An orange-tailed monkey, a pink dolphin and a stingray with a honeycomb pattern on its back were among 381 animals and plants from the Amazon officially recognized by science as new species in 2014 and 2015, says a new report from the World Wildlife Fund and Brazil's Mamirauá Institute.

The fire-tailed titi monkey from the southern Amazon owes its name to its long, bright orange tail. The species is under threat from deforestation. (WWF)

The report released this week, New Species of Vertebrates and Plants in the Amazon, compiles descriptions of new species in the Amazon published in peer-reviewed scientific journals between January 2014 and December 2015.

Two of the species, both mammals, were fossils. But the other 379 were still living in the Amazon region that includes most of Brazil, along with parts of Bolivia, Colombia, Ecuador, French Guiana, Guyana, Peru, Suriname and Venezuela.

The new frog Tepuihyla obscura is nocturnal and lives high in the mountains of Venezuela, hiding on bromeliad plants during the day. (Philippe J.R. Kok)

Among the new species were:

216 plants, including a new species of Solanum, related to tomatoes and potatoes

93 fish, including a beautiful freshwater stingray and two iridescent, rainbow-coloured fish found in temporary ponds

32 amphibians, including a nocturnal frog that hides on bromeliad plants

19 reptiles, including a brightly spotted lizard found on a mountaintop

18 living mammals, including the fire-tailed titi monkey and the new pink dolphin, and two fossil mammals

one bird, named Chico's tyrannulet

Chico’s tyrannulet is the only bird among the 381 new species. It's named after the rubber tapper and environmentalist Francisco Alves Mendes Filho, better known as Chico Mendes. (Bret Whitney/WWF)

Many of those newly discovered species are threatened by human activity, the report says. For example, the pink dolphin may be harmed by the construction of hydroelectric dams as well as farming, cattle ranching and industrial activities, while the fire-tailed titi monkey is losing its habitat to deforestation.

Compilations of newly described species in the Amazon had previously been done for 1999 to 2009 and 2010 to 2013, representing a total of more than 2,000 new species discovered over the past 17 years.

This beautiful fish, named Maratecoara gesmonei, was discovered in a temporary pond just 50 centimetres deep, on an island in the middle of the Xingu River in the state of Para, Brazil. (Dalton Tavaras Bressone Nielsen)

The latest report shows an average of one new species described approximately every two days — a 50 per cent increase in the rate of new species discovery in the Amazon compared to 1999 to 2013.

And those discoveries don't even include invertebrates like insects.

The lizard Riolama inopinata was discovered on the summit of a mountain 2,400 metres high in Venezuela. (Philippe J.R. Kok)

Most of the new species have been found along main rivers, near big cities and some well-studied protected areas.

Joao Valsecchi do Amaral, technical scientific director of the Mamiraua Institute, said there are still many areas of the Amazon for which scientists have little or no information.

"The probability that new species will be found in these places is quite high," he said in a statement.

The WWF says discovering new species and knowing how many species are in the region provides an important baseline for monitoring declines and extinctions, guiding environmental and resource management and deciding where to establish protected areas.