This Jurassic Spider, Here for 150 Million Years, Faces Extinction Due to Forest Fires

Cambridge Prisms: extinction, signed in particular by John Woinarski (Charles Darwin University) and Michael Rix (Queensland Museum), alert on the extent of the “invisible” extinctions of invertebrates in Australia. More than 9,000 species would have disappeared since European colonization, without even being documented. This observation highlights a major bias: conservation focuses on emblematic species, to the detriment of these essential creatures for ecological balance.

A single spider: heiress of dinosaurs

Zephyrarchaea Austini, better known as the murderous spider of Kangaroo Island, is a rare witness to the distant past of the earth. It belongs to a line that emerged during the time of dinosaurs. This spider crossed massive extinctions and climate upheavals before being rediscovered in 2010 by Michael Rix and Mark Harvey. Their study revealed a singular anatomy which distinguishes it radically from other arachnids. Its head, perched on an elongated “neck”, supports formidable stylish cherries, perfectly suited to grasp and pierce other spiders. “” Their silhouette is unreal, almost alien », Observes Rix, fascinated by this intact scalable heritage, reports The Guardian.

These spiders belong to the Archaeidae family, long known only by fossils. Their discovery in Australia was all the more astonishing since, until the 19th century, the only living specimens had been reported in Madagascar. On Kangaroo Island, they go far into microhabitats of rare stability. Namely heaps of fresh and humid vegetable litter, nestled under a dense canopy. This environment offers them the humidity essential to their survival. But above all it houses their main prey, other spiders that they capture with a strategic slowness.

But this extraordinary predator is not invincible. Its distribution is extremely limited: barely 20 km² in the northwest of the island. This fragmented area, surrounded by threats, makes it one of the most vulnerable invertebrates in Australia. Its already weak workforce struggles to resist the disturbances which dry up its fragile habitat. The scarcity and specialization of the species testify to its evolutionary history. And unfortunately, they also make him a designated victim of the rapid changes imposed by human activity.

A habitat in danger in the face of flames and drought

The Kangaroo Island assassin spider therefore lives in an extreme precarious environment. Its natural habitat is limited to small pockets of humid vegetable litter, nestled under groves of native trees. These microclimates, essential to its survival, maintain a constant humidity which protects the species from thermal variations. But this delicate balance was deeply disturbed by a succession of ecological disasters.

Disvastor fires of the 2019-2020 black summer dashed nearly 210,000 hectares, or half the surface of Kangaroo Island. These fires of unprecedented intensity destroyed the vegetation and sterilized the soils. They in fact eliminated entire areas of refuge for the spider. “” We thought the species disappeared after these fires “Admit Dr Jess Marsh, researcher at the University of Adélaide. The fortuitous discovery of two individuals in 2021 in a fragment of unruly forest gave fragile hope. However, the following statements have continued to alert a dramatically low residual population.

To these destruction are added two years of almost continuous drought. The precipitation, at the lowest in a century, leave the arid soil and the dry forest litter. Jane Ogilvie, of the Invertebrates Australia organization, testifies: ” Everything is so dry that we have trouble believing that such humidity existed here ».

Finally, the propagation of phytophthora, a pathogenic mushroom of the roots, completes to weaken this ecosystem. By decimating canopy and nourishing plants, it further reduces vital humidity in the microhabitat. According to Michael Rix, ” the species is literally at an ecological disaster in extinction ».

Invisible extinctions: the case of Australian invertebrates

The decline of the assassin spider illustrates a larger and much more alarming phenomenon: the massive disappearance of invertebrates in Australia. According to a study published in Cambridge Prisms: extinction By John Woinarski (Charles Darwin University), Michael Rix (Queensland Museum) and their colleagues, around 9,000 non -marine invertebrates have disappeared since the arrival of European settlers. This figure is amazing compared to the 10 species of invertebrates officially declared extinguished in the country. The majority of these losses would be “ghost extinctions”. In other words, species still unknown to science that have turned off without ever having been listed.

This observation highlights a structural bias in conservation efforts. The invertebrates, which however represent most of terrestrial biodiversity, suffer from a deficit in recognition and investment. Public policies and opinion focus on emblematic species such as Koala or Wombat. They thus leave in the shadow of the thousands of discreet species, but essential to the proper functioning of ecosystems. After fires from 2019-2020, $ 12 million was mobilized to save the Koala. By way of comparison, the hundreds of invertebrate species having seen all their burned habitat received a fraction of this sum.

The study highlights a disturbing rhythm of 1 to 3 extinctions of invertebrates per week. At this rate, the objective of the Australian government announced in 2022 – avoid any extinction by 2032 – already appears out of reach. For Woinarski and his colleagues, only a radical overhaul of conservation priorities would avoid the silent loss of a whole section of Australian evolutionary heritage.

Digital memory in the face of oblivion

Faced with the accelerated disappearance of invertebrates, some scientists bet on digital conservation to preserve the trace of these threatened species. On Kangaroo Island, entomologist Richard Glatz devoted more than two decades to collect and document local entomological fauna. Its collection, with 80,000 specimens, houses many rare species, sometimes unique on the island. After the 2019 fires, Glatz made a radical decision. He wanted to build a fireproof building to house his samples. “” The loss would have been invaluable He says.

Thanks to Biodiversity Data Program Mobilizationhe was able to digitize more than 16,000 specimens. These data were integrated into the Atlas of Living Australia. This national base makes Australian biodiversity accessible to researchers and to the general public. This work remains essential to improve knowledge of species whose very existence remains often ignored. For the assassin spider and other invertebrates of Kangaroo Island, this digital memory represents a form of insurance in the face of an uncertain future.

But this strategy, as precious as it is, does not replace conservation in the field. Without concrete measures to restore habitats and limit threats, these archives are likely to become the only vestiges of missing species. The invertebrate crisis highlights the urgency of a paradigm shift: protect the small and the invisible as much as the iconic. To preserve biodiversity is also to preserve the discreet cogs of the ecosystems on which life depends on earth. In this sense, each microhabitat saved, each species identified, is a victory against forgetfulness.