For a decade, the International Institute for Species Exploration at the College of Environmental Science and Forestry (ESF) has been compiling an annual list of the most exciting and fascinating new species discovered over the prior 12 months. This year's list is as compelling as ever, featuring a bizarre beetle that lives undercover among ants, a fish living deeper in the ocean than ever thought possible, and a previously undiscovered single-celled organism found in an aquarium in California.

"I'm constantly amazed at how many new species show up and the range of things that are discovered," says Quentin Wheeler, President of ESF. "We name about 18,000 per year but we think at least 20,000 per year are going extinct. … So many of these species – if we don't find them, name them and describe them now – will be lost forever. And yet they can teach us so much about the intricacies of ecosystems and the details of evolutionary history."

These 10 species were selected by an international committee of taxonomists, from the approximately 18,000 new species discovered and named over the past 12 months. The annual list is unveiled every year on May 23 to celebrate the birthday of 18th century Swedish botanist, Carl Linnaeus, the founder of modern taxonomy.

Unknown in the wild

Ancoracysta twista is a single-celled protist discovered on tropical coral in an aquarium in San Diego, California. This unexpected discovery, never seen in the wild, appeared to connect to an early lineage of Eukaryota, revealing a rich new insight into the early evolution of these primordial organisms.

A new critically endangered tree

A century ago, a single Amazonian tree called Dinizia excelsa was identified. It was thought to be the only tree of its genus type until the Dinizia jueirana-facao was recently discovered. Slightly smaller than its sister-species, the new discovery is still massive, reaching up to 130 feet (40 m) and weighing 62 tons (56,000 kg). Limited to the fringes of Reserva Natural Vale in northern Espirito Santo, Brazil, only 25 of these trees have been identified, making it a new critically endangered species.

The hunchback of the Southern Ocean

Epimeria quasimodo is one of 26 new species of amphipods recently discovered in the Southern Ocean. Named after the infamous Quasimodo from Victor Hugo's classic novel, this species of amphipod is notable for its humped back.

The undercover beetle

Nymphister kronaueri is a tiny beetle found living among a single species of army ants in Costa Rica. This amazing beetle lives and feeds when its host colony of ants is stationary but when they are on the move it hitches a ride by grasping onto an ant's abdomen. The beetle evolved to look precisely the same color and shape of the abdomen of a worker ant, making it virtually invisible when hitchhiking to the colony's next location.

A new species of Orangutan

In 2001, a distinct species of Orangutan was identified in Sumatra and Borneo, but a small population of isolated animals in northwestern Sumatra have know been recognized as their own distinct species. Pongo tapanuliensis is the first new non-human great ape species identified in nearly a century, and with only an estimated 800 individuals existing, they are immediately a critically endangered species.

The deepest fish in the sea

Belonging to the Liparidae, or snailfish family, Pseudoliparis swirei was discovered swimming deep in the Mariana Trench in the western Pacific. Collected at a depth between 22,000 and 26,000 feet (6,898 and 7,966 m) this tiny fish was found close to what is believed to be the deepest point a fish can survive. The study recorded another fish at 27,000 feet (8,230 m), but it could not be recovered so it's unknown if that was the same species or something new, making this snailfish the deepest underwater fish ever officially identified.

A flowery-fungus fusion

Non-photosynthesizing plants are rare, and new plants in Japan are even rarer, so the discovery of Sciaphila sugimotoi is exciting for several reasons. This beautiful and alien-looking parasitic plant derives its nutrition from a symbiotic relationship with a specific fungus. Called mycoheterotrophs, these rare plants are only seen for a short period when they are flowering, and this particular species has only been seen on a single island near Okinawa.

Volcanic bacteria

In 2011, the eruption of an undersea volcano off the coast of El Hierro in the Canary Islands completely razed the local marine ecosystem. A few years later, scientists discovered a strange, almost hair-like, white mat covering the newly formed sea bed. It was revealed that this white sheath was a new species of protobacteria called Thiolava veneris, which thrived on the novel habitat created by the submarine eruption. It was dubbed Venus's hair by scientists.

An Australian lion

Fossils recovered from the Riversleigh World Heritage Area in Queensland revealed a previously unknown species of marsupial lion that roamed Australia's north-east around 25 million years ago. Wakaleo schouteni is part of a new lineage of marsupial lions that were omnivores and disappeared around 19 million years ago. About the size of a Siberian husky dog, the discovery suggests Australia once had a much more diverse range of marsupial lions than previously thought.

A Chinese cave beetle

Xuedytes bellus was discovered in a limestone cave in Du'an, Guangxi Provine. It's a troglobitic beetle that evolved to live in darkness and, although less than half an inch in length, this strange beetle contains an unusually elongated head and prothorax. The scientists describe the beetle as, "the most extremely cave-adapted trechine in the world."

Source: ESF

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