"Most people go, yeah, who cares, it's just spiders. Another thing I've got to squash," said ecologist and Bush Blitz manager Jo Harding. A new species of snail discovered at Skull Bone Plains in Tasmania. "People don't realise how important this is." Without taxonomy – the description and classification of organisms – "you don't know if [an organism] is rare or threatened or a biosecurity risk … Or if it contains the cure for cancer," Ms Harding said. The 13 new spider species add to the more than 6600 arachnid species already described and named in Australia. These make up nearly 7 per cent of the world's 102,000 arachnid species. (By comparison, Australians make up just 0.3 per cent of the world's human population.)

Discovering a new species may not be as hard as people think, Ms Harding said. Three-quarters of the 570,000 plant and animal species scientists estimate are in Australia are yet to be named and described. A curtain web spider, one of 18 new species of spider discovered at Fish River Station in the NT. Credit:R. Whyte "You don't have to go to the Amazon to discover new species. There are species right in our backyard that have never been discovered," she said. While most people would probably like to discover a kangaroo or other large mammal, the most commonly-discovered new species are bugs, spiders, snails, moths and plants. A new species of Lacebug Lasiacantha discovered at Charles Darwin Reserve, WA. Credit:C. Symonds

"It's often the things that are small and less showy. There [are] far fewer butterfly species discovered these days, for example. People tend to like the pretty shiny things that are active during the day." Primary school teacher Leslie Carr, from Maribyrnong Primary in the ACT, discovered a new species of brush-footed trapdoor spider, which she hopes will be named in her honour. Some 18,000 new species a year are discovered around the world - an average of nearly 50 a day. "My most exciting day was when I learnt to dig up spiders. I knew nothing about them in the morning and by the afternoon I was capable of digging up three spiders successfully all by myself," Ms Carr said. Michael Hammer, curator of fishes at the Museum and Art Gallery of the Northern Territory, collected a delicate blue-eye fish.

"When I saw this little guy I knew straight away he was different from the fish in the Northern Territory. We are confident this group is more than just one species, but we need to find enough of them to be sure," Dr Hammer said. "This group of fish is like a big puzzle and we have finally found the missing piece … It's exciting to be on the brink of a new fish species." More than 90 per cent of Australia's marine area and 45 per cent of the continent have never been comprehensively surveyed, according to the Bush Blitz website. Worldwide, estimates of the total number of species range from 5 million to 100 million, although the most recent Australian government report on the number of living species in Australia and the world uses the number 11 million. About 18,000 new species a year are discovered around the world - an average of nearly 50 new species a day.