Where and when did ticks originate? - briefly
Ticks probably first evolved on land during the late Carboniferous, roughly 300 million years ago, as ectoparasites of early amniotes. Molecular and fossil evidence places their origin in the Paleozoic era, predating the diversification of modern mammals and birds.
Where and when did ticks originate? - in detail
Ticks belong to the order Ixodida, a lineage of arachnids that became obligate hematophages. Their evolutionary emergence is documented by both fossil records and molecular-clock analyses, which together define a temporal and geographic framework.
The oldest unequivocal tick fossils appear in mid‑Cretaceous amber from Myanmar, dated to approximately 99 million years ago. Comparable specimens from Spanish amber (≈125 Ma) and Canadian amber (≈100 Ma) confirm the presence of hard‑tick genera during the early Cretaceous. Isolated cuticular fragments from the Late Triassic (≈210 Ma) have been interpreted as tick‑like, but the taxonomic assignment remains disputed.
Molecular phylogenies, calibrated with the aforementioned fossils, estimate the divergence of the principal tick families—hard (Ixodidae) and soft (Argasidae)—at roughly 120–150 million years ago. This places the initial radiation of the group in the Late Jurassic to Early Cretaceous, a period characterized by the expansion of forested habitats and the diversification of early mammals and reptiles that served as hosts.
Biogeographic reconstructions indicate that ancestral ticks inhabited humid, temperate forests of the Laurasian supercontinent. The availability of vertebrate hosts in these ecosystems facilitated the development of specialized feeding structures. Subsequent continental drift and the formation of land bridges allowed dispersal into Gondwanan regions, leading to the modern cosmopolitan distribution of tick species.
Chronological outline
- Late Jurassic (≈150 Ma): molecular estimate of the first split within Ixodida.
- Early Cretaceous (≈125–100 Ma): appearance of hard‑tick fossils in amber deposits.
- Mid‑Cretaceous (≈99 Ma): well‑preserved specimens from Burmese amber confirm morphological similarity to extant taxa.
- Post‑Cretaceous (≈70 Ma onward): diversification and global spread aligned with mammalian radiation.
These data collectively demonstrate that ticks originated in forested Laurasian environments during the Late Jurassic to Early Cretaceous, with a fossil record extending back to at least 100 million years ago.