| Pterygotidae Temporal range: Llandovery – Early Devonian |
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| Reconstruction of Acutiramus cummingsi | |
| Scientific classification | |
| Kingdom: | Animalia |
| Phylum: | Arthropoda |
| Class: | Merostomata |
| Order: | †Eurypterida |
| Suborder: | †Eurypterina |
| Superfamily: | †Pterygotioidea |
| Family: | †Pterygotidae Clarke & Ruedemann, 1912 |
| Genera | |
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See text |
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| Synonyms | |
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†Jaekelopteridae Størmer, 1974 |
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Pterygotidae are an extinct family of eurypterids. They were members of the superfamily Pterygotioidea,[1] and were the only eurypterids to have a truly worldwide distribution,[2] and include the largest arthropods to have ever lived.
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Pterygotidae, which lived from the late Early Silurian to the Middle Devonian,[3][4] were characterized by small to large exoskeletons with semilunar scales. The telson, (tail) was expanded, or flatter than it was tall. Pterygotidae also had chelicerae (claws in front of the mouth) that were large and long, with strong, well developed teeth on the claws. Their walking legs were small and slender, without spines.[5] They were the largest arthropods to have ever lived; the largest described fragments shows individuals up to 350 cm at the largest length.[6][7] The pterygotids had good binocular vision and chelicerae adapted for cutting or crushing, making them some of the most formidable predators of the Paleozoic.
The genus Slimonia is thought to represent the sister group to the pterygotids.[6] Although the clade Pterygotidae is one of the best supported within the Eurypterida, relationships within the clade have been difficult to resolve.
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The interrelationships of the pterygotids, based on studies by Braddy et al.[6] and Tetlie and Briggs;[3] the synapomorphies are as follows:
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