1350 / 2019-08-09 17:19:02

An ammonite trapped in Burmese amber

14、古生物、古地理与古环境 > 专题3：中生代陆地生态系统演化

Amber is fossilized tree resin that usually contains inclusions of terrestrial and rarely aquatic organisms. Marine fossils are extremely rare in Cretaceous and Cenozoic ambers. Here, we report the first records of an ammonite, marine gastropods, and intertidal isopods, with diverse terrestrial arthropods as syninclusions in mid-Cretaceous Burmese amber. We used X-ray micro-computed tomography (CT) to obtain high-resolution three-dimensional images of the ammonite including its sutures. The ammonite is a juvenile Puzosia (Bhimaites) and provides robust evidence for an early Cenomanian age of the amber. There is a diverse assemblage (at least 32 individuals) of arthropods in this amber sample, from both terrestrial and marine habitats, including Isopoda, Acari (mite), Araneae (spider), Diplopoda (millipede) and representatives of the insect Blattodea (cockroach), Coleoptera (beetle), Diptera (true fly), and Hymenoptera (wasp). The co-occurrence of marine and terrestrial inclusions in this amber demonstrates that the Burmese amber forest abutted the shoreline or was temporarily influenced by the nearby sea. Given the exceptional nature of marine fauna in this amber, it could represent an exceptional event that introduced water or wind-borne and marine organisms into the amber-producing forest, such as a tsunami or hurricane. Our findings not only represent the first record of an ammonite in amber but also provide new insights into the taphonomy of amber and the paleoecology of Cretaceous amber forests.