Megalograptidae

Megalograptidae
Megalograptus
Scientific classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Arthropoda
Subphylum: Chelicerata
Order: Eurypterida
Infraorder: Diploperculata
Superfamily: Carcinosomatoidea
Family: Megalograptidae
Caster & Kjellesvig-Waering, 1955
Genera

Megalograptidae are a family of eurypterids, an extinct group of chelicerate arthropods commonly known as "sea scorpions".

The megalograptids were likely the first major successful group of eurypterids, evidenced by a Late Ordovician radiation. All known members of the Megalograptidea are from the Late Ordovician of Laurentia with the exception of the large Pentecopterus from the Middle Ordovician.