Fossil Friday: Insects Part 4

Now that we’ve seen the “true flies” we can take a look at the many other groups of insects with “fly” attached to their names. Most of these groups are much older, and in my humble opinion would do quite well for a little inspiration for alien lifeforms!

There are a few of these that I do not mention a specific time period, because I could not find any conclusive information on when exactly they appeared. All I know is that insects in all of these groups have been around at least since the Jurassic, and many are from the Carboniferous or Permian. I sometimes forget the precise order of the many geological time periods, it’s simply mind boggling how huge a span of time we’re talking about here! So here’s a brief reminder, for myself as well!

  • Carboniferous: About 359-299 million years ago…giant bugs, huge explosion of tree growth, reign of amphibians.
  • Permian: About 299-252 million years ago…rise of reptiles, earliest relatives of mammals, which includes Dimetrodon-not-a-dinosaur!
  • Triassic: About 252-201 million years ago…dawn of the dinosaurs, pterosaurs, mammals, and marine reptiles like Plesiosaurs.
  • Jurassic: About 201-145 million years ago…”golden age” of dinosaurs, pterosaurs, and marine reptiles.

The first stone flies appeared during the Permian Period, long before the first dinosaurs, but it was in the Jurassic that they truly diversified. They begin their lives as nymphs in lakes and streams, where their presence is a welcome sign of the purity of the water. They can live this way for several years before finally emerging to shed their final skin. The adults only live a week or two, never straying far from the water (some adults keep their gills). Plants are their food of choice, if they eat at all.
These insects are considered “living fossils” because their appearance has changed very little since the Jurassic, a time when they were very diverse and widespread across the globe. Modern snakeflies are only found in places with cooler temperatures, but in the Jurassic they were plentiful in the tropics as well. Most snakefly larvae prefer to burrow under bark, where they hunt for other grubs, a diet they share with their parents. What looks like a stinger is present in females, and is used for laying eggs.
These insects are actually more closely related to fleas than true flies, and they are excellent hunters of other insects and carrion, though some prefer a more vegetarian diet of nectar. What looks like a stinger is used for love, not defense, and is only seen in the males. They prefer to have their romance in more moist environments such as leaf litter or moss, and the eggs can lay dormant for months until the wet season arrives. The larvae appear very much like caterpillars, and are voracious vegetarians.
A once abundant group of insects in the scorpionfly family, there is now only one species left on Earth- Notiothauma reedi. A “living fossil”, this modern species behaves very much like a cockroach. It is nocturnal and scuttles along the forest floor, where it eats rotting leaf litter and other plants.
This member of the scorpionfly family hung from the stems of plants as early as the Triassic Period, but it was during the Jurassic that they truly flourished and diversified as a group. They wait for passing flies or other insects to grab with their powerful hind legs. They are often confused for crane flies, but crane flies did not appear until the Cretaceous, and have two wings instead of four.
These very large insects (typical wingspan is 7in/ 18cm) are not nearly as fierce as they look. Like a stag’s antlers, those jaws are used to impress females and sometimes knock out the competition if there is a rival. Some species in this group have shorter “tusks,” but then offer a special gift for their lady friend instead. Like many early insects, the larvae are aquatic and voracious hunters, and can remain so until conditions are ideal to shed their final skins and emerge from the water as adults for a few weeks. Both larvae and adult are nocturnal, but the adults do not share the appetite of their young.
Unlike their close relative the Dobsonfly, these insects are small, usually less than an inch in length. They never stray far from the stream they grew up in, and in the Jurassic females would lay their eggs on the ferns and horsetails nearby. When the many eggs hatch, the larvae drop straight into the water, or else crawl to it, where they stay submerged for up to two years. They breath by a number of filaments along their bodies, which act as gills as they hunt in the water.
These insects are large like their close relatives the Dobsonfly, with an average wingspan of about 3in/8cm. They lay their eggs on plants by the water, where the larvae drop into the water and immediately begin hunting small aquatic creatures with relish. They live this aquatic lifestyle for a few years before finally emerging as adults on land, where they spend the last week in the egg business between lunch breaks for river plants, minnows, and tadpoles.
Dragonflies are an ancient group of insects, with its first relatives known from famous, giant individuals during the Carboniferous Period. These early relatives are sometimes known as Griffonflies because of their larger size, but dragonflies as we know them today did not appear until the Jurassic Period. Like many early insects, they begin life in the water as nymphs before emerging as adults to hunt other insects from the air.
Damselflies are often mistaken for their relatives the dragonflies, but can be recognized by their slender bodies and how they often fold their wings back along their length when at rest. These are actually the older of the two, appearing in the early Permian alongside their giant Griffinfly cousins. When courting, partners will join together and fly for many hours in this way, often resting in a pose that forms two halves of a heart. When not in love, they are excellent predators of smaller flying insects.
Mayflies are almost unchanged since the first flying insects appeared during the Carboniferous Period, except perhaps for a giant individual at the time known to have a wingspan of 18in/45cm. They are an older relative to Dragonflies and Damselflies, though not in the same family, and share the habit of life as an aquatic nymph before emerging from the water with wings. The presence of nymphs in a stream is a sign of its purity, for they cannot survive in even mildly polluted water. The adults eat nothing at all, and some may have an adult lifespan as short as five minutes! Their only goal is to bring in the next generation.


Any sort of list for prehistoric insects was mostly unhelpful. Research for this page mostly involved painstaking unwinding of threads from modern groups, then tracing back on which ones are the oldest and most “primitive” groups. Sometimes Wikipedia had a handy little chart on the upper right-hand corner to say when in time a group of insects appeared, but mostly I went down names of groups one by one to see if there were any fossils from that group, or modern species that look nearly identical to their fossil ancestors.

Once I crawled into the rabbit hole I just had to keep going, even when I realized I’d bitten into quite a bit more than I could chew. I hope you enjoyed it as much as I did!

I am eternally grateful that Wikipedia is such a great resource. From the sheer numbers of insects I discovered I’m afraid I did not have the time to cross reference with other resources, but feel free to look into the many resources Wikipedia lists at the bottom of each article if you want to find out more!

“List of Prehistoric Insects.” Wikipedia,

“Insect.” Wikipedia,

“Dicodylia.” Wikipedia,

“Snakefly.” Wikipedia,

“Mecoptera.” Wikipedia,

“Eomeropidae.” Wikipedia,

“Hanging Fly.” Wikipedia,

“Megaloptera.” Wikipedia,

“Plecoptera.” Wikipedia,

“Dobsonfly.” Wikipedia,

“Alderfly.” Wikipedia,

“Fishfly.” Wikipedia,

“Odonata.” Wikipedia,

“Dragonfly.” Wikipedia,

“Damselfly.” Wikipedia,

“Mayfly.” Wikipedia,

4 thoughts on “Fossil Friday: Insects Part 4

  1. Soo cool! I think this is my favorite in the bug series so far–so many I’ve never heard of before, like the scorpion and fish flies! I like how you seem to choose all the prettiest designs. πŸ˜›


    1. Thank you very much! This was one of my favorites too, for the all the interesting shapes and insects I’d never heard of before. Like that hanging fly, how weird is that? πŸ˜€

      Hehe, and just because it’s a bug doesn’t mean it can’t be pretty. After all, this is the Paleo Petshop, and people tend to have the pretty bugs as pets. πŸ˜›


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