Rare giant spider species spotted in Queensland

The Euoplos dignitas specimen sits in its habitat in Queensland, Australia. (Michael Rix)

A new and large species of spider has been found living in Queensland, Australia, and researchers say it's in need of protection.

Rare and colourful, the tarantula-like creature is a type of golden trapdoor spider belonging to the genus Euoplos, which since 2017 has been the subject of an extensive research program, according to a study published March 15 in the Journal of Arachnology.

Now called Euoplos dignita, the species was first discovered in the early 20th century, near the towns of Monto and Eidsvold, but it remained undescribed and unnamed due to a lack of research, said study author Michael Rix, principal curator of arachnology at the Queensland Museum Network, via email.

For years, there have been only a handful of Euoplos dignita specimens in the Queensland Museum's collection, all but one of which were collected before the 1970s. There were no known males among them — which posed a significant obstacle for Rix and his research team.

A journey of rediscovery

Having a male specimen is important for being able to identify and name a species within the Mygalomorphae order, which Euoplos spiders are part of, said Paula Cushing, senior curator in vertebrate zoology at the Denver Museum of Nature and Science. Cushing, who is also secretary of the American Arachnological Society, wasn't involved in the study.

"Oftentimes, in order to figure out if what you're looking at is new to science, you almost always, with spiders, have to examine the genitalia," she added.

So the researchers needed new genetic material they could test from a living male specimen — which meant they had to find one.

They finally spotted what they were looking for on a roadside in the Eidsvold-Monto region after a three-day search in May 2021. It was the first collection of the species since the 1990s.

After comparing their find to other specimens in the museum's collection, the research team officially described Euoplos dignitas. Dignitas is "Latin for dignity or greatness, in reference to the really spectacular nature of this spider," Rix said in a YouTube video published by the Queensland Museum Network. "It's a big, beautiful species."

Females of the species have a red-brown carapace, burrow-building behaviour and can grow to 2 inches long, which is "very large" for this type of spider, according to the study. The males have a "striking 'honey-red' carapace and legs," and their abdomens are grayish brown.

"These spiders are pretty cool because they are so long lived. Some trapdoor mygalomorphs can live for literally decades," Cushing said. "The longest-lived trapdoor tarantula was 43 years old."

Protecting Euoplos dignitas

Protection is needed for this rare species, the researchers also found. When the researchers located the male Euoplos dignitas specimen, they observed that most of the roadside habitats that would typically be available for this species had been cleared for agriculture or highly disturbed, which is "extremely destructive for trapdoor spiders, their burrows and the integrity of their habitat," according to the researchers.

"Until detailed survey work is completed, we won't know how many remaining populations exist," Rix said. "But the natural range of the species is small (and) highly fragmented, and we were only able to discover one living (specimen) at the time."