eurypterid - Body structure, Eurypterid fossils, Classification by Tollerton, 1989

An extinct, aquatic water scorpion; large, up to 3 m/10 ft in length; resembling a scorpion with a stout body bearing fangs anteriorly and a long, slender tail; known from the Ordovician period to the end of the Palaeozoic era. (Phylum: Arthropoda. Class: Eurypterida.)

?Eurypterids Conservation status: Fossil
Eurypterid from Ernst Haeckel's Artforms of Nature, 1904.
Scientific classification
Kingdom: Animalia Phylum: Arthropoda Subphylum: Chelicerata Class: Eurypterida
Orders
†Stylonuroidea Diener, 1924 †Eurypteroidea Burmeister, 1843

The eurypterids were the largest known arthropods that ever lived (with the possible exception of Anomalocarids).

Eurypterus is perhaps the most well-known genus of eurypterid, of which 200 fossil species are known.

Body structure

The typical eurypterid had a large, flat, semicircular carapace, followed by a jointed section, and finally a tapering, flexible tail, with a long spine at the end.

Although many eurypterids had legs too tiny to do more than allow them to crawl over the sea bottom, a number of forms had large stout legs, and were clearly capable of terrestrial locomotion (like land crabs today).

Eurypterid fossils

Eurypterid fossils have been found on nearly every continent.

Among the largest eurypterids are the Hibbertopterina, named after the British palaeontolgist S.

Eurypterids are related to the modern marine horseshoe crabs and land scorpions.

Classification by Tollerton, 1989

There are more than 300 identified species of the extinct sea scorpions. They have been classified by Tollerton (1989) and others in more than 60 genera and in about 20 families:

Glyptoscorpioidae

Glyptoscorpiidae Glyptoscorpius G. wigodensis

Slimonioidea

Slimoniidae Slimonia S. acuminata

Hughmillerioidea

Hughmilleriidae Hastimima H. imhofi

Mixopteroidea

Mixopteridae Mixopterus M. kiaeri Lanarkopteridae

Megalograptoidea

Megalograptidae Megalograptus M. clevelandi

Eurypteroidea

Eurypteridae Eurypterus E. princetoni Erieopteridae

Stylonuroidea

Stylonuridae Stylonurus S. scouleri

Dolichocephala

Claypolidae (?) Claypole C.? lacoana Drepanopteridae Parastylonuridae Laurieipteridae

Kokomopteroidea

Kokomopteridae Hardieopteridae

Brachyopterelloidea

Brachyopterellidae

Rhenopteroidea

Rhenopteridae Rhenopterus R. diensti

Mycopteropoidea

Mycteropidae Mycterops M. mathieui Woodwardopteridae Woodwardopterus

Pterygotoidea

Jaekelopteridae Pterygotidae Pterygotus P. (P.) bilobus Acutiramus Erettopterus Himantopterus

Incertae sedis (phylogeneticly troublesome)

Willwerathia Tylopterella Tarsopterella Pittsfordipterus Dorfopterus Melbournopterus Hallipterus Megarachne Palmichnium Waeringoopterus