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Insects

Insects are the most diverse group of organisms on earth. Most orders are represented by fossils and some, namely Coleoptera (beetles) and Nematoceran Diptera (chironomid midges), have been extensively studied. The skeletal material of insects, chitin, is a stable polymer which preserves well in lake, bog and floodplain deposits, asphalt seeps, and middens, both rodent and human.


Elytra (wing cases) and pronota (thoraces) of
several species of beetles with a chitin-based
14C AMS age of 14,760±95 yr BP from
the Kitsap Formation, Seattle, Washington.



Quaternary fossils are mostly three-dimensional skeletal parts: heads, prothoraces, wingcases, sternites, and genitalia. Delicate features, such as setae and structural colors, are often preserved. The fossils are mostly of extant species and an understanding of the autecology of living specimens has been used in paleoecological, paleoclimatological and biogeographical studies. Typically, fossil assemblages are dated indirectly by 14C of associated sediments or less frequently by direct dating of the chitin using AMS 14C methods. Studies are utilized by archaeologists, biogeographers, conservation biologists, evolutionary biologists and paleoclimatologists. North American fossil beetle data is currently being formatted for Neotoma from Ashworth's unpublished North American Fossil Beetle Database.