This well-preserved partial ichthyosaur was found in the Blue Lias shales by Lewis Winchester-Ellis in 2018. The vertebrae you see are from the tail section of this marine reptile.
The find includes stomach contents that tell us a little about how this particular fellow liked to dine.
As with most of his brethren, he enjoyed fish and cephalopods. Lewis found fishbone and squid tentacle hooklets in his belly.
Oh yes, these ancient cephies had grasping hooklets on their tentacles. I am picturing them wiggling all ominously. The hooklets were the only hard parts of the animal preserved in this case as the softer parts of this ancient calamari were fully or partially digested before this ichthyosaur met his end.
Ichthyosaurus was an extinct marine reptile first described from fossil fragments found in 1699 in Wales. Shortly thereafter, fossil vertebrae were published in 1708 from the Lower Jurassic and the first member of the order Ichthyosauria to be discovered.
To give that a bit of historical significance, this was the age of James Stuart, Jacobite hopeful to the British throne. While scientific journals of the day were publishing the first vertebrae ichthyosaur finds, he was avoiding the French fleet in the Firth of Forth off Scotland. This wasn’t Bonnie Prince Charlie, this was his Dad. Yes, that far back.
Though not often referenced in the literature, the very first well-articulated ichthyosaur skeleton was discovered in 1749 by the German physician, Albert Mohr. Mohr found the fossil specimen near Bad Boll in Upper Swabia, a municipality in the district of Göppingen in Baden-Württemberg, Germany.
But at the time, Mohr did not realize exactly what he had found. He thought the bones to be those of a fish — possibly a shark or ray. Georg Friedrich Jaeger wrote up a monograph in 1824 celebrating — and slightly inflating the interpretation of Mohr's work — though Jaeger's manuscript was produced in Latin so not often referenced in an ever Anglicized field of science.
Not long after Mohr's discovery, another fairly well-articulated skeleton was discovered by Mary Anning & her brother Joseph along the Dorset Jurassic Coast. Joseph had mistakenly, but quite reasonably, taken the find for an ancient crocodile.
Mary excavated the specimen a year later and it was this and others that she found that would supply the research base others would publish on.
Mohr does not often get credited — those accolades usually go to Mary Anning. Mary's find was described by a British surgeon, Sir Everard Home, an elected Fellow of the Royal Society, in 1814. The specimen is now on display at the Natural History Museum in London bearing the name Temnodontosaurus platyodon, or “cutting-tooth lizard.”
In 1821, William Conybeare and Henry De La Beche, a friend of Mary's, published a paper describing three new species of unknown marine reptiles based on Anning's finds.
The Rev. William Buckland would go on to describe two small ichthyosaurs from the Lias of Lyme Regis, Ichthyosaurus communis and Ichthyosaurus intermedius, in 1837.
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Lithography from William Buckland's 1824 Paper
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Remarkable, you'll recall that he was a theologian, geologist, palaeontologist AND Dean of Westminster. It was Buckland who published the first full account of a dinosaur in 1824, coining the name,
Megalosaurus.
Here is an image from that 1824 publication showing a lithograph of the anterior extremity of the right lower jaw of the Megalosaurus from Stonesfield near Oxford.
The Age of Dinosaurs—and the reign of the mighty marine reptiles—had begun. Ichthyosaurs have long been known from the Blue Lias near Lyme Regis and the Black Ven Marls, with more recent finds emerging from the higher beds near Seatown.
A few years ago, Paddy Howe, the Lyme Regis Museum geologist, uncovered a beautiful Ichthyosaurus breviceps skull. Then, in 2008, a landslip on the Church Cliffs exposed a few ribs. A careful excavation revealed something extraordinary: only the ninth breviceps skull ever discovered, complete with teeth and paddles.
Beyond Britain, ichthyosaur remains have been recovered across Europe—in Belgium, England, Germany, and Switzerland—as well as in Indonesia. Some of the most spectacularly preserved specimens come from the limestone quarries of Holzmaden in southern Germany, where entire skeletons lie frozen in exquisite detail.
Ichthyosaurs themselves spanned a remarkable size range, from tiny species just a foot or two long to true leviathans exceeding twenty-six metres. Streamlined and powerful, they bore a striking resemblance to modern fish and dolphins—a classic case of convergent evolution.
Vertebrate palaeontologists Dean Lomax and Sven Sachs—both prolific researchers and genuinely delightful humans—have described one such giant: Shonisaurus sikanniensis, from the Upper Triassic (Norian) Pardonet Formation of northeastern British Columbia. Reaching an astonishing 30–35 metres in length, this colossal marine reptile now dominates the galleries of the Royal Tyrrell Museum of Palaeontology in Alberta.
The significance of this discovery ultimately tipped the vote in favour of designating Shonisaurus as British Columbia’s Official Fossil.
Other ichthyosaur remains are known from Vancouver Island, Haida Gwaii, and additional sites across British Columbia, but it was Shonisaurus that captured the province’s imagination. Interestingly, the very first specimens of Shonisaurus were found not in Canada but in the 1990s by Peter Langham at Doniford Bay on the Somerset coast of England.
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| Roy Chapman Andrews, AMNH 1928 Expedition to the Gobi Desert |
Dr. Betsy Nicholls—Rolex Laureate and renowned vertebrate palaeontologist at the Royal Tyrrell Museum—led one of the most ambitious fossil excavations ever undertaken when she uncovered the type specimen of Shonisaurus sikanniensis.
Over three intense field seasons from 1999 to 2001, she poured everything she had into the project, both in the field and through determined advocacy at home.
Her perseverance was rewarded. In 2004, she formally published the description of this new species—a landmark contribution that stands as the culmination of her life’s work. Heartbreakingly, it was also her final paper; Betsy passed away from cancer later that autumn.
I connected with the ever-excellent John-Paul (JP) Zonneveld—Professor, palaeontologist, sedimentary geologist, and field scientist at the University of Alberta—who worked alongside Betsy at the original Shonisaurus sikanniensis site. “She was an awesome person, a dear friend, and an outstanding field scientist,” he told me. I could not agree more. Betsy was pure delight.
In a wonderfully charming footnote to her life, Betsy maintained a correspondence with Roy Chapman Andrews, the former director of the American Museum of Natural History, beginning in the late 1950s as she explored a potential career in palaeontology.
If you’ve ever seen the AMNH’s iconic expedition photographs from the early-20th-century Gobi Desert campaigns in what is now southern Mongolia, you’ll know how unforgettable they are. Andrews led those expeditions, and those images helped ignite my own lifelong passion for palaeontology.
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Shonisaurus popularise
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We have found at least 37 specimens of
Shonisaurus in Triassic outcrops of the Luning Formation in the Shoshone Mountains in northwestern Nye County of Nevada, USA.
The finds go back to the 1920s. They were later brought back into the spotlight by the collecting efforts of Margaret Wheat of Fallon and Dr C. L. Camp, UCMP, in the 1950s.
The aptly named Shonisaurus popularis became the Nevada State Fossil in 1977. Our Shoni got around.
Isolated remains have been found in a section of sandstone in Belluno, in the Eastern Dolomites, Veneto region of northeastern Italy. The specimens were published by Vecchia et al. in 2002.
And for a time, Shonisaurus was the largest ichthyosaurus known.
Move over, Shoni, as a new marine reptile find competes with the Green Anaconda, Eunectes murinus, and the Blue Whale, Balaenoptera musculus, for size at a whopping twenty-six (26) metres. The find is the prize of fossil collector turned co-author, Paul de la Salle, who — you guessed it — found it in the lower part of the intertidal area that outcrops strata from the latest Triassic Westbury Mudstone Formation of Lilstock on the Somerset coast. He contacted Dean Lomax and Judy Massare who became co-authors on the paper.
The find and conclusions from their paper put the dinosaur bones from the historic Westbury Mudstone Formation of Aust Cliff, Gloucestershire, UK site into full reinterpretation.
And remember the Ichthyosaur communis the good Reverend Buckland described back in 1837? Dean Lomax was the first to describe a wee baby. A wee baby ichthyosaur! Awe. I know, right? He and palaeontologist Nigel Larkin published this adorable first in the journal of Historical Biology in 2017.
They had teamed up previously on another first back in 2014 when they completed the reconstruction of an entire large marine reptile skull and mandible in 3D, then graciously making it available to fellow researchers and the public. The skull and braincase in question were from an Early Jurassic, and relatively rare, Protoichthyosaurus prostaxalis. The specimen had been unearthed in Warwickshire back in the 1950s. Unlike most ichthyosaur finds of this age, it was not compressed and allowed the team to look at a 3D specimen through the lens of computerized tomography (CT) scanning.
Another superb three-dimensional ichthyosaur skull was found near Lyme Regis by fossil hunter-turned-entrepreneur-local David Sole and prepped by the late David Costain. I am rather hoping it went into a museum collection as it would be wonderful to see the specimen studied, imaged, scanned and 3D printed for all to share.
Lomax and Sven Sachs also published on an embryo from one of the largest ichthyosaurs known, a new species named Ichthyosaurus somersetensis. Their paper in the ACTA Palaeontologica Polonica from 2017, describes the third embryo known for Ichthyosaurus and the first to be positively identified to species level. The specimen was collected from the Lower Jurassic strata (lower Hettangian, Blue Lias Formation) of Doniford Bay, Somerset, UK and is housed in the collection of the Niedersächsisches Landesmuseum (Lower Saxony State Museum) in Hannover, Germany.
We have learned a lot about them in the time we've been studying them. We now have thousands of specimens, some whole, some as bits and pieces. Many specimens that have been collected are only just now being studied and the tools we are using to study them are getting better and better.
While they resembled fish and dolphins, Ichthyosaurs were large marine reptiles belonging to the order known as Ichthyosauria or Ichthyopterygia. In 2018, Benjamin Kear and his team were able to study ichthyosaur remains at the molecular level, Their findings suggest ichthyosaurs had skin and blubber quite similar to our modern dolphins.
While ichthyosaurs evolved from land-dwelling, lung-breathing reptiles, they returned to our ancient seas and evolved into the fish-shaped creatures we find in the fossil record today.
Their limbs fully transformed into flippers, sometimes containing a very large number of digits and phalanges. Their flippers tell us they were entirely aquatic as they were not well-designed for use on land. And it was their flippers that first gave us the clue that they gave birth to live young; a find later confirmed by fossil embryo and wee baby ichy finds.
They thrived during much of the Mesozoic era; based on fossil evidence, they first appeared around 250 million years ago (Ma) and at least one species survived until about 90 million years ago into the Late Cretaceous.
During the early Triassic period, ichthyosaurs evolved from a group of unidentified land reptiles that returned to the sea. They were particularly abundant in the Late Triassic and Early Jurassic before being replaced as a premier aquatic predator by another marine reptilian group, the Plesiosauria, in the later Jurassic and Cretaceous periods.
In the Late Cretaceous, ichthyosaurs were hard hit by the Cenomanian-Turonian anoxic event. As the deepest benthos layers of the seas became anoxic, poisoned by hydrogen sulphide, deep water marine life died off. This caused a cascade that wreaked havoc all the way up the food chain. At the end of that chain were our mighty predaceous marine reptiles. Bounty turned to scarcity and a race for survival began. The ichthyosaurs lost that race as the last lineage became extinct. It may have been their conservative evolution as a genus when faced with a need for adaptation to the world in which they found themselves and/or being outcompeted by early mosasaurs.
There are promising discoveries coming out of strata from the Cretaceous epeiric seas of Texas, USA from Nathan E. Van Vranken. His published paper from 2017, "An overview of ichthyosaurian remains from the Cretaceous of Texas, USA," looks at ichthyosaurian taxa from the mid-Cretaceous (Albian–Cenomanian) time interval in North America with an eye to ichthyosaurian distribution and demise.
Image One: The find and photos are all credited to Lewis Winchester-Ellis. Thank you for sharing your tremendous specimen with us. Lewis did much of the preparation of the specimen, removing the majority of the matrix. The spectacular final prep is credited to Lizzie Hingley, Stonebarrow Fossils, Oxfordshire. Her skill with an air scribe is unparalleled.
Link to Lomax Paper: https://journals.plos.org/plosone/article…
Link to Nathan's Paper: https://www.tandfonline.com/…/10.1080/03115518.2018.1523462…
Nicholls Paper: E. L. Nicholls and M. Manabe. 2004. Giant ichthyosaurs of the Triassic - a new species of Shonisaurus from the Pardonet Formation (Norian: Late Triassic) of British Columbia. Journal of Vertebrate Paleontology 24(4):838-849 [M. Carrano/H. Street]
Image Two: Lithography from William Buckland's "Notice on the Megalosaurus or great Fossil Lizard of Stonesfield", 1824. Anterior extremity of the right lower jaw of the Megalosaurus from Stonesfield near Oxford. Mary Morland (later Buckland; 1797–1857) - Plate 40 (XL) of William Buckland: Notice on the Megalosaurus or great Fossil Lizard of Stonesfield. Transactions of the Geological Society of London. Series 2, vol. 1, no. 2, 1824, S. 390–396 (digital copy at geolsoc.org.uk).
HOME, E. (1814) Some Account of the Fossil Remains of an Animal more nearly allied to Fishes than any of the Other Classes of Animals. Phil. Trans. R. Soc. Lond. 104, 571- 577.
JAEGER, G.F. (1824) De Ichthyosauri sive Proteosauri fossils speciminibus in Agro Bollensi in Wurtembergia repertis. Stuttgart.
LHUYD, E. (1699) Lithophylacii Britannici Ichnographia. London.
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