Extinct Hell Ants - Were their Deadly Jaws Their Downfall?

Ryan Zschomler

1 day ago

3 min read

By Keith Sturgeon

Guest Contributor | Amber Bugs

What are Hell Ants?

Haidomyrmex belonged to an extraordinary extinct group known as the hell ants—Cretaceous predators unlike any ant alive today.

And perhaps their most remarkable differences were all in their heads.

Haidomyrmex Hell Ant in clear yellow amber — ***A Haidomyrmex hell ant*** - a rare extinct species only found in Cretaceous amber. Note the verticle scythe-like mandibles. No modern ant has this feature.

Hell ants flourished during the Cretaceous as highly specialized predators. Unlike modern ants, whose mandibles generally close from side to side, hell ants evolved an extraordinary feeding apparatus. Their elongated mandibles moved vertically, snapping upward toward specialized projections on the head.

It was a radically different solution to a familiar problem: how to capture prey.

The ancestors of ants were ultimately derived from predatory aculeate wasps. As early ants diversified during the Cretaceous, evolution experimented with some remarkable body plans.

The hell ants took one of the strangest paths.

Hell Ant's remarkable verticle scythe-like jaws

Over time, their mandibles became increasingly elongated, specialized, and reoriented. Different hell ants developed dramatically different jaws and head structures—some curved, some blade-like, and others extraordinarily long.

But were these remarkable mandibles used only for feeding? I would suggest another possibility.

Structures this prominent and highly mobile could conceivably have played a role in courtship, competition, or mating as well.

That raises an intriguing question.

What do hell ant's jaws tell us about their sexual dimorphism?

Could some of the variation in mandible size and shape that we see among fossil hell ants represent sexual dimorphism—differences between males and females—rather than differences between species?

To date, I have found no published study proposing this explanation for hell-ant diversity, so it should be regarded as speculation.

But I find the possibility compelling—and worthy of consideration.

Whatever their purpose, these remarkable jaws may eventually have become a liability.

Why did hell ants go extinct?

As Cretaceous forests changed, prey communities shifted, and modern ant lineages diversified, the extreme specialization that once made hell ants successful predators may have made adaptation increasingly difficult.

Eventually, the entire lineage disappeared.

But does that make hell ants an evolutionary failure?

Consider this.

At my best estimate, there are currently at least 11 genera described and parsed into 17 distinct species.

Their fossils have been discovered across four continents—from Brazil, to France, Myanmar, and Canada—and their known fossil record spans tens of millions of years.

They survived enormous environmental changes. They diversified. They spread across much of the world. And they persisted for millions upon millions of years. So perhaps extinction shouldn’t be confused with evolutionary failure.

Hell ants may simply have been extraordinarily successful creatures whose specialized way of life eventually collided with a changing world.

Evolutionary failure?

Or simply…

a casualty of change?