A two-metre long monitor lizard from the northern Philippines had managed to remain hidden from science — until now. The lizard, Varanus bitatawa, is one of the Top 10 new species discovered in 2010 according to the International Institute for Species Exploration at Arizona State University.

For each of the past four years, the institute has put out a list of what it considers the most interesting and important finds among thousands of new species discovered the previous year.

A small African antelope, known as Walter's duiker, was a surprising find in 2010. Duikers are a well-studied group of mammals, but this particular species had ever been described before. It was first discovered at a bushmeat market in West Africa.

Some species on the list were chosen for their association with world events, such as a bacterium that spends its time consuming iron-oxide from the Titanic. A new species of fish was found in the region affected by the Gulf of Mexico oil spill. The Louisiana pancake batfish is flat as a pancake and hops on its fins.

Other species were chosen for their unique features. These include an underwater mushroom, a large toothed leech, and a cockroach that can jump just as well as a grasshopper.

The Top 10 list is rounded out with a spider named after Charles Darwin, a glowing mushroom and a cricket that pollinates a rare orchid.  

Anyone can nominate a new species for the annual list, provided it was described for the first time during the previous year. A committee of taxonomic experts choose the Top 10 from the nominations.

The International Institute for Species Exploration also puts out an annual report that looks at the overall totals and trends in new species discoveries in a given year. This lags a few years behind the Top 10. The most recent report from 2010 looked at the 2008 calendar year, when over 18,000 new living species were described.

The institute estimates that more than 10 million species of plants and animals exist on earth but as of 2008, less than 2 million had been described.