A new amber Lagerstätte from the Lower Cretaceous of Japan

During the Early Cretaceous, terrestrial ecosystems underwent a critical transition driven by the emergence and diversification of angiosperms. Amber-rich deposits from this period are crucial for understanding the diversity, interactions, and evolution of terrestrial biota. However, their occurrences are limited both geographically and stratigraphically. Here, we report a new amber Lagerstätte from the upper Aptian (116–114 Ma) in northern Hokkaido, Japan. The abundant amber occurs within deep-sea deposits and is rich in bio-inclusions: arthropods (hymenopterans, mites), fungi, and plant remains (tracheids, stellate hairs, pollen grains), with submicron-scale morphological details. This is the first report of fossiliferous amber-rich deposits from the Aptian in Asia. It is also recognized as one of the older amber-rich localities with bio-inclusions following those in northeastern Italy (Carnian, Upper Triassic), the Levantine area (Tithonian, Upper Jurassic; Barremian), Austria (Hauterivian), the United Kingdom (lower Barremian), and southern Congo (upper Aptian). This finding fills a paleobiogeographical gap in fossil record and provides anatomical and ecological insights into a critical interval marked by the rise of modern-type forest ecosystems. • We report the first Aptian amber Lagerstätte in Asia. • The amber preserves arthropods, fungi, and plants with exquisite anatomical details. • Records of Aptian amber are scarce both temporally and geographically. • This discovery fills a paleogeographic gap in amber deposit records. • Bio-inclusions reveal terrestrial micro- and meso-biota during the early angiosperm rise.