Remains of 18-Foot-Long Sea Monster Found with Its Favorite Foods

By Laura Geggel, Senior Writer | October 30, 2017 10:57am ET

An exquisitely preserved fossil of an ichthyosaur — a dolphin-like reptile that lived during the dinosaur age — found alongside the remains of hard-shelled ammonites is one of a kind: It's the only Jurassic ichthyosaur ever found in India, according to a new study.

The nearly 18-foot-long (5.5 meters) ichthyosaur lived during the Kimmeridgian, an age within the Jurassic period lasting from about 157 million to 152 million years ago, the researchers said.

The discovery "throws light on the evolution and diversity of ichthyosaurs in the Indo-Madagascan region," study lead researcher Guntupalli Prasad, a geologist at the University of Delhi, said in a statement.

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Ancient reptile mystery solved as 2 extinct species found to be the same

March 8, 2017 

Ichthyosaurs, which are similar-shaped to dolphins and sharks, but are reptiles, swam the seas for millions of years during the Triassic, Jurassic and Cretaceous periods. They were the first, large extinct reptiles brought to the attention of the scientific world. 

Dean Lomax, a palaeontologist and Honorary Scientist at The University of Manchester, working with Professor Judy Massare of Brockport College, New York, have studied thousands of ichthyosaur fossils and have delved through hundreds of years of records to solve an ancient mystery.

Many ichthyosaur fossils were found in England during the early 19th century, but it was not until 1821 that the first ichthyosaur species was described - called Ichthyosaurus communis. This species has become one of the most well-known and iconic of all the British fossil reptiles. A sea of Ichthyosaurus fossils can be seen on display at the Natural History Museum, London.

In 1822, three other species were described, based on differences in the shape and structure of their teeth. Two of the species were later re-identified as other types of ichthyosaur, whereas one of these species, called Ichthyosaurus intermedius, was still considered closely related to I. communis.

In the years that followed, many eminent scientists, including Sir Richard Owen (the man who coined the word dinosaur), studied ichthyosaur fossils collected from Dorset, Somerset, Yorkshire and other locations in England. Their studies and observations of Ichthyosaurus communis and I. intermedius resulted in confusion with the species, with many skeletons identified on unreliable grounds.

Lomax said, "The early accounts of ichthyosaurs were based on very scrappy, often isolated, remains. This resulted in a very poor understanding of the differences between species and thus how to identify them. To complicate matters further, the original specimen of Ichthyosaurus communis is lost and was never illustrated.

Similarly, the original specimen of I. intermedius is also lost, but an illustration does exist. This has caused a big headache for palaeontologists trying to understand the differences between the species".

In the mid-1970s, palaeontologist, Dr Chris McGowan was the first to suggest that Ichthyosaurus communis and I. intermedius may represent the same species. He could not find reliable evidence to separate the two species. Subsequent studies argued for and against the separation of the species.

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Marine dinosaurs evolved extremely quickly, study finds

MAY 22, 2016

by Susanna Pilny

Hundreds of millions of years ago, marine reptiles like the ichthyosaurs and plesiosaurs ruled the seas—but researchers were never quite sure about their origins, or their rise to dominance. Now, research published from paleobiologists from the University of Bristol has shed some light on their mysterious past.

As told in their paper in Paleobiology, the scientists have uncovered evidence that during the Mesozoic-- an era about 252 to 66 million years ago—these predators suddenly burst onto the scene, instead of a slow evolution into their environment.

"We show that when marine reptiles first entered the oceans in the Triassic period, they rapidly became very diverse and had many morphological adaptations related to feeding on varied prey,” said the lead author of the study, Dr. Tom Stubbs, in a statement.

“Within a relatively short space of time, marine reptiles began feeding on hard-shelled invertebrates, fast-moving fish and other large marine reptiles. The range of feeding-related morphological adaptations seen in Triassic marine reptiles was never exceeded later in the Mesozoic."

Studying the fossil record

The team came to these conclusions after carefully studying the fossil record of Mesozoic marine reptiles and using statistic to quantify the variation in the shape and function of jaws and teeth across these predators. Before now, studies had mostly been based on estimates of biodiversity across time. But this new study shook things up by tying the shape of jaws and teeth to their different modes of life (like their different modes of feeding).

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What killed off the ichthyosaurs? This study has the answer.

MARCH 9, 2016

by John Hopton

Ichthyosaurs were like an awesome cross of dinosaurs and dolphins-- could there be anything cooler? All good things must come to an end, and cool as they were, ichthyosaurs (yeah, we know they're not technically dinosaurs) had to die out eventually. Scientists think they just discovered exactly how that happened.

The dolphin-like marine reptiles likely became extinct 94 million years ago due to the combination of global warming and their inability to evolve quickly enough, Reuters reports. 

Around that time, Earth was approaching its hottest period of the past 250 million years, leading to strong fluctuations in sea levels and temperatures that left huge sections of seafloor without the oxygen necessary for air-breathing ichthyosaurs to live. These shifts prompted changes to ichthyosaur migratory routes, food availability, and birthing grounds.

A rapid demise 

The research challenges an older hypothesis that the animals were victims of competition with emerging predators such as the ocean-going lizards, mosasaurs. The new study shows that ichthyosaurs went extinct before mosasaurs even appeared.

This study suggests ichthyosaurs' demise happened much more rapidly than the previously posited decline over tens of millions of years.

"We find that the extinction was abrupt, not gradual," said University of Oxford paleontologist Roger Benson.

The researchers examined the ichthyosaur fossil record in order to reconstruct the group's evolutionary diversity, at the same time scrutinizing evidence of climate change that coincided with their extinction.

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'Out of Time' Fossil Reveals Ancient Ocean Diversity

Stephanie Pappas, LiveScience Senior Writer

A fossil that once lined a mule track in Iraq has revealed the surprising survival of a group of ichthyosaurs, marine reptiles that swam the seas more than 66 million years ago.

Researchers had previously believed that ichthyosaurs declined throughout the Jurassic Period, which lasted from 199 million to 145 million years ago, with the only survivors rapidly evolving to keep ahead of repeated extinction events. The new fossil, however, dates from the Cretaceous Period, which lasted from 145 million to 66 million years ago. It looks remarkably like its Jurassic brethren, revealing a surprising evolutionary statis.

The fossil "represents an animal that seems 'out of time' for its age," study researcher Valentin Fischer of the University of Liège in Belgium said in a statement.

Ichthyosaur evolution

Ichythyosaurs were dolphin-shaped swimming reptiles that gave birth to live young. They lived in the oceans at the same time dinosaurs were tromping around on land. Previously, researchers thought only one group of ichthyosaurs, called ophthalmosaurids, made it out of the Jurassic into the Cretaceous. The newly named fossil, dubbed Malawania anachronus, is a Cretaceous survivor that does not belong to the ophthalmosaurids, however. That means a "ghost lineage" of ichthyosaurs survived alongside the ophthalmosaurids, changing very little over millions of years.

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Giant Fossil Predator Provides Insights Into the Rise of Modern Marine Ecosystem Structures

Jan. 7, 2013 — An international team of scientists has described a fossil marine predator measuring 8.6 meters in length (about 28 feet) recovered from the Nevada desert in 2010 as representing the first top predator in marine food chains feeding on prey similar to its own size.

A paper with their description will appear the week of Jan. 7, 2013 in the early electronic issue of Proceedings of the National Academy of Sciences.

Scientists who studied the fossil include lead author Dr. Nadia Fröbisch and Prof. Jörg Fröbisch (both at Museum für Naturkunde Leibniz-Institut für Evolutions- und Biodiversitätsforschung), Prof. P. Martin Sander (Steinmann Institute of Geology, Mineralogy, and Paleontology, Division of Paleontology, University of Bonn), Prof. Lars Schmitz (W. M. Keck Science Department, Claremont McKenna, Pitzer, and Scripps Colleges, Claremont, California) and Dr. Olivier Rieppel (The Field Museum, Chicago, Illinois).

The 244-million-year-old fossil, named Thalattoarchon saurophagis (lizard-eating sovereign of the sea) is an early representative of the ichthyosaurs, a group of marine reptiles that lived at the same time as dinosaurs and roamed the oceans for 160 million years. It had a massive skull and jaws armed with large teeth with cutting edges used to seize and slice through other marine reptiles in the Triassic seas. Because it was a meta-predator, capable of feeding on animals with bodies similar in size to its own, Thalattoarchon was comparable to modern orca whales.

Read on:  http://www.sciencedaily.com/releases/2013/01/130107151422.htm