But unlike its namesake this “monster” was actually tiny, only 3cm across (1.2″). It was discovered in the fine-grained Wenlock limestones of the UK, and dates to the late Silurian, about 430 million years ago. Its exceptionally well-preserved state makes it the first ophiocistioid with known fossilized internal structures, including evidence of its water vascular system.
Unfortunately this high level of detail comes at a cost — the tiny Wenlock fossils are preserved in three dimensions inside hard concretions and are almost impossible to extract or interpret from split-open cross-sections, and highly expensive CT scans don’t give a good enough resolution. So the only way to actually “see” them is to destroy them, grinding away a tiny layer at a time and taking a photograph at each step, then assembling a digital reconstruction from the hundreds of slices.
The Saint Helena giant earwig (Labidura herculeana) was, as its name suggests, an enormous species of earwig. Growing as large as 8.4cm long (3.3″) it was the biggest of its kind in the world, and was completely flightless with no hind wings.
It lived in deep burrows in the arid plain and gumwood forest regions of the island, and only came out at night during the summer rains. Since it was probably descended from the shore earwig (Labidura riparia) it was likely a similar sort of opportunistic carnivore, eating smaller invertebrates and carrion.
Humans didn’t reach Saint Helena until the early 1500s, and it wasn’t until 1798 that the earwig was noticed by naturalists and given its scientific name. Then it was more or less forgotten about, and scientific interest in it didn’t start to resume until the 1960s.
But by then it was just very slightly too late.
Extensive habitat destruction and predation by invasive cats, rodents, and centipedes had taken a huge toll on the earwig, and it had become incredibly rare. The last sighting of a live individual was in 1967, and attempts to locate more for potential captive breeding programs in the 1980s and 1990s failed to find any at all.
The Koʻolau spurwing long-legged fly (Emperoptera mirabilis, sometimes classified as Campsicnemus mirabilis) was found only on Mount Tantalus in the southern Koʻolau Range of Oʻahu, close to Honolulu. About 2mm long (>0.1″), its wings were reduced to thin stiff spines, and it moved around by walking and hopping in leaf litter in the moist cool forest at elevations of about 300m (~1000ft).
Like most other long-legged flies it would have been predatory, hunting other tiny invertebrates.
The Koʻolau spurwing was actually still common on Tantalus as recently as the early 1900s, but multiple searches since the 1980s have failed to find any more of them at all. The species is most likely completely extinct, probably due to a combination of predation from invasive ants and habitat destruction from feral wild boar rooting up the forest floor.
Of the other flightless Hawaiian long-legged flies several other species are now possibly extinct — only one out of the five known Emperoptera species still definitely survives on the highest slopes of Mount Kaʻala, and one of the three Campsicnemus is either very rare or also extinct.
The Hawaiian islands also have three endemic species of flightless crane fly in the genus Dicranomyia, all of which are incredibly rare.
Did you know butterflies weren’t the first insects to look like butterflies?
Lepidopterans (the group of insects containing moths and butterflies) have been around since the Late Triassic – but it wasn’t until the diversification of flowering plants during the Cretaceous that recognizable moths would have evolved, and true butterflies didn’t actually appear until the early Cenozoic.
Known as the kalligrammatids, these insects were giant members of the lacewing group, related to modern forms like antlions and owlflies. But unlike their predatory relatives the kalligrammatids were specialized pollinators, possibly having a mutualistic relationship with the flower-like cones of bennettitales or the pollination drops of some types of conifers. They seem to have originated in China and were found across Asia and Europe by the Late Jurassic, but a few fossils from South America suggest they were even more widespread and may just have a poor fossil record.
They reached wingspans of up to 16cm (~6″), comparable to some of the largest modern butterflies, and often sported conspicuous anti-predator markings on their wings such as stripes and eyespots – so it’s not surprising that they’re often nicknamed the “butterflies of the Jurassic”.
Rather ironically, the extinction of the kalligrammatids was probably linked to the rise of the flowering plants that the true butterflies would later be so dependent on. As flowers diversified and plants like the bennettitales declined, the kalligrammatids dwindled and disappeared, with the last known fossil record coming from the mid-Cretaceous of Brazil about 113 million years ago.
But while they were around, I do wonder if they also exhibited some similar behaviors – such as mud-puddling for extra nutrients, and specifically the habit of drinking the tears of larger animals that we see in some species. Perhaps some non-avian dinosaurs like this Dilong occasionally put up with kalligrammatids sitting on their faces!
While this might look like a sci-fi alien design, it was actually a very real Earth animal!
This strange-looking creature was Clausocaris lithographica, a member of a group of unique marine arthropods known as thylacocephalans. Only about 3.5cm long (1.4″), it lived in a shallow tropical lagoon environment during the Late Jurassic of Germany, about 150-145 million years ago.
Like most other thylacocephalans it had a narrow flattened shield-like carapace, three pairs of large grasping limbs, and a battery of swimming appendages further back – along with absolutely enormous bulbous eyes. Based on this anatomy it would have been a highly visual hunter, using its huge eyes to locate prey items and then snagging them with its long spiny limbs.
And we’re not even entirely sure what type of arthropods thylacocephalans actually were. They’re generally thought to be some sort of crustacean, but their highly modified anatomy makes linking up their exact evolutionary affinities very difficult. Whatever they were, they must have been incredibly successful as a group because they first appeared in the early Cambrian (~518 mya) and survived all the way into the Late Cretaceous (~94 mya).
About 4cm long (1.6″), it had a wormlike body covered in spicules (tiny spines) which suggests it was a member of the aplacophoran molluscs – but it also had a row of seven larger shells along its back resembling those of chitons.
Modern aplacophorans are all shell-less and were traditionally thought to be a very early branch of the mollusc lineage that retained a “primitive” ancestral body plan. More recently, however, a combination of genetic evidence and fossil discoveries of animals like Kulindroplax have revealed that they’re actually close relatives of the chitons and instead lost their shells much more recently during the course of their evolution.
Nicknamed “Santa Claws”, Sanctacaris uncata was a marine arthropod from the Middle Cambrian (~505 mya) Burgess Shale deposits of Canada. Its exact evolutionary relationships are unclear, but it’s thought to have been very closely related to or part of an early branch of the chelicerates – the lineage that includes modern arachnids and horseshoe crabs.
Measuring up to about 9cm long (3.5″), it had forward-facing eyes and five pairs of grasping appendages on the underside of its head, adaptations that suggest it was an active predator convergently similar to anomalocaridids. It probably swam around grabbing onto whatever small prey items it could catch, trapping them in its “limb basket” while it ate them.
Vaderlimulus tricki, a horseshoe crab from the Early Triassic of Idaho, USA (~251-247 mya). Named for its resemblance to the shape of Darth Vader’s helmet, it’s the earliest known Mesozoic horseshoe crab from North America and was closely related to another oddly-shaped form from Australia.
It was much smaller than its modern relatives, only about 10cm long (4″), and probably lived in a brackishestuary environment where seawater and freshwater met.
This little lobopodian was very closely related to the famous Cambrian Hallucigenia, but it lived over 70 million years later – giving us the first evidence that these weird worms weren’t just short-lived “evolutionary experiments”, but must have actually been a very successful lineage that thrived for quite a long time.
Measuring around 3.5cm long (1.4″), it had seven pairs of legs tipped with one or two claws each, and at least two pairs of shorter tentacles on its neck. The head region of the only known fossil specimen wasn’t preserved, so it’s unclear exactly what its front end looked like – but it would have probably been quite similar to Hallucigenia with a slender oval head, two simple eyes, and a small round mouth ringed by tiny teeth.
Unlike its spiky relative, however, Thanahita’s back was covered in rows of numerous small raised soft-tissue “tufts”. I’ve reconstructed it here with them brightly warning colored, mimicking stinging coral polyps.