Zoologger is our weekly column highlighting extraordinary animals – and occasionally other organisms – from around the world.

The spikes on this minor worker of Pheidole drogon species might be for defence Masako Ogasawara/Sarnat et al.

Species: Pheidole drogon and Pheidole viserion

Habitat: Papua New Guinea

This ant may look like a fearsome dragon, but it can be a shy little thing. It is one of two newly described ant species from Papua New Guinea, and has some of the most impressive spikes among the widespread Pheidole genus of ants – found on every continent north of Antarctica.

Pheidole ants have more than one “caste” of worker ants – often, an all-purpose caste called a minor worker (see picture above) and a more specialised major worker for defence or breaking down food (see picture below).


The major workers in these two species have enormous heads, while the minor workers are smaller and have longer spines relative to their size, says Eli Sarnat at the Okinawa Institute of Science and Technology in Japan, who along with his colleagues has described the ants.

Because of the ants’ fearsome look, the team has named them after dragons from the Games of Thrones series. The jet-black species is called Pheidole drogon after Drogon, the beast of the same colour, and the gold-hued Pheidole viserion is named after the white and gold Viserion.

Beautiful and shy

“These ants that are being described are amazing,” says James Traniello of Boston University. “They’re absolutely beautiful.”

But despite their appearance, the major workers are shy for dragons. “They’re often the first to run away and hide,” says Sarnat. Their role is not usually in defence or attack. They use their huge mandibles to chomp into thick seeds, while the more abundant minor workers maintain the nest and raise young.

Their spiny pincushion body plan could be helpful in discouraging bird predators, because the spines would get stuck in an animal’s throat, says Sarnat.

The huge head of this major worker is used to bite into seeds Masako Ogasawara

But the team believe that the spines aren’t just for defence – they could also help support the major workers’ big heads. The group used X-rays to create 3D images of the ants and saw that the spines directly behind the major workers’ necks are full of muscles that are well placed to hold up the head, says Sarnat. The spines further from the head are hollow and are probably for defence.

Adaptable ants

Over 1000 species of Pheidole ants have been described so far, and it’s still not clear what has made the group so successful at adapting to different environments, says Diana Wheeler at the University of Arizona in Tucson.

One reason could be the different castes of worker ants, which would help them exploit more niches than if all the workers were the same. Describing more species helps scientists unravel how the Pheidole genus evolved, Wheeler says.

And there are many of these ants left to discover. “The vast majority of the Pheidole species in New Guinea are undescribed,” says Sarnat.

Reference: PLOS One, DOI: 10.1371/journal.pone.0156709

Read more: Kiss of death marks young ant rivals for worker kill squad