Megalograptus
Encyclopedia
Megalograptus is a 4 feet (1.2 m) Ordovician
eurypterid
(sea scorpion), and was among the earliest known genera
(and was a member of the family Megalograptidae
). The generic name is derived from the fact that its first fossils were of its very spiny leg
s, which were mistaken for massive graptolite
s. It lived from 460 to 445 mya. Megalograptus preyed on fish
, trilobites, other sea scorpions, and smaller orthocones, using the spines on their claws to feel for their prey hiding in the sand and mud. However, adult Cameroceras, alongside with the bigger sea scorpion
species preyed on it instead. Megalograptus did not have a stinger, but may have curled its tail and sword-like telson
forward as a threat pose, much like a scorpion
.
was short and lanceolate.
Megalograptus is distinguishable from other members of the family by the third walking legs, which are characterized by short diverging spines.
's Sea Monsters: A Walking with Dinosaurs Trilogy series, where they were imagined to have behaved similarly to horseshoe crab
s, coming to shore to mate, lay eggs in the surf and sand, and minimize the risk of being attacked during a moult
. They also appeared as eurypterid
s in the first episode of Animal Armageddon
, as among the animal survivors of the first mass extinction on Earth.
Ordovician
The Ordovician is a geologic period and system, the second of six of the Paleozoic Era, and covers the time between 488.3±1.7 to 443.7±1.5 million years ago . It follows the Cambrian Period and is followed by the Silurian Period...
eurypterid
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...
(sea scorpion), and was among the earliest known genera
Genus
In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...
(and was a member of the family Megalograptidae
Megalograptidae
Megalograptidae is a family of extinct eurypterids.-Description:Megalograptids were characterized by large exoskeletons with ovate to triangular scales. The prosoma was subquadrate, with a tonguelike anterior process bearing marginal spines, and compound eyes on the top front of the head. The...
). The generic name is derived from the fact that its first fossils were of its very spiny leg
Arthropod leg
The arthropod leg is a form of jointed appendage of arthropods, usually used for walking. Many of the terms used for arthropod leg segments are of Latin origin, and may be confused with terms for bones: coxa , trochanter , femur, tibia, tarsus, ischium, metatarsus, carpus, dactylus ,...
s, which were mistaken for massive graptolite
Graptolite
Graptolithina is a class in the animal phylum Hemichordata, the members of which are known as Graptolites. Graptolites are fossil colonial animals known chiefly from the Upper Cambrian through the Lower Carboniferous...
s. It lived from 460 to 445 mya. Megalograptus preyed on fish
Fish
Fish are a paraphyletic group of organisms that consist of all gill-bearing aquatic vertebrate animals that lack limbs with digits. Included in this definition are the living hagfish, lampreys, and cartilaginous and bony fish, as well as various extinct related groups...
, trilobites, other sea scorpions, and smaller orthocones, using the spines on their claws to feel for their prey hiding in the sand and mud. However, adult Cameroceras, alongside with the bigger 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...
species preyed on it instead. Megalograptus did not have a stinger, but may have curled its tail and sword-like telson
Telson
The telson is the last division of the body of a crustacean. It is not considered a true segment because it does not arise in the embryo from teloblast areas as do real segments. It never carries any appendages, but a forked "tail" called the caudal furca is often present. Together with the...
forward as a threat pose, much like a scorpion
Scorpion
Scorpions are predatory arthropod animals of the order Scorpiones within the class Arachnida. They have eight legs and are easily recognized by the pair of grasping claws and the narrow, segmented tail, often carried in a characteristic forward curve over the back, ending with a venomous stinger...
.
Description
Megalograptids were characterized by large exoskeletons with ovate to triangular scales. The prosoma (head) was subquadrate, with a tonguelike anterior process bearing marginal spines, and compound eyes on the top front of the head. The chelicerae (claws in front of the mouth) were small and short. The first and third pairs of walking legs were short, with diverging or closely spaced spines. The second pair of walking legs was enormously developed, with long paired spines. The fourth pair of walking legs was nearly spineless. The preabdomen, the front portion of the body, was narrow with axial furrows, while the postabdomen was moderately narrow with broad, flat and curved appendages on the last body segment. The telsonTelson
The telson is the last division of the body of a crustacean. It is not considered a true segment because it does not arise in the embryo from teloblast areas as do real segments. It never carries any appendages, but a forked "tail" called the caudal furca is often present. Together with the...
was short and lanceolate.
Megalograptus is distinguishable from other members of the family by the third walking legs, which are characterized by short diverging spines.
Popular culture
Megalograptus was featured in the Ordovician (the "seventh deadliest sea") 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...
's Sea Monsters: A Walking with Dinosaurs Trilogy series, where they were imagined to have behaved similarly to horseshoe crab
Horseshoe crab
The Atlantic horseshoe crab, Limulus polyphemus, is a marine chelicerate arthropod. Despite its name, it is more closely related to spiders, ticks, and scorpions than to crabs. Horseshoe crabs are most commonly found in the Gulf of Mexico and along the northern Atlantic coast of North America...
s, coming to shore to mate, lay eggs in the surf and sand, and minimize the risk of being attacked during a moult
Moult
In biology, moulting or molting , also known as sloughing, shedding, or for some species, ecdysis, is the manner in which an animal routinely casts off a part of its body , either at specific times of year, or at specific points in its life cycle.Moulting can involve the epidermis , pelage...
. They also appeared as eurypterid
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...
s in the first episode of Animal Armageddon
Animal Armageddon
Animal Armageddon is an American paleontology-based documentary television miniseries that originally aired from to on Animal Planet. All the prehistoric scenes are created 100% in Lightwave...
, as among the animal survivors of the first mass extinction on Earth.
External links
- http://www.bbc.co.uk/science/seamonsters/factfiles/seascorpion.shtml BBC, including image
- http://www.taxonomy.nl/Taxonomicon/TaxonTree.aspx?id=15937