Critter of the Week: new species under our feet

This week we are featuring some new species of nematode worms that have recently been found at Hataitai Beach in Wellington, just two minutes away from NIWA’s Greta Point facilities. Taxonomist Daniel Leduc decided to grab a few handfuls of sand from the beach on his way to work one morning and voila- three species new to science! This is one of the many reasons why New Zealand is such a great country for studying marine biodiversity.

These nematode worms are only about one millimetre in length (just barely visible to the naked eye), which is why nobody noticed them before. They are quite numerous though, probably a few thousands of individuals of each species per square metre of beach. An electron microscope was used to obtain detailed images of the specimens (magnified up to 3000 times their actual size). Each new species will be given a name in the near future.

This new species of the genus Desmodorella is covered in minute spines to help it anchor itself in the sand grains. The swirly structure on the head is called an amphid, an organ thought to be used for smelling (chemoreception). [Daniel Leduc, NIWA]

This new species of Dracograllus possesses modified hairs (ambulatory setae) on its head and near the tail which act as suckers. It uses them to walk around like a caterpillar! [Daniel Leduc, NIWA]

This new species of Latronema is a fierce predator that feeds on other nematode worms. Its mouth is equipped with 21 sharp teeth that don’t leave any chance of escape. [Daniel Leduc, NIWA]

Of the species that were isolated from the sample this is the only one which was not new to science: Epsilonema dentatum rugatum Lorenzen, 1973. It was originally described from Breakers Bay. The skin of this one consists of many overlapping, rigid rings, and it also possesses modified hairs (adhesion tubes) which have a similar function to the ones in Dracograllus. It is quite small (about a third of a millimetre in length) and requires some patience to find amongst all the sand and debris! [Daniel Leduc, NIWA]