Petroglyph logo Petroglyph logo
Home     Contact us     Search     Who we are
     General Information    Research    Literature    Databases    Images

General Information

  Pets and humans
  Where to find worms
  Why study these worms?

General Information -> Where to find worms

Where are Nematomorphs found?

As discussed in the "Nematomorphs" section (see tool bar to the left), consists of two groups (classes).  The nectonematids are parasites of marine crustaceans such as crabs and shrimp.  The gordiids are usually parasites of terrestrial arthropods such as crickets, grasshoppers, beetles, mantids and cockroaches.  Thus, nectonematids are found only in the oceans, and gordiids are found only in freshwater systems.

If you have found a nematomorphs, chances are that it is a freshwater gordiid.


The marine genus Nectonema is known from several locations worldwide (including the Northern Atlantic, the Mediterranean, Indonesia, and Japan), with the latest report being from New Zealand. With two exceptions, reports are usually made of single worms.  The exceptions have been from the Bay of Fundy and some fjords in Norway. In most cases, Nectonema was found inside its hosts and rarely free-living.

Worms have often been reported from dredged crabs, or other marine crustacean collected from the ocean floor.  However, several reports exist of adult worms being collected near shore during high tide.


Gordiids are far more common than nectonematids.  They are often encountered in rivers, lakes, streams.  However, sometimes gordiids can be seen around the home (click on "Pets and humans" on the tool bar to the right).

Gordiids have been collected from every continent, except Antarctica.  Often they are found by themselves, but sometimes gordiids are encountered in large Gordian knots.  These knots are composed of dozens to hundreds of individuals.  

Here are just some locations from which people have reported gordiids:

  • lakes
  • streams
  • puddles
  • dredged from the bottom of the Lower Mississippi River
  • driveways, especially after the first hard spring rain
  • grass of a lawn after a rain or watering
  • toilets
  • dog bowls
  • hot tubs
  • swimming pools
  • water storage tanks
  • underwear
This sample was found in the invertebrate teaching collection
of the University of Nebraska-Lincoln.  This sample
was brought to the attention of Ben Hanelt by John Janovy Jr.
The exact source or case information of this sample is unclear.


Copyright 2014 Ben Hanelt, Matt Bolek, and Andreas Schmidt-Rhaesa
Updated: July 2015