Fossil
Aquatic Beetle
Class
Insecta, Order
Coleoptera, Family Dystiscidae
Geological
Time: Lower Cretaceous, Late Aptian-Cenomanian (108-92 million years
ago)
Size: 28
mm
Fossil
Site: Crato Formation, Nova Olinda Member, Ceara, Brazil
Description:
The Araripe Basin of Brazil is home to a fantastic array of exquisitely-detailed
Early Cretaceous fossils, some of which have been preserved in three
dimensions. While the entire formation has until the last decade
or so been termed the Santana Formation, David Martill has separated
out the slightly older insect-bearing strata as the Nova Olinda
Member of the Crato Formation. Quarrying operations for the purposes
of obtaining paving stones exposes the remarkable insect fauna in
much the same way that quarrying for lithographic limestone in Solnhofen
has afforded a panoply of wonderfully preserved Jurassic fossils
in Germany. In addition to the many orders of insects, spiders,
scorpions, decapod crustaceans, and many plants have been found.
Interestingly, to date no pterosaurs or terrestrial vertebrates
have been found, in stark contrast to the overlying Santana Formation
deposits. This fine example shows a predaceous diving beetle with
its legs extended, frozen in its last swim for the past 100 million
years. Diving beetles are excellent swimmers, using the legs in
unison to propel them in pursuit of prey which can include small
fish.
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