Carcinosoma is a genus of an extinct arthropod. Up to 30 cm long, these eurypterid

Eurypterid

Eurypterids are an extinct group of arthropods related to arachnids which include the largest known arthropods that ever lived. They are members of the extinct order Eurypterida ; which is the most diverse Paleozoic chelicerate order in terms of species...

s were found in New York and in other states of the United States. It is from the Late Silurian

Silurian

The Silurian is a geologic period and system that extends from the end of the Ordovician Period, about 443.7 ± 1.5 Mya , to the beginning of the Devonian Period, about 416.0 ± 2.8 Mya . As with other geologic periods, the rock beds that define the period's start and end are well identified, but the...

.

Description

Carcinosoma were characterized by small to large exoskeletons with scattered minute tubercules or raised tongue-shaped scales. The prosoma (head) was subtriangular, with small compound eyes at the front. The chelicerae (claws in front of the mouth) were small. The walking legs were covered with long spines, and the second pair of walking legs was the longest. The preabdomen, the front portion of the body, was broad and ovate, while the postabdomen was cylindrical and narrow. The telson

Telson

The telson is the last division of the body of a crustacean. It is not considered a true segment because it does not arise in the embryo from teloblast areas as do real segments. It never carries any appendages, but a forked "tail" called the caudal furca is often present. Together with the...

was a curved spine.

Species

• Carcinosoma Claypole, 1890
  • ?Carcinosoma harleyi Kjellesvig-Waering, 1961 — Silurian ,England
  • Carcinosoma libertyi Copeland & Bolton, 1960 — Silurian, Canada
  • Carcinosoma newlini Claypole, 1890 — Silurian, USA
    • = Carcinosoma ingens Claypole, 1894 — Silurian, USA
  • ?Carcinosoma punctatum (Salter in Huxley & Salter, 1859) — Silurian ,England
  • Carcinosoma scorpioides (Woodward, 1868) — Silurian, Scotland
    • = Pterygotus raniceps Woodward, 1868 — Silurian, Scotland
  • Carcinosoma scoticus (Laurie, 1899) — Silurian, Scotland
  • ?Carcinosoma spiniferumKjellesvig-Waering & Heubusch, 1962 — Silurian, USA

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