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Taxonomic group

Dugesiidae: Neppia

Diagnostic features

The dugesiid flatworms are related to the land flatworms, and are characterised by highly flexible bodies that are usually (but not always) flattened. Like many flatworms Neppia has two obvious eyes on top of the head, but unlike other common freshwater flatworms, Neppia has distinct ear-like auricles protruding from the sides of the head.

Typical habitats

Neppia is sometimes referred to as the “mountain flatworm” because it is common in stony bottom mountain streams.


They are predators of other freshwater invertebrates, including snails and worms.

Indicator value

  • Hard bottom: unassigned; general flatworm value 3
  • Soft bottom: unassigned; general flatworm value 0.9

The tolerance values (ranging from 0 to 10) give an indication of which are the sensitive taxa (values of 8 or more) and which are the tolerant taxa (values of 3 or less). For more information see: Indicator species

Neppia is found in many good quality mountain streams, but it has not been assigned tolerance values. The Phylum Platyhelminthes, which includes Neppia and other more pollution-tolerant flatworms, has been assigned low tolerance values of 3 (hard bottom sites) and 0.9 (soft bottom sites).