THE BONE MINE

Some time ago we looked at a Permian Paleobotanical Pompeii found during mining operations in China.  A just published paper announces the discovery of another fantastic window on the past uncovered by strip mining, this time in Spain.  This publication documents the work done primarily by Luis Alcala and his colleagues from the Museo Aragonés de Paleontología in Spain. 

While Europe has a long history of dinosaur discoveries, including the first dinosaurs ever illustrated, described, and named in scientific literature, the continent lacks the spectacular bone quarries, such as Dinosaur National monument, that are seen in western North America.

Limbs, vertebrae, and other bones of a plant eating dinosaur from the strip mine floor.

 

The Spanish site contains a remarkably diverse array of fossils, including several kinds of dinosaurs, crocodiles, turtles, boney and cartilaginous fish, invertebrates (including bacteria!) and plants and pollen.  The lignite coal mine northeast of Teruel is managed by a family run company Sociedad Anonima Minera Catalano-Aragonesa, which has been running excavations in the area since 1919.  The fossil producing level is fortuitously situated immediately below the lowest level where the coal is extracted.  This means that when the mining is finished at a particular area the exposed rock on the mine floor is the fossil producing bed.  The fossils are Albian (Lower Cretaceous) in age and this is the most important Albian dinosaur site yet known from the continent. The fossils were deposited in marshes that were part of a system of lagoons and barrier islands, similar to those along the coastline of present day North Carolina.

Scanning electron microscopy image of a strip mine coprolite.  Rod-shaped objects are fossilized bacteria.

 

 Some 150,000 m²  of the bone deposit have been already been prospected and since it is newly exposed, there is no covering or vegetation to hide the fossils.  Without the mining these fossils would remain buried hundreds of meters below ground, completely unknown to paleontologists.

The Albian dinosaur bone mine in Spain.  Fossils occur in the floor of the mine.  Note large orange colored mining machinery for scale.

 

However, paleontological work in an active mine is fraught with danger and scientists must work around the mine operations.  Some of the fossils collected are in extreme danger from mine activities and their collection is rushed.  In other areas a more standard paleontological excavation and mapping program can be followed.  Because this is a strip mine, with a road spiraling down into the mine, the contours of the mine are being changed by earth moving machinery all the time of time, , water pipes are installed and moved, roads are relocated, immense trucks are driving across the area, erosion occurs, etc..  Safety of both company and scientific staff is of paramount importance. 

The skull of a strip mine goniopholid crocodilian, seen from above and with snout towards right.

Nevertheless the rewards are great, with over 4,000 bones having been collected by the end of 2011.  And as the mining proceeds more of the fossil layer will be exposed and more fossils discovered.  The paper appearing today is a preliminary description of the site, its geology, and the fossils. Numerous other, more detailed papers, are currently being written as we speak.  I, for one, am looking forward to reading them.  

PHOTOS

All photos from Alcala et al. 2012 (see SOURCES below).

SOURCE

Alcala, L. et al. 2012. A new Lower Cretaceous vertebrate bonebed near Arino (Teruel, Aragon, Spain); found and managed in a joint collaboration between a mining company and a paleontological park.  Geoheritage, published on line 19 September 2012   DOI 10.1007/s12371-012-0068-y  (freely available at http://www.springerlink.com/content/7013q83t03x1500q/fulltext.pdf)

OUT ON THE TOWN WITH FOSSILS

Fossils can be frustratingly, even maddeningly, rare, especially those of vertebrates. Invertebrates, including the hard parts of single cell organisms, can sometimes be so abundant as to make up nearly all of the composition of a rock. Since some types of rocks are used in buildings it's not surprising that fossils sometimes show up in very public places.   One only needs to look for them to see them.

A spiral, chambered ammonite shell in vertical cross section, City Creek Mall.

The use of limestone as a decorative building stone often results in abundant fossils that most people simply walk past without ever noticing.  The newly opened City Creek Mall in Salt Lake City, with many highly polished slabs of Mesozoic limestone lining its stairways and escalators, is a fine example of this.

The pen shaped internal skeleton of a squid-like belemnite, City Creek Mall.  In the living animal the head and tentacles would be on the right.

Uncertain fossil, probably sponge or coral, in cross-section, City Creek Mall

I've even seen cross sections of fossils shells in the limestone partitions in men's rooms stalls.  I had more pressing concerns on my mind at the time and didn't think of taking my camera with me into the bathroom, so sorry no photos.


The sandstone of the 190,000,000 Early Jurassic Nugget Sandstone is a common building stone in Salt Lake City and environs.  This rock, formed by a vast sand dune desert that covered most of the intermountain west at that time, can be nicely split  and used as paving stones. If you keep your  eyes open, you might catch something like this....

An ancient scorpion trail in a stone stairway made of slabs of Nugget Sandstone, undisclosed site.  Each circular pit is a leg impression. Direction of travel is to the right.

Criss-crossing fossil trails made by arthropod larvae preserved in sidewalk slabs of in Nugget Sandstone, undisclosed site.

Three footprints made by a long extinct reptile walking up the front slope of a dune in the Nugget Sandstone, undisclosed site.  Note the clear toe impressions in the upper track.

Nugget walkway slabs are also sold to the public.  Lowe's carries large numbers of them in our area and I've often stopped to take a quick peek at the piles.  Good thing too, because one day there was a single slab with hand and foot impressions of a reptile that walked across these ancient dunes eons ago.  For $6.95 it was mine.

Reptilian hand and foot impressions, Nugget Sandstone, Lowe's, Vernal.

Homeowners pile up rocks on their property to form walls, for decorative purposes, or just to get them out of the way.  This ring of rocks around the base of a tree on a front lawn shows fragmentary remains of Cretaceous plant foliage.

However,  one cannot always believe one's eyes. You need to be alert for pseudofossils --- features, shapes, etc. that look like a fossil but are of inorganic origin.  The example below is one of the pillars on the front of the Utah State Capitol building.  The pillar, as most of the buildings at the Capitol, is granite, a volcanic rock that forms from the solidification of molten rock in ancient magma chambers. Jellyfish are remarkable for sure, living in environments ranging from the cold waters of the polar regions to the warm waters of the tropics, in fresh water and salt water, and from sunny surface waters to the deepest parts of the ocean in excess of 30,000 feet. Yet no jellyfish are known to live in magma chambers. The dark shape is a natural curiosity of dark mafic minerals that crystallized into a shape that the human visual system and memory interprets as a jellyfish.

 At the County Court House in Vernal, Utah there's a plaque mounted on a block of Cretaceous Frontier Sandstone However, on the backside of the block there's more interesting reading. Hidden behind a tall patch of flowers is the impression of a fairly large Cretaceous ammonite mollusk.

Memorial plaque celebrating Utah's statehood centennial, Vernal.

The more interesting back side of the memorial block, with the impression of a spiral ammonite shell.

And speaking of fossil impressions, one of my earliest fossil memories is that of a stone shed on my grandmother's property in New Jersey. It was built of stones rounded by tumbling for millennia in river beds . Of the hundreds of stones cemented in its walls, one cobble bore the distinct impression of a small brachiopod. When the gaze of my young eyes first fell upon this fossil it seemed as amazing as any treasure of ancient Egypt. How no one had seemed to notice it was beyond me.  Even more puzzling was everyone's apparent lack of interest even after it was pointed out to them. For some inexplicable reason they wouldn't let me take a hammer and bash it out.  I suppose they didn't want me to damage the wall.  Besides, they were sure that I would soon certainly grow out of my childish mania about fossil. HA-HA, the joke was on them!

PHOTOS

All photos by the author, with the exception of the reptile tracks from an undisclosed site which is courtesy of Brian Switek..

IF YOU LOVE THEM TELL SO

For the third time in less than a month someone I know has buried an adult child who died way too young. The most recent, and the most personal, was my nephew Matt Den Bleyker, who passed away suddenly from a chronic illness, at the tender age of just 25.

Matt Den Bleyker (1986-2012) and Bella

Too often our hectic and rushed lives make talking with friends and loved ones a hurried affair. Phone calls are brief, letter writing is a lost art, emails can be impersonal, and text messages are restricted to just 140 characters. It's worth stopping for a moment and thinking about that.  If there's someone you care about, let them know. No one ever says "I told him/her that I loved them too many times."  More commonly, people wish they had just one more chance to let the deceased know how much they cared. We often get caught up in the things of everyday life and put off meeting or calling those closest to us, with the best of intentions that "I'll do it tomorrow."  So if you love someone, tell them.  That goes double for the men who say "me too" on the phone when whomever they are talking to tells them they love them.  Do you think anyone overhearing that doesn't know what's being  said?

While I am an atheist and hold no religious or spiritual beliefs, I've always been impressed by the truth of a passage in the Hindu religious epic The Mahabarata, which goes

"Question: And what is the greatest mystery of all?

Answer:  That Death stalks us everyday, yet we live as though we were immortal."

If we work hard at it and are lucky enough to get a good roll of the genetic dice, we just might squeeze
out nine decades wandering the surface of this rocky inner planet orbiting a mediocre star in the outer part of one of the arms of the insignificant Milky Way spiral galaxy.  Often it's less, sometimes way too less.  So use it as best you can and enjoy the ride. And if you love someone, stay in ouch with them and take -- no make -- the time to tell them. You will never regret it.

BRINGING THE DEAD BACK TO LIFE

I haven’t done any book reviews on Land of the Dead because many of the paleontology books I read are filled with descriptions of bones and detailed analyses of evolutionary relationships.  Interesting for me, but pretty dry stuff for the non-specialist.  However, the just published volume, Dinosaur Art, is a different kind of book, one that both paleontologists and non-paleontologists will find fascinating.The specifics are Steve White (editor) 2012 Dinosaur Art: The World's Greatest PaleoArt.  Titan Books: 188 pages. www.titanbooks.com $34.95

With a few notable exceptions, much of the fossil record of past animal life consists of only hard parts ---- jaws, teeth, shells, bones. In the case of many fossil vertebrates, skeletons may be diagnostically different but incomplete, sometimes woefully so. Given a good enough skeleton, or enough partial remains, a complete reconstruction of the skeleton can be undertaken.  That’s often as far as it goes for paleontologists.  Fleshing out those bones and bringing the dead, and the environment they lived in, back to life falls to those talented artists who specialize in paleontological art.  I’m not talking about scientific illustration, which serves technical publications by carefully and accurately showing anatomical details.  Rather these paleoartists, working in close collaboration with paleontologists, restore the past denizens of our planet in their full glory.  Their awesome talents leave us with our most striking visions of those long lost worlds.

The Cretaceous mammal Repenomamus robustus carrying off a young dinosaur.  Fossils of this mammal have been found with the bones of its last meal, hatchling Psittacosaurus dinosaurs, preserved in its stomach area (artist: Julius Csotonyi).

In the late Cretaceous of Asia a Tarbosaurus invites two Gallimimus to brunch (artist: John Conway).

Dinosaur Art: The World’s Greatest PaleoArt is a sumptuous book, a visual treat featuring numerous pieces by 10 of the world’s leading practitioners of these dark arts. It is oversized, allowing for large size reproductions which makes the pieces really shine.  The cover art, by Raul Martin, showing the giant Cretaceous crocodilian Deinosuchus preparing to dine on a tyannosaurid Albertosaurus, is one of the most striking pieces of paleoart I have ever seen.  It is dramatic, powerful, realistic, and certainly draws one’s attention to the book.  I don’t see how one cannot fail but to open this volume after seeing the cover.  Given the very large number of beautiful illustrations and the very high quality of those reproductions the $34.95 price is quite reasonable.

The remarkable large, horned, South American predatory dinosaur Carnotaurus sastrei (artist: Luis Rey).

Gone are the days of a restored dinosaur standing still on a blank background. Modern paleoartists often recreate not just the animal but the total environment it lived in, frequently in spectacular detail.  The scene is sometimes shown from an intriguing angle, a lizard’s view looking up at a massive sauropod dinosaur or a pterosaur’s view of a dinosaur herd as it soars effortlessly above the behemoths. Modern paleoartists use a wide range of media.  Acrylics, oils, pencil, ink, digital, and digital and photographic combinations are used to render powerful and dynamic images. Some are so detailed and realistic that they seem to be photographs of living animals.

Leedsichthys, a whale sized filter-feeding fish of the Mesozoic ocean (artist: Robert Nicholls).

360 million years ago, giant eurypterid sea scorpions (Pterygodus), swim above  the sea floor of New York (artist: Doug Henderson).

Each chapter in Dinosaur Art highlights a single artist.  In addition to showcasing the  artwork there is an interview with each artist that provides insight into how they became interested in paleoart, their approaches and techniques, which media they prefer and why, their inspirations, and many other fascinating details about these necromancers.

The long legged, running crocodilian Kaprosuchus saharicus, from the Late Cretaceous of Niger (artist: Todd Marshall).

Bad day at the tar pits, as a sabre-toothed cat (Smilodon) attacks an already entrapped giant ground sloth, Paramylodon (artist: Mauricio Anton).

The title Dinosaur Art is a wee bit misleading, although it will help sell the book.  Granted the bulk of the art is of dinosaurs, but there are many other fossil vertebrates featured, ranging from Paleozoic amphibians to Pliocene hominids. Maruricio Anton, one of the artists, specializes just in  rendering fossil mammals and Cenozoic environments.  The book focuses solely on two dimensional art, so no sculptures are shown. 

Towering nearly 15 feet tall, the aptly named Gigantoraptor, both toothless and feathered, struts its stuff in the Cretaceous of Asia (artist: Raul Martin).

 

The crocodilian Pristachampsus runs down two early horses (Hyracotherium) (artist: John Sibbick).

In this post I have reproduced one piece from each artist, to give you a sense of the book’s beauty and the range of fossil vertebrates illustrated.  It was difficult to pick just one, as there are many illustrations for each artist. If you find these interesting or enjoyable, get a copy of this book.  You will not be disappointed.  You will be amazed and enthralled.

 

Two giant pterosaurs (Quetzalcoatlus northropi) exchange insults with a juvenile T. rex (artist: Greg Paul).

THE JOYS OF JELLIES

Musing over the medusae of transparent Moon jellies (Aurelia sp.), at Monterey Bay Aquarium

ETHEREAL JELLIES

While I’ve never seen an organism I would call ugly, some are certainly more pleasing to the eyes than others and among the most beautiful of all are jellyfish.  I recently visited the Monterey Peninsula in California and had the opportunity to spend a day in the Monterey Bay Aquarium, as spectacular an array of living exhibits of sea life as one might ever hope to see.  

  

I was particularly intrigued by the extensive exhibits of living jellyfish.  These diaphanous, almost otherworldly, creatures, are mesmerizing to watch as they gently drift and pulsate in their large tanks.  Some are transparent and nearly invisible without the aquarium lighting while others are opaque or even somewhat brightly colored. 

Unidentified jelly, Monterey Bay Aquarium.

White spotted jelly (Phyllorhiza punctata), Monterey Bay Aquarium.

Moon jelly (Aurelia sp.) Monterey Bay Aquarium

It was exciting to see many hundreds of jellies while kayaking in the opaque waters of the kelp forest at Monterey. However, watching them in large exhibit tanks where currents, water filtration, and lighting are controlled allow you to a more intimate, close up, and more dramatic view.   

Blue blubber jellyfish (Catostylus mosaicus), Monterey Bay Aquarium

Pacific sea nettle  (Chrysaora fuscescens) Monterey Bay Aquarium

Crown jellyfish, Monterey Bay Aquarium.

 These are among the most popular attractions, which is a good thing because maintaining a collection of jellies is a complex and expensive proposition.

Pacific sea nettles spark the imagination and wonder of a future marine biologist at Monterey Bay Aquarium.

Although primitive, jellies were likely the first group of multicelluar organisms to achieve movement through muscular activity.  First appearing in the Cambrian, some 500+  million years ago, jellies are a very successful group and an important component of modern marine ecosystems.  They are universally carnivorous, feeding on a wide range of organisms, from small invertebrates to boney fish, with some species specializing in feeding on other jellies.  Jellies have exploited an amazing range of environments, from cold arctic oceans to warm tropical seas and from sunny, surface waters to the abyss, 25,000+ feet deep with frigid cold, immense pressure, and eternal darkness.  There are even freshwater species. 

 

A swarm of golden jellyfish, Mastigias cf. papua etpisoni in the freswater lake of Palau.

The crown or helmet jellyfish (Periphylla periphylla) inhabits ocean depths down to 7,000 meters (23,000 feet)!

 

The smallest jelly, the Irukandji, is  a mere 5 millimetres (0.20 in) wide, with tentacle close to 1 meter in length.  The lion’s mane (Cyanea capillata), on the other hand, reaches a body diameter of 2.29 m (7 feet 6 inches) with tentacles 37 m (120 feet) long.

The Irukandji (Malo kingi) is both the smallest and deadliest jellyfish.

 Cyanea capillata, the lion's mane is the largest known jellyfish and inhabits cold waters.

Remarkably, jellyfish have diversified and survived with a very primitive body plan.  The umbrella shaped body, or bell,  pulsates for locomotion while the long trailing tentacles bear stinging sells for capturing and killing prey. Jellies lack a centralized brain, instead having a diffuse network of nerves running across their epidermis. However, their behavioral responses to tides, currents, other jellies (friendly and predatory), daily vertical and horizontal migration, navigation, etc. suggest that this is due to more than just simple reflexes.  There is certainly some coordination of stimulus and response within the nervous system.

Jellies don’t need gills or a respiratory system because they absorb oxygen directly through the body wall. They also lack a circulatory system. The mass of the bell is composed of a non-living jelly-like substance, the mesoglea, sandwiched between two layers of skin, each only one or a few cells thick. To top it off, they are 99% water!  Most jellies have light sensitive organs around the margin of their bells that can discern patterns of light and dark but little detail. Yet in spite of this simplicity and apparent fragility, jellyfish have weathered the five great mass extinctions in the history of life on Earth and continue to flourish and survive.

 

STONE JELLIES

Rhizostomites admirandus, a large, late Jurassic jellyfish fossil from the Solnhofen Limestone.

 

Often, while I am looking at living organisms several questions come to mind. What are these things related to?  How far back in time does this group go? What is their fossil record like?  In the case of jellies, which lack any hard parts and seem to be composed of almost nothing, the fossil record question seems particularly intriguing. 

Given that jellies are, well gelatinous, they would seem to have little chance of being fossilized.  A quick glance of the scientific literature might give the impression that many fossil jellies have, in fact, been discovered, going back into the latter part of the 19^th century.  However, more recent analyses with a more critical eye have shown that many of these circular and/or domed fossils have other origins.  A wide range of things have been identified as fossil jellies, such as trace fossils of marine invertebrates (like infilled feeding and dwelling burrows of worms and crustaceans),  fossil algae, and sedimentary structures of inorganic origin(such as sediment disruption from ancient releases of gases), concretions, sand volcanoes, evaporite pseudomorphs, etc.   

The supposed jellyfish Laotira cambria ultimately turned out to be fossilized, infilled burrows of ancient marine invertebrates.

Sometimes the jelly  is really the partial remains of other kinds of animals, such as Peytoia, the Cambrian jellyfish (below left) that turned out to be the peculiar circular mouthparts of the giant marine arthropod Anomalocaris (below right), the 2 meter predatory terror of the Cambrian seas.

Nevertheless, there are still some fossils that are bonafide jellies.  The record is sparse, no more than nine jelly bearing rock units can be identified with certainty (Young and Hagadorn 2010).  Some of these rock units may be the same unit, but are physically  separated and not continuous, which means that distinct jelly bearing rock units may well be less than nine. In many cases the units have yielded less than 30 specimens in total.  “This is a shockingly small fossil record for groups with such importance in modern seas (Young and Hagadorn 2010).

The beautiful, graceful jelly bell-shape in the ocean often transforms into an amorphous gelatinous blob once it washes onshore.  Tentacles are delicate and are the first parts of a jelly to disappear as decomposition proceeds.  The mesoglea rapidly dehydrates when out of water so the bell may become distorted or shriveled on the beach.  So recognizing a fossil jelly (and being able to differentiate it from other kinds of fossils and sedimentary structures) can be a difficult undertaking, often requiring the careful study of  multiple specimens and considerably more detective work than, say, recognizing a bone is from a dinosaur.

A modern swarm of jellies stranded on the beach by a retreating tide.

Jellies occur in enormous numbers under the right conditions in right environment.  These swarms sometimes come in with the tides and are stranded on the beach when the sea retreats. As they continue to pump their bells in an attempt to escape, they often fill their stomach and other internal cavities with sand.  Similar ancient strandings can produce spectacular fossil concentrations. In Wisconsin and New York on ripple marked intertidal beds of Cambrian age (more than 510,000,000 years old), have produced tens of thousands of jellyfish fossils. 

 A fossilized swarm of stranded jellyfish from the Cambrian of Wisconsin. A: rippled beach sand with numerous jellyfish impressions. D, E, F closeup of individual jelly fossils.

Interestingly, there are no mass strandings of jellies known in the fossil record after the Cambrian period.  This absence is not because jellies no longer occurred in mass groups, we know they continued to do so right up to the present.  Rather this peculiar record is the result of other biological factors.  During the Cambrian ALL life was in the oceans. There was no plant or animal life on land.  I don’t mean no reptiles or amphibians on land, I mean NO life on land.  Hence there were no shoreline scavengers to feed on the dead jellies.  Furthermore, during the Cambrian organisms occupied only the surface of the sea floor --- no groups had yet evolved to burrow and feed within sea floor and beach sediments.  So there were no invertebrate sediment dwellers to consume the jellies after they were buried.

Jelly fossils are also known from other kinds of ocean environments. Cambrian subtidal deposits of the Marjum Formation have yielded exceptional jellies that, unlike the Wisconsn and New York localities, have soft anatomy, such as tentacles, muscles, and reproductive organs, clearly preserved.  

Unnamed fossil jellies (left) and living representatives of the groups each fossil belongs to, Marjum Formation, UT.

The ironstone concretions of the Mazon Creek of Illinois, approximately 300 million years old, have yielded more than 35,000 specimens of jellyfish!!!.

The fossil cubozoan jellyfish Anthracomedusa turnbulli, from Mazon Creek  with a life restoration.

  

The Late Jurassic Solnhofen limestone, most famous for producing skeletons of Archaeopteryx, the oldest bird, contains abundant large jellies, up to 50 cm in diameter. Like the Marjum, these fossils also show remarkable soft tissue preservation.

A partial fossil of the large Solnhofen jelly Rhizostomites admirandus

Close up of Rhizostomites admirandus specimen above, showing impressions of circular muscles around the margin of the bell.

 The soft tissue preservation in the Marjum and Solnhofen are the result of peculiar bottom conditions in each ocean.  The Marjum has anoxic bottom waters, meaning that the oxygen levels in the water were extremely low. In the Solnhofen the bottom waters were hypersaline.  In each case, the result was that there were no scavenegers or bottom dwelling fauna to feed on or decompose the jelly carcasses after they sunk to the bottom.  The Francis Creek jellies were preserved in the brackish waters of an estuary, where iron mineral formation around dead organisms preserved many soft body animals.

 

Surprisingly, no unambiguous jelly fossils have been found in post-Jurassic rocks. Although some have been reported closer study has revealed them to be feeding and dwelling trace fossils. So for the last 150,000,000 years of Earth history there is no fossil record for these beautiful carnivores!  Hopefully future discoveries will begin to lift the veil on this dark and unknown chapter of jelly evolution.

Pacific sea nettle tank, Monterey Bay Aquarium.

A NOTE TO NITPICKERS

I have used jelly and jellyfish interchangeably here and both in the popular sense.  I am aware that true jellies are members of the class Scyphozoa, that hydromedusan jellies (including the Portugese Man of War ) are Class Hydrozoa, and cubozoan jellies are, well, Class Cubozoa. I’ve written about “jellies” in the sense that they are all medusae, i.e. umbrella shaped free swimming cnidarians, because most general followers of Land of the Dead would think of them as jellyfish.

I haven’t included comb jellies in the discussion because they belong to an entirely different phylum of animals (Ctenophora) with only a distant relationship to the Cnidaria. Yes, most people would think of a comb jelly as a jellyfish, but that was just too much of a phylogenetic stretch for me.

And yes, I know that jelly fish are not fish.

SOURCES

Albert, D.J. 2011. What’s on the mind of a jellyfish? A review of behavioural observations on Aurelia sp. jellyfish.  Neuroscience and Biobehavioral Review 35(3): 474-482.

Graham Young: Ancient Shore Blog: Recognizing Ancient Jellyfish

http://ancientshore.com/2010/12/05/recognizing-fossil-jellyfish/

 

Graham Young: Ancient Shore Blog: Anthracomedusa

http://ancientshore.com/2009/11/17/monday-museum-6-box-jelly/

                                                                                                      

Angier, N., June 6, 2011. So Much More Than Plasma and Poison

http://www.nytimes.com/2011/06/07/science/07jellyfish.html?_r=2

Cartwright, P., Halgedahl, S.L., Hendricks, J.R., Jarrad, R.D., Marques, A.C., Collins, A.G., and Lieberman, B.S. 2007.  Exceptionally preserved jellyfishes from the Middle Cambrian. PloS One 2(10): e1121

Garm, A., Oskarsson, M., and Nilsson, D.E. 2011.  Box jellyfish use terrestrial visual cues for navigation.  Current Biology 21(9): 798-803.

Hagadorn, J.W. and Belt, E.S. 2008.  Stranded in upstate New York: Cambrian scyphomedusae from the Potsdam Sandstone.  Palaios 23: 424-441.

Hagadon, J.W., Dott, R.H., and Damrow, D.  2002. Stranded on a Late Cambrian shoreline: medusae from central Wisconsin. Geology 3092): 147-150.

Selden, P. and Nudds, J. 2004. Evolution of Fossil Ecosystems.  Chicago University Press: 160 pages. (see chapter on Mazon Creek Beds, pages 59-70)

Young, G.A. and Hagadorn, J.W. 2010.  The fossil record of cnidarian medusae.  Palaeoworld 19: 212-221.

 

PHOTOS

All photos in Monterey Bay Aquarium by the blogger.

Golden jellyfish: Credit: Michael Dawson, University of California at Merced

http://www.biology-blog.com/blogs/archives/Animal-science-blog/1434973288-Sep-15-2009.html

Periphylla periphhylla

http://oceana.org/en/explore/marine-wildlife/deep-sea-jellyfish

Irukandji

http://www.oddee.com/contrib_9259.aspx

lion’s mane jelly

http://www.bforbel.com/2012/01/worlds-largest-jellyfish-measured.html

Rhizostomites admirandus

http://commons.wikimedia.org/wiki/File:Rhizostomites_admirandus_1.JPG and

http://www.solnhofen-fossilienatlas.de/fossil.php?fossilid=1466

http://www.solnhofen-fossilienatlas.de/fossil.php?fossilid=1466

Laotira cambria

http://ancientshore.com/2010/12/05/recognizing-fossil-jellyfish/

Peytoia

http://www.trilobites.info/background.html

Anomalocaris

 http://paleoking.blogspot.com/2009/09/anomalocaris-first-super-predator.html

Modern jellies stranded on beach:

Vultures and Dead Jellyfish: Loose Leaf Noes Blog

http://www.looseleafnotes.com/notes/2007/02/vultures_and_jellyfish.html

Cambrian jelly stranding in Wisconsin:

Hagadorn, J.W. and Belt, E.S. 2008 (see citation in Sources below).

Marjum Formation fossil jellies from Utah

http://news.nationalgeographic.com/news/2007/10/071031-jellyfish.html

Anthracomedusa

http://ancientshore.com/2009/11/17/monday-museum-6-box-jelly/