''Strobilopterus'' is a genus of prehistoric

eurypterid Eurypterids, often informally called sea scorpions, are a group of extinct marine arthropods that form the Order (biology), order Eurypterida. The earliest known eurypterids date to the Darriwilian stage of the Ordovician period, 467.3 Myr, mil ...

of the family Strobilopteridae. The genus contains four species, two from the

Devonian The Devonian ( ) is a period (geology), geologic period and system (stratigraphy), system of the Paleozoic era (geology), era during the Phanerozoic eon (geology), eon, spanning 60.3 million years from the end of the preceding Silurian per ...

Wyoming Wyoming ( ) is a landlocked U.S. state, state in the Mountain states, Mountain West subregion of the Western United States, Western United States. It borders Montana to the north and northwest, South Dakota and Nebraska to the east, Idaho t ...

United States The United States of America (USA), also known as the United States (U.S.) or America, is a country primarily located in North America. It is a federal republic of 50 U.S. state, states and a federal capital district, Washington, D.C. The 48 ...

(''S. princetonii'' and ''S. proteus''), one from the Devonian of

Ohio Ohio ( ) is a U.S. state, state in the Midwestern United States, Midwestern region of the United States. It borders Lake Erie to the north, Pennsylvania to the east, West Virginia to the southeast, Kentucky to the southwest, Indiana to the ...

, United States (''S. richardsoni'') and one from the

Silurian The Silurian ( ) is a geologic period and system spanning 23.5 million years from the end of the Ordovician Period, at million years ago ( Mya), to the beginning of the Devonian Period, Mya. The Silurian is the third and shortest period of t ...

Estonia Estonia, officially the Republic of Estonia, is a country in Northern Europe. It is bordered to the north by the Gulf of Finland across from Finland, to the west by the Baltic Sea across from Sweden, to the south by Latvia, and to the east by Ru ...

(''S. laticeps'').Dunlop, J. A., Penney, D. & Jekel, D. 2015. A summary list of fossil spiders and their relatives. In World Spider Catalog. Natural History Museum Bern, online at http://wsc.nmbe.ch , version 16.0 http://www.wsc.nmbe.ch/resources/fossils/Fossils16.0.pdf (PDF).

Description

Strobilopterus proteus subadult and adult

''Strobilopterus'' was a large strobilopterid eurypterid, with adults of the species ''S. proteus'' measuring approximately 15 to 20 centimetres in length. The

carapace A carapace is a dorsal (upper) section of the exoskeleton or shell in a number of animal groups, including arthropods, such as crustaceans and arachnids, as well as vertebrates, such as turtles and tortoises. In turtles and tortoises, the unde ...

of ''Strobilopterus'' was wide and semicircular in shape, with the lateral eyes lunate to crescentic with the palpebral lobe between the central and centrimesial sectors. The first pair of appendages were small, lacking denticles, and the subsequent four pairs of appendages were likewise also small, but with fixed spines and serrated distal

podomere The arthropod leg is a form of jointed appendage of arthropods, usually used for walking. Many of the terms used for arthropod leg segments (called podomeres) are of Latin origin, and may be confused with terms for bones: ''coxa'' (meaning hip, : ...

margins. The sixth and last pair of appendages were short but were powerfully serrated on the anterior margins of the podomeres. The type A genital appendage was long and undivided, the type B appendage was more oval in shape.

References

Eurypteroidea Devonian eurypterids Fossils of the United States Eurypterids of North America Silurian eurypterids Eurypterids of Europe {{Eurypterid-stub