Showing posts with label nude. Show all posts
Showing posts with label nude. Show all posts

Thursday, February 1, 2024

AMMONITE OF THE RHÔNE

An exquisite specimen of the delicately ridged ammonite, Porpoceras verticosum, from Middle Toarcian outcrops adjacent the Rhône in southeastern France.

Porpoceras (Buchman, 1911) is a genus of ammonite that lived during the early and middle Toarcian stage of the Early Jurassic. We see members of this genus from the uppermost part of Serpentinum Zone to Variabilis Subzone. These beauties are found in Europe, Asia, North America and South America.

Ammonites belonging to this genus have evolute shells, with compressed to depressed whorl section. Flanks were slightly convex and venter has been low. The whorl section is sub-rectangular. 

The rib is pronounced and somewhat fibulate on the inner whorls — just wee nodes here — and tuberculate to spined on the ventrolateral shoulder. It differs from Peronoceras by not having a compressed whorl section and regular nodes or fibulation. Catacoeloceras is also similar, but it has regular ventrolateral tubercules and is missing the classic nodes or fibulation of his cousins.

This specimen hails from southern France near the Rhône, one of the major rivers of Europe. It has twice the average water level of the Loire and is fed by the Rhône Glacier in the Swiss Alps at the far eastern end of the Swiss canton of Valais then passes through Lake Geneva before running through southeastern France. This 10 cm specimen was prepared by the supremely talented José Juárez Ruiz

Friday, January 26, 2024

FIRST DINOSAUR FROM VANCOUVER ISLAND

This dapper fellow is a pine needle and horsetail connoisseur. He's a hadrosaurus — a duck-billed dinosaur. They were a very successful group of plant-eaters that thrived throughout western Canada during the late Cretaceous, some 70 to 84 million years ago.

Hadrosaurs lived as part of a herd, dining on pine needles, horsetails, twigs and flowering plants.

Hadrosaurs are ornithischians — an extinct clade of mainly herbivorous dinosaurs characterized by a pelvic structure superficially similar to that of birds. They are close relatives and possibly descendants of the earlier iguanodontid dinosaurs. 

They had slightly webbed, camel-like feet with pads on the bottom for cushioning and perhaps a bit of extra propulsion in water. They were primarily terrestrial but did enjoy feeding on plants near and in shallow water. There had a sturdy build with a stiff tail and robust bone structure. 

At their emergence in the fossil record, they were quite small, roughly three meters long. That's slightly smaller than an American bison. They evolved during the Cretaceous with some of their lineage reaching up to 20 meters or 65 feet.

Hadrosaurs are very rare in British Columbia but a common fossil in our provincial neighbour, Alberta, to the east. Here, along with the rest of the world, they were more abundant than sauropods and a relatively common fossil find. They were common in the Upper Cretaceous of Europe, Asia, and North America.

There are two main groups of Hadrosaurs, crested and non-crested. The bony crest on the top of the head of the hadrosaurs was hollow and attached to the nasal passages. It is thought that the hollow crest was used to make different sounds. These sounds may have signalled distress or been the hadrosaur equivalent of a wolf whistle used to attract mates. Given their size it would have made for quite the trumpeting sound.

This beautiful specimen graces the back galleries of the Courtenay and District Museum on Vancouver Island, British Columbia, Canada. I was very fortunate to have a tour this past summer with the deeply awesome Mike Trask joined by the lovely Lori Vesper. The museum houses an extensive collection of palaeontological and archaeological material found on Vancouver Island, many of which have been donated by the Vancouver Island Palaeontological Society.

Dan Bowen, Chair of the Vancouver Island Palaeontological Society, shared the photo you see here of the first partly articulated dinosaur from Vancouver Island ever found. The vertebrate photo and illustration are from a presentation by Dr. David Evans at the 2018 Paleontological Symposium in Courtenay.  The research efforts of the VIPS run deep in British Columbia and this new very significant find is no exception. A Hadrosauroid dinosaur is a rare occurrence and further evidence of the terrestrial influence in the Upper Cretaceous, Nanaimo Group, Vancouver Island — outcrops that we traditionally thought of as marine from years of collecting well-preserved marine fossil fauna.

CDM 002 / Hadrosauroid Caudal Vertebrae
The fossil bone material was found years ago by Mike Trask of the Vancouver Island Palaeontological Society. You may recall that he was the same fellow who found the Courtenay Elasmosaur on the Puntledge River.

Mike was leading a fossil expedition on the Trent River. While searching through the Upper Cretaceous shales, the group found an articulated mass of bones that looked quite promising.

Given the history of the finds in the area, the bones were thought to be from a marine reptile.

Since that time, we've found a wonderful terrestrial helochelydrid turtle, Naomichelys speciosa, but up to this point, the Trent had been known for its fossil marine fauna, not terrestrial. Efforts were made to excavate more of the specimen, and in all more than 25 associated vertebrae were collected with the help of some 40+ volunteers. Identifying fossil bone is a tricky business. Encased in rock, the caudal vertebrae were thought to be marine reptile in origin. Some of these were put on display in the Courtenay Museum and mislabeled for years as an unidentified plesiosaur.

In 2016, after years of collecting dust and praise in equal measure, the bones were reexamined. They didn't quite match what we'd expect from a marine reptile. Shino Sugimoto, Fossil Preparator, Vertebrate Palaeontology Technician at the Royal Ontario Museum was called in to work her magic — painstakingly prepping out each caudal vertebrae from the block.

Once fully prepped, seemingly unlikely, they turned out to be from a terrestrial hadrosauroid. This is the second confirmed dinosaur from the Upper Cretaceous Nanaimo Group. The first being a theropod from Sucia Island consisting of a partial left thigh bone — the first dinosaur fossil ever found in Washington state.

Dr. David Evans, Temerty Chair in Vertebrate Palaeontology, Department of Natural History, Palaeobiology from the Royal Ontario Museum, confirmed the ID and began working on the partial duck-billed dinosaur skeleton to publish on the find.

Drawing of Trent River Hadrosauroid Caudal Vertebrae
Now fully prepped, the details of this articulated Hadrosauriod caudal vertebrae come to light. We can see the prominent chevron facets indicative of caudal vertebrae with a nice hexagonal centrum shape on its anterior view.

There are well-defined long, raked neural spines that expand distally — up and away from the acoelous centrum. 

Between the successive vertebrae, there would likely have been a fibrocartilaginous intervertebral body with a gel-like core —  the nucleus pulposus — which is derived from the embryonic notochord. This is a handy feature in a vertebrate built as sturdily as a hadrosaur. Acoelous vertebrae have evolved to be especially well-suited to receive and distribute compressive forces within the vertebral column.

This fellow has kissing cousins over in the state of New Jersey where this species is the official state fossil. The first of his kind was found by John Estaugh Hopkins in New Jersey back in 1838. Since that time, we've found many hadrosaurs in Alberta, particularly the Edmontosuaurs, another member of the subfamily Hadrosaurine.

In 1978, Princeton University found fifteen juvenile hadrosaurs, Maiasaura ("good mother lizard") on a paleontological expedition to the Upper Cretaceous, Two Medicine Formation of Teton County in western Montana. 

Their initial finds of several small skeletons had them on the hunt for potential nests — and they found them complete with wee baby hatchlings!

Photo One: Fossil Huntress / Heidi Henderson, VIPS

Photo Two / Sketch Three: Danielle Dufault, Palaeo-Scientific Ilustrator, Research Assistant at the Royal Ontario Museum, Host of Animalogic. 

The vertebrate photo and illustration were included in a presentation by Dr. David Evans at the 2018 BCPA Paleontological Symposium in Courtenay, British Columbia, Canada.

Photo Four: Illustration by the talented Greer Stothers, Illustrator & Natural Science-Enthusiast.

Sunday, January 7, 2024

TEETH, CLAWS & HUNGER: SMILODON

This fierce predator with the luxurious coat and claws getting the upper hand in this fight is Smilodon fatalis — a compact but robust killer that weighed in around 160 to 280 kg and was 1.5 - 2.2 metres long.

Smilodon is a genus of the extinct machairodont subfamily of the felids. It is one of the most famous prehistoric mammals and the best known saber-toothed cat. 

Although commonly known as the saber-toothed tiger, it was not closely related to the tiger or other modern cats.

Up until a few years ago, all the great fossil specimens of this apex predator were found south of us in the United States. That was until some interesting bones from Medicine Hat, Alberta got a second look.

A few years ago, a fossil specimen caught the eye of researcher Ashley Reynolds as she was rummaging through the collections at the Royal Ontario Museum in Toronto. 

Back in the 1960s,  University of Toronto palaeontologist C.S. Churcher and his team had collected and donated more than 1,200 specimens from their many field seasons scouring the bluffs of the South Saskatchewan River near Medicine Hat, Alberta.

Churcher is a delightful storyteller and a palaeontologist with a keen eye. I had the very great pleasure of listening to many of his talks out at the University of British Columbia and a few Vancouver Paleontological Society meetings in the mid-2000s. 

"Rufus" was a thoroughly charming storyteller and shared many of his adventures from the field. 

He moved out to the West Coast for his retirement, first to Gabriola Island then to Victoria, but his keen love of the science kept him giving talks to enthralled listeners keen to hear about his survey of the Dakhleh Oasis in the Western Desert of Egypt, geomorphology, stratigraphy, recent biology, Pleistocene and Holocene lithic cultures, insights learned from Neolithic Islamic pottery to Roman settlements.

The specimens he had collected had been roughly sorted but never examined in detail. Reynolds, who was researching the growth patterns and life histories of extinct cats saw a familiar-looking bone from an ancient cat's right front paw. That tiny paw bone had reached through time and was positively identified as Canada's first Smilodon.

These Apex Predators used their exceptionally long upper canine teeth to hunt large mammals. 

Isotopes preserved in the bones of S. fatalis in the La Brea Tar Pits in California tell us that they liked to dine on bison (Bison antiquus) and camels (Camelops) along with deer and tapirs. Smilodon is thought to have killed its prey by holding it still with its forelimbs and biting it. And that was quite the bite!

Their razor-sharp incisors were arranged in an arch. Once they bit down, the teeth would hold their prey still and stabilize it while the canine bite was delivered — and what a bite that was. They could open their mouths a full 120 degrees.

Smilodon died out at the same time that most North and South American megafauna disappeared, about 10,000 years ago. Its reliance on large animals has been proposed as the cause of its extinction, along with climate change and competition with other species. 

The images above are the work of the extremely talented Daniel Eskridge. To see more of his work visit his site at: https://daniel-eskridge.pixels.com/

Saturday, September 30, 2023

FOSSILS FROM THE GAULT

The chunky ammonite Proeuhoplites subtuberculatus, bed II (iv), Folkstone Gault Clay, county of Kent, southeast England.

This matrix you see here is the Gault Clay, known locally as the Blue Slipper. This fine muddy clay was deposited 105-110 million years ago during the Lower Cretaceous (Upper and Middle Albian) in a calm, fairly deep-water continental shelf that covered what is now southern England and northern France.

Lack of brackish or freshwater fossils indicates that the gault was laid down in open marine environments away from estuaries. The maximum depth of the Gault is estimated 40-60m a figure which has been reached by the presence of Borings made by specialist Algal-grazing gastropods and supported by a study made by Khan in 1950 using Foraminifera. Estimates of the surface water temperatures in the Gault are between 20-22°c and 17-19°c on the seafloor. These estimates have been reached by bulk analysis of sediments which probably register the sea surface temperature for calcareous nanofossils.

It is responsible for many of the major landslides around Ventnor and Blackgang the Gault is famous for its diverse fossils, mainly from mainland sites such as Folkestone in Kent.

Folkestone, Kent is the type locality for the Gault clay yielding an abundance of ammonites, the same cannot be said for the Isle of Wight Gault, however, the south-east coast of the island has proved to be fossiliferous in a variety of ammonites, in particular, the Genus Hoplites, Paranahoplites and Beudanticeras.

While the Gault is less fossiliferous here on the island it can still produce lovely marine fossils, mainly ammonites and fish remains from these muddy mid-Cretaceous seas. The Gault clay marine fossils include the ammonites (such as Hoplites, Hamites, Euhoplites, Anahoplites, and Dimorphoplites), belemnites (such as Neohibolites), bivalves (notably Birostrina and Pectinucula), gastropods (including the lovely Anchura), solitary corals, fish remains (including shark teeth), scattered crinoid remains, and crustaceans (look for the crab Notopocorystes).

Occasional fragments of fossil wood may also be found. The lovely ammonite you see here is from the Gault Clays of Folkstone. Not all who name her would split the genus Euhoplites. There’s a reasonable argument for viewing this beauty as a very thick form of E. loricatus with Proeuhoplites being a synonym of Euhoplites. Collected, photographed and prepped by Thomas Miller. Approx 35mm across.

Jack Wonfor shared a wealth of information on the Gault and has many lovely examples of the ammonites found here in his collections. If you wish to know more about the Gault clay a publication by the Palaeontological Association called 'Fossils of the Gault clay' by Andrew S. Gale is available in Dinosaur Isle's gift shop.

There is a very good website maintained by Fred Clouter you can look at for reference. It also contains many handy links to some of the best fossil books on the Gault Clay and Folkstone Fossil Beds. Check it out here: http://www.gaultammonite.co.uk/