Ichthyopterygia
Encyclopedia
Ichthyopterygia was a designation introduced by Sir Richard Owen
in 1840 to designate the Jurassic ichthyosaur
s that were known at the time, but the term is now used more often for both true Ichthyosauria and their more primitive early and middle Triassic
ancestors.
Basal
ichthyopterygians (prior to and ancestral to true Ichthyosauria) were mostly small (a meter or less in length) with elongate bodies and long spool shaped vertebrae, indicating that they swam in a sinuous eel
-like manner. This allowed for quick movements and maneuverability that were an advantage in shallow-water hunting. Even at this early stage they were already very specialised animals with proper flippers, and would have been incapable of movement on land.
These animals seem to have been widely distributed around the coast of the northern half of Pangea, as they are known the Late Olenekian
and Early Anisian
(early part of the Triassic
period) of Japan
, China
, Canada
, and Spitsbergen
(Norway
). By the later part of the Middle Triassic they were extinct, having been replaced by their descendents the true ichthyosaurs.
after Motani (1998, 1999) and Nicholls & Manabe (2001):
1 Neodiapsida
, 2 Ichthyopterygia, 3 Eoichthyosauria, 4 Ichthyosauria, 5 Merriamosauria, 6 Euichthyosauria, 7 Parvipelvia
, 8 Thunnosauria
Richard Owen
Sir Richard Owen, FRS KCB was an English biologist, comparative anatomist and palaeontologist.Owen is probably best remembered today for coining the word Dinosauria and for his outspoken opposition to Charles Darwin's theory of evolution by natural selection...
in 1840 to designate the Jurassic ichthyosaur
Ichthyosaur
Ichthyosaurs were giant marine reptiles that resembled fish and dolphins...
s that were known at the time, but the term is now used more often for both true Ichthyosauria and their more primitive early and middle Triassic
Triassic
The Triassic is a geologic period and system that extends from about 250 to 200 Mya . As the first period of the Mesozoic Era, the Triassic follows the Permian and is followed by the Jurassic. Both the start and end of the Triassic are marked by major extinction events...
ancestors.
Basal
Basal (phylogenetics)
In phylogenetics, a basal clade is the earliest clade to branch in a larger clade; it appears at the base of a cladogram.A basal group forms an outgroup to the rest of the clade, such as in the following example:...
ichthyopterygians (prior to and ancestral to true Ichthyosauria) were mostly small (a meter or less in length) with elongate bodies and long spool shaped vertebrae, indicating that they swam in a sinuous eel
Eel
Eels are an order of fish, which consists of four suborders, 20 families, 111 genera and approximately 800 species. Most eels are predators...
-like manner. This allowed for quick movements and maneuverability that were an advantage in shallow-water hunting. Even at this early stage they were already very specialised animals with proper flippers, and would have been incapable of movement on land.
These animals seem to have been widely distributed around the coast of the northern half of Pangea, as they are known the Late Olenekian
Olenekian
In the geologic timescale, the Olenekian is an age in the Early Triassic epoch or a stage in the Lower Triassic series. It spans the time between 249.7 ± 0.7 Ma and 245 ± 0.7 Ma . The Olenekian follows the Induan and is followed by the Anisian.The Olenekian saw the deposition of a large part of the...
and Early Anisian
Anisian
In the geologic timescale, the Anisian is the lower stage or earliest age of the Middle Triassic series or epoch and lasted from 245 million years ago until 237 million years ago, approximately...
(early part of the Triassic
Triassic
The Triassic is a geologic period and system that extends from about 250 to 200 Mya . As the first period of the Mesozoic Era, the Triassic follows the Permian and is followed by the Jurassic. Both the start and end of the Triassic are marked by major extinction events...
period) of Japan
Japan
Japan is an island nation in East Asia. Located in the Pacific Ocean, it lies to the east of the Sea of Japan, China, North Korea, South Korea and Russia, stretching from the Sea of Okhotsk in the north to the East China Sea and Taiwan in the south...
, China
China
Chinese civilization may refer to:* China for more general discussion of the country.* Chinese culture* Greater China, the transnational community of ethnic Chinese.* History of China* Sinosphere, the area historically affected by Chinese culture...
, Canada
Canada
Canada is a North American country consisting of ten provinces and three territories. Located in the northern part of the continent, it extends from the Atlantic Ocean in the east to the Pacific Ocean in the west, and northward into the Arctic Ocean...
, and Spitsbergen
Spitsbergen
Spitsbergen is the largest and only permanently populated island of the Svalbard archipelago in Norway. Constituting the western-most bulk of the archipelago, it borders the Arctic Ocean, the Norwegian Sea and the Greenland Sea...
(Norway
Norway
Norway , officially the Kingdom of Norway, is a Nordic unitary constitutional monarchy whose territory comprises the western portion of the Scandinavian Peninsula, Jan Mayen, and the Arctic archipelago of Svalbard and Bouvet Island. Norway has a total area of and a population of about 4.9 million...
). By the later part of the Middle Triassic they were extinct, having been replaced by their descendents the true ichthyosaurs.
Taxonomy
- Superorder Ichthyopterygia
- Family Utatsusauridae
- Family Parvinatatoridae
- Order Grippidia
- Order IchthyosaurIchthyosaurIchthyosaurs were giant marine reptiles that resembled fish and dolphins...
ia
Phylogeny
CladogramCladogram
A cladogram is a diagram used in cladistics which shows ancestral relations between organisms, to represent the evolutionary tree of life. Although traditionally such cladograms were generated largely on the basis of morphological characters, DNA and RNA sequencing data and computational...
after Motani (1998, 1999) and Nicholls & Manabe (2001):
1 Neodiapsida
Neodiapsida
Neodiapsida is a clade or major branch of the reptilian family tree, that includes all Diapsids apart from some early primitive types known as Araeoscelidia....
, 2 Ichthyopterygia, 3 Eoichthyosauria, 4 Ichthyosauria, 5 Merriamosauria, 6 Euichthyosauria, 7 Parvipelvia
Parvipelvia
Parvipelvia is an extinct clade of euichthyosaur ichthyosaurs from the Late Triassic to the early Late Cretaceous of Asia, Australia, Europe, North America and South America...
, 8 Thunnosauria
Thunnosauria
Thunnosauria is an extinct clade of parvipelvian ichthyosaurs from the Early Jurassic to the early Late Cretaceous of Asia, Australia, Europe, North America and South America...