Astraspis
Encyclopedia
Astraspis is an extinct genus of primitive jawless fish
from the Ordovician
of Central North America
and Bolivia
(Gagnier, 1993) . It is related to other Ordovician fishes, such as the South America
n Sacabambaspis
, and the Australia
n Arandaspis
.
covered with small protective plates (<1mm) and a head region covered with much larger plates (>>2mm). The specimen from North America (described by Sansom et al., 1997) is to have had relatively large, lateral
eyes and a series of eight gill
openings on each side. The specimen was generally oval
in cross-section. The protective bony
plates covering the animal were composed of aspidin (chemically similar to modern shark's
teeth), covered by tubercles composed of dentine. It is from these tubercles (which are generally star-shaped) that the name 'Astraspis' (literally "star-shield") is derived.
series Sea Monsters: A Walking with Dinosaurs Trilogy, a spin-off to the famed Walking with Dinosaurs
, where Nigel Marven
uses a dead Astraspis as bait to attract a sea scorpion
. The creature is identified in the series' novelisation. It is also said to be an armour-plated fish in the documentary, whereas is more closely related to the modern lamprey
. Astraspis was also featured in Animal Armageddon
.
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...
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...
of Central North America
North America
North America is a continent wholly within the Northern Hemisphere and almost wholly within the Western Hemisphere. It is also considered a northern subcontinent of the Americas...
and Bolivia
Bolivia
Bolivia officially known as Plurinational State of Bolivia , is a landlocked country in central South America. It is the poorest country in South America...
(Gagnier, 1993) . It is related to other Ordovician fishes, such as the South America
South America
South America is a continent situated in the Western Hemisphere, mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere. The continent is also considered a subcontinent of the Americas. It is bordered on the west by the Pacific Ocean and on the north and east...
n Sacabambaspis
Sacabambaspis
Sacabambaspis is an extinct genus of jawless fish that lived in the Ordovician period. It is related to Astraspis.-Description:Sacabambaspis had a head shield made from a large upper plate that rose to a slight ridge in the midline, and a deep curved lower plate...
, and the Australia
Australia
Australia , officially the Commonwealth of Australia, is a country in the Southern Hemisphere comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands in the Indian and Pacific Oceans. It is the world's sixth-largest country by total area...
n Arandaspis
Arandaspis
Arandaspis prionotolepis is an extinct species of jawless fish that lived in the Ordovician period, about 480 to 470 million years ago. It is the oldest known vertebrate....
.
Basic Anatomy
Astraspids are hypothesized to have been about 200mm in length. They are supposed to have had a mobile tailTail
The tail is the section at the rear end of an animal's body; in general, the term refers to a distinct, flexible appendage to the torso. It is the part of the body that corresponds roughly to the sacrum and coccyx in mammals, reptiles, and birds...
covered with small protective plates (<1mm) and a head region covered with much larger plates (>>2mm). The specimen from North America (described by Sansom et al., 1997) is to have had relatively large, lateral
Lateral
Lateral may refer to:*Lateral , an anatomical direction*Lateral canal, a canal built beside another stream*Lateral consonant, an ℓ-like consonant in which air flows along the sides of the tongue...
eyes and a series of eight gill
Gill
A gill is a respiratory organ found in many aquatic organisms that extracts dissolved oxygen from water, afterward excreting carbon dioxide. The gills of some species such as hermit crabs have adapted to allow respiration on land provided they are kept moist...
openings on each side. The specimen was generally oval
Oval
An oval is any curve resembling an egg or an ellipse, such as a Cassini oval. The term does not have a precise mathematical definition except in one area oval , but it may also refer to:* A sporting arena of oval shape** a cricket field...
in cross-section. The protective bony
Bone
Bones are rigid organs that constitute part of the endoskeleton of vertebrates. They support, and protect the various organs of the body, produce red and white blood cells and store minerals. Bone tissue is a type of dense connective tissue...
plates covering the animal were composed of aspidin (chemically similar to modern shark's
Shark
Sharks are a type of fish with a full cartilaginous skeleton and a highly streamlined body. The earliest known sharks date from more than 420 million years ago....
teeth), covered by tubercles composed of dentine. It is from these tubercles (which are generally star-shaped) that the name 'Astraspis' (literally "star-shield") is derived.
In popular culture
It has a small cameo in the 2003 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 Sea Monsters: A Walking with Dinosaurs Trilogy, a spin-off to the famed Walking with Dinosaurs
Walking with Dinosaurs
Walking with Dinosaurs is a six-part documentary television miniseries that was produced by BBC, narrated by Kenneth Branagh, and first aired in the United Kingdom, in 1999. The series was subsequently aired in North America on the Discovery Channel in 2000, with Branagh's voice replaced with that...
, where Nigel Marven
Nigel Marven
Nigel Marven is a British wildlife presenter, television producer, author, and ornithologist.-Career:Marven studied botany at Bristol University until the age of 22 when he left to begin his career at the BBC Natural History Unit in Bristol...
uses a dead Astraspis as bait to attract a 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...
. The creature is identified in the series' novelisation. It is also said to be an armour-plated fish in the documentary, whereas is more closely related to the modern lamprey
Lamprey
Lampreys are a family of jawless fish, whose adults are characterized by a toothed, funnel-like sucking mouth. Translated from an admixture of Latin and Greek, lamprey means stone lickers...
. Astraspis was also featured in 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...
.
External links
- PalaeosPalaeosPalaeos.com is a web site on biology, paleontology, cladistics and geology and which covers the history of Earth. The site is well respected and has been used as a reference by professional paleontologists such as Michael J. Benton, the professor of vertebrate palaeontology in the Department of...
' Pteraspidomorphi