New Zealand flatworm

From Wikipedia, the free encyclopedia

Kingdom:	Animalia
Phylum:	Platyhelminthes
Class:	Turbellaria
Order:	Tricladida
Genus:	Arthurdendyus
Species:	A. triangulatus

Binomial name

Arthurdendyus triangulatus
(Dendy, 1894)

Synonyms

Artioposthia triangulata

The New Zealand flatworm (Arthurdendyus triangulatus) is a large flatworm native to New Zealand. It can vary from 5 mm in length when hatched to approximately 17 cm in mature adults. The ventral surface of the flatworm is a pale buff colour while the dorsal surface is dark brown. Young flatworms vary in colour from white to pale orange and develop their adult colouration as they grow.

During the day, flatworms can be found resting on the surface of soil underneath objects in close contact with the ground. They may also be found beneath the soil surface hunting for earthworms.

Reproduction involves the production of egg capsules of about 8 mm in length. The capsules are shiny, flexible and cherry red in colour at first and later darken to black after several days. After an unknown incubation period, several pale, tiny flatworms hatch out of the brittle capsule. One egg capsule is produced at a time with the bulge clearly visible in the dorsum of the adult worm.

It is an invasive species in Europe, feeding there almost exclusively on earthworms.^[1] This degrades soil quality. European earthworm predators are reluctant to eat it although cases of frogs and beetle larvae consuming flatworms have been recorded. It has been seen in England, Scotland, Northern Ireland and the Faroe Islands. It might have arrived in the early 1960s, being first recorded in Belfast in 1963. The New Zealand flatworm is easily transported accidentally in plant pots in adult or egg form. They tend to be common in garden centres and may have arrived in the UK with exotic plants.