Ichthyosaur Overview and Characteristics

Ichthyosaur Overview

• Ichthyosaurs were ancient reptilian predators that ruled the oceans alongside dinosaurs and pterosaurs.
• They first appeared 251 million years ago during the Triassic Period, 20 million years before dinosaurs emerged.
• "Ichthyosaur" means "fish lizard" in Greek, reflecting their initial lizard-like appearance with fins.
• They evolved over 100 million years, becoming more fish-like in shape.
• Ichthyosaurs shared physical similarities with dolphins and whales, but were reptiles.
• They dominated the seas during the Triassic and Jurassic periods (251 to 145 million years ago).

Ichthyosaur Physical Characteristics

• Ichthyosaurs had long, narrow skulls with sharp teeth for catching fish and squid.
• Their eyes were the largest ever recorded in any animal, reaching over 10 inches wide, enabling them to see in deep, dark waters.
• Ichthyosaur sizes varied:
  • Some were as small as two feet long.
  • The largest known specimen was about 85 feet long. (Possibly 80 ft if the found jaw was complete.)
• They possessed paddle-like fins and a vertical tail, allowing them to swim at speeds over 22 miles per hour despite their size.

Ichthyosaur Discovery

• In spring 2020, Justin and Ruby Reynolds found an ichthyosaur fossil on Blue Anchor Beach in Somerset, England. The fossil was initially only four inches long. (10 cm)
• A second fossil jawbone was found by Paul de la Salle in 2016.
• This discovery confirmed a new ichthyosaur species: Ichthyotitan severnensis.
• Both jawbones date to the end of the Triassic period (around 202 million years ago).
• Dr. Dean Lomax and his team assisted the Reynolds in finding additional pieces.
• Their quest concluded in October 2022, reconstructing a section of the marine reptile's lower jaw, estimated to have measured over six feet (1.8 m) long if complete, potentially an 80-foot (24 m) animal - the equivalent of two buses.

Ichthyotitan severnensis

• Ichthyotitan severnensis was between 72 and 85 feet long, making it one of the largest marine reptiles ever discovered, rivaling the size of a blue whale.
• Ichthyotitan severnensis lived 13 million years later than other known ichthyosaurs.
• It is estimated to have survived until a global mass extinction event approximately 201 million years ago. (Potentially a maximum of 80 feet (24 m).
• Ruby and Justin Reynolds were co-authors on the study published in PLOS One on April 17, 2024.

Ichthyosaur Extinction

• Ichthyosaur dominance ended in the late Cretaceous Period, approximately 25 million years before the asteroid that wiped out dinosaurs.
• The exact cause of their extinction remains unknown.
• Some scientists speculate that severe climate change may have played a role.

Explore the fascinating world of ichthyosaurs, ancient marine reptiles that thrived alongside dinosaurs. This quiz covers ichthyosaur evolution, physical traits, and their eventual extinction. Test your knowledge on these unique 'fish lizards' and their aquatic lifestyle.