New species discovered in 2010

A long-tailed slug (Ibycus rachelae) Perhaps the rarest of the extensive invertebrate species group are slugs which, according to scientists, are infrequently encountered. At great altitudes on Borneo, several rare and highly endemic species appear to exist, including one new colourful green and yellow species, Ibycus rachelae, described from Sabah, Malaysia, in the Heart of Borneo. Discovered on leaves in primary montane forest at altitudes up to 1,900m on Gunung Kinabalu, the species has a particularly long tail, three times the length of its head, with a body length of 4cm. According to scientists, the slug has the habit of wrapping the long tail around its body when resting. From the Ariophantidae family, this unusual species makes use of so-called ‘love darts’ in courtship. Made of calcium carbonate, the love dart is harpoon-like which pierces and injects a hormone into a mate, and may play a role in increasing the chances of reproduction Photograph: guardian.co.uk

Lemur featured in the BBC's Decade of Discovery programme Photograph: BBC

The barreleye fish, already known as a species but filmed in the deep for the first time by the Monterey Bay Aquarium Research Institute (MBARI). The green orbs are its eyes, directed upwards to detect its prey in silhouette through its transparent head Photograph: BBC

A dragonfish from Australia. For many animals in the deep sea it may be weeks to months between meals. If they find something to eat, they hang on to it. This is why so many deep-sea fishes have lots of big teeth. This fish has teeth on its tongue. They would be terrifying animals if they weren't the size of a banana Photograph: Dr. Julian Finn/Museum of Victoria

A enteropneust hemichordate (acorn worm) from the benthic boundary layer, which was found attached to seafloor by adhesive tentacles Photograph: David Shale/University of Aberdeen/guardian.co.uk

New species of beaked toad, genus Rhinella, found in the rainforests of Chocó department of Colombia, during the 'search for lost frogs'. This individual, around 2cm in length, is thought to skip the tadpole stage, hatching directly into toadlets from eggs laid on the forest floor. The colour and shape of the head make the toad resemble the dead leaves on which it lives © Robin Moore/iLCP Photograph: Robin Moore/iLCP

Blue fang skeleton tarantula (Ephebopus cyanognathus) More than 1,200 species have been discovered in the Amazon over the past 10 years, according to the WWF Photograph: WWF/Peter Conheim

New Amazon species: a bald parrot (Pyrilia aurantiocephala) Photograph: WWF/Arthur Grosset

Microscopic marine life. Zooplankton: Rosacea tentacles stretch a metre away from the main body and contract when disturbed by potential food items. The beads are stinging cells that immobilise and kill the prey Photograph: L. Madin/WHOI/guardian.co.uk

New species discovered by British Antarctic Survey: Brittle stars (several different species). They are a very important part of seafloor communities around Antarctica and are rich in species Photograph: British Antarctic Survey

New species discovered by British Antarctic Survey: Isopod crustacean. These animals (woodlice of the sea) resemble fossil trilobites and are among the hundreds of new species discovered in the deep sea Photograph: British Antarctic Survey

This image provided by NOAA shows a deep-sea chimaera. Chimaeras are most closely related to sharks, although their evolutionary lineage branched off from sharks nearly 400m years ago, and they have remained an isolated group ever since. According to scientists the lateral lines running across this chimaera are mechano-receptors that detect pressure waves (just like ears). The dotted-looking lines on the frontal portion of the face (near the mouth) are ampullae de lorenzini and they detect perturbations in electrical fields generated by living organisms. Scientists using cutting-edge technology to explore waters off Indonesia predicted that as many as 40 new plant and animal species may have been discovered during a three-week expedition Photograph: AP

New species discovered in Foja mountains on Indonesian island of New Guinea: Long-nosed tree frog Photograph: Tim Laman/guardian.co.uk

New species discovered in Foja mountains on Indonesian island of New Guinea: Tree mouse Photograph: Tim Laman/guardian.co.uk

Lost worlds: New species found in Ecuador. This tiny scaly-eyed gecko, Lepidoblepharis buschwaldii, never gets much larger than this one Photograph: Paul S Hamilton/guardian.co.uk

The Hawaiian bobtail squid, Euprymna scolopes, has a clever way of duping predators during its nightly activities. It uses a symbiotic luminescent bacteria, Vibrio fischeri, to light up its underside, so that upwards-looking predators don't see a dark, edible form silhouetted against a moonlit or starlit sky. Instead, hungry sharks or other fish see only sky - the squid is invisible
Photograph: Mattias Ormestad/kahikai.org