{{Automatic taxobox | name = Eusarcana | fossil_range = Middle Silurian–Early Devonian, | image = Eusarcana scorpionis fossil.png | image_caption = Fossil of E. scorpionis. | display_parents = 2 | taxon = Eusarcana | authority = Strand, 1942 | synonyms = {{collapsible list|bullets = true |title=<small>Alternative combinations</small> |Eurypterus acrocephalus Semper, 1898 |Eurypterus obesus Woodward, 1868 |Carcinosoma acrocephalus (Semper, 1898) |Carcinosoma obesus (Woodward, 1868) |Carcinosoma scorpionis (Grote & Pitt, 1875) }} | type_species = †Eusarcana scorpionis| type_species_authority = (Grote & Pitt, 1875) | subdivision_ranks = Species | subdivision = *†E. acrocephalus (Semper, 1898) †E. obesus (Woodward, 1868) †E. scorpionis (Grote & Pitt, 1875) }}Eusarcana (meaning "true flesh") is a genus of eurypterid, an extinct group of aquatic arthropods. Fossils of Eusarcana have been discovered in deposits ranging in age from the Early Silurian to the Early Devonian. Classified as part of the family Carcinosomatidae, the genus contains three species, E. acrocephalus, E. obesus and E. scorpionis, from the Silurian-Devonian of Scotland, the Czech Republic and the United States respectively.Eusarcana is known for its odd proportions and features; the broad abdomen, thin and long tail, spined and forward-facing walking appendages and sharp and curved tail spike differentiate it from most other eurypterids, but are shared with other carcinosomatid eurypterids. The triangular carapace, oddly positioned forward-facing eyes differentiate the genus further from its closest relatives. At 80 centimetres (31.5 in) in length, E. scorpionis represents a moderately large species of eurypterid, and far exceeded other representatives of the genus in size, such as the 4 cm (1.5 in) long E. obesus. Originally described under the name Eusarcus, this name was preoccupied by a genus of living harvestmen in the family Gonyleptidae. Following the discovery of this homonym, the genus was also wrongly recognized as synonymous with the related Carcinosoma and was only given replacement names for the older name decades after the error was discovered, first as Eusarcana in 1942 and later as Paracarcinosoma (assumed to have been named without knowledge of the earlier replacement name) in 1964. Description Eusarcana can be differentiated from other eurypterids by the considerably narrow border between the prosoma (head) and opisthosoma (abdomen), which is particularly thin considering the subsequent broad and large ellipse-shape of the abdomen. The postabdomen (or tail) also narrows rather quickly from the preceding segments. Further features distinctive of the genus include that the carapace (segment covering the head) is clearly triangular in shape,