Scientists Finally Complete the Millipede Family Tree — and It Goes Back 460 Million Years
If someone asked you to name an ancient, world-shaping creature, you might think of dinosaurs or maybe the first fish to crawl onto shore. Millipedes probably would not make the list. But according to a new study published in the journal Current Biology, these quiet, many-legged decomposers have one of the most remarkable origin stories on Earth. Scientists have now completed the first full evolutionary family tree of all living millipede orders — the most comprehensive picture ever assembled of how these creatures developed over time — and it pushes their history back nearly 460 million years. That is about 80 million years before the first vertebrates, animals with backbones like fish and amphibians, made it onto dry land.
The research was led by Paul Marek, an associate professor at Virginia Tech, along with an international team of scientists. To build such a detailed family tree, the team combined two very different types of evidence. First, they analyzed DNA from 82 modern millipede species. DNA, or deoxyribonucleic acid, is the chemical code stored inside every living cell that carries instructions for building and running an organism — and it also contains a kind of biological history, recording how species have changed and branched apart over millions of years. Second, they incorporated physical evidence from 29 fossils, the preserved remains of ancient millipedes locked in rock. By combining genetic data with fossil evidence, the researchers could estimate not just how millipede groups are related, but roughly when each branch of the family appeared.
For over a century, two rare millipede groups had remained frustratingly absent from these kinds of studies. The groups, known as Siphoniulida and Siphonocryptida, were so hard to find that researchers had never managed to collect fresh specimens for DNA analysis. One group lives entirely underground and measures less than a centimeter in length. The other survives in only a tiny number of known locations worldwide. Marek called them his team's "white whales" — a phrase meaning something you have been chasing for a very long time. To finally catch them, researchers traveled to Los Tuxtlas in Mexico and the Canary Islands of Spain. Finding even a single adult millipede took a team of ten people more than a week of searching. First author Fernanda Vasquez-Valverde, who earned her doctorate at Virginia Tech, described mistaking the creature for a tiny worm until the team got it under a microscope.
The DNA from these newly collected specimens, combined with hundreds of genes compared across all 82 species, allowed the researchers to slot both mystery groups into the millipede family tree for the first time. The results surprised everyone. Siphonocryptida turned out not to be its own separate order at all, but rather part of an already-known lineage that had simply been misclassified. Siphoniulida was finally placed next to its closest evolutionary relatives. The project generated terabytes of genetic data — more information than most laptops could even store — and required Virginia Tech's powerful research computers to process.
Perhaps the most striking finding was just how far back the millipede story goes. The analysis suggested millipedes may have originated around 460 million years ago, roughly 35 million years earlier than the oldest millipede fossils ever found. That gap between when we think millipedes first appeared and when we have actually found them preserved in rock is a reminder that the fossil record, while incredibly valuable, only ever captures a fraction of life's history. Back in those ancient days, Earth would have looked almost unrecognizable. Marek described a world with no trees, no flowers, no seeds, no leaves, and no vertebrates — just millipedes picking through decaying mosses and early organic material on a bare rocky surface. They were not just surviving; they were actively recycling nutrients and helping build the conditions that would eventually allow more complex life to follow.
The study also used the completed family tree to pinpoint when millipedes first evolved their famous chemical defenses. These defenses — which can include repellent secretions, toxic compounds, and even hydrogen cyanide in some species — are thought to have appeared around 260 million years ago. Marek described millipedes as "little chemical factories," and this research gives scientists the clearest timeline yet for when that chemistry first appeared. Today, more than 14,000 millipede species are known to science, but researchers believe tens of thousands more remain undiscovered. New species have been found in places as unexpected as Los Angeles and the campus of Virginia Tech itself. For scientists like Vasquez-Valverde, that is exactly what makes this field exciting: most of the story is still out there, waiting to be found.
Source: ScienceDaily