The evolutionary history of Earth’s earliest terrestrial fauna, specifically millipedes, has been significantly illuminated with the integration of two previously elusive lineages, Siphoniulida and Siphonocryptida, into phylogenetic reconstructions, a feat achieved by a cohort of entomologists affiliated with Virginia Tech.
To date, 14,232 millipede species have been described, with at least as many still awaiting discovery. Image credit: Vasquez-Valverde et al., doi: 10.1016/j.cub.2026.05.035.
“Millipedes preceded vertebrates in colonizing terrestrial environments by over 80 million years,” remarked Dr. Paul Marek, the senior author of the investigation and a researcher at Virginia Tech.
“Their presence fundamentally prepared the ground for subsequent terrestrial life, encompassing both humans and vertebrates.”
In the course of their investigation, Dr. Marek and his associates amalgamated genomic data derived from extant millipede species with morphological evidence meticulously extracted from fossil specimens.
An extensive analysis was conducted, examining hundreds of genes across a sample of 82 millipede species, and incorporating data points from 29 fossilized remains.
A pivotal advancement was the successful acquisition of DNA material from two particularly cryptic groups—Siphoniulida and Siphonocryptida—whose genetic profiles had remained unsequitorially documented until this study.
The research team undertook expeditions to Los Tuxtlas in Mexico and to Spain’s Canary Islands to procure specimens of Siphoniulius neotropicus and Hirudicryptus canariensis, respectively.
“Locating just a single, diminutive 10-millimeter adult required the concerted effort of ten individuals for an entire week,” stated Luisa ‘Fernanda’ Vasquez-Valverde, the primary author of the study and also affiliated with Virginia Tech.
“Their detection in their natural habitat proved challenging, as initially, we were merely observing what appeared to be a rudimentary nematode.”
“Confirmation of its identity as a millipede was only achieved subsequent to microscopic examination.”
It was discovered that one of the two groups previously considered ‘missing,’ Siphonocryptida, did not constitute a distinct order but rather belonged to an established lineage. The other group, Siphoniulida, was definitively positioned within the evolutionary timeline.
The analytical framework employed by the team facilitated the tracing of millipede origins back to approximately 460 million years ago, during the Ordovician period. This temporal placement precedes the earliest known millipede fossils by roughly 35 million years, indicating that these arthropods emerged considerably earlier than previously posited.
Having established a terrestrial presence over 80 million years before vertebrates, millipedes stand as some of the initial trailblazers of life on land. They subsisted on decomposing organic matter in an era preceding the evolution of trees, leaves, or flowering plants.
“The most astonishing revelation was the profound antiquity of certain of these taxonomic lines,” commented Dr. Marek.
The investigation further substantiates the evolution of millipedes’ defensive chemical mechanisms to approximately 260 million years ago, positioning them among Earth’s earliest organisms to develop sophisticated biochemical defense systems.
“They were instrumental in the genesis of chemical weaponry. In essence, they are miniature biochemical production facilities,” Dr. Marek elaborated.
The findings resulting from this research have been published in the esteemed journal Current Biology and are accessible via the following link.
_____
Vasquez-Valverde, Luisa F., et al. “Reshaping the Millipede Tree of Life by Inclusion of the Last Two Unsampled Orders.” Current Biology, published online June 12, 2026; doi: 10.1016/j.cub.2026.05.035.
