The subphylum Chelicerata constitutes one of the major subdivisions of the phylum Arthropoda. It contains the sea spiders, arachnids, and several extinct lineages, such as the eurypterids.
Xiphosurans are an order of arthropods related to arachnids, or, according to one recent study, actually arachnids. They are sometimes called horseshoe crabs. They first appeared in the Hirnantian. Currently, there are only four living species. They are members of the order Xiphosura, which contains two suborders, Xiphosurida and Synziphosurina.
Pterygotus is a genus of giant predatory eurypterid, a group of extinct aquatic arthropods. Fossils of Pterygotus have been discovered in deposits ranging in age from Late Silurian to Early Devonian, and have been referred to several different species. Fossils have been recovered from four continents; Australia, Europe, North America and South America, which indicates that Pterygotus might have had a nearly cosmopolitan (worldwide) distribution. The type species, P. anglicus, was described by Swiss naturalist Louis Agassiz in 1839. Agassiz mistakenly believed the remains were of a giant fish, with the name Pterygotus translating to "winged fish". He would only realize the mistake five years later in 1844.
Hibbertopterus is a genus of giant eurypterid, a group of extinct aquatic arthropods, that lived during the Devonian and Carboniferous.
The order Trigonotarbida is a group of extinct arachnids whose fossil record extends from the late Silurian to the early Permian. These animals are known from several localities in Europe and North America, as well as a single record from Argentina. Trigonotarbids can be envisaged as spider-like arachnids, but without silk-producing spinnerets. They ranged in size from a few millimetres to a few centimetres in body length and had segmented abdomens, with the tergites across the backs of the animals' abdomens, which were characteristically divided into three or five separate plates. Probably living as predators on other arthropods, some later trigonotarbid species were quite heavily armoured and protected themselves with spines and tubercles. About seventy species are currently known, with most fossils originating from the Carboniferous coal measures. In July 2014 scientists used computer graphics to re-create a possible walking gait for the animal.
Megarachne is a genus of eurypterid, an extinct group of aquatic arthropods. Fossils of Megarachne have been discovered in deposits of Late Carboniferous age, from the Gzhelian stage, in San Luis, Argentina. The fossils of the single and type species M. servinei have been recovered from deposits that had once been a freshwater environment. The generic name, composed of the Ancient Greek μέγας (megas) meaning "great" and Latin arachne meaning "spider", translates to "great spider", because the fossil had been misidentified as a large prehistoric spider.
Acutiramus is a genus of giant predatory eurypterid, an extinct group of aquatic arthropods. Fossils of Acutiramus have been discovered in deposits of Late Silurian to Early Devonian age. Seven species have been described, five from North America and two from the Czech Republic. The generic name derives from Latin acuto and Latin ramus ("branch"), referring to the acute angle of the final tooth of the claws relative to the rest of the claw.
Jaekelopterus is a genus of predatory eurypterid, a group of extinct aquatic arthropods. Fossils of Jaekelopterus have been discovered in deposits of Early Devonian age, from the Pragian and Emsian stages. There are two known species: the type species J. rhenaniae from brackish to fresh water strata in the Rhineland, and J. howelli from estuarine strata in Wyoming. The generic name combines the name of German paleontologist Otto Jaekel, who described the type species, and the Greek word πτερόν (pteron) meaning "wing".
Nanahughmilleria is a genus of eurypterid, an extinct group of aquatic arthropods. Fossils of Nanahughmilleria have been discovered in deposits of Devonian and Silurian age in the United States, Norway, Russia, England and Scotland, and have been referred to several different species.
Erettopterus is a genus of large predatory eurypterid, an extinct group of aquatic arthropods. Fossils of Erettopterus have been discovered in deposits ranging from Early Silurian to the Early Devonian, and have been referred to several different species. Fossils have been recovered from two continents; Europe and North America. The genus name is composed by the Ancient Greek words ἐρέττω (eréttō), which means "rower", and πτερόν (pterón), which means "wing", and therefore, "rower wing".
Parahughmilleria is a genus of eurypterid, an extinct group of aquatic arthropods. Fossils of Parahughmilleria have been discovered in deposits of the Devonian and Silurian age in the United States, Canada, Russia, Germany, Luxembourg and Great Britain, and have been referred to several different species. The first fossils of Parahughmilleria, discovered in the Shawangunk Mountains in 1907, were initially assigned to Eurypterus. It would not be until 54 years later when Parahughmilleria would be described.
Adelophthalmus is a genus of eurypterid, an extinct group of aquatic arthropods. Fossils of Adelophthalmus have been discovered in deposits ranging in age from the Early Devonian to the Early Permian, which makes it the longest lived of all known eurypterid genera, with a total temporal range of over 120 million years. Adelopthtalmus was the final genus of the Eurypterina suborder of eurypterids and consisted the only known genus of swimming eurypterids from the Middle Devonian until its extinction during the Permian, after which the few surviving eurypterids were all walking forms of the suborder Stylonurina.
Unionopterus is a genus of eurypterid, an extinct group of aquatic arthropods commonly known as "sea scorpions". Fossils have been registered from the Early Carboniferous period. The genus contains only one species, U. anastasiae, recovered from deposits of Tournaisian to Viséan stages in Kazakhstan. Known from one single specimen which was described in a publication of Russian language with poor illustrations, Unionopterus' affinities are extremely poorly known.
Pterygotioidea is a superfamily of eurypterids, an extinct group of aquatic arthropods. Pterygotioids were the most derived members of the infraorder Diploperculata and the sister group of the adelophthalmoid eurypterids. The group includes the basal and small hughmilleriids, the larger and specialized slimonids and the famous pterygotids which were equipped with robust and powerful cheliceral claws.
Waeringopteridae is a family of eurypterids, an extinct group of aquatic arthropods. The Waeringopteridae is the only family classified as part of the superfamily Waeringopteroidea, which in turn is classified within the infraorder Diploperculata in the suborder Eurypterina. The earliest known member of the group, Orcanopterus, has been recovered from deposits of Katian age and the latest known surviving member, Grossopterus, has been recovered from deposits of Siegenian age. The name Waeringopteridae is derived from the type genus Waeringopterus, which is named in honor of eurypterid researcher Erik N. Kjellesvig-Waering.
Adelophthalmidae is a family of eurypterids, an extinct group of aquatic arthropods. Adelophthalmidae is the only family classified as part of the superfamily Adelophthalmoidea, which in turn is classified within the infraorder Diploperculata in the suborder Eurypterina.
Eurypterina is one of two suborders of eurypterids, an extinct group of chelicerate arthropods commonly known as "sea scorpions". Members of the suborder are collectively and informally known as "eurypterine eurypterids" or "eurypterines". They are known from fossil deposits worldwide, though primarily in North America and Europe.
This timeline of eurypterid research is a chronologically ordered list of important fossil discoveries, controversies of interpretation, and taxonomic revisions of eurypterids, a group of extinct aquatic arthropods closely related to modern horseshoe crabs that lived during the Paleozoic Era.
