Stylonurus
Encyclopedia
Stylonurus is a genus of prehistoric eurypterid
of the Family Stylonuridae
.
, which lived from the Ordovician
to Lower Permian
periods, were small to very large forms with scales developing into tubercules and knobs. The prosoma (head) exhibited variable shape, with arcuate compound eyes located subcentrally, or anteriorly. Their abdomens were slender. Their walking legs were long and powerful, sometimes characterized by spines. Most genera did not have swimming legs.
Stylonurus is distinguishable from other stylonurids by their smooth surface, and the greatly elongated 5th (last) pair of walking legs, which reached as far as the telson
, which was long and styliform. The prosoma (head) varied from semiovate to subrectangular.
, one of which is of uncertain placement:
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...
of the Family Stylonuridae
Stylonuridae
Stylonuridae are an extinct family of prehistoric eurypterids within the Superfamily Stylonuroidea.-Description:Stylonuridae, which lived from the Ordovician to Lower Permian periods, were small to very large forms with scales developing into tubercules and knobs. The prosoma exhibited variable...
.
Description
StylonuridsStylonuridae
Stylonuridae are an extinct family of prehistoric eurypterids within the Superfamily Stylonuroidea.-Description:Stylonuridae, which lived from the Ordovician to Lower Permian periods, were small to very large forms with scales developing into tubercules and knobs. The prosoma exhibited variable...
, which lived from the Ordovician
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...
to Lower 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...
periods, were small to very large forms with scales developing into tubercules and knobs. The prosoma (head) exhibited variable shape, with arcuate compound eyes located subcentrally, or anteriorly. Their abdomens were slender. Their walking legs were long and powerful, sometimes characterized by spines. Most genera did not have swimming legs.
Stylonurus is distinguishable from other stylonurids by their smooth surface, and the greatly elongated 5th (last) pair of walking legs, which reached as far as the 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...
, which was long and styliform. The prosoma (head) varied from semiovate to subrectangular.
Species
The genus contains two speciesSpecies
In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...
, one of which is of uncertain placement:
- Stylonurus powriensis Page, 1856
-
- = Stylonurus ensiformis Woodward, 1864
- ?Stylonurus shaffneri Willard, 1933
- = Stylonurus ensiformis Woodward, 1864