Top 10 new species of 2018 include volcanic bacterium and a hitchhiking beetle

From a tree to an orangutan to bacterium, the annual top 10 new species list has the newest stars of Earth's biodiversity.

The list is compiled by the State University of New York's College of Environmental Science and Forestry and its International Institute for Species Exploration (IISE), which first began their list in 2008.

In order to make the cut, the animal or plant must have been discovered and placed on the evolutionary tree of life, described in a scientific journal and given a scientific name over the past year.

Included this year is the Pongo tapanuliensi, a new species of orangutan found in the north Sumatra's forests. It was discovered that, while the northern Sumatra and Borneo species separated roughly 674,000 years ago, this new species diverged roughly 3.38 million years ago. It's estimated that only 800 individuals remain, making it the most endangered great ape in the world.

• New 'smiley face' bee named after University of Manitoba researcher
• All-female fish species shows sex is overrated

But it's not just big animals that make the list.

Thiolava veneris is a new species of protobacteria found in the Canary Islands. It was discovered three years after the submarine volcano Tagoro erupted off the coast of El Hierro in 2011.

The new species produces hair-like structures made up of bacterial cells and a sheath. It created a white mat extending nearly 2,000 metres around the summit of the new Tagoro cone about 130 metres below the surface following the eruption.

According to Quentin Wheeler, director of the IISE, it's estimated that roughly 18,000 new species are discovered each year, and there are still roughly 10 million undiscovered species. Even though it may seem like good news that so many species are being discovered, Wheeler said the disappearance of species is of great concern, too.

"We don't know how many [species] there are in total ... but a conservative estimate is that 20,000 species per year are going extinct," he said. "So this is probably the first time in human history when species are disappearing faster than we're discovering them."

Still, he's excited by the species that are being found and he says that part of the reason he started this list is to "just make people appreciate what an amazing planet we live on.

"It's just awesome what exists out there."

Below are the other species that made the list.

• Pseudoliparis swirei,is found in the western Pacific Ocean in the depths of the Mariana Trench, the deepest place in the world's oceans. This tadpole-like fish is only 112 mm long but lives at depths between 6,898 and 7,966 metres, making it the deepest-dwelling fish ever discovered.
• Sciaphila sugimotoi, is a plant that feeds off organisms rather than the sun. This plant was found on Ishigaki Island, Japan.
• Dinizia jueirana-facao is a tree found in Brazil that towers up to 40 metres and weighs roughly 62 tonnes.
• Epimeria quasimodo is named for, you guessed it, Quasimodo from Victor Hugo's The Hunchback of Notre Dame. This tiny species that looks like a mini shrimp was found in the Antarctic Ocean and measures just 50 mm. 
• Ancoracysta twista was first discovered in a San Diego aquarium. This single-celled protist is an early lineage of eukaryota, organisms with cells in which genetic material is contained in a nucleus.
• Nymphister kronaurei is a hitchhiking beetle discovered in Costa Rica. The beetle — measuring just 1.5 mm — lives among nomadic ants and, when the ants move to build another nest, uses its mouth to grab the skinny part of the ant's abdomen and hitches a ride. 
• Wakaleo schouteni, a marsupial lion, roamed Australia 23 million years ago.
• Xuedytes bellus was found in Chinese caves. The 9-mm-long beetle has, like many cave-dwelling beetles, evolved with spider-like legs and a loss of wings. But it's the elongation of its head and prothorax (the segment of its body that lies directly behind its head) that makes this critter stand out.

​The list is released annually around May 23 to mark the birthday of Carolus Linnaeus, considered the "father of taxonomy." Linnaeus' work in the mid-18th century marked the start of the modern naming and classification system of animals and plants.