Campylocephalus

Campylocephalus
Temporal range: Carboniferous-Late Permian, 326.4–251.9 Ma
Drawing of the carapace of C. oculatus by its original descriptor, Stepan S. Kutorga (1838)
Scientific classification Edit this classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Arthropoda
Subphylum: Chelicerata
Order: Eurypterida
Superfamily: Mycteropoidea
Family: Hibbertopteridae
Genus: Campylocephalus
Eichwald, 1860
Type species
Campylocephalus oculatus
(Kutorga, 1838)
Species
  • C. oculatus (Kutorga, 1838)
  • C. permianus (Ponomarenko, 1985)
  • †?C. salmi (Štúr, 1877)
Synonyms
  • Eidothea Scouler, 1831, preoccupied
  • Campylognathus Diener, 1924, preoccupied

Campylocephalus is a genus of eurypterid, a group of extinct aquatic arthropods. Fossils of Campylocephalus have been discovered in deposits ranging from the Carboniferous period in the Czech Republic (the species C. salmi) to the Permian period of Russia (species C. oculatus and C. permianus). The generic name is composed of the Greek words καμπύλος (kampýlos), meaning "curved", and κεφαλή (kephalē), meaning "head".

It was a member of the hibbertopterid family of eurypterids and probably looked much the same as the other members of the family, Hibbertopterus and Vernonopterus, in that it was a large, broad and heavy animal quite different from the famous swimming eurypterids (such as Pterygotus and Eurypterus) which had been common during earlier periods. Like all other stylonurine eurypterids, Campylocephalus completely lacked swimming paddles.

Hibbertopterids such as Campylocephalus were, as many other families within the stylonurine suborder, sweep-feeders. Sweep-feeding food strategies involve specialized appendages with blades that could be used by the animals to rake through the substrate of their living environments in search for small prey items.

The species C. permianus, known from deposits of Late Permian age in Russia, is the only species of Campylocephalus preserved well enough to allow for size estimates, published estimates putting its size at potentially 1.4 metres (4.6 feet) in length. This species was among the last known surviving eurypterid, living just before or during the Permian–Triassic extinction event 251.9 million years ago. Before the extinction event, eurypterids had been declining in numbers and diversity for millions of years; Campylocephalus had been the only known genus of living eurypterids for more than 20 million years since the extinction of the related genus Hastimima.