People generally greet spiders with screams of terror not shrieks of delight, but that was the reaction of scientists who discovered a previously unrecorded genus of tarantula in the Northern Territory.

Species discovery program Bush Blitz spent this week with scientists at the Judbarra/Gregory National Park in the Top End, and uncovered seven new species of spider, including a tarantula that they say is completely new to science.

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A whopping three quarters of biodiversity in Australia remains undiscovered, said program manager Jo Harding.

“The world of spiders is huge… so it’s not that surprising that you can go to a fairly popular national park for tourists and still uncover new species,” she said.

She said the tarantula, uncovered by Adelaide University PhD student Sophie Harrison, “is so different they’ll make a new genus for it”.

Ms Harrison was thrilled with the discovery.

Tarantulas live at the bottom of long straight burrows, which they dig as babies and live in for their whole lives, which can be over 30 years.

“They were quite hard to get out of the ground… we had to dig a hole in shifts with a pick, a knee-high hole, and a beautiful big spider was at the bottom, a lovely silvery browny beautiful tarantula, so we got her out and she was something new,” she told AAP.

The group uncovered about a dozen specimens of the new tarantula, which are being transported to Queensland for a new genus record to be made, and to have their venom milked to see if there’s anything unusual about them.

Bush Blitz has discovered almost 900 species over five years, located another 250 threatened species, and recorded 12,000 types of plants and animals in previously unknown areas.

Other discoveries this week include a brush-footed trapdoor spider and a saddle-kneed trapdoor spider, along with an eel species never before detected in that river catchment and a flock of the beautiful but endangered Gouldian finches.

Bush Blitz will next travel to Cape York in July, followed by the central desert and then northern NSW in November.