The focus on sex also leaves out organisms that reproduce asexually. Other definitions consider ancestry, though where the lines should be drawn is unclear – are we the same species as our water-dwelling ancestors? Further definitions focus on ecology, geography and physiology.

This Q&A originally appeared in BBC Wildlife Magazine, and was answered by Leoma Williams.

How many species go extinct each day?

This is impossible to answer precisely. New species appear all the time and can go extinct before they’ve even been described, and estimates as to the rates of extinction very enormously. One approach to working it out would be to first take the yearly ‘natural extinction rate’ – the rate at which species would go extinct if we humans weren’t around. This is often stated as one per million (or 0.00001%) per year – but again, opinion on this varies.

Experts now believe that current rates of extinction have soared to between 1,000 and 10,000 times this natural rate. So, take the natural rate as one per million and that brings current rates to between 0.01 and 0.1% per year. There are said to be 1.6 million described species on our planet, but some experts believe there could be as many as 100 million. So, work out the worse- case scenario maths and the daily rate of extinction comes in at 273 species per day.

We are said to be in the midst of a sixth extinction. Unlike previous mass extinction events, which were the result of climatic shifts, geological activity and a very large asteroid, responsibility for the current losses is down to us.

This Q&A originally appeared in BBC Wildlife Magazine, and was answered by Sarah McPherson.

New species described in 2021:

Here we feature a few of the extant species that have been described so far this year, from impressive spiders in Papua New Guinea named after the activist Greta Thunberg to a tiny chameleon in Madagascar. We have also provided links to the taxonomic papers in which the new species have been described.

Feiruz wood lizard, Peru: Enyaliodies feiruzae

A new species of dragon-like lizard called Enyalioides feiruzae has been formally described, following seven years of field studies, which involved hand-picking sleeping individuals from plants at nights.

The lizards, particularly the males, can come in a variety of colours ranging between turquoise, green, grey and brown, with lines on their backs and spots on their sides.

Part of the wood lizard genus, Enyalioides, they’re found in northern South America and Panama, and are very similar to the geographically separated E. rudolfarndti. E. feiruzae is found in the basin of the Huallaga River in the Peruvian Andes, an understudied area due to various conflicts with terrorist organisations and drug traffickers in the 1980s and 1990s.

The name comes from Feiruz, a female green iguana, whose owner Catherine Thomson supported the taxonomic research through the BIOPAT initiative.

Read the full paper in Evolutionary Systematics.

Killer tobacco plant, Australia: Nicotiana insecticida 

This wild tobacco plant is one of seven newly described species in the Nicotiana genus. The ‘killer tobacco plant’ (N. insecticida) was so-named as it’s covered in sticky glands that capture and kill small insects – the first wild tobacco plant to do so. It is not known if it gains nutritional benefit from the insects and thus isn’t yet classified as carnivorous.

All the new species are found in the Australian arid zone. N. insecticida was found by a truck stop on the Northwest Coastal Highway in Western Australia.

Read the paper in Curtis’s Botanical Magazine.

Brittlestar, southwest Pacific Ocean near New Caledonia: Ophiojura exbodi

This brittlestar is the only living representative of a lineage that split from its closest relatives180 million years ago, just as the dinosaurs were starting to go full tilt. Not only does Ophiojura exbodi get a genus all to itself, but a whole new family was created to accommodate it. Its most obvious distinguishing feature is its eight arms rather than the usual five.

Collected from a seamount – a submarine mountain – called the Durand Bank, near New Caledonia in the Pacific, its distinctive skeletal features are strikingly similar to fossils found in early Jurassic rocks from Normandy.

Read the paper in Proceedings of the Royal Society B.

Frog, Guinea Shield: Synapturanus zombie

This underground-dwelling frog is one of three new Synapturanus species. The call of the male can only be heard during or after heavy rainfall. To find the animals, scientists need to dig them out of the ground using their bare hands (usually getting soaked in the process). It’s this rather eerie scenario that has given rise to the name Synapturanus zombie.

All three frog species are found in an incredibly biodiverse region of South America known as the Guiana Shield. The scientists believe there may be six times as many Synapturanus species than have been described so far.

Read the paper in Zoologischer Anzeiger.

Ant, Ecuador: Strumigenys ayersthey

When a species is named after a person, convention holds that the name ends in the suffix ae (after females) or i (males). But what if the person being honoured identifies as neither male nor female? The solution, in the case of this trap-jaw ant named after artist Jeremy Ayers, was to use ‘they’ as the suffix.

Just a single specimen has been collected so far, in tropical forest in northern Ecuador. Extensive efforts to find more proved fruitless, suggesting it is very rare. Its spring-loaded jaws may be a specialisation for catching nimble springtails.

Read the full paper in ZooKeys.

Centipede, Japan: Scolopendra alcyona

This huge centipede – 20cm long and 2cm broad – is only the third amphibious species known to science. It comes in blue-legged and yellow-legged varieties, and is named after Alcyone of Greek mythology, who was turned into a kingfisher – an allusion to its colour and proficiency in and out of the water.

S. alcyona is the first new centipede to be described from Japan in 143 years. It is found under rocks near forest streams on the Ryukyu Islands. Several individuals escaped capture by plunging into the water.

Read the paper in Zootaxa.

Greta spiders, Madagascar and Mayotte: Thunberga

When the huntsman spider genus Thunberga was named last year after a certain Swedish environmentalist, it contained just a single species. Now, it contains 26. Some of the 25 new ‘Greta spiders’ have been named in honour of other inspirational young people, including human rights activist Malala Yousafzai and environmental entrepreneur Boyan Slat.

All 25 new species hail from Madagascar and its tiny neighbour Mayotte. The females of many of these ambush predators bear numerous scars on their bodies, which are thought to be inflicted by the fangs of males as they grasp them during mating.

Read the paper in Arachnology.

Snake, Papua New Guinea: Stegonotus aplini

If snakes were hot drinks, Stegonotus aplini would be a latte macchiato. It’s the seamless transition from milk- white to coffee-brown along its length that sets this serpent apart from its closest relatives, which tend to be a uniform shade of grey or brown.

In the region of southern Papua New Guinea where S. aplini hunts on forest floors at night, local people are highly fearful of the species – even though it is apparently harmless to humans. Perhaps this is because of its superficial resemblance to a more distantly related, venomous snake that also occurs in the region.

Read the paper in Zootaxa.

Chameleon, Madagascar: Brookesia nana

A tiny chameleon the size of a seed could be a contender for the title of the smallest reptile on Earth. The male nano-chameleon (pictured) has a body just 13.5mm long, yet its genitals are one-fifth of its body size, possibly allowing it to mate with the larger female.

An international team of eagle-eyed scientists spied the reptile within degraded montane rainforests in northern Madagascar. Fortunately, its habitat has been placed under protection, but the researchers have recommended that the bijou chameleon is listed as Critically Endangered on the IUCN Red List of Threatened Species.

Read the full paper in Nature.

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