アメリカ自然史博物館のインスタグラム(amnh) - 5月31日 03時06分

It's time for #TrilobiteTuesday! Cutting for nearly 600 miles on a south-to-north path through the heart of the Sakha Republic in distant Siberia are the Lena and Anabar Rivers. On their own merit, these closely aligned bodies of water would most likely retain their relative anonymity upon the global stage. However, some of the world's oldest trilobites have been discovered in the 520 million-year-old sedimentary outcrops carved out by these waterways. This area is home to trilobites ranging in size from the diminutive Delgadella lenaica, which rarely exceeded 1 cm, to Bathyuriscellus siniensis, pictured here, which often attained lengths of 8 cm. Perhaps the first trilobite in the entire fossil lineage, Profallotaspis jakutensis, has been documented in adjacent mudstone layers, marking this remote Siberian outpost as one of unique paleontological significance.

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