Arthropterygius is an ichthyosaur

Ichthyosaur

Ichthyosaurs were giant marine reptiles that resembled fish and dolphins...

 which existed in 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...

 during the late Jurassic

Jurassic

The Jurassic is a geologic period and system that extends from about Mya to  Mya, that is, from the end of the Triassic to the beginning of the Cretaceous. The Jurassic constitutes the middle period of the Mesozoic era, also known as the age of reptiles. The start of the period is marked by...

 period. It contains 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...

 Arthropterygius chrisorum, named in 2010

2010 in paleontology

-Anomalocaridids:-Newly named crustaceans:-Newly named insects:* A new family, Cascopleciidae, is published by Poinar Jr.* A new family of ceraphronoid Hymenopters, Radiophronidae, is published by Ortega-Blanco, Rasnitsyn, and Delclòs....

 by Erin E. Maxwell. Arthropterygius is the generic replacement name for Ophthalmosaurus chrisorum, named in 1993 from fossils found on Melville Island in the Northwest Territories

Northwest Territories

The Northwest Territories is a federal territory of Canada.Located in northern Canada, the territory borders Canada's two other territories, Yukon to the west and Nunavut to the east, and three provinces: British Columbia to the southwest, and Alberta and Saskatchewan to the south...

. It's fossils are the most complete of any ichthyosaur in the Canadian Arctic. A. chrisorum has several features that separate it from the genus Ophthalmosaurus

Ophthalmosaurus

Ophthalmosaurus is an ichthyosaur of the Middle to Late Jurassic period , named for its extremely large eyes. It had a graceful 6 metre long dolphin-shaped body, and its almost toothless jaw was well adapted for catching squid...

, including a highly angled articulation between the radius

Radius

In classical geometry, a radius of a circle or sphere is any line segment from its center to its perimeter. By extension, the radius of a circle or sphere is the length of any such segment, which is half the diameter. If the object does not have an obvious center, the term may refer to its...

 and ulna

Ulna

The ulna is one of the two long bones in the forearm, the other being the radius. It is prismatic in form and runs parallel to the radius, which is shorter and smaller. In anatomical position The ulna is one of the two long bones in the forearm, the other being the radius. It is prismatic in form...

 and the humerus

Humerus

The humerus is a long bone in the arm or forelimb that runs from the shoulder to the elbow....

 and a foramen for the internal carotid artery

Internal carotid artery

In human anatomy, the internal carotid arteries are two major arteries, one on each side of the head and neck. They arise from the common carotid arteries where these bifurcate into the internal and external carotid artery, and they supply the brain....

 (a major artery that supplies blood to the brain) on the posterior surface of the basisphenoid. Maxwell 2010 found it to be the sister taxon of Caypullisaurus

Caypullisaurus

Caypullisaurus is an extinct genus of large ichthyosaur from the Late Jurassic to the Early Cretaceous of Argentina. Its holotype was collected from the Vaca Muerta Formation of Cerro Lotena, Neuquen, dating to the early Tithonian stage of the Late Jurassic, about 150 million years ago...

, an ophthalmosaurid from Argentina

Argentina

Argentina , officially the Argentine Republic , is the second largest country in South America by land area, after Brazil. It is constituted as a federation of 23 provinces and an autonomous city, Buenos Aires...

.