New Guinea flatworm
Platydemus manokwari
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Photo credit: Larsonek (licensed under http://creativecommons.org/licenses/by-nc/4.0/)
Platydemus manokwari – New Guinea Flatworm
Description:
Habitat:
Origin and Distribution:
Impacts:
Is it found in Northern Ireland?
How could it get here?
Prevent Spread
Current legislative position (Entered into Force on 7th August 2025): This species must not intentionally be brought into the Union; kept; bred; transported to, from or within the United Kingdom, unless for the transportation to facilities in the context of eradication; placed on the market; used or exchanged; permitted to reproduce, grown or cultivated; or released into the environment.
For further queries, you can contact the Invasive Non Native Species (INNS) Team in the Northern Ireland Environment Agency on 028 9056 9558 or Email: invasivespecies@daera-ni.gov.uk
Platydemus manokwari – New Guinea Flatworm
Description:
- The body is a dark or olive brown with a pale brown central line on its dorsal side
- Ventral side is a pale brown/grey
- Both ends of the flatworm are pointed, especially the head which possess two eyes near the tip
- Typically 40-65mm in length and 4-7mm wide but quite flat at less than 2mm thick
Habitat:
- Found primarily in tropical/subtropical regions
- Typically resides among leaf litter and prefers wet conditions
- Unable to survive in completely dry habitats
- It’s suggested that 10°C is the threshold temperature for its establishment, as prolonged exposure to temperatures lower than this decreased the survival rate of the species
Origin and Distribution:
- Native to New Guinea
- Mainly spread throughout the Pacific (eg. Australia, Philippines, Japan, Hawaii, French Polynesia, Somoa, etc)
- It has aso been found in Singapore, Miami, and Puerto Rico
- In Normandy, France in 2013, a sighting was recorded in a hothouse in botanical gardens
Impacts:
- Its diet is primarily snails and has been recorded in established areas to have caused significant decline in native and endemic snail species; in some cases, contributing to local extinctions
- There is potential for this to have a knock-on effect on wildlife preying on native snail populations, and on decomposition processes and nutrient recycling within ecosystems
- Listed among top 100 world’s worst invasive species due to damage caused in Pacific islands where it was introduced
Is it found in Northern Ireland?
- It is not currently present in Northern Ireland
How could it get here?
- Human-mediated spread through plant/soil trade
- Secondary dispersal is possible through local exchange of plants and soil from infected nurseries, botanical gardens, garden centres and independent gardeners
Prevent Spread
- Prevention via enforcing the IAS (Enforcement and Permitting) Order (Northern Ireland) ensuring that Platydemus manokwari is not introduced to Northern Ireland
- Reporting any sightings so that Rapid Response can be instigated
- Inspect incoming consignments of plants
- Check plant products for flatworms
- You can help by reporting any sightings:@ the Centre for Environmental Data & Recording (CEDaR) - Or via the iRecord App.
Current legislative position (Entered into Force on 7th August 2025): This species must not intentionally be brought into the Union; kept; bred; transported to, from or within the United Kingdom, unless for the transportation to facilities in the context of eradication; placed on the market; used or exchanged; permitted to reproduce, grown or cultivated; or released into the environment.
For further queries, you can contact the Invasive Non Native Species (INNS) Team in the Northern Ireland Environment Agency on 028 9056 9558 or Email: invasivespecies@daera-ni.gov.uk