shape of Eusarcana suggests that it was a rather slow and inactive animal that was not very agile, possibly adapted for burrowing or ambush predation. In such a lifestyle, a venomous and agile tail spike would greatly aid in securing prey and defense in absence of other prehensile and powerful organs with long reach. Ecology As a considerable majority of described eurypterid species are known from the Silurian, particularly the late Silurian, researchers have concluded that the group peaked in diversity and number during this time. Complex eurypterid faunas, compromising several different species in different ecological roles, are typical of the period. All species of Eusarcana described so far occur together with other eurypterid species. E. acrocephalus is known from both the Silurian and the Devonian of the Czech Republic, with a somewhat apparent difference in other fauna depending on the time period. Devonian E. acrocephalus occur together with other eurypterids Slimonia, Pterygotus and Acutiramus as well as with various trilobites (including Crotalocephalina, Otarion, Warburgella, Proetus, Tropidocare, Leonaspis and Ceratocephala), crustaceans (including Ceratiocaris and Aristozoe), ostracods, conodonts, gastropods and crinoids. The Silurian-aged fauna of the same general area, also preserving E. acrocephalus, were home to other eurypterids Erettopterus, Pterygotus and Acutiramus, a less diverse assemblage of trilobites (Otarion, Scharyia and Prionopeltis), crustacean Ceratiocaris, cephalopods (including Cycloceras and Corbuloceras), ostracods, gastropods, crinoids, conodonts and bivalves. Silurian E. obesus from the United Kingdom lived in a marine environment also home to other eurypterids Nanahughmilleria, Pterygotus, Slimonia, Carcinosoma, Parastylonurus and Erettopterus as well as phyllocarid crustaceans, xiphosurans, gastropods and anaspid fish Birkenia. In Silurian deposits of New York, E. scorpionis occurs together with a diverse fauna of eurypterids composed of Buffalopterus, Dolichopterus, Erettopterus, Eurypterus, Pterygotus and Acutiramus. Also present were xiphosurans, crustaceans (Gonatocaris), ostracods, bivalves, gastropods and cephalopods. Carcinosomatid eurypterids such as Eusarcana'' were among the most marine eurypterids, known from deposits that were once reefs, some in lagoonal settings, and deeper waters. See also List of eurypterid genera Timeline of eurypterid research References Silurian eurypterids Devonian eurypterids Devonian arthropods of Europe Silurian arthropods of Europe Devonian arthropods of North America Silurian arthropods of North America Fossil taxa described in 1942 Fossils of Scotland Fossils of the Czech Republic Fossils of the United States Bertie Formation Eurypterids of Europe Eurypterids of North America Carcinosomatoidea