropods. Check rotifers and hydra on the first page.

Group		key features	Micscape links
Crustacea - Ostracods		bean-like shell <2 mm	Freshwater crustacea
Crustacea - Copepods		long antennae, tiny eyespot: 0.5 - 3 mm	Freshwater crustacea Cyclops.The one-eyed pond organism
Crustacea - Water fleas 'Cladocera'		antennae, large compound eye 0.3 - several mm	Water-flea anatomy - a fun interactive suite of images Water fleas - fascinating pond organisms The giant water flea Leptodora kindtii 10 mm! Daphnia collecting techniques parts I-IV
Water bears (Tardigrades)		8 stumpy legs body <1 mm See gallery links on the right for some of the finest video clips on the Web of these cute critters!	Hunting for 'bears' in the backyard The incredible water bear Water bear video gallery I Water bear video gallery II
Water mites		8 legs, round body 0.5 - 5 mm	Water mites
Mosquito larvae (e.g. fly)		long body, often moves in S-shaped curves 1 - 20 mm	In praise of blackflies The mosquito Aedes aegypti and Dengue fever
Other Insect stages		wide variety of forms >1 mm	Go to Insect stages overview: e.g. caddisfly larva, dragonfly nymph, water beetles, etc.
Some larger freshwater crustacea -where Micscape has resources		Water louse (isopod) 10 mmFairy shrimp 10 cm and tadpole shrimp (branchiopods) 10 mm	Woodlouse or waterlouse. An interesting pond organismTadpole shrimp and fairy shrimp: Two rare British crustaceans
Freshwater shrimps (not true shrimps but amphipods)		curved, compressed body centimeter 25 mm	No Micscape resources. (Articles welcomed!)

Protozoa	First Page	Insects
Algae	Collecting tips	Worms

This page with links hopefully gives a useful overview, but it's neither a formal identification guide nor comprehensive. Water bears have been included here as well as on the first page, because some resources regard them as an arthropod phyla.

Acknowledgements: Many thanks to all the Micscape contributors whose articles this guide links to. For clarity their names are omitted in the links above.

---

An Introduction to Microscopy

Comments to the compilers Wim van Egmond and Dave Walker are welcomed.

Microscopy UK Front Page
Micscape Magazine
Article Library

All images © Wim van Egmond