Leeches (Richardsonianus)

Taxonomic group

Hirudinidae: Richardsonianus

Diagnostic features

Richardsonianus mauianus is one of the few blood-sucking leeches in New Zealand. Like other leeches they are visibly segmented, very flexible and there is a suction disc at the tail end. Richardsonianus is larger than the more common glossiphoniids, and it is easily recognised by its yellow and black longitudinal stripes. The curved row of 10 eyes in Richardsonianus is also quite different to the eye arrangements of the more common leeches.

[Richardsonianus]. Image: Stephen Moore1 Image — Richardsonianus. Image: Stephen Moore1

[Richardsonianus] head. Image: Stephen Moore Image — Richardsonianus head. Image: Stephen Moore

Typical habitats

Richardsonianus is occasionally found in lakes and slow flowing weedy streams. They are common in the Oruarangi Creek in Mangere.

Feeding

They are blood suckers, and will latch on to the bare legs of humans wading in their habitats

Indicator value

Hard bottom: unassigned; general leech value 3
Soft bottom: unassigned; general leech value 1.2

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

Richardsonianus is too rarely recorded to be a useful water quality indicator. This genus has not been assigned tolerance values but the Subclass Hirudinea (leeches) have low tolerance values of 3 (hard bottom sites) and 1.2 (soft bottom sites).