Showing posts with label ichthyosaur. Show all posts
Showing posts with label ichthyosaur. Show all posts

Friday, 1 November 2024

SHONISAURUS OF NEVADA

The beauties you see here are ichthyosaurs. The largest of their lineage is the genus Shonisaurus who ruled our ancient seas 217 million years ago.

At least 37 incomplete fossil specimens of the marine reptile have been found in hard limestone deposits of the Luning Formation, in far northwestern Nye County of Nevada. This formation dates to the late Carnian age of the late Triassic period when present-day Nevada and parts of the western United States were covered by an ancient ocean.

The first researcher to recognize the Nevada fossil specimens as ichthyosaurs was Siemon W. Muller of Stanford University. He had the work of Sir Richard Owen and others to build on. That being said, there are very few contenders for a species that boasts vertebrae over a foot wide and weighing in at almost 10 kg or 21 lbs. Muller contacted the University of California Museum of Paleontology at Berkeley. Surface collecting by locals continued at the site but no major excavation was planned.

Sir Richard Owen, the British biologist, comparative anatomist and paleontologist, coined the name ichthyopterygia, or "fish flippers," one hundred and fourteen years earlier, but that wee bit of scientific knowledge hadn't made its way west to the general population. The finds at Luning were still, "marine monsters."

Owen, too, was building on research going back to 1699, the very first recorded fossil fragments found of these beasties in Wales. Shortly thereafter, fossil vertebrae were published in 1708 from the Lower Jurassic.

The first complete skeleton was discovered in the early 19th century by Mary Anning and her brother Joseph along the Dorset Jurassic Coast. 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 the 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. All of this early work was instrumental in aiding the researchers who would join the project at Luning.

Owen is considered to have been an outstanding naturalist with a remarkable gift for interpreting fossils. Contrary to common belief, advanced study does help with identifying fossils, but what is truly needed is a keen eye. The finds at Luning were blessed to be seen by an enthusiastic local with just that right kind of keen eye.

Almost a quarter of a century after Muller's initial reports, Dr. Charles L. Camp from UCMP received correspondence further detailing the finds from a lovely Mrs. Margaret Wheat of Fallon. She wrote to Camp in September of 1928 to say that she'd been giving the quarry section a bit of a sweep, as you do, and had uncovered a nice aligned section of vertebrae with her broom. The following year, Dr. Charles L. Camp went out to survey the finds and began working on the specimens, his first field season of many, in 1954.

Back in the 1950s, these large marine reptiles were rumoured to be "marine monsters," as the concept of an ichthyosaur was not well understood by the local townsfolk. Excitement soon hit West Union Canyon as the quarry began to reveal the sheer size of these mighty beasts. Four of the specimens were fully excavated. Most of the ichthyosaur bones were left in situ, partially because the work was tremendously difficult, and partially to allow others to see how the specimens were laid down over 200 million years ago.

Camp continued to work with Wheat at the site and brought on Sam Welles and a host of students to help with excavations. The team understood the need for protection at the site. They canvassed the Nevada Legislature to establish the Ichthyosaur Paleontological State Monument. You can see one of the Park Rangers above giving a tour within the lovely Fossil Hut building they built on the site to protect the fossils.

In 1957, the site was incorporated into the State Park System and Berlin-Ichthyosaur State Park was born. The park Twenty years later, in 1977, the population of Nevada weighed in and the Legislature designated Shonisaurus popularis as the State Fossil of Nevada. Visitors are welcome to collect fossils from the exposures of the Upper Triassic (Early Norian, Kerri Zone) of the Luning Formation, West Union Canyon, just outside Berlin-Ichthyosaur State Park.

Address: State route 844, Austin, NV 89310, United States. Area: 4.58 km². Open 24 hours;
Elevation: 6,975 ft (2,126 m); Tel: +1 775-964-2440; http://parks.nv.gov/parks/berlin-ichthyosaur

Wednesday, 7 February 2024

VANCOUVER ISLAND'S TRENT RIVER PALAEONTOLOGY

Dan Bowen, Chair, VIPS, Trent River
The rocks that make up the Trent River on Vancouver Island are on the move. They were laid down near of the equator as small, tropical islands. They rode across the Pacific heading north and slightly east over the past 85 million years to where we find them today.

The Pacific Plate is an oceanic tectonic plate that lies beneath the Pacific Ocean. And it is massive. At 103 million km2 (40 million sq mi), it is the largest tectonic plate and continues to grow fed by volcanic eruptions that piggyback onto its trailing edge.

This relentless expansion pushes the Pacific Plate into the North American Plate. The pressure subducts it beneath our continent where it then melts back into the earth. Plate tectonics are slow but powerful forces. 

The island chains that rode the plates across the Pacific smashed into our coastline and slowly built the province of British Columbia. And because each of those islands had a different origin, they create pockets of interesting and diverse geology.

It is these islands that make up the Insular Belt — a physio-geological region on the northwestern North American coast. It consists of three major island groups — and many smaller islands — that stretches from southern British Columbia up into Alaska and the Yukon. These bits of islands on the move arrived from the Late Cretaceous through the Eocene — and continues to this day.

The rocks that form the Insular Superterrane are allochthonous, meaning they are not related to the rest of the North American continent. The rocks we walk over along the Trent River are distinct from those we find throughout the rest of Vancouver Island, Haida Gwaii, the rest of the province of British Columbia and completely foreign to those we find next door in Alberta.

To discover what we do find on the Trent takes only a wee stroll, a bit of digging and time to put all the pieces of the puzzle together. The first geological forays to Vancouver Island were to look for coal deposits, the profitable remains of ancient forests that could be burned to the power industry.

Jim Monger and Charlie Ross of the Geological Survey of Canada both worked to further our knowledge of the complex geology of the Comox Basin. They were at the cutting edge of west coast geology in the 1970s. It was their work that helped tease out how and where the rocks we see along the Trent today were formed and made their way north.

We know from their work that by 85 million years ago, the Insular Superterrane had made its way to what is now British Columbia. 

The lands were forested much as they are now but by extinct genera and families. The fossil remains of trees similar to oak, poplar, maple and ash can be found along the Trent and Vancouver Island. We also see the lovely remains of flowering plants such as Cupanities crenularis, figs and breadfruit.

Heading up the river, you come to a delineation zone that clearly marks the contact between the dark grey marine shales and mudstones of the Haslam Formation where they meet the sandstones of the Comox Formation. Fossilized material is less abundant in the Comox sandstones but still contains some interesting specimens. Here you begin to see fossilized wood and identifiable fossil plant material.

Further upstream, there is a small tributary, Idle Creek, where you can find more of this terrestrial material in the sandy shales. As you walk up, you see identifiable fossil plants beneath your feet and jungle-like, overgrown moss-covered, snarly trees all around you.

Walking west from the Trent River Falls at the bottom, you pass the infamous Ammonite Alley, where you can find Mesopuzosia sp. and Kitchinites sp. of the Upper Cretaceous (Santonian), Haslam Formation. Minding the slippery green algae covering some of the river rocks, you can see the first of the Polytychoceras vancouverense zone.

Continuing west, you reach the first of two fossil turtle sites on the river — amazingly, one terrestrial and one marine. If you continue, you come to the Inland Island Highway.

The Trent River has yielded some very interesting marine specimens, and significant terrestrial finds. We have found a wonderful terrestrial helochelydrid turtle, Naomichelys speciosa, and the caudal vertebrae of a Hadrosauroid dinosaur. Walking down from the Hadrosaur site you come to the site of the fossil ratfish find — one of the ocean's oddest fish.

Ratfish, Hydrolagus Collie, are chimaera found in the north-eastern Pacific Ocean today. The fossil specimen from the Trent would be considered large by modern standards as it is a bruiser in comparison to his modern counterparts. 

This robust fellow had exceptionally large eyes and sex organs that dangled enticingly between them. You mock, but there are many ratfish who would differ. While inherently sexy by ratfish standards, this fellow was not particularly tasty to their ancient marine brethren (or humans today) — so not hugely sought after as a food source or prey.

A little further again from the ratfish site we reach the contact of the two Formations. The rocks here have travelled a long way to their current location. With them, we peel away the layers of the geologic history of both the Comox Valley and the province of British Columbia.

The Trent River is not far from the Puntledge, a river whose banks have also revealed many wonderful fossil specimens. The Puntledge is also the name used by the K'ómoks First Nation to describe themselves. They have lived here since time immemorial. Along with Puntledge, they refer to themselves as Sahtloot, Sasitla and Ieeksun.

References: Note on the occurrence of the marine turtle Desmatochelys (Reptilia: Chelonioidea) from the Upper Cretaceous of Vancouver Island Elizabeth L. Nicholls Canadian Journal of Earth Sciences (1992) 29 (2): 377–380. https://doi.org/10.1139/e92-033; References: Chimaeras - The Neglected Chondrichthyans". Elasmo-research.org. Retrieved 2017-07-01.

Directions: If you're keen to explore the area, park on the side of Highway 19 about three kilometres south of Courtenay and hike up to the Trent River. Begin to look for parking about three kilometres south of the Cumberland Interchange. There is a trail that leads from the highway down beneath the bridge which will bring you to the Trent River's north side.

Monday, 15 January 2024

NEVADA FOSSILS: CARNIAN-NORIAN BOUNDARY

Time Slows at Berlin-Ichthyosaur State Park
High on the hillside up a long entry road sits the entrance to Berlin-Ichthyosaur State Park in central Nevada.

A worn American flag and sun bleached outbuildings greet you on your way to the outcrops. Away from the hustle and bustle that define the rest of Nevada this place feels remarkably serene. Your eyes squint against the sun as you search for ammonoids and other marine fossil fauna while your nose tends to the assault from the bracing smell of sage brush.

This site holds many stories. The interpretive centre displays wonderful marine reptiles, ichthyosaurs in situ, as you might expect from the name of the park — but it also showcases years of history lovingly tended. This stretch of dry golden low hills dappled with the yellow of creosote and desert grasses is an important locality for our understanding of the Carnian-Norian boundary (CNB) in North America.

The area is known worldwide as one of the most important ichthyosaur Fossil-Lagerstätte because of the sheer volume of remarkably well-preserved, fully articulated (all the sweet bones laid out all in a row...) specimens of Shonisaurus popularis.

Rich ammonoid faunas outcrop in the barren hills of the Upper Triassic (Early Norian, Kerri zone), Luning Formation, West Union Canyon, Nevada. They were studied by N. J. Silberling (1959) and provide support for the definition of the Schucherti and Macrolobatus zones of the latest Carnian — which are here overlain by well-preserved faunas of the earliest Norian Kerri Zone. 

The genus Gonionotites, very common in the Tethys and British Columbia, is for the moment, unknown in Nevada. The Upper Carnian faunas are dominated by Tropitidae, while Juvavitidae are conspicuously lacking. 

Middle Triassic Ammonoids
Despite its importance, no further investigations had been done at this site for a good 50 years. That changed in 2010 when Jim Haggart, Mike Orchard and Paul Smith — all local Vancouverites — collaborated on a project that took them down to Nevada to look at the conodonts and ammonoids. They did a bed-by-bed sampling of ammonoids and conodonts in West Union Canyon during October of that year.

October is an ideal time to do fieldwork in this area. There are a few good weeks between screaming hot and frigid cold. It is also tarantula breeding season so keep your eyes peeled. Those sweet little burrows you see are not from rodents but rather largish arachnids. 

The eastern side of the canyon provides the best record of the Macrolobatus Zone, which is represented by several beds yielding ammonoids of the Tropites group, together with Anatropites div. sp. 

Conodont faunas from both these and higher beds are dominated by ornate metapolygnthids that would formerly have been collectively referred to Metapolygnathus primitius, a species long known to straddle the CNB. Within this lower part of the section, they resemble forms that have been separated as Metapolygnathus mersinensis. Slightly higher, forms close to Epigondolella' orchardi and a single Orchardella n. sp. occur. This association can be correlated with the latest Carnian in British Columbia.

Higher in the section, the ammonoid fauna shows a sudden change and is dominated by Tropithisbites. Few tens of metres above, but slightly below the first occurrence of Norian ammonoids Guembelites jandianus and Stikinoceras, two new species of conodonts (Gen et sp. nov. A and B) appear that also occur close to the favoured Carnian/Norian boundary at Black Bear Ridge, British Columbia. Stratigraphically higher collections continue to be dominated by forms close to M. mersinensis and E. orchardi after BC's own Mike Orchard.

The best exposure of the Kerri Zone is on the western side of the West Union Canyon. Ammonoids, dominated by Guembelites and Stikinoceras div. sp., have been collected from several fossil-bearing levels. Conodont faunas replicate those of the east section. The collected ammonoids fit perfectly well with the faunas described by Silberling in 1959, but they differ somewhat from coeval faunas of the Tethys and Canada. 

The ammonoid fauna paints a compelling picture of Tethyan influence with a series of smoking guns. We see an abundance of Tropitidae in the Carnian, a lack of Pterosirenites in the Norian, copious Guembelites, the Tethyan species G. philostrati, the stratigraphic position of G. clavatus and the rare occurrence of Gonionotites. Their hallelujah moment was likely finding an undescribed species of the thin-shelled bivalve Halobia similar to Halobia beyrichi — the clincher that perhaps seals this deal on Tethyan influence. 

I'll take a boo to see what Christopher McRoberts published on the find. A jolly good idea to have him on this expedition as it would have been easy to overlook if the focus remained solely on the conodonts and ammonoids. McRoberts has published on the much-studied Pardonet Formation up in the Willison Lake Area of Northeastern, British Columbia. He knows a thing or two about Upper Triassic Bivalvia and the correlation to coeval faunas elsewhere in the North American Cordillera, and to the Boreal, Panthalassan and Tethyan faunal realms. 

If you fancy a read, they published a paper: "Towards the definition of the Carnian/Norian Boundary: New data on Ammonoids and Conodonts from central Nevada," which you can find in the proceedings of the 21st Canadian Paleontology Conference; by Haggart, J W (ed.); Smith, P L (ed.); Canadian Paleontology Conference Proceedings no. 9, 2011 p. 9-10.

Fig. 1. Location map of Berlin-Ichthyosaur State Park

Marco Balini, James Jenks, Riccardo Martin, Christopher McRoberts, along with Mike Orchard and Norman Siberling, did a bed by bed sampling in 2013 and published on The Carnian/Norian boundary succession at Berlin-Ichthyosaur State Park (Upper Triassic, central Nevada, USA) and published in January 2014 in Paläontologische Zeitschrift 89:399–433. That work is available for download from ResearchGate. The original is in German, but there is a translation available.

After years of reading about the correlation between British Columbia and Nevada, I had the very great pleasure of walking through these same sections in October 2019 with members of the Vancouver Paleontological Society and Vancouver Island Palaeontological Society. It was with that same crew that I'd originally explored fossil sites in the Canadian Rockies in the early 2000s. Those early trips led to paper after paper and the exciting revelations that inspired our Nevada adventure.

If you plan your own adventure, you'll want to keep an eye out for some of the other modern fauna — mountain lions, snakes, lizards, scorpions, wolves, coyotes, foxes, ground squirrels, rabbits, falcons, hawks, eagles, bobcats, sheep, deer and pronghorns.

Figure One: Location map of Berlin-Ichthyosaur State Park. A detailed road log with access information for this locality is provided in Lucas et al. (2007).

Wednesday, 3 January 2024

UPPER TRIASSIC LUNING FORMATION, NEVADA

Exposures of the Upper Triassic (Early Norian, Kerri zone), Luning formation, West Union Canyon, just outside Berlin-Ichthyosaur State Park, Nevada.

The Berlin-Ichthyosaur State Park in central Nevada is a very important locality for the understanding of the Carnian-Norian boundary (CNB) in North America.

Rich ammonoid faunas from this site within the Luning Formation were studied by Silberling (1959) and provided support for the definition of the Schucherti and Macrolobatus zones of the latest Carnian, which are here overlain by well-preserved faunas of the earliest Norian Kerri Zone. Despite its importance, no further investigations have been done at this site during the last 50 years.

Jim Haggart, Mike Orchard and Paul Smith (all local Vancouverites) collaborated on a project that took them down to Nevada to look at the conodonts (Oh, Mike) and ammonoids (Jim's fav); the group then published a paper, "Towards the definition of the Carnian/Norian Boundary: New data on Ammonoids and Conodonts from central Nevada," which you can find in the proceedings of the 21st Canadian Paleontology Conference; by Haggart, J W (ed.); Smith, P L (ed.); Canadian Paleontology Conference Proceedings no. 9, 2011 p. 9-10.

They conducted a bed-by-bed sampling of ammonoids and conodonts in West Union Canyon during October 2010. The eastern side of the canyon provides the best record of the Macrolobatus Zone, which is represented by several beds yielding ammonoids of the Tropites group, together with Anatropites div. sp. Conodont faunas from both these and higher beds are dominated by ornate 'metapolygnthids' that would formerly have been collectively referred to Metapolygnathus primitius, a species long known to straddle the CNB. Within this lower part of the section, they resemble forms that have been separated as Metapolygnathus mersinensis. Slightly higher, forms close to Epigondolella' orchardi and a single Orchardella n. sp. occur. This association can be correlated with the latest Carnian in British Columbia.

Higher in the section, the ammonoid fauna shows a sudden change and is dominated by Tropithisbites. Few tens of metres above, but slightly below the first occurrence of Norian ammonoids Guembelites jandianus and Stikinoceras, two new species of conodonts (Gen et sp. nov. A and B) appear that also occur close to the favoured Carnian/Norian boundary at Black Bear Ridge, British Columbia. Stratigraphically higher collections continue to be dominated by forms close to M. mersinensis and E. orchardi. after BC's own Mike Orchard.

The best exposure of the Kerri Zone is on the western side of the West Union Canyon. Ammonoids, dominated by Guembelites and Stikinoceras div. sp., have been collected from several fossil-bearing levels. Conodont faunas replicate those of the east section. The collected ammonoids fit perfectly well with the faunas described by Silberling in 1959, but they differ somewhat from coeval faunas of the Tethys and Canada.

The genus Gonionotites, very common in the Tethys and British Columbia, is for the moment unknown in Nevada. More in general, the Upper Carnian faunas are dominated by Tropitidae, while Juvavitidae are lacking.

After years of reading about the correlation between British Columbia and Nevada, I had the very great pleasure of walking through these same sections in October 2019 with members of the Vancouver Paleontological Society and Vancouver Island Palaeontological Society. It was with that same crew that I'd originally explored fossil sites in the Canadian Rockies in the early 2000s. Those early trips led to paper after paper and the exciting revelations that inspired our Nevada adventure.

Monday, 25 December 2023

AMMONOIDS, BIVALVES AND POLAR BEARS OF SVALBARD

 This marvellous block is filled with Aristoptychites (syn=Arctoptychites) euglyphus (Mojsisovics, 1886) and Daonella sp., oyster-like saltwater clams or bivalves from the Middle Triassic (Ladinian) outcrops in the Botneheia Formation of Spitzbergen, in Edgeøya and Barentsøya, eastern Svalbard, Norway. 

Daonella and Monotis are important species for our understanding of biostratigraphy in the Triassic and are useful as an index fossil. Daonellids preferred soft, soupy substrates and we tend to find them in massive shell beds.

Svalbard is a Norwegian archipelago between mainland Norway and the North Pole. One of the world’s northernmost inhabited areas, it's known for its rugged, remote terrain of glaciers and frozen tundra sheltering polar bears, reindeer and Arctic fox. The Northern Lights are visible during winter, and summer brings the “midnight sun”—sunlight 24 hours a day.

The Botneheia Formation is made up of dark grey, laminated shales coarsening upwards to laminated siltstones and sandstones. South of the type area, the formation shows several (up to four) coarsening-upward units. 

The formation is named for Botneheia Mountain, a mountain in Nordenskiöld Land at Spitsbergen, Svalbard. It has a height of 522 m.a.s.l., and is located south of Sassenfjorden, east of the valley of De Geerdalen. 

Polar Bears, Ursus maritimus
As well as lovely ammonoids and bivalves, we have found ichthyosaur remains. 

It is not a huge surprise. We had been expecting too, but it was not until the early 2000s that the first bones were found.

Two specimens have of ichthyosaur have been recovered. They comprise part of the trunk and the caudal vertebral column respectively. 

Some features, such as the very high and narrow caudal and posterior thoracic neural spines, the relatively elongate posterior thoracic vertebrae and the long and slender haemapophyses tell us that they probably represent a member of the family Toretocnemidae. 

Numerous ichthyosaur finds are known from the underlying Lower Triassic Vikinghøgda Formation and the overlying Middle to Upper Triassic Tschermakfjellet Formation, the new specimens help to close a huge gap in the fossil record of the Triassic ichthyosaurs from Svalbard.

There is a resident research group working on the Triassic ichthyosaur fauna, the Spitsbergen Mesozoic Research Group. Lucky for them, they often find the fossil remains fully articulated — the bones having retained their spacial relationship to one another. Most of their finds are of the tail sections of primitive Triassic ichthyosaurs. In later ichthyosaurs, the tail vertebrae bend steeply downwards and have more of a fish-like look. In these primitive ancestors, the tail looks more eel-like — bending slightly so that the spines on the vertebrae form more of the tail.

Maisch, Michael W. and Blomeier, Dierk published on these finds back in 2009: Neues Jahrbuch für Geologie und Paläontologie - Abhandlungen Band 254 Heft 3 (2009), p. 379 - 384. Nov 1, 2009

The lovely block you see here is in the collections of the deeply awesome John Fam. The image of the Polar Bears, Ursus maritimus, is courtesy of the Fossil Huntress. 

Saturday, 23 April 2022

BERLIN-ICHTHYOSAUR STATE PARK

At least 37 incomplete fossil specimens of the marine reptile have been found in hard limestone deposits of the Luning Formation, in far northwestern Nye County of Nevada. 

This formation dates to the late Carnian age of the late Triassic period when present-day Nevada and parts of the west were covered by an ancient ocean.

The first researcher to recognize the Nevada fossil specimens as ichthyosaurs was Siemon W. Muller of Stanford University. 

Muller had the work of Sir Richard Owen to build upon from Owen's 1840 publications. That being said, there are very few contenders for a species that boasts vertebrae over a foot wide and weighing in at almost 10 kg or 21 lbs. 

Muller contacted the University of California Museum of Paleontology at Berkeley. Surface collecting by locals continued at the site but no major excavation was planned.

Almost a quarter of a century after Muller's initial correspondence to the UCMP, Dr. Charles L. Camp received correspondence further detailing the finds from a lovely Mrs. Margaret Wheat of Fallon. She wrote to Camp in September of 1928 to say that she'd been giving the quarry section a bit of a sweep, as you do, and had uncovered a nice aligned section of vertebrae with her broom. The following year, Dr. Charles L. Camp went out to survey the finds and began working on the specimens, his first field season of many, in 1954.

Back in the 1950s, these large marine reptiles were rumoured to be "marine monsters," as the concept of an ichthyosaur was not well understood by the local townsfolk. Excitement soon hit West Union Canyon as the quarry began to reveal the sheer size of these mighty beasts. In the end, the ichthyosaur bones were left in situ to better understand how they were laid down over 200 million years ago.

Camp continued to work with Wheat at the site and brought on Sam Welles to help with excavations. The team understood the need for protection at the site. They canvassed the Nevada Legislature to establish the Ichthyosaur Paleontological State Monument. You can one of the Park Rangers above giving a tour within the lovely building they built on the site to protect the fossils.

In 1957, the site was incorporated into the State Park System and Berlin-Ichthyosaur State Park was born. The park Twenty years later, in 1977, the population of Nevada weighed in and the Legislature designated Shonisaurus popularis as the State Fossil of Nevada.

Know Before You Go — Berlin-Ichthyosaur State Park

This is a wonderful place to explore for a very reasonable sum of $5.00 US. Open year-round (though check regarding accessibility during Covid). They have accessible outcrops just outside the park boundary where you can collect ammonoid fossils. 

Contact information: Tel: 775-964-2440 / Email: bisp@parks.nv.gov. 

Address: State Route 844, Austin, NV 89310, United States. Area: 4.58 km². Elevation: 6,975 ft (2,126 m); Tel: +1 775-964-2440; http://parks.nv.gov/parks/berlin-ichthyosaur

Wednesday, 16 February 2022

THE MIGHTY MARINE REPTILES

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.

Lithography from William Buckland's 1824 Paper
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 Era of the Mighty Marine Reptile had begun. Ichthyosaurs have been collected in the Blue Lias near Lyme Regis and the Black Ven Marls. More recently, specimens have been collected from the higher succession near Seatown. Paddy Howe, Lyme Regis Museum geologist, found a rather nice Ichthyosaurus breviceps skull a few years back. A landslip in 2008 unveiled some ribs poking out of the Church cliffs and a bit of digging revealed the ninth fossil skull ever found of a breviceps, with teeth and paddles to boot.

Specimens have since been found in Europe in Belgium, England, Germany, Switzerland and in Indonesia. Many tremendously well-preserved specimens come from the limestone quarries in Holzmaden, southern Germany.

Ichthyosaurs ranged from quite small, just a foot or two, to well over twenty-six metres in length and resembled both modern fish and dolphins.

Dean Lomax and Sven Sachs, both active — and delightful — vertebrate palaeontologists, have described a colossal beast, Shonisaurus sikanniensis from the Upper Triassic (Norian) Pardonet Formation of northeastern British Columbia, Canada, measuring 3-3.5 meters in length. The specimen is now on display in the Royal Tyrrell Museum of Palaeontology in Alberta, Canada. It was this discovery that tipped the balance in the vote, making it British Columbia's Official Fossil. 

Ichthyosaurs have been found at other sites in British Columbia, on Vancouver Island and Haida Gwaii but Shonisaurus tipped the ballot. The first specimens of Shonisaurus were found in the 1990s by Peter Langham at Doniford Bay on the Somerset coast of England. 

Roy Chapman Andrews, AMNH 1928 Expedition to the Gobi Desert
Dr. Betsy Nicholls, Rolex Laureate Vertebrate Palaeontologist from the Royal Tyrrell Museum, excavated the type specimen of Shonisaurus sikanniensis over three field sessions in one of the most ambitious fossil excavations ever ventured. 

Her efforts from 1999 through 2001, both in the field and lobbying back at home, paid off. Betsy published on this new species in 2004, the culmination of her life’s work and her last paper as we lost her to cancer in the autumn of that year. 

I recently connected with the awesome John-Paul (JP) Zonneveld, Professor, Palaeontologist, Sedimentary Geologist and Field Scientist at the University of Alberta, who worked with Betsy on the original Shonisaurus sikanniensis site many years ago. "She was an awesome person, a dear friend and an outstanding field scientist." I could not agree more. Betsy was pure delight.

Charmingly, Betsy had a mail correspondence with Roy Chapman Andrews, former director of the American Museum of Natural History, going back to the late 1950s as she explored her potential career in palaeontology. Do you recall the AMNH’s sexy paleo photos of expeditions to the Gobi Desert in southern Mongolia in China in the early 20th century? You would remember if you had seen them. Roy Chapman Andrews was the lead on that trip. His photos are what fueled the flames of my own interest in palaeontology.

Shonisaurus popularise
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.


Friday, 24 December 2021

ICE, SNOW, REINDEER AND ICHTHYOSAURS: SVALBARD

Reindeer, Rangifer tarandus 
Ice, Snow, Reindeer & Ichthyosaurs — Svalbard is just what I imagine my version of Valhalla to be like, without all the mead, murder and mayhem. 

This Norwegian archipelago sits between mainland Norway and the North Pole. 

One of the world’s northernmost inhabited areas, it is known for its rugged, remote terrain of glaciers and frozen tundra sheltering polar bears, reindeer and Arctic fox. 

It is also known for reindeer. The lovelies you see here are all females as the males lose their antlers in the winter. So Rudolf and the rest of Santa's crew who pull his sleigh for him would have all been females as they are pictured with antlers. They are also shown flying across the sky, so the science gets a bit creative.

The Northern Lights or Nordlys are visible during winter, and summer brings the Midnight Sun — sunlight 24 hours a day. Norway or Norge is one of the very few locations where sunset merges into the sunrise, with no darkness in between, creating a soft, captivating twilight in which to view the world. 

The Botneheia Formation is made up of dark grey, laminated shales coarsening upwards to laminated siltstones and sandstones. South of the type area, the formation shows four coarsening-upward units. 

The formation is named for Botneheia Mountain, a mountain in Nordenskiöld Land at Spitsbergen, Svalbard. It has a height of 522 m.a.s.l., and is located south of Sassenfjorden, east of the valley of De Geerdalen. 

Svalbard, Norway
I was asked recently if folk head out in the torrential rain or ice and snow to fossil collect. I would generally say yes for those where the potential prize always outweighs the weather. For Svalbard, it is a resounding yes. 

You have to remove the snow cover — or ice if you are impatient or unlucky — to get to the outcrops here. It is well worth the effort. Beneath the icy cover, you find lovely ammonoids and bivalves. 

Tastier still, ichthyosaur remains are found here. The first Triassic ichthyosaurs from Svalbard were found in the early 20th century. Now there are quite a few Triassic and Jurassic ichthyosaur species from this archipelago.

Two ichthyosaur specimens have been recovered that are of particular interest. They comprise part of the trunk and the caudal vertebral column respectively. 

Some features, such as the very high and narrow caudal and posterior thoracic neural spines, the relatively elongate posterior thoracic vertebrae and the long and slender haemapophyses indicate that they probably represent a member of the family Toretocnemidae. 

Ichthyosaur Bones
Numerous ichthyosaur finds are known from the underlying Lower Triassic Vikinghøgda Formation and the overlying Middle to Upper Triassic Tschermakfjellet Formation, the new specimens help to close a huge gap in the fossil record of the Triassic ichthyosaurs from Svalbard. 

There is a resident research group working on the Triassic ichthyosaur fauna, the Spitsbergen Mesozoic Research Group. 

Lucky for them, they often find the fossil remains fully articulated — the bones having retained their spatial relationship to one another. 

Most of their finds are of the tail sections of primitive Triassic ichthyosaurs. In later ichthyosaurs, the tail vertebrae bend steeply downwards and have more of a fish-like look. 

In these primitive ancestors, the tail looks more eel-like — bending slightly so that the spines on the vertebrae form more of the tail. 

Maisch, Michael W. and Blomeier, Dierk published on these finds back in 2009: Neues Jahrbuch für Geologie und Paläontologie - Abhandlungen Band 254 Heft 3 (2009), p. 379 - 384. Nov 1, 2009.

Svalbard, Norway (Norge)
Svalbard was so remote that there were no Inuit or First Nation settlements. It is certainly possible an earlier people came through these islands, but they did not leave any trace of their travels. 

The first documented travellers to explore Spitsbergen arrived in 1795 as part of a hunting expedition. They included people from the arctic town of Hammerfest in Norway's far north. They were an excellent choice as they were used to barren, inhospitable lands and sailed to discover more. 

We know them as the Coast Sámi — a hearty, rugged people probably best known in history for their chieftain, Ottar. He left Hammerfest in the 9th century to visit then join King Alfred the Great's court in a newly forming England. 

Expeditions to the remote islands of Svalbard continued into the early 1800s and finally, a settlement was eked out of the cold landscape and slowly expanded to the rest of the islands. While today the islands are called Svalbard, I would have named them for the Norwegian word for remote — fjernkontroll.

Aristoptychites euglyphus and Daonella sp.
This marvellous block is filled with Aristoptychites (syn = Arctoptychites) euglyphus (Mojsisovics, 1886) and Daonella sp., oyster-like clams or bivalves from the Middle Triassic, Ladinian, rugged windswept outcrops at the top of the Daonella Shales, Botneheia Formation, Spitzbergen, Edgeøya and Barentsøya, eastern Svalbard, Norway. 

Daonella and Monotis are important species for our understanding of biostratigraphy in the Triassic and are useful as Index fossils. 

Index fossils are fossils used to define and identify geologic periods or faunal stages. To be truly useful, they need to have a short vertical range, wide geographic distribution and rapid evolutionary development.

Daonellids preferred soft, soupy substrates and we tend to find them in massive shell beds. Generally, if you find one, you find a whole bunch cemented together in coquina. The lovely block you see here is in the collections of the deeply awesome John Fam. 

Learning Languages

The Sámi languages (/ˈsɑːmi/ SAH-mee), Sami or Saami, are a group of Uralic languages spoken by the Sámi people in Northern Europe in parts of northern Finland, Norway, Sweden, and extreme northwestern Russia. Of the world's languages, I find them the most difficult for my mind and tongue to wrap around. The Uralic languages will be familiar to you as Hungarian (Magyar nyelv), Finnish and Estonian. 

Since my Sámi is terrible, I will share a few words of Norwegian that may come in handy if you visit Svalbard and have a hankering for their tasty fossils or fossiler. To say, ice, snow, reindeer and ichthyosaurs in Norwegian, you would say: is, snø, reinsdyr og ikthyosaurer

To say, "hello, where can I find fossils?" Use, "Hei, hvor kan jeg finne fossiler?" An expression you may not need but circumstances being what they are, "That is a big polar bear," is "Det er en stor isbjørn." A solid follow-up would be, "nice bear, run..." as "Fin bjørn, løp..." Good luck with that.

Wishing you and yours the very best of the holidays however you celebrate. 

Tuesday, 29 June 2021

TEMNODONTOSAURUS CRASSIMANUS

Temnodontosaurus crassimanus
This big beastie is the ichthyosaur, Temnodontosaurus crassimanus, who graced our ancient oceans 180 million years ago. The species was originally named by Richard Owen, the first superintendent of the Natural History Museum. Owen lived at the height of the gentleman scientist and it was Owen who first coined the name dinosaur. Dean Lomax did some work with this specimen as part of his research leading up to his PhD.

The fellow you see here is the Type Specimen for the species and he lives on display in the Yorkshire Museum. As the reference specimen for the species, all hopeful specimens that may belong to this species are checked against the Type Specimen to see if they share diagnostic features.

The Yorkshire Museum was given this important ichthyosaur fossil back in 1857, albeit in bits and pieces. The first bits of fossil bones were found near Whitby on the North Yorkshire coast by workmen quarrying alum. They recognized the bones as belonging to a fossilized reptile and alerted local authorities who in turn alerted the good Master Owen.

It was quite an undertaking to recover as it was found in more than fifty pieces in massive shale blocks and the alum quarry was active at the time. Alum quarrying helped share the Yorkshire Coast as an important staple of the textile industry going back to the 16th-century. By the 1860s, alum quarrying was slowing down. The ability to manufacture synthetic alum by 1855 had shifted the industry and it died out entirely by 1871. Lucky for us, the last years of alum production gifted us this well-preserved eight-metre specimen, one of the largest ichthyosaurs ever discovered in the UK.

Paleo-coordinates: 54.5° N, 0.6° W: paleocoordinates 42.4° N, 9.3° E

Friday, 23 April 2021

UNRAVELLING THE CARNIAN-NORIAN BOUNDARY

Berlin-Ichthyosaur State Park
The Berlin-Ichthyosaur State Park in central Nevada is an important locality for our understanding of the Carnian-Norian boundary (CNB) in North America.

The area is also known worldwide as one of the most important ichthyosaur Fossil-Lagerstätte because of the sheer volume of remarkably well-preserved, fully articulated specimens of Shonisaurus popularis.

Rich ammonoid faunas outcrop in the Upper Triassic (Early Norian, Kerri zone), Luning Formation, West Union Canyon, Nevada. They were studied by N. J. Silberling (1959) and provide support for the definition of the Schucherti and Macrolobatus zones of the latest Carnian — which are here overlain by well-preserved faunas of the earliest Norian Kerri Zone. 

The genus Gonionotites, very common in the Tethys and British Columbia, is for the moment, unknown in Nevada. The Upper Carnian faunas are dominated by Tropitidae, while Juvavitidae are conspicuously lacking. 

Middle Triassic Ammonoids
Despite its importance, no further investigations had been done at this site for a good 50 years. That changed in 2010 when Jim Haggart, Mike Orchard and Paul Smith — all local Vancouverites — collaborated on a project that took them down to Nevada to look at the conodonts and ammonoids. They did a bed-by-bed sampling of ammonoids and conodonts in West Union Canyon during October of that year.

October is an ideal time to do fieldwork in this area. There are a few good weeks between screaming hot and frigid cold. It is also tarantula breeding season so keep your eyes peeled. Those sweet little burrows you see are not from rodents but rather largish arachnids. 

The eastern side of the canyon provides the best record of the Macrolobatus Zone, which is represented by several beds yielding ammonoids of the Tropites group, together with Anatropites div. sp. 

Conodont faunas from both these and higher beds are dominated by ornate metapolygnthids that would formerly have been collectively referred to Metapolygnathus primitius, a species long known to straddle the CNB. Within this lower part of the section, they resemble forms that have been separated as Metapolygnathus mersinensis. Slightly higher, forms close to Epigondolella' orchardi and a single Orchardella n. sp. occur. This association can be correlated with the latest Carnian in British Columbia.

Higher in the section, the ammonoid fauna shows a sudden change and is dominated by Tropithisbites. Few tens of metres above, but slightly below the first occurrence of Norian ammonoids Guembelites jandianus and Stikinoceras, two new species of conodonts (Gen et sp. nov. A and B) appear that also occur close to the favoured Carnian/Norian boundary at Black Bear Ridge, British Columbia. Stratigraphically higher collections continue to be dominated by forms close to M. mersinensis and E. orchardi after BC's own Mike Orchard.

The best exposure of the Kerri Zone is on the western side of the West Union Canyon. Ammonoids, dominated by Guembelites and Stikinoceras div. sp., have been collected from several fossil-bearing levels. Conodont faunas replicate those of the east section. The collected ammonoids fit perfectly well with the faunas described by Silberling in 1959, but they differ somewhat from coeval faunas of the Tethys and Canada. 

The ammonoid fauna paints a compelling picture of Tethyan influence with a series of smoking guns. We see an abundance of Tropitidae in the Carnian, a lack of Pterosirenites in the Norian, copious Guembelites, the Tethyan species G. philostrati, the stratigraphic position of G. clavatus and the rare occurrence of Gonionotites. Their hallelujah moment was likely finding an undescribed species of the thin-shelled bivalve Halobia similar to Halobia beyrichi — the clincher that perhaps seals this deal on Tethyan influence. 

I'll take a boo to see what Christopher McRoberts published on the find. A jolly good idea to have him on this expedition as it would have been easy to overlook if the focus remained solely on the conodonts and ammonoids. McRoberts has published on the much-studied Pardonet Formation up in the Willison Lake Area of Northeastern, British Columbia. He knows a thing or two about Upper Triassic Bivalvia and the correlation to coeval faunas elsewhere in the North American Cordillera, and to the Boreal, Panthalassan and Tethyan faunal realms. 

If you fancy a read, they published a paper: "Towards the definition of the Carnian/Norian Boundary: New data on Ammonoids and Conodonts from central Nevada," which you can find in the proceedings of the 21st Canadian Paleontology Conference; by Haggart, J W (ed.); Smith, P L (ed.); Canadian Paleontology Conference Proceedings no. 9, 2011 p. 9-10.

Fig. 1. Location map of Berlin-Ichthyosaur State Park

Marco Balini, James Jenks, Riccardo Martin, Christopher McRoberts, along with Mike Orchard and Norman Siberling, did a bed by bed sampling in 2013 and published on The Carnian/Norian boundary succession at Berlin-Ichthyosaur State Park (Upper Triassic, central Nevada, USA) and published in January 2014 in Paläontologische Zeitschrift 89:399–433. That work is available for download from ResearchGate. The original is in German, but there is a translation available.

After years of reading about the correlation between British Columbia and Nevada, I had the very great pleasure of walking through these same sections in October 2019 with members of the Vancouver Paleontological Society and Vancouver Island Palaeontological Society. It was with that same crew that I'd originally explored fossil sites in the Canadian Rockies in the early 2000s. Those early trips led to paper after paper and the exciting revelations that inspired our Nevada adventure.

If you plan your own adventure, you'll want to keep an eye out for some of the other modern fauna — mountain lions, snakes, lizards, scorpions, wolves, coyotes, foxes, ground squirrels, rabbits, falcons, hawks, eagles, bobcats, sheep, deer and pronghorns.

Figure One: Location map of Berlin-Ichthyosaur State Park. A detailed road log with access information for this locality is provided in Lucas et al. (2007).

Saturday, 27 March 2021

ICHTHYOSAUR BASIOCCIPITAL BONE AND TELEOST FISH

Ichthyosaur Basioccipital Bone / Liam Langley
A very exciting find of an Ichthyosaur basioccipital bone. This is the bone next to the skull that connected to the vertebrae. He found this in situ so not very water warn as you might expect. This lovely bone was found by the deeply awesome Liam Langley on the Yorkshire Coast.

Ichthyosaurs became extinct during the Upper Cretaceous, about 30 million years before the K/T extinction event. There was an ocean anoxic event at the Cenomanian–Turonian stage boundary. The deeper layers of the seas became anoxic and poisoned by hydrogen sulphide. As life died off in the lower (benthos) levels of the sea, so did the predators at the top of the food chain. The last pliosaurs and ichthyosaurs became extinct.

Ichthyosaurs had been dwindling in numbers for some time; they were no longer the force they once were in the Upper Triassic and Lower Jurassic. By the middle Jurassic, it was thought they all belonged to the single clade, the Ophthalmosauridae. By the Cretaceous, it was thought that only three genera survived. For the last 50+ years, it has been thought that only one genus, Platypterygius, was known at the time of the anoxic event in the Upper Cretaceous.

Ichthyosaur Basioccipital Bone / Liam Langley
There was still diversity in ichthyosaurs a few million years before the extinction event. They may have survived right up to the extinction event. Ichthyosaurs had declined from their peak.

By the Cretaceous, they certainly had more competitors than in the Triassic and more elusive prey. The adaptive radiation of teleost fish meant their new prey was fast swimming and highly evasive.

The difference between teleosts and other bony fish lies mainly in their jawbones; teleosts have a movable premaxilla and corresponding modifications in the jaw musculature which make it possible for them to protrude their jaws outwards from the mouth.

This is of great advantage, enabling them to grab prey and draw it into the mouth. In more derived teleosts, the enlarged premaxilla is the main tooth-bearing bone, and the maxilla, which is attached to the lower jaw, acts as a lever, pushing and pulling the premaxilla as the mouth is opened and closed. Other bones further back in the mouth serve to grind and swallow food.

Another difference is that the upper and lower lobes of the tail (caudal) fin are about equal in size. The spine ends at the caudal peduncle, distinguishing this group from other fish in which the spine extends into the upper lobe of the tail fin.

The most basal of the living teleosts are the Elopomorpha, eels and their allies, and the Osteoglossomorpha, those whacky elephantfish and their friends. There are over 800 species of elopomorphs; each with thin leaf-shaped larvae known as leptocephali specialized for a marine environment.

Among the elopomorphs, eels have elongated bodies with lost pelvic girdles and ribs and fused elements in the upper jaw. The 200 species of osteoglossomorphs are defined by a bony element in the tongue. This element has a basibranchial behind it, and both structures have large teeth that are paired with the teeth on the parasphenoid in the roof of the mouth.

The clade Otocephala includes the Clupeiformes, tasty herrings, and Ostariophysi  — carp, catfish and their friends. Clupeiformes are made up of 350 living species of herring and herring-like fish. This group is characterized by an unusual abdominal scute and a different arrangement of the hypurals. In most species, the swim bladder extends to the braincase and plays a role in hearing. Ostariophysi, which includes most freshwater fishes, has developed some unique adaptations.

One is the Weberian apparatus, an arrangement of bones, called Weberian ossicles, connecting the swim bladder to the inner ear. This enhances their hearing, as sound waves make the bladder vibrate, and the bones transport the vibrations to the inner ear. They also have a chemical alarm system; when a fish is injured, the warning substance gets in the water, alarming nearby fish. Excellent for the predatory fish, less so for their poor injured brethren.

The teleosts included fast-swimming predatory fish, which would have been competing for similar food resources to our ichthyosaur friends. Had they complained about the teleosts they would have been deeply aghast to know what was coming next — big, hungry mosasaurs. The ichthyosaurs and pliosaurs were replaced in the marine ecology by the giant mosasaurs. The mosasaurs were probably ambush-hunters, whose sit-and-wait strategy apparently proved most successful. So, teleost fish, the ocean anoxic event and the rise of mosasaurs all contributed to the end of the ichthyosaurs.

Photos 1-2: By the awesome Liam Langley
Image 3: By Sir Francis Day - Fauna of British India, Fishes (www.archive.org), Public Domain, https://commons.wikimedia.org/w/index.php?curid=1919094

Monday, 22 March 2021

ICHTHYOSAURS, SHARKS AND BLUBBER

We've learned much about the mighty ichthyosaur since first discovering their bones in Wales back in 1699. That's over three hundred years of knowledge.

We have classified them as an extinct order of marine reptiles from the Mesozoic era. We know that they were visibly dolphin-like in appearance and share some other qualities as well. They were warm-blooded, used their colouration as camouflage and had insulating blubber to keep them warm.

Ichthyosaurs are interesting because they have many traits in common with dolphins, but are not at all closely related to those sea-dwelling mammals. We aren't exactly sure of their biology either. They have many features in common with living marine reptiles like sea turtles, but we know from the fossil record that they gave live birth, which is associated with warm-bloodedness. This study reveals some of those biological mysteries.

We find their fossil remains in outcrops spanning the mid-Cretaceous to the earliest Triassic. As we look through the fossils, we see a slow evolution in body design moving towards that enjoyed by dolphins and tuna by the Upper Triassic, albeit with a narrower, more pointed snout.

Johan Lindgren, Associate Professor at Sweden's Lund University and lead author on the paper,  described the 180 million-year-old specimen, Stenopterygius, from outcrops in the Holzmaden quarry in Germany.

Both the body outline and remnants of internal organs are clearly visible in the specimen. Remarkably, the fossil is so well-preserved that it is possible to observe individual cellular layers within its skin.

Stenopterygius quadriscissus
Researchers identified cell-like microstructures containing pigment organelles on the surface of the fossil.

This ancient skin revealed a feature we recognized from marine dwelling animals, the ability to change colour, providing camouflage from potential predators. They also found traces of what might have been the animal's liver.

When they put some of the tissue through chemical analysis, it was consistent with what we'd look for in adipose tissue or blubber. Not surprising as dolphins today use blubber for buoyancy and to help to thermally insulate for thermal regulation in cold seas. It's a highly useful adaptation and one that led me to wonder what other vertebrates might use blubber or some other adaptation to maintain a warmer body temperature independent of icy cold conditions.

Today, blubber is an important part of the anatomy of seals, walruses and whales. It covers the core of their bodies, storing energy, insulating them from cold seas and providing extra buoyancy. 

A rather fetching Walrus, Odobenus rosmarus
Fat and blubber are not the same. The main differences are their consistency and blood supply —  blubber contains many more blood vessels than fat, and is far denser because it's made up of a mix of collagen fibres and lipids.

Blubber layers can be incredibly thick. Walruses deposit most of their body fat into a thick layer of blubber — a layer of fat reinforced by fibrous connective tissue that lies just below the skin of most marine mammals.

This blubber layer insulates the walrus and streamlines its body. It also functions as an energy reserve. Blubber covers the core of their bodies but does not grace their fins, flippers and flukes.

Not all marine animals need blubber. Our cold-blooded marine friends: sharks, crabs, fish, are able to let their body temperatures dropdown to very chilly levels, some as low as 36 degrees Fahrenheit.

They have a few tricks up their sleeves to make this happen. Sharks have evolved specialized physiology to keep their metabolic rate high and their hearts are able to contract in the icy depths because of a special protein. These adaptations allow sharks to enjoy a wide range of habitats and follow their food from warm tropical seas to the icy waters of the North Pacific.

Gray Shark, Carcharhinus amblyrhynchos
With the advent of genetics, we've now learned that the Great White Shark’s genetic code and many of the proteins they use to control metabolism are more closely related to humans than zebrafish, the quintessential fish model.

In a very cool bit of science, researchers sequenced a shark's heart transcriptome – the messenger molecules produced from the shark’s genome, including those active in making proteins. Then they categorized the proteins based on their functions.

What they found that the proportions of white shark proteins in many categories matched humans more closely than zebrafish. Of particular interest was that white shark had a closer match to humans for proteins involved in metabolism. Great White Sharks have a rare trait in fish called regional endothermy. This allows them to keep the body temperature of some of their organs warmer than the ambient water — a highly useful trait for fast swimming, digestion and hunting in colder waters.

References and additional reading:

Fancy a read? Check out the work by Michael Stanhope, professor of evolutionary genomics at Cornell’s College of Veterinary Medicine, and scientists at the Save Our Seas Shark Research Center at Nova Southeastern University (NSU). He published the shark genetic study in the November 2013 issue of BMC Genomics. It lays the foundation for genomic exploration of sharks and vastly expands genetic tools for their conservation.

Johan Lindgren, Peter Sjövall, Volker Thiel, Wenxia Zheng, Shosuke Ito, Kazumasa Wakamatsu, Rolf Hauff, Benjamin P. Kear, Anders Engdahl, Carl Alwmark, Mats E. Eriksson, Martin Jarenmark, Sven Sachs, Per E. Ahlberg, Federica Marone, Takeo Kuriyama, Ola Gustafsson, Per Malmberg, Aurélien Thomen, Irene Rodríguez-Meizoso, Per Uvdal, Makoto Ojika, Mary H. Schweitzer. Soft-tissue evidence for homeothermy and crypsis in a Jurassic ichthyosaur. Nature, 2018; DOI: 10.1038/s41586-018-0775-x

North Carolina State University. (2018, December 5). Soft tissue shows Jurassic ichthyosaur was warm-blooded, had blubber and camouflage. ScienceDaily. Retrieved September 7, 2019, from www.sciencedaily.com/releases/2018/12/181205134118.htm

Photo: By Haplochromis - Own work, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=5825284