Excavating the “Sea Dragon Dinosaur Dolphin Fossil” – AKA, The Rutland Ichthyosaur

^1*Dean R. Lomax, ²Nigel R. Larkin, ^3,4Mark Evans, ⁵Emma L. Nicholls, ⁶Ian Boomer, ⁷Steven Dey, ⁸Darren Withers, ⁹Emily J. Swaby, ¹⁰Paul de la Salle, ⁸David Savory, and ⁸Mick Beeson

^1*Department of Earth and Environmental Sciences, The University of Manchester; ²University of Reading; ³British Antarctic Survey; ⁴University of Leicester; ⁵Horniman Museum and Gardens, London; ⁶University of Birmingham; ⁷ThinkSee3D; ⁸Peterborough Geological and Palaeontological Group; ⁹Open University; ¹⁰The Etches Collection

In January 2021, a string of semi-articulated ichthyosaur vertebrae was uncovered at the Rutland Water Nature Reserve during some routine maintenance of one of the reserve’s lagoons. The chance find was made by Joe Davis, Conservation Team Leader for the Leicestershire and Rutland Wildlife Trust, which runs the reserve in partnership with Anglian Water who own the land. Following a one-day exploratory dig in February, which revealed what appeared to be a complete skeleton embedded in the Early Jurassic clay (Toarcian Whitby Mudstone Formation), a full excavation was undertaken in Summer 2021. Spread across three weeks, the excavation revealed a 10-metre-long, mostly articulated specimen representing the most complete skeleton of a large prehistoric reptile ever found in Britain. Our initial assessment suggests that it is an example of Temnodontosaurus, possibly T. trigonodon. If correct, this would be the first definite occurrence in the UK. The discovery was formally announced in January 2022, almost a year after the find had been made, and was covered extensively in the media.

 

An Introduction to the Ichthyosaurs of The Kimmeridge Clay

Steve Etches

The Etches Collection Museum of Jurassic Marine Life, Kimmeridge, Dorset, UK

I will be discussing the paucity of articulated ichthyosaurs skeletons found in the Kimmeridge Clay: Three specimens are in The Etches Collection and there are one each in the Natural History Museum London and the Bristol City Museum.  Of the three Specimens at the Etches Collection only one has been studied and described. However, the evidence in these specimens gives a good indication of their particular lifestyle that has been ignored up to now. Also, although individual ichthyosaur bones are the most common finds in the Kimmeridge Clay, why do we not find complete articulated specimens? The answer is the rise of the mega predators i.e. Pliosaurs and Metriorhynchid crocodiles. The evidence shows that ichthyosaurs amongst other reptiles are commonly a major food source for these predators. I will illustrate this by showing many predated and scavenged ichthyosaur elements.

 

Exploration and Redetermination of Fossil Marine Reptile Material at the Horniman Museum – The Lost, Misidentified and Unknown

Emma Nicholls

The Horniman Museum and Gardens, London, UK

Walter Bennett (1892-1971) was a mining engineer and amateur fossil collector. He amassed a collection of ca.175,000 specimens, from over 50 countries, throughout the first half of the 20^th century. Around a quarter is vertebrate material, predominantly ichthyosaurs, plesiosaurs, crocodilians, and fish. The collection was transferred to the Horniman Museum in 1989 and bulk-accessioned under one number, with less than 2% added to the collections management database over the last 30 years.

Recent research has uncovered scientifically significant information about this hitherto poorly known material. Many of the marine reptile specimens were collected at quarries that are listed as Sites of Special Scientific Interest or Geological Conservation Review sites, some of which are no longer accessible.

Investigations have also recovered a figured, yet ‘lost’, partial ichthyosaur paddle, and redetermined plesiosaur and metriorhynchid material, previously misidentified as Dacentrurus and plesiosaur respectively. This paper will provide an overview of the marine reptile material in the collection and explore new insights into its significance.

 

A New Cryptoclidid from the Oxford Clay Formation of Cambridgeshire, UK

¹Hilary Ketchum, ^2*Roger Benson, ^3*Mark Graham, ^4*Carl Harrington, ^4*Heather Middleton, ^4*Cliff Nicklin, ^4*Shona Tranter, and ^4*Mark Wildman

¹Oxford University Museum of Natural History; ²Department of Earth Sciences, University of Oxford; ³Natural History Museum, London; ⁴Oxford Clay Working Group

*Authors in alphabetical order

Cryptoclididae is a species-rich clade of plesiosaurians that spanned from the Middle Jurassic to the Early Cretaceous. Here we present a substantially complete skeleton of a long-necked cryptoclidid from Whittlesey, Cambridgeshire, discovered by the Oxford Clay Working Group in 2014. The specimen was extracted and donated to the Oxford University Museum of Natural History in 2015, following 450 hours of preparation of the postcranial skeleton. After it reached the museum, the field jacket containing the skull was CT scanned to facilitate its removal from the matrix. Around 500 hours of preparation revealed that the skull is exceptionally well preserved. Other than Cryptoclidus, the skulls of cryptoclidids are generally poorly known due to their fragile construction. This new specimen therefore provides much additional anatomical information for the clade. The specimen has several autapomorphies, indicating that it is a new species, probably most closely related to Muraenosaurus.

 

Functional Reconstruction of the Ichthyosaurian Jaw Using 3D Computed Tomography

^1,2Sarah Jamison-Todd, ¹Benjamin Moon, ¹Andre Rowe, ³Matt Williams, ¹Michael Benton

¹Palaeobiology Research Group, University of Bristol; ²Earth Sciences, University College London; ³Bath Royal Literary and Scientific Institute

Early Jurassic ichthyosaurs are known for their excellent preservation and substantial diversity, being an important component of the marine ecosystems at this time. The ecology and functional palaeobiology of these marine reptiles have been considered qualitatively from time to time, but they offer great potential for quantitative studies. Here we present a quantitative study of ichthyosaur jaw mechanics using material from the exceptionally preserved Toarcian Strawberry Bank locality of Ilminster, UK. Using 3D CT scanned skulls referred to Hauffiopteryx typicus (BRLSI M1399) and Stenopterygius triscissus (BRLSI M1409), we reconstruct the posterior cranial musculature involved in jaw adduction, applying finite element modelling to the ichthyosaur jaw for the first time. Our results show a combined muscle force of 291 N that translates to a posterior bite force of 181 N (using lever mechanics) in H. typicus and total force of 158 N with posterior bite force of 68 N in S. triscissus. Most force is derived from the M. depressor mandibulae in both taxa, but H. typicus has relatively higher stresses in the antorbital region than S. triscissus reflecting the gracility of the nasals. Differences in reconstructed bite force are explained by the different sizes of these specimens, however, S. triscissus has a relatively weaker bite force than H. typicus for its size despite the more robust cranial architecture and larger teeth. These data support previous hypotheses of different feeding strategies between the two taxa and likely different prey preferences with H. typicus likely hunting softer prey than S. triscissus.

 

New Insight into Prenatal Development in Ichthyosaurs

^1,2Feiko Miedema

¹Staatliches Museum für Naturkunde Stuttgart; ²Hohenheim University

The Ichthyosauria is a clade of diapsids secondarily adapted to marine life. All members of the group were viviparous. We know this because of the numerous fossil pregnant females found in many species throughout phylogeny. There is a large sample size in specimens of several taxa, such as Stenopterygius and Mixosaurus, because they are regularly found in Lagerstätten deposits in Germany and the Alpine region. This lends us the opportunity to study their osteological development in great detail. In Stenopterygius specifically we were able to establish for the first time four separate prenatal stages on the basis of the relative onset and timing of ossification of the cranial elements. Dermatocranial elements ossified earlier than chondro- and splanchnocranial elements. In the dermotacranial elements specifically the circumorbital elements are more advanced throughout development whereas the skull roof lags most other elements continuously. In Mixosaurus the same overall pattern of dermatocranial elements ossifying earlier than chondro – and splanchnocranial elements is also present. Moreover, the development of the braincase elements of Mixosaurus compared to Stenopterygius is interesting as in Mixosaurus early developmental remnants of possible basal tubera are found. These are entirely lost throughout the development of Stenopterygius. In both late-stage embryonic material of Stenopterygius and Mixosaurus the skull roof elements have established a tight connection, however the antimeric midline connections are not established. We therefore hypothesize that this non-closure functions as a fontanelle convergent to other animals. Lastly, we are developing a proxy for staging ichthyosaur embryos in other taxa based on relative notochord pit size.

 

Posters

Tanystropheus was a Marine Diapsid, not a Terrestrial Diapsid

Tracy Lee Ford

Tanystropheus was a strange looking diapsid/archosauromorph. It had a small head and hyper-elongate neck, long body, and long tail. It has been theorized they lived a terrestrial life as juveniles and a marine lifestyle as an adult. They would feed by standing on the edge of a river and dip their head into it in search of fish. Small specimens of Tanystropheus longibardicus have multi-tooth morphs, long skull, while large individuals only have conical and a smaller number of teeth, and the adult specimens had only conical teeth. Some authors have questioned where or not these two morphs belong to the same species, and recently the ‘adult’ specimens have been separated from the juvenile and were named Tanystropheus hydroides. The majority of specimens of Tanystropheus have been found in marine deposits in Germany, Italy, Poland, Switzerland, Romania, Israel, and China. Some specimens from Italy have been found with belemnite hooklets in their stomach region. That and being found in marine environments is a good indication that they were marine animals. The adult skull of Tanystropheus is reinterpreted with a dorsally placed naris, and interlocking teeth similar to that seen in sauropterygians. During the Middle Triassic, Tanystropheus was one of the largest marine predators. A question that needs to be answered is whether or not they had the muscle power to hold the long neck outside of a marine environment.

 

Preparation of Hugh Miller Reptile Bed Plesiosaurs by the new Deep Time Laboratory, University of Edinburgh

¹Matthew D. McKeown, ¹Kim J. Kean, ¹Thomas J. Challands, ¹Davide Foffa, and ¹Stephen L. Brusatte

¹University of Edinburgh

Despite being discovered nearly 200 years ago, the Hugh Miller Reptile Bed on the Isle of Eigg has received little attention. The bone bed was first found by Miller in 1844-45, where he noted the fossilised remains of reptiles and fish in a thin red limestone to the north and east of the island. The Reptile Bed is a constituent of the Kildonnan Member of the Lealt Shale Formation, and falls at the base of the Bathonian in the Great Estuarine Group. The Reptile Bed was deposited in freshwater, shallow lagoons in an environment similar to a subtropical barrier island system. Since Hugh Miller's discovery of the Reptile Bed, marine turtles, crocodiles, and plesiosaurs have been reported from the site. Although research has gone into the palaeoenvironment of the Reptile Bed, the reptiles are yet to be formally described. Here we present work conducted by the new Palaeontology Deep Time Laboratory at the University of Edinburgh on the Middle Jurassic plesiosaurs from the Hugh Miller Reptile Bed. The laboratory is preparing material collected in 2017 using mechanical and chemical techniques. Currently the plesiosaur material yielded from the 2017 trip includes incomplete vertebrae, ribs, and a potential jaw bone which will be CT scanned. As with previous plesiosaur bones reported from Eigg, the material is surprisingly small, raising important questions over the island’s plesiosaur population. Further research is required to determine if the plesiosaurs of Eigg represent a small-bodied species, or if the shallow lagoon environment was used as a nursery.

 

Digital 3D for the Study and Presentation of Marine Reptiles: a 3D Practioner’s Viewpoint

Steven Dey

ThinkSee3D

Steven Dey runs ThinkSee3D Ltd, a small professional digital 3D studio providing dedicated 3D services to museums and academics including scanning, digital 3D modelling, 3D visualisation, animation and digital to physical replication using 3D printing. In his poster/(discussion) Steven gives an overview of his experiences of 3D methods applied to marine reptile research and public presentation. Starting with 3D scanning methods including the use of photogrammetry and x-ray CT scanning, going on to the advantages of measuring specimens digitally and then a brief tour of the many applications of digital 3D from 3D printed replicas to digital visualisations of specimens. Steven discusses Thinksee3D, experiences over the last 6 years, having worked on numerous MR projects including scanning a juvenile ichthyosaur (from the Lapworth museum), 3D printing missing specimen limbs (including the Birmingham Thinktank Ichthyosaur). Creating tactile exhibits (like the pliosaur paddle on permanent display in the Oxford Natural History Museum) and exhibition works (like the 1.4m long pliosaur skull for ‘Doris’ at Bristol City Museum). Most recently, and most excitingly, Steven discusses his work 3D scanning and 3D modelling the remarkable 10m long Rutland Ichthyosaur Temnodontosaurus including the creation of a 10m long high resolution printed banner of the above and various visualisations of the dig site and the extracted specimen.

 

Signs of life: Trace Fossils from the Kimmeridgian (Late Jurassic) Deposits of Dorset, UK, Held in The Etches Collection: Museum of Jurassic Marine Life

¹Nigel Larkin and ²Steve Etches

¹School of Biological Sciences, University of Reading; ²The Etches Collection Museum of Jurassic Marine Life, Kimmeridge, Dorset, UK

Trace fossils are abundant at certain horizons within the Kimmeridge Clay Formation and include ichnotaxa not reported from elsewhere. The trace fossils held in the Etches Collection comprise not just hundreds of coprolites, which one might expect, plus scores of predation and scavenging traces and dozens of invertebrate burrows and borings, but also includes possible regurgitate, the first recorded example of ammonite eggs and the world’s oldest fossil urolith (kidney/bladder stone). Maybe even traces of the world’s oldest example of bone-eating worms. Are these rarer trace fossils evidence of exceptional preservation, or exceptional collecting – or both?

 

‘The Plesiosaur’s Neck’, a New Children’s Picture Book to Encourage Evidence-Based Creative Thinking

¹Adam S. Smith and ²Jonathan Emmett

¹Nottingham Natural History Museum, Wollaton Hall; ²jonathanemmett.com

Since the first complete plesiosaurs were discovered in the early 1800s, palaeontologists have puzzled over the purpose of their unusually long necks. Several hypotheses have been put forward to explain this unique adaptation over the decades, some reasonable, some fanciful, and some highly unlikely. ‘The Plesiosaur’s Neck’ (2021) is a children’s picture book that introduces this topic to 5 to 11-year-olds. Different hypotheses are demonstrated by Poppy, an Albertonectes plesiosaur (the genus with the longest neck), and readers are encouraged to consider the evidence. The main rhyming text is supplemented on each spread by a text box with more detailed scientific information. A pair of cephalopod characters, Alfie Ammonite and Bella Belemnite, also appear on each spread alongside Poppy to provide a running commentary and jokes. We struck a balance between making the characters and creatures in the book anatomically accurate while also appealing to young readers. All of the creatures, including those lurking in the background, are either known directly from fossils from the Late Cretaceous Bearpaw Shale (where the only known specimen Albertonectes is from), or their presence at that time and place can be regarded with confidence, e.g. jellyfish and seaweeds. We also developed a schools’ session in which children use a ¼ scale plesiosaur puppet to test out the different hypotheses. Current evidence is inconclusive, so the book ends with a question: “…what do you think that immense neck was for?”

 

Marine crocodyliform (Thalattosuchian) Discoveries and Donations from the Oxford Clay Formation of Cambridgeshire by the Oxford Clay Working Group (OCWG)

¹Mark R. Graham, ³Roger Benson, ¹Carl Harrington, ²Hilary Ketchum, ¹Heather Middleton, ¹Cliff Nicklin, ¹Shona Tranter, and ¹Mark Wildman

¹Oxford Clay Working Group; ² Oxford University Museum of Natural History; ³ Department of Earth Sciences, University of Oxford

In February 2020 a partial mandible, sections of rib and loose teeth from a metriorhynchid crocodyliform were found in a clay quarry during fieldwork. Due to the subsequent Covid 19 lockdown, recovery of any further material was postponed for six months when, between August 2020 and April 2021, further material from the specimen including sections of the jaws, some vertebrae, and a beautifully preserved and articulated partial hind limb were recovered.

In May 2021, an osteoderm from a second crocodyliform was found at the same level in another part of the quarry which led to the recovery of a remarkable, large, and partly articulated specimen, tentatively assigned to the machimosaurid Neosteneosaurus edwardsi. The recovery of isolated bones included mandible and maxillary elements, articulated vertebrae (including the distal in-situ tail), limb elements and an ilium, while three concretions contained parts of the skull and jaws, complete with teeth. The distance from the snout to the tail vertebrae was measured at 5 meters which, together with the size of recovered elements, suggests a fully grown adult.

Both specimens have been donated by transfer of title from the quarry owner Forterra, on behalf of the Oxford Clay Working Group, to the Natural History Museum, London (NHMUK).