Attercopus
Encyclopedia
Previously interpreted as the world's oldest spider
, Attercopus fimbriunguis belongs to an extinct order of arachnids named Uraraneida; thought to be close to the origins of spiders. Attercopus can be envisaged as a spider-like animal able to produce silk
, but which lacked true spinnerets and retained a segmented abdomen bearing a flagellum-like tail resembling that of a whip scorpion.
This important fossil from the Early Devonian
(about ) of Gilboa, New York
, was originally described as a member of the extinct order Trigonotarbida
and named Gelasinotarbus? fimbriunguis. It was later assigned to a new genus Attercopus and reinterpreted as the oldest, and most primitive, example of a true spider (Araneae). This hypothesis was based on the supposed presence of unique spider features such as silk-producing spinnerets and the opening of a venom gland on the fang of the chelicera.
Further study – based on new fossils from a comparable Devonian locality called South Mountain – and comparison with other material from the Permian
of Russia
indicates that Attercopus does not actually have spinnerets. The specimen which looked like a tubular spinneret is actually a folded sheet of cuticle. It would, however, have produced silk from a series of silk gland openings, or spigots, located across plates on the underside of the abdomen.
It seems unlikely that Attercopus spun webs, but it may have used its silk to wrap eggs, lay draglines or construct burrow walls. The opening for the venom gland is also a misinterpretation. A segmented tail, or flagellum, also belonged to this animal. Attercopus fimbriunguis is not a spider, but it is probably close to the type of animals which did give rise to modern spiders today.
Its name is taken from the English dialect word "attercop" (= "spider"), which came from Old English = "poison-head", from ("poison"), from the Proto-Germanic ("poisonous ulcer"), and ("head").
Spider
Spiders are air-breathing arthropods that have eight legs, and chelicerae with fangs that inject venom. They are the largest order of arachnids and rank seventh in total species diversity among all other groups of organisms...
, Attercopus fimbriunguis belongs to an extinct order of arachnids named Uraraneida; thought to be close to the origins of spiders. Attercopus can be envisaged as a spider-like animal able to produce silk
Spider silk
Spider silk is a protein fiber spun by spiders. Spiders use their silk to make webs or other structures, which function as nets to catch other animals, or as nests or cocoons for protection for their offspring...
, but which lacked true spinnerets and retained a segmented abdomen bearing a flagellum-like tail resembling that of a whip scorpion.
This important fossil from the Early Devonian
Devonian
The Devonian is a geologic period and system of the Paleozoic Era spanning from the end of the Silurian Period, about 416.0 ± 2.8 Mya , to the beginning of the Carboniferous Period, about 359.2 ± 2.5 Mya...
(about ) of Gilboa, New York
Gilboa, New York
Gilboa is a town in Schoharie County, New York, United States. The population was 1,215 at the 2000 census.The Town of Gilboa is in the south part of the county and is southwest of Albany.- History :The town was first settled around 1760....
, was originally described as a member of the extinct order Trigonotarbida
Trigonotarbida
The Order Trigonotarbida is an extinct group of 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...
and named Gelasinotarbus? fimbriunguis. It was later assigned to a new genus Attercopus and reinterpreted as the oldest, and most primitive, example of a true spider (Araneae). This hypothesis was based on the supposed presence of unique spider features such as silk-producing spinnerets and the opening of a venom gland on the fang of the chelicera.
Further study – based on new fossils from a comparable Devonian locality called South Mountain – and comparison with other material from the Permian
Permian
The PermianThe term "Permian" was introduced into geology in 1841 by Sir Sir R. I. Murchison, president of the Geological Society of London, who identified typical strata in extensive Russian explorations undertaken with Edouard de Verneuil; Murchison asserted in 1841 that he named his "Permian...
of Russia
Russia
Russia or , officially known as both Russia and the Russian Federation , is a country in northern Eurasia. It is a federal semi-presidential republic, comprising 83 federal subjects...
indicates that Attercopus does not actually have spinnerets. The specimen which looked like a tubular spinneret is actually a folded sheet of cuticle. It would, however, have produced silk from a series of silk gland openings, or spigots, located across plates on the underside of the abdomen.
It seems unlikely that Attercopus spun webs, but it may have used its silk to wrap eggs, lay draglines or construct burrow walls. The opening for the venom gland is also a misinterpretation. A segmented tail, or flagellum, also belonged to this animal. Attercopus fimbriunguis is not a spider, but it is probably close to the type of animals which did give rise to modern spiders today.
Its name is taken from the English dialect word "attercop" (= "spider"), which came from Old English = "poison-head", from ("poison"), from the Proto-Germanic ("poisonous ulcer"), and ("head").