The Largest Dragonfly That Ever Existed

The largest dragonfly‐like insect ever recorded is Meganeuropsis permiana, which appeared during the early Permian period, approximately 285 million years ago. Fossils indicate a wingspan of up to 75 cm, far exceeding that of any modern odonate. Its exceptional size reflects the high atmospheric oxygen levels and warm, swampy ecosystems of the Permian, where arthropods could achieve much greater dimensions than they do today.

Prehistoric Giants: Meganeuropsis and Meganeura

Meganeuropsis: The Record Holder

Meganeuropsis permiana holds the record for the largest insect wingspan ever discovered. Fossil remains, primarily wing impressions, were first Discovered in fossil beds in Kansas, USA, and named by scientist Frank Morton Carpenter in 1939, this creature was a true giant., revealing this prehistoric behemoth's impressive dimensions:

Wingspan: Up to 71-75 cm (28-30 inches) - roughly the wingspan of a crow or small hawk
Body length: Approximately 43 cm (17 inches) from head to tail
Wing length: 33 cm (13 inches) for a single wing
Weight: Estimated to be around 100-150 grams.

A closely related species, Meganeuropsis americana, discovered in Noble, Oklahoma in 1940, had slightly larger individual wings but a marginally smaller overall wingspan than M. permiana. Some researchers consider M. americana to likely be a junior synonym of M. permiana rather than a distinct species.

The Largest Dragonfly That Ever Existed | Giant Prehistoric Insect (Meganeuropsis permiana)

3D Reconstruction of Meganeuropsis permiana and Fossil Cast of Meganeuridae.

Meganeuropsis permiana is known from fossilized wing fragments found in Kansas and Oklahoma. Insects like this one fossilize poorly due to their delicate exoskeletons, often leaving behind isolated wings or partial segments.

Meganeura: Another Prehistoric Giant

Another enormous prehistoric insect was Meganeura monyi, which lived during the Late Carboniferous period approximately 300 million years ago. While slightly smaller than Meganeuropsis, it was still gigantic by modern standards:

Wingspan: about 65-75 cm (2.13-2.46 ft)
Single wing length: 32 centimeters (13 inches)

Fossils of Meganeura were first discovered in Coal Measures of Commentry, France in 1880, and the genus was named by French paleontologist Charles Brongniart in 1885. The name "Meganeura" means "great-nerved," referring to the extensive network of veins supporting its massive wings.

13-Inch Fossilized Wing of Meganeuropsis – The Largest Insect Ever Discovered.

Key Differences between Meganeura & Meganeuropsis

Genus: Distinct but closely related genera within the Meganisoptera order.
Time Period: Meganeura lived in the Late Carboniferous (315–300 Mya); Meganeuropsis in the Early Permian (290–280 Mya).
Size: Meganeuropsis contains the largest known species (M. permiana) and was generally slightly larger than Meganeura.
Geography: Meganeura fossils are primarily from Europe (e.g., France); Meganeuropsis fossils are mainly from North America (e.g., USA).

Not True Dragonflies

Taxonomic Classification

It's important to note that neither Meganeuropsis nor Meganeura were true dragonflies as we know them today. These insects belonged to the extinct order Meganisoptera, also known as griffinflies. While superficially similar to modern dragonflies, they exhibited differences in wing venation and other characteristics that place them in a separate taxonomic order.

Both genera belonged to the family Meganeuridae, which includes other similarly giant dragonfly-like insects that existed from the Late Carboniferous to Middle Permian periods. While they weren't true dragonflies, they were part of the broader group Odonatoptera, which includes modern dragonflies and damselflies.

Physical Characteristics and Lifestyle

These prehistoric giants were fearsome predators. Like modern dragonflies, they had:

Large, bulging eyes relative to body size
Long, slender bodies
Wings with extensive networks of veins that provided structural support
Spines on their appendages, possibly used for capturing prey
Super Eyes: Like modern dragonflies, it had large compound eyes with thousands of lenses, ideal for spotting prey.

Why They Grew So Large

During the Late Carboniferous and Early Permian, atmospheric oxygen reached 30–35%, compared to 21% today. This high-oxygen environment allowed insects, which rely on a tracheal system for breathing, to efficiently deliver oxygen to their tissues, supporting much larger bodies than modern insects can sustain.

With no birds or flying reptiles (appearing ~150 and ~228 million years later), Meganeuropsis ruled the skies, favoring the evolution of their massive size.

Fossils of this giant have been found not just in Kansas but also in China, Russia, and France, showing it lived across ancient supercontinent Pangaea. It soared over lush forests, hunting in a warm, oxygen-rich environment that fueled its enormous size.

Why It Matters: Studying Meganeuropsis permiana helps us understand how Earth’s environment shapes life. Its giant size shows how oxygen levels can influence evolution, while its extinction highlights the impact of environmental change.

Fossil of Meganeura monyi – Giant Carboniferous Dragonfly | Museum of Toulouse Paleontology Collection.

Why Did It Disappear?

By the end of the Permian period, around 252 million years ago, giant insects like Meganeuropsis vanished. Falling oxygen levels made it harder for large insects to survive, as their breathing systems couldn’t support such big bodies. Climate changes and the rise of new predators, like early reptiles, also played a role. These shifts ended the era of giant insects, leaving only fossils to tell their story.

Modern Comparison

For perspective, the largest living dragonfly species is the helicopter damselfly (Megaloprepus caerulatus) from Central American rainforests, with a wingspan of up to 19 centimeters (7.5 inches). This makes the prehistoric Meganeuropsis nearly four times larger in wingspan than its largest modern relative.

The giant hawker from Southeast Asia and Australia's giant dragonflies are also among the largest modern species, with wingspans of approximately 16 centimeters. The largest dragonfly species found in the UK has a wingspan of about 12 centimeters.