Pterygotus
Encyclopedia
Pterygotus is the second-largest known eurypterid
, or sea scorpion
and one of the largest arthropod
s of all time.
, which lived from the Early Silurian to Devonian periods, were characterized by small to large exoskeletons with semilunar scales. The telson (tail) was expanded, or flatter than it was tall. Pterygotids 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.
Pterygotus is distinguishable from other Pterygotids by the curved distal margin of the chelae. The prosoma (head) is subtrapezoidal (a trapezoid with rounded corners), with compound eyes located near the edge of the front corners. The telson has a pronounced dorsal carina (or keel) running down its center, terminating in a short spine.
Pterygotus could reach a length of 2.3 metres (7.5 ft), had a pair of large compound eyes, as well as another pair of smaller eyes in the center of its head. It had 4 pairs of walking legs, a fifth pair modified into swimming paddles, and a pair of large chelae (pincers) for subduing prey. The foremost 6 tergites, or tail sections, contained gills and the reproductive organs of the animal.
's tail does. It would steer and stabilize itself using its legs. The larger pair of Pterygotus' eyes strongly suggests that it was a visually oriented predator. It used its paddles to swim, though, it could probably accelerate by using its tail as a third paddle.
It was one of the top predators in the Paleozoic seas. It lived in shallow coastal areas, hunting fish, trilobite
s and other animals using stealth. It would have ambushed its prey by burying itself in sand. Then, when a fish or other unwitting animals came within range, Pterygotus would rise up and grab it with its claws.
period, and eventually died out during the early to mid-Devonian
. It was related to the larger Jaekelopterus and the freshwater Slimonia
. Fossils have been found in all continents except for Antarctica.
Fossils of Pterygotus are relatively common, although complete skeletons are rare. It was one of the last of the gigantic sea scorpions: later species were much smaller and more nimble. The decline of the larger sea scorpions may be related to their relative slowness and possible vulnerability during molting, since they could not escape to land like smaller sea scorpions. However, the latter is unlikely since Pterygotus was such a large creature.
series Walking with Monsters
, where it menaced a Brontoscorpio that was pursuing the Devonian
jawless fish Cephalaspis
.
Eurypterid
Eurypterids are an extinct group of arthropods related to arachnids which include the largest known arthropods that ever lived. They are members of the extinct order Eurypterida ; which is the most diverse Paleozoic chelicerate order in terms of species...
, or sea scorpion
Sea Scorpion
Sea Scorpion may refer to:* Eurypterids, members of the extinct class Eurypterida* some members of the Cottidae family of fish including the Long-spined Sea Scorpion and Short-spined Sea Scorpion...
and one of the largest arthropod
Arthropod
An arthropod is an invertebrate animal having an exoskeleton , a segmented body, and jointed appendages. Arthropods are members of the phylum Arthropoda , and include the insects, arachnids, crustaceans, and others...
s of all time.
Description
Pterygotid eurypteridsPterygotidae
Pterygotidae are an extinct family of eurypterids. They were members of the superfamily Pterygotioidea, and were the only eurypterids to have a truly worldwide distribution, and include the largest arthropods to have ever lived.-Description:...
, which lived from the Early Silurian to Devonian periods, were characterized by small to large exoskeletons with semilunar scales. The telson (tail) was expanded, or flatter than it was tall. Pterygotids 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.
Pterygotus is distinguishable from other Pterygotids by the curved distal margin of the chelae. The prosoma (head) is subtrapezoidal (a trapezoid with rounded corners), with compound eyes located near the edge of the front corners. The telson has a pronounced dorsal carina (or keel) running down its center, terminating in a short spine.
Pterygotus could reach a length of 2.3 metres (7.5 ft), had a pair of large compound eyes, as well as another pair of smaller eyes in the center of its head. It had 4 pairs of walking legs, a fifth pair modified into swimming paddles, and a pair of large chelae (pincers) for subduing prey. The foremost 6 tergites, or tail sections, contained gills and the reproductive organs of the animal.
Ecology
Pterygotus was an accomplished swimmer and could move with speed and agility through the water. It would swim by flapping its long, flat tail up and down; the broad, flat part at the end would push it through the water in much the same way as the fluke on the whaleWhale
Whale is the common name for various marine mammals of the order Cetacea. The term whale sometimes refers to all cetaceans, but more often it excludes dolphins and porpoises, which belong to suborder Odontoceti . This suborder also includes the sperm whale, killer whale, pilot whale, and beluga...
's tail does. It would steer and stabilize itself using its legs. The larger pair of Pterygotus
It was one of the top predators in the Paleozoic seas. It lived in shallow coastal areas, hunting fish, trilobite
Trilobite
Trilobites are a well-known fossil group of extinct marine arthropods that form the class Trilobita. The first appearance of trilobites in the fossil record defines the base of the Atdabanian stage of the Early Cambrian period , and they flourished throughout the lower Paleozoic era before...
s and other animals using stealth. It would have ambushed its prey by burying itself in sand. Then, when a fish or other unwitting animals came within range, Pterygotus would rise up and grab it with its claws.
Stratigraphy and biogeography
Pterygotus first arose during the SilurianSilurian
The Silurian is a geologic period and system that extends from the end of the Ordovician Period, about 443.7 ± 1.5 Mya , to the beginning of the Devonian Period, about 416.0 ± 2.8 Mya . As with other geologic periods, the rock beds that define the period's start and end are well identified, but the...
period, and eventually died out during the early to mid-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...
. It was related to the larger Jaekelopterus and the freshwater Slimonia
Slimonia
Slimonia is a genus of Silurian eurypterid roughly similar to the genus Pterygotus. Slimonia resembled Pterygotus, save that the former's telson is larger, and that its body was smaller and more slender than the latter. Unlike Pterygotus, which lived in estuaries, Slimonia species lived...
. Fossils have been found in all continents except for Antarctica.
Fossils of Pterygotus are relatively common, although complete skeletons are rare. It was one of the last of the gigantic sea scorpions: later species were much smaller and more nimble. The decline of the larger sea scorpions may be related to their relative slowness and possible vulnerability during molting, since they could not escape to land like smaller sea scorpions. However, the latter is unlikely since Pterygotus was such a large creature.
Species
- Pterygotus anglicus Agassiz, 1844 — Devonian, Scotland & Canada
- Pterygotus arcuatus Salter in Huxley & Salter, 1859 — Devonian, England
- ?Pterygotus australis McCoy, 1899 — Silurian, Australia
- Pterygotus barrandei Semper, 1898 — Silurian, Czech Republic
- Pterygotus bolivianus Kjellesvig-Waering, 1964 — Devonian, Bolivia
- Pterygotus carmani Kjellesvig-Waering, 1961 — Devonian, USA
- Pterygotus cobbi Hall, 1859 — Silurian, USA, Canada
- Pterygotus denticulatus Kjellesvig-Waering, 1961 — Silurian, England
- Pterygotus floridanus Kjellesvig-Waering, 1950 — Devonian, USA
- Pterygotus gaspesiensis Russell, 1953 — Devonian, Canada
- ?Pterygotus grandidentatus Kjellesvig-Waering, 1961 — Silurian England
- ?Pterygotus impacatus Kjellesvig-Waering, 1964 — Silurian, Estonia
- Pterygotus kopaninensis Barrande, 1872 — Silurian, Czech Republic
- Pterygotus lanarkensis Kjellesvig-Waering, 1964 — Silurian, Scotland
- Pterygotus lightbodyi Kjellesvig-Waering, 1961 — Silurian England
- Pterygotus ludensis Salter in Huxley & Salter, 1859 — Silurian, England
- Pterygotus marylandicus Kjellesvig-Waering, 1964 — Silurian, USA
- Pterygotus monroensis Sarle 1902 — Silurian, USA
In popular culture
Pterygotus was featured in the Silurian portion of the first episode of the BBCBBC
The British Broadcasting Corporation is a British public service broadcaster. Its headquarters is at Broadcasting House in the City of Westminster, London. It is the largest broadcaster in the world, with about 23,000 staff...
series Walking with Monsters
Walking with Monsters
Walking with Monsters is a three-part British documentary film series about life in the Paleozoic, bringing to life extinct arthropods, fish, amphibians, synapsids, and reptiles...
, where it menaced a Brontoscorpio that was pursuing the 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...
jawless fish Cephalaspis
Cephalaspis
Cephalaspis was a genus of armored goldfish-sized to trout-sized detritivorous fish that lived in freshwater streams and estuaries of early Devonian Western Europe...
.
Sources
- Haines, Tim and Paul Chambers. The Complete Guide to Prehistoric LifeThe Complete Guide to Prehistoric LifeThe Complete Guide to Prehistoric Life is an encyclopedia featuring 111 of the prehistoric animals from the Walking With... series, as well as an additional one . It was published in 2006 by Firefly Books, and written by Tim Haines with Paul Chambers...
. Pg. 25. Canada: Firefly Books Ltd. 2006.