LATE HETTANGIAN FOSSIL FAUNA FROM THE TASEKO LAKES: BRITISH COLUMBIA

The late Hettangian ammonite fauna from Taseko Lakes is diverse and relatively well‐preserved. Over three field seasons, thirty-five taxa from the Mineralense and Rursicostatum zones were studied and three new species discovered and named: Fergusonites hendersonae, Eolytoceras constrictum and Pseudaetomoceras victoriense. 

This material is very important as it greatly expands our understanding of the fauna and ranges of ammonites currently included in the North American regional ammonite zonation. 

I had the very great honour of having the fellow below, Fergusonites hendersonae, a new species of nektonic carnivorous ammonite, named after me by palaeontologist Louse Longridge from the University of British Columbia. 

I'd met Louise as an undergrad and was pleased as punch to hear that she would be continuing the research by Dr. Howard Tipper, the authority on this area of the Chilcotins and Haida Gwaii — which he dearly loved. 

"Tip" was a renowned Jurassic ammonite palaeontologist and an excellent regional mapper who mapped large areas of the Cordillera. He made significant contributions to Jurassic paleobiogeography and taxonomy in collaboration with Dr. Paul Smith, Head of Earth and Ocean Science at the University of British Columbia. 

Tip’s regional mapping within BC has withstood the test of time and for many areas became the regions' base maps for future studies. The scope of Tip’s understanding of Cordilleran geology and Jurassic palaeontology will likely never be matched. He passed away on April 21, 2005. His humour, knowledge and leadership will be sorely missed. 

Fergusonites hendersonae

Before he left us, he shared that knowledge with many of whom who would help to secure his legacy for future generations. We did several trips over the years up to the Taseko Lake area of the Rockies joined by many wonderful researchers from Vancouver Island Palaeontological Society and Vancouver Paleontological Society, as well as the University of British Columbia. 

Both Dan Bowen and John Fam were instrumental in planning those expeditions and each of them benefited greatly from the knowledge of Dr. Howard Tipper. 

If not for Tipper's early work in the region, our shared understanding and much of what was accomplished in his last years and after his passing would not have been possible. 

Over the course of three field seasons, we endured elevation sickness, rain, snow, grizzly bears and very chilly nights  — we were sleeping right next to a glacier at one point — but were rewarded by the enthusiastic crew, helicopter rides — which really cut down the hiking time — excellent specimens including three new species of ammonites, along with a high-spired gastropod and lobster claw that have yet to be written up. This area of the world is wonderful to hike and explore — stunningly beautiful country. We were also blessed with access as the area is closed to all fossil collecting except with a permit.

This fauna understanding helps us to understand the correlations between different areas: (1) the Mineralense and Rursicostatum zones are present in Taseko Lakes and can be readily correlated with contemporaneous strata elsewhere in North America; (2) the Mineralense and Rursicostatum zones of North America are broadly equivalent to the Canadensis Zone and probably the Arcuatum horizon of the South American succession; (3) broad correlations are possible with middle–late Hettangian and earliest Sinemurian taxa in New Zealand; (4) the Mineralense and Rursicostatum zones are broadly equivalent to the circum‐Mediterranean Marmoreum Zone; (5) the Mineralense Zone and the lower to middle portion of the Rursicostatum Zone are probably equivalent to the Complanata Subzone whereas the upper portion of the Rursicostatum Zone may equate to the Depressa Subzone of the north‐west European succession.

Taseko Lake Area, BC

The Taseko Lakes area has yielded the best preserved and most diverse collection of late Hettangian ammonites yet discovered in British Columbia (BC). Early studies of the fauna were undertaken by Frebold (1951, 1967). At that time, eastern Pacific ammonite faunas were poorly understood and species were frequently shoehorned into established north‐west European taxa. 

Since then, knowledge of eastern Pacific Hettangian ammonite faunas has improved considerably. 

Detailed systematic studies have been completed on faunas from localities in other areas of BC, Alberta, Alaska, Oregon, Nevada, Mexico and South America (e.g. Guex 1980, 1995; Imlay 1981; Hillebrandt 1981, 1988, 1990, 1994, 2000a–d; Smith and Tipper 1986; Riccardi et al. 1991; Jakobs and Pálfy 1994; Pálfy et al. 1994, 1999; Taylor 1998; Hall et al. 2000; Taylor and Guex 2002; Hall and Pitaru 2004). 

These studies have demonstrated that Early Jurassic eastern Pacific ammonites had strong Tethyan affinities as well as a high degree of endemism (Guex 1980, 1995; Taylor et al. 1984; Smith et al. 1988; Jakobs et al. 1994; Pálfy et al. 1994). Frebold’s early studies were also hampered because they were based on small collections, which limited understanding of the diversity of the fauna and variation within populations. However, recent mapping has greatly improved our understanding of the geology of Taseko Lakes (Schiarizza et al. 1997; Smith et al. 1998; Umhoefer and Tipper 1998) and encouraged further collecting that has dramatically increased the size of the sample.

A study of the ammonite fauna from Taseko Lakes is of interest for several reasons. The data are important for increasing the precision of the late Hettangian portion of the North American Zonation. 

Owing to the principally Tethyan or endemic nature of Early Jurassic ammonites in the eastern Pacific, a separate zonation for the Hettangian and Sinemurian of the Western Cordillera of North America has been established by Taylor et al. (2001). Except for information available from the early studies by Frebold (1951, 1967), the only Taseko Lakes taxa included in the North American Zonation of Taylor et al. (2001) were species of Angulaticeras studied by Smith and Tipper (2000). 

Since then, Longridge et al. (2006) made significant changes to the zonation of the late Hettangian and early Sinemurian based on a detailed study of the Badouxia fauna from Taseko Lakes (Text‐fig. 2). An additional taxonomic study was recently completed on the late Hettangian ammonite Sunrisites (Longridge et al. 2008) and this information has not yet been included within the zonation. 

Hettangian Zonation

The systematics of the remaining ammonite fauna from Taseko Lakes are presented here. A comprehensive study of this material is important because the exceptional quality and diversity of the fauna provide important data for updating the North American Zonation, making it more comprehensive and more widely applicable, especially in Canada.

The Taseko Lakes fauna can improve Hettangian correlations within North America as well as between North America and the rest of the world. 

North‐west European ammonite successions (e.g. Dean et al. 1961; Mouterde and Corna 1997; Page 2003) are considered the primary standard for Early Jurassic biochronology (Callomon 1984). 

In north‐west Europe, the turnover from schlotheimiid dominated faunas in the late Hettangian to arietitid dominated faunas in the early Sinemurian was sharp (e.g. Dean et al. 1961; Bloos 1994; Bloos and Page 2002). In other areas, by contrast, these faunas were not so mutually exclusive and the transition was much more gradual. 

This makes correlations between north‐west Europe and other areas difficult (e.g. Bloos 1994; Bloos and Page 2000, 2002). Correlations are further impeded by endemism and provincialism. 

The Taseko Lakes fauna addresses these problems because it contains many taxa that are common throughout the eastern Pacific as well as several cosmopolitan taxa that make intercontinental correlation possible. Correlation between North America and other areas is of particular significance in that the interbedded volcanic and fossiliferous marine rocks in North America permit the calibration of geochronological and biochronological time scales (Pálfy et al. 1999, 2000). 

This correlation between the late Hettangian fauna in the Taseko Lakes area and contemporaneous faunas in other areas of North America, South America, New Zealand, western and eastern Tethys, and north‐west Europe is of particular interest to me — especially the correlation of the faunal sequences of Nevada, USA. 

Reference: PaleoDB 157367 M. Clapham GSC C-208992, Section A 09, Castle Pass Angulata - Jurassic 1 - Canada, Longridge et al. (2008)

L. M. Longridge, P. L. Smith, and H. W. Tipper. 2008. Late Hettangian (Early Jurassic) ammonites from Taseko Lakes, British Columbia, Canada. Palaeontology 51:367-404

PaleoDB taxon number: 297415; Cephalopoda - Ammonoidea - Juraphyllitidae; Fergusonites hendersonae Longridge et al. 2008 (ammonite); Average measurements (in mm): shell width 9.88, shell diameter 28.2; Age range: 201.6 to 196.5 Ma. Locality info: British Columbia, Canada (51.1° N, 123.0° W: paleo coordinates 22.1° N, 66.1° W)

Photo One: Hettangian Ammonites and Gastropods, Taseko Lakes. Photo Two: Fergusonites hendersonae, a Late Hettangian (Early Jurassic) ammonite from the Taseko Lakes area of British Columbia, Canadian Rockies, named by Dr. Louise Longridge after Heidi Henderson, Chair, Vancouver Paleontological Society who collected and subsequently donated many Hettangian specimens from Taseko Lakes to the GSC collections. Holotype. GSC 127423 from the Rursicostatum Zone, Castle Pass section A, level 06, Taseko Lakes.

Map: Localities of sections and isolated outcrops bearing late Hettangian ammonites in the Taseko Lakes map area. Figure Two: Zonation for the Hettangian showing correlation of North American zones with South America, north‐west Europe, western Tethys (circum‐Mediterranean), eastern Tethys and New Zealand. Only approximate correlations are implied. 

CIBELELLA CORONATA

Cibelella Coronata / Photo: Alexei Molchanov

A spectacular creamy toned specimen of the trilobite Cibelella Coronata striking a very animated pose. 

The Genal spines give this fellow a bit of a starship look as though taking off in flight. 

This beauty is from upper Ordovician deposits along the Neva River at the head of the Gulf of Finland on the Baltic Coast, Saint Petersburg, Russia.

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.

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/