'Death ball' sponge, tiny opossum among cool new species of 2025

A wanderer with extra-long crotch (for a goodness reason out); a carnivorous cat that wears its prey's body parts; and a tiny, mountain-dwelling opossum are among the cool new species described by science in 2025.

A new recent study reports that about 16,000 new species are "discovered" each year, a rate that is accelerating — 15 per cent of all known species have been newly described in just the past 20 years. 

"Our good news is that this rate of new species discovery far outpaces the rate of species extinctions, which we calculated to about 10 per year," John Wiens, an ecology professor at the University of Arizona who co-authored the study, said in a news release.

Many aren't truly new discoveries. In many cases, they were known or photographed locally, or collected many years ago for museums. They were just never identified and described by science until now.

But scientists say this official documentation step is important. Wiens noted, "We can't safeguard a species from extinction if we don't know it exists."

It's also a great way for us to learn about some interesting and unique creatures that we've never seen or heard of before. Here's a closer look at some of them.

Four new tarantula species were discovered in the Horn of Africa and Arabian Peninsula. What's special about them? Well, their males have the longest genitalia among all known tarantulas.

The largest species, named Satyrex ferox, has a leg-span of 14 centimetres (about the width of a slice of bread). But if you're not impressed yet, males have genitalia called palps that measure five centimetres long; that's nearly as long as their longest legs.

Alireza Zamani, a researcher at the University of Turku who led the study describing the new tarantulas, suggests that the long palps "might allow the male to keep a safer distance during mating to help him avoid being attacked and devoured by the highly aggressive female."

Most caterpillars are vegetarians, but this year scientists in Hawaii found a caterpillar that lives in spider webs, eats prey trapped in the webs and then weaves their body parts into a coat or case around its body (that later becomes its cocoon).

The unique  "bone collector" caterpillar, which turns into a moth with feathery wings, was described in Science in April. It's been found only in a small 15-square-kilometre patch of forest in the Wai'anae mountain range on O'ahu, suggesting that it's endangered.

The deep ocean is a part of the planet that humans have explored very little, and each expedition there turns up many new and amazing species. In October, the Nippon Foundation-Nekton Ocean Census announced 30 new species discovered in the Southern Ocean near Antarctica.

They include the "death-ball" sponge, which doesn't filter feed like most sponges, but instead has spheres covered in tiny hooks to trap prey. New sea star species and an armoured, iridescent scale worm are also on the list.

Shallower waters also yielded some beautiful and unique new species, including a sea slug that looks like it's covered in fried eggs, named Phyllidia ovata. It's one of two beautiful new species of wart sea slugs that prey on sponges and steal their toxins for self-defence.

Their bright colours warn potential predators that they're toxic. The new species had previously been photographed by divers in North Sulawesi up to 23 years ago, Indonesia, but only described by science this past July.

One of the new species discovered in Canada this year was also an aquatic creature. The Okanagan crayfish is found in B.C.'s Okanagan Lake. It was previously mistaken for the common, lookalike signal crayfish. The new species' distinguishing feature is that it lacks a distinctive white mark found on the signal crayfish's claw.

Unfortunately, the new species is thought to be endangered, and scientists are especially concerned because Okanagan Lake is heavily used by humans.

Canadian researchers were also involved in the discovery of six tiny new species of tube-nosed bats from the Philippines.

Judith Eger and Burton Lim of the Royal Ontario Museum co-authored a study describing the species just before Halloween. The bats, which weigh just four to 14 grams each, were collected by researchers in the Philippines and at the Field Museum in Chicago on expeditions over the past 30 years. 

Some new species every year are named for famous characters, real or imagined. Two reptiles this year with famous namesakes are the long-nosed Pinocchio chameleon of Madagascar and a new wolf snake from India's Great Nicobar Islands named Lycodon irwini after the late Steve Irwin, star of The Crocodile Hunter TV series.

Here's one of the less scary animals on this year's list: a small, spectacled marsupial found in the Peruvian Andes in 2018. The tiny mouse opossum Marmosa chachapoya is mouse sized (about 10 centimetres, with a 15 cm tail) and lives at a much higher elevation than other mouse opossums.  It was described in June in the journal American Museum Novitiates.

We haven't had any amphibians on the list yet, so let's add some before we go.

Three of the unusual species discovered this year include toads that live in trees, far from water, in the Eastern Arc Mountains of Tanzania. That makes the tadpole stage of their life cycle a challenge — so they skip it and give birth to live toadlets.

"Live-bearing is exceptionally rare among frogs and toads, practiced by less than one per cent of frog species, making these new species exceptionally interesting," said H. Christoph Liedtke, a researcher from the Spanish National Research Council, who co-authored a description of the new species in November.

The new species were identified through physical and genetic analysis of museum specimens that were originally thought to be the same species. Two of the new species are already believed to be critically endangered.

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