Eocursor
Encyclopedia
Eocursor was a primitive genus
of dinosaur
which lived during the Late Triassic
(Norian
age), around 210 million years ago. It was an ornithischian which lived in what is now South Africa
. Remains of this animal have been found in the Lower Elliot Formation and are the most complete known from a Triassic ornithischian, shedding new light on the origin of this group.
Fossils of Eocursor were originally collected in 1993, but were not formally described until fourteen years later. The type species
, Eocursor parvus, was described in 2007 by Richard J. Butler, Roger M. H. Smith, and David B. Norman
. Eocursor was one of the earliest known ornithischians, and sheds some light on early dinosaur relationships because early dinosaurs are known from mostly incomplete skeletons. Eocursor is known from partial skeletal elements, including skull fragments, spinal elements, pelvis, long leg bones, and unusually large grasping hands.
and Scutellosaurus
. Its large hands resembled those of the Heterodontosauridae
, a clade
of primitive ornithischians. The morphology of the triangular teeth, not unlike those of an iguana
, suggests partial herbivory. The tibia
was significantly longer than the femur
, indicating Eocursor was a swift runner.
specimen of Eocursor (SAM-PK-K8025) was collected from the Lower Elliot Formation in Free State
, South Africa. The skeleton, although only partially complete, is one of the best-preserved early ornithischian skeletons ever found. The fossils include a partial skeleton: portions of the skull, lower jaw, vertebrae, and limbs.
In June 2007, the fossils were formally described by an international team of paleontologists
: Richard Butler of the Natural History Museum
, London, and the University of Cambridge
, David Norman of the University of Cambridge
, and Roger M. H. Smith of the Iziko South African Museum. The fossils were named Eocursor parvus, from the Greek
word eos (meaning "dawn"), and the Latin
words cursor (meaning "runner") and parvus ("little"), "in reference to the early occurrence of this ornithischian, its apparent locomotory abilities and its small size."
, Triceratops
, and Iguanodon
. Butler et al. consider Eocursor more primitive than Lesothosaurus, but more derived than the Heterodontosauridae and Pisanosaurus
, as a basal ornithischian forming a sister clade
of Genasauria
.
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...
of dinosaur
Dinosaur
Dinosaurs are a diverse group of animals of the clade and superorder Dinosauria. They were the dominant terrestrial vertebrates for over 160 million years, from the late Triassic period until the end of the Cretaceous , when the Cretaceous–Paleogene extinction event led to the extinction of...
which lived during the Late Triassic
Late Triassic
The Late Triassic is in the geologic timescale the third and final of three epochs of the Triassic period. The corresponding series is known as the Upper Triassic. In the past it was sometimes called the Keuper, after a German lithostratigraphic group that has a roughly corresponding age...
(Norian
Norian
The Norian is a division of the Triassic geological period. It has the rank of an age or stage . The Norian lasted from 216.5 ± 2.0 to 203.6 ± 1.5 million years ago. It was preceded by the Carnian and succeeded by the Rhaetian.-Stratigraphic definitions:The Norian was named after the Noric Alps in...
age), around 210 million years ago. It was an ornithischian which lived in what is now South Africa
South Africa
The Republic of South Africa is a country in southern Africa. Located at the southern tip of Africa, it is divided into nine provinces, with of coastline on the Atlantic and Indian oceans...
. Remains of this animal have been found in the Lower Elliot Formation and are the most complete known from a Triassic ornithischian, shedding new light on the origin of this group.
Fossils of Eocursor were originally collected in 1993, but were not formally described until fourteen years later. The type species
Type species
In biological nomenclature, a type species is both a concept and a practical system which is used in the classification and nomenclature of animals and plants. The value of a "type species" lies in the fact that it makes clear what is meant by a particular genus name. A type species is the species...
, Eocursor parvus, was described in 2007 by Richard J. Butler, Roger M. H. Smith, and David B. Norman
David B. Norman
David Bruce Norman is a British paleontologist, currently Director of the Sedgwick Museum, Cambridge University. He is a fellow at Christ's College, Cambridge where he teaches geology in the Natural Sciences tripos. He is a member of the Palaeontological Association. He has studied Iguanodon...
. Eocursor was one of the earliest known ornithischians, and sheds some light on early dinosaur relationships because early dinosaurs are known from mostly incomplete skeletons. Eocursor is known from partial skeletal elements, including skull fragments, spinal elements, pelvis, long leg bones, and unusually large grasping hands.
Description
Eocursor was a lightly built bipedal dinosaur with an estimated length of about 1 m (3 ft). The general aspect of the animal resembles the one of the early Jurassic ornithischians such as LesothosaurusLesothosaurus
Lesothosaurus is an herbivorous ornithischian dinosaur. It was named by paleontologist Peter Galton in 1978, the name meaning "lizard from Lesotho". The genus is monotypic, having only one valid species, Lesothosaurus diagnosticus, within the genus....
and Scutellosaurus
Scutellosaurus
Scutellosaurus is a genus of herbivorous dinosaur that lived in North America around 200 to 196 million years ago, in the Early Jurassic times....
. Its large hands resembled those of the Heterodontosauridae
Heterodontosauridae
Heterodontosauridae is a family of early ornithischian dinosaurs that were likely among the most basal members of the group...
, a clade
Clade
A clade is a group consisting of a species and all its descendants. In the terms of biological systematics, a clade is a single "branch" on the "tree of life". The idea that such a "natural group" of organisms should be grouped together and given a taxonomic name is central to biological...
of primitive ornithischians. The morphology of the triangular teeth, not unlike those of an iguana
Iguana
Iguana is a herbivorous genus of lizard native to tropical areas of Central America and the Caribbean. The genus was first described in 1768 by Austrian naturalist Josephus Nicolaus Laurenti in his book Specimen Medicum, Exhibens Synopsin Reptilium Emendatam cum Experimentis circa Venena...
, suggests partial herbivory. The tibia
Tibia
The tibia , shinbone, or shankbone is the larger and stronger of the two bones in the leg below the knee in vertebrates , and connects the knee with the ankle bones....
was significantly longer than the femur
Femur
The femur , or thigh bone, is the most proximal bone of the leg in tetrapod vertebrates capable of walking or jumping, such as most land mammals, birds, many reptiles such as lizards, and amphibians such as frogs. In vertebrates with four legs such as dogs and horses, the femur is found only in...
, indicating Eocursor was a swift runner.
Discovery and naming
In 1993, the holotypeHolotype
A holotype is a single physical example of an organism, known to have been used when the species was formally described. It is either the single such physical example or one of several such, but explicitly designated as the holotype...
specimen of Eocursor (SAM-PK-K8025) was collected from the Lower Elliot Formation in Free State
Free State
The Free State is a province of South Africa. Its capital is Bloemfontein, which is also South Africa's judicial capital. Its historical origins lie in the Orange Free State Boer republic and later Orange Free State Province. The current borders of the province date from 1994 when the Bantustans...
, South Africa. The skeleton, although only partially complete, is one of the best-preserved early ornithischian skeletons ever found. The fossils include a partial skeleton: portions of the skull, lower jaw, vertebrae, and limbs.
In June 2007, the fossils were formally described by an international team of paleontologists
Paleontology
Paleontology "old, ancient", ὄν, ὀντ- "being, creature", and λόγος "speech, thought") is the study of prehistoric life. It includes the study of fossils to determine organisms' evolution and interactions with each other and their environments...
: Richard Butler of the Natural History Museum
Natural History Museum
The Natural History Museum is one of three large museums on Exhibition Road, South Kensington, London, England . Its main frontage is on Cromwell Road...
, London, and the University of Cambridge
University of Cambridge
The University of Cambridge is a public research university located in Cambridge, United Kingdom. It is the second-oldest university in both the United Kingdom and the English-speaking world , and the seventh-oldest globally...
, David Norman of the University of Cambridge
University of Cambridge
The University of Cambridge is a public research university located in Cambridge, United Kingdom. It is the second-oldest university in both the United Kingdom and the English-speaking world , and the seventh-oldest globally...
, and Roger M. H. Smith of the Iziko South African Museum. The fossils were named Eocursor parvus, from the Greek
Ancient Greek
Ancient Greek is the stage of the Greek language in the periods spanning the times c. 9th–6th centuries BC, , c. 5th–4th centuries BC , and the c. 3rd century BC – 6th century AD of ancient Greece and the ancient world; being predated in the 2nd millennium BC by Mycenaean Greek...
word eos (meaning "dawn"), and the Latin
Latin
Latin is an Italic language originally spoken in Latium and Ancient Rome. It, along with most European languages, is a descendant of the ancient Proto-Indo-European language. Although it is considered a dead language, a number of scholars and members of the Christian clergy speak it fluently, and...
words cursor (meaning "runner") and parvus ("little"), "in reference to the early occurrence of this ornithischian, its apparent locomotory abilities and its small size."
Classification
Eocursor was an early ornithischian, one of the first so-called "bird-hipped" dinosaurs, a group which would eventually give rise to animals such as StegosaurusStegosaurus
Stegosaurus is a genus of armored stegosaurid dinosaur. They lived during the Late Jurassic period , some 155 to 150 million years ago in what is now western North America. In 2006, a specimen of Stegosaurus was announced from Portugal, showing that they were present in Europe as well...
, Triceratops
Triceratops
Triceratops is a genus of herbivorous ceratopsid dinosaur which lived during the late Maastrichtian stage of the Late Cretaceous Period, around 68 to 65 million years ago in what is now North America. It was one of the last dinosaur genera to appear before the great Cretaceous–Paleogene...
, and Iguanodon
Iguanodon
Iguanodon is a genus of ornithopod dinosaur that lived roughly halfway between the first of the swift bipedal hypsilophodontids and the ornithopods' culmination in the duck-billed dinosaurs...
. Butler et al. consider Eocursor more primitive than Lesothosaurus, but more derived than the Heterodontosauridae and Pisanosaurus
Pisanosaurus
Pisanosaurus is a genus of primitive ornithischian dinosaur from the Late Triassic of what is now South America. It was a bipedal herbivore described by Argentine paleontologist Rodolfo Casamiquela in 1967. Only one species, the type, Pisanosaurus mertii, is known, based on a single partial skeleton...
, as a basal ornithischian forming a sister clade
Clade
A clade is a group consisting of a species and all its descendants. In the terms of biological systematics, a clade is a single "branch" on the "tree of life". The idea that such a "natural group" of organisms should be grouped together and given a taxonomic name is central to biological...
of Genasauria
Genasauria
Genasauria is an extinct clade of beaked, herbivorous dinosaurs. The group was first named by paleontologist Paul Sereno in 1986, and is typically split into Thyreophora, a group of armored dinosaurs; and Neornithischia, which included the horned and duck-billed dinosaurs...
.