Mammoths and Mastodons were Year Round Residents of the Ohio River Valley during the Late Pleistocene

The bones and teeth of an extinct animal provide scientists with information about the life history of that particular individual.  Recently, 2 scientists analyzed the chemistry of 8 mammoth ( Mammuthus columbi ) and 4 mastodon ( Mammut americana ) teeth collected from Hamilton County, Ohio and Bullitt and Gallatin Counties, Kentucky–in other words, the Cincinnati area.  They determined 11 of these animals spent their entire lives in what was to become the Cincinnati area.  They also learned 7 of the mammoths ate different plant foods than the mastodons, but the diet from 1 individual mammoth did overlap with mastodon diets.

Hamilton County, Ohio

Mammoths and Mastodons lived year round in the Ohio River Valley.  They were 2 completely different species of proboscidean.

Scientists are able to determine where an animal lived during its lifetime by measuring the ratio of strontium and strontium isotopes in their teeth.  Strontium leaches from local bedrock into the water supply, and animals absorb the strontium into their bones when they drink.  Different geographical regions exhibit different ratios of strontium isotopes, so it’s possible to figure out where an animal spent time during its life.  A previous study of mastodon and mammoth teeth collected from Florida determined mastodons there migrated back and forth from central Florida to central Georgia, while Florida mammoths did not migrate.  But this study suggests most of the mastodons that lived in the Ohio River valley did not migrate.  However, there were exceptions.  The strontium ratio from 1 specimen indicated this individual wandered north from either north Georgia or southern Tennessee to the Ohio River valley.  The authors of this study estimated this could have been accomplished in as little as 5 days based on how fast modern elephants can travel.

The bone chemistry tells us mammoths mostly ate grass, while mastodons ate plants that grew in forested environments.  But again there was 1 exception–1 mammoth that fed upon forest vegetation.  During the Last Glacial Maximum much of this region was a cool arid steppe environment.  After the nearby ice sheet retreated, the steppe was transformed into an open spruce parkland, then eventually an oak and hardwood dominated forest.  This mammoth apparently adapted to the latter changes.

Mammoths and mastodons had no need to migrate away from the Ohio River.  The rich floodplain habitat and numerous mineral licks provided enough nutrition to support year round populations of both.

Reference:

Baumann, Eric; and Brook Crowley

“Stable Isotopes Reveal Ecological Differences among now Extinct Proboscideans from the Cincinnati Region, USA”

Boreas 2015

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The Lost Pleistocene World of the Georges Bank

I’m taking an imaginary vacation this week away from southeastern North America to visit one of the few ice free spots in the northeast during the Last Glacial Maximum.

The Georges Bank used to be one of the richest fisheries in the world.  During the LGM it was an extension of the mainland inhabited by many species of megafauna.

East of the Gulf of Maine the sea floor rises 330 feet.  Both cold and warm currents sweep over this submerged island, and light can reach the shallow bottom which ranges between 10-50 feet deep.  The light and the mixture of currents create an ideal habitat for a rich zone of phytoplankton.  The phytoplankton  is the foundation of a food chain that feeds over 100 species of fish, and the gravel bottom, eroded from glacier-pushed rocks, provides excellent spawning structure.  One of the richest fisheries in the world used to be found here before fleets of international factory ships decimated the naturally abundant stocks in the 20th century.  Long before Basque fishermen discovered this amazing fishing ground in the 11th century, the Georges Bank existed as a special and beautiful part of the North American mainland.

20,000 years ago, a massive glacier, one mile thick, depressed the entire area of what’s now New England.  The weight of all that ice literally pushed the earth’s crust down.  Glaciers from previous Ice Ages had already gouged a trough off what today is Maine’s coast, explaining why the Gulf of Maine is so deep.  The most recent glacier, the Laurentide, advanced over the dried-out trough toward the receding Atlantic Ocean.  The ocean was receding because so much of the world’s water was becoming locked up as ice.  But on the narrow strip of higher land in the vicinity of the Atlantic Ocean, the climate was warmer, perhaps keeping the glacier at bay.

The Georges Bank was an extension of the mainland, 140 miles long and 75 miles wide.  It was bounded on one side by the enormous glacier, and on the other by the ocean.  The climate consisted of cool summers, thanks to the monstrous ice cube next door, and snowy but bearable winters because moderating oceanic winds prevented temperatures from plummeting as low as occurred farther inland.

Icebergs drift off shore here within site of the sand dunes where beach grass, beach pea, and bayberry grow.  Walruses swim to and fro from small ice floes to the beach.  Behind the beach dunes, brackish lagoons host ducks and geese and loons.  Forests of pine, spruce, fir, birch, and alder cover most of the island, interrupted here and there with cranberry bogs.  Grassy windswept steppes are located on the northern part of the island and on nearby Sable Island.

Tim Wichinbach dredged up this partial mastodon tusk while fishing for scallops over the Georges Bank.  Fishermen have accidentally caught Pleistocene fossils in their nets in more than 40 sites on the Georges Bank.  The list of accidental bycatch includes fossils of mastodon, mammoth, woodland musk-ox, stag-moose, long-nosed peccary, walrus, bearded seal, and wood from ancient forests.  Reportedly, tapir and ground sloth bones have also been dredged, but I can’t find documentation in the scientific literature.  A good comprehensive catalogue of Georges Bank fossils has not been published.  Information is limited to 3 old articles from very obscure scientific journals.

An early October snowstorm covers a north facing slope, yellow grass tufts stick above the white layer.  A herd of dwarf mammoths and lean musk-oxen graze on the grass, the mammoths clearing the snow with their tusks.  The horns on the musk-oxen cover their skulls like football helmets.  Closer to a forest edge in a low lying area on the other side of the slope, steam rises from a bog.  A huge solitary stag-moose stands ankle deep, a mouthful of green slime hangs from his mouth.  I think it’s a clump of duckweed.  In the open forest mastodons use their trunks to tear branches from young spruce and red pine saplings.  I can hear them grind the cellulose between their giant molars.  One of the hairy elephants has an itchy hindquarter.  He backs up against a jack pine and rubs, but it’s a dead rotten tree, and it snaps and falls over, startling a spruce grouse which flies away in panic.

5,000 years later, the climate warms, and the Laurentide glacier melts as rapidly as 300 meters a year.  Birch forests colonize the newly available land, and the animals follow, but soon, rising sea levels inundate not only the Gulf of Maine, but areas of the coast that are currently above sea level, including the future sites of Augusta and Bangor.  As the heavy weight of the glacier recedes, the land area of Maine rebounds because there is nothing pressing the earth’s crust down here any more.  This is known as isostatic rise.  Meanwhile, the Georges Bank has become a true island, surrounded by ocean water on all sides.  Eventually, sea levels rise more, dooming the animals that didn’t migrate west.  The Grand Banks to the north also falls below sea level.  Only a small spit of sand, the highest point of Sable Island, still remains above sea level in this region.

A Sad Timeline of the Rape of the Georges Bank Fishery

The Georges Bank was an astonishingly rich fishery.  When first discovered by Basque fishermen around 1000 AD, they kept it a secret for over 500 years.  Cod were so abundant fishermen could just stick a basket in the water and 50 pound cod would fill it immediately.  Early colonists living near Cape Cod complained about having to eat lobster every night.  The cod take continued to remain strong until the 20th century when industrial ships from all over the world caught thousands of tons of fish.  Finally, in 1977 the U.S. banned foreign trawlers but it was too late.  American fishermen continued to overfish and now there’s little left–a testament to man’s shortsighted greed.  It’s another sickening example of poor natural resource management.

1830–Right whales nearly exterminated

1850–Halibut disappear

1977–Herring fishery collapses

1994–Commercial cod fishing collapses.  Law passed to outlaw commercial cod fishing proves ineffective.  It’s still not policed.

In my opinion all commercial fishing on the Georges Bank should be banned for 20 years.  Maybe then, it would recover.

The Congaree National Park, Home of the Giants

The Congaree National Park in South Carolina still held some surprises for me, even though I traversed this biggest last stand of bottomland forest in 1988.  Then, it was just a National Monument but in 2003 was upgraded to National Park status.  The park hosts 17 national and/or state record trees, including an 156 foot tall loblolly pine; and record shumard, southern red, and overcup oaks; as well as champion water hickory, Carolina ash, holly, box elder, persimmon, and paw paw.

Loblolly Pine–Pinus taeda

Loblolly pine.  The state record tree located in this park has a circumference of 16 feet.  This one looks to be at about 9 or 10.

The tree on the right is the loblolly pine from the previous photo.  The tree to the left is a red maple.  Some of the stands of loblolly pine in the park were found to be 227 years old.  The same study found that this species sprouts following hurricanes which open up the forest canopy.  The ages of stands corresponded with the history of hurricanes. (I took all the photos for this blog entry.)

This species is also known as old field pine because it reseeds so easily in lots devoid of other trees.  It has become a dominant tree throughout the southeast since much of the cotton and corn fields and horse pastures, which 100 years ago made up the face of the southern lands, were abandoned and went fallow.  Before European settlement it was merely a common component, but today it grows in pure stands as well as mixed with other species.  Therefore, it’s sometimes given the name bull pine due to its predominance.  Not only does it grow in upland locations, but it reaches prodigious size in wet areas from whence it gets its name, loblolly, which means mud puddle.  In the Congaree they grow in wet mud.

Sweetgum–Liquidamber styraciflua

Forked sweetgum trunk.

Another surprise for me.  I didn’t know this species could grow with its root system submerged in water, but I saw plenty of individuals in the Congaree growing in 6-12 inches of water.  Some had roots spread in structures similar to those of cypress and tupelo, enabling them to balance without tipping over in muddy soils.  Sweetgums, like loblolly pines, reseed readily in fields and are a common tree in upland sites.  But they’re adaptible enough to thrive in low muddy land as well.

Cypress–Taxodium distichum and Tupelo– Nyssa sp.

Cypress tree trunk.

Look at all of these cypress knees.  Scientists are unsure whether the cypress knees, which are part of the root system, grow for respiration or balance.

Up close view of a cypress knee.  Cypress trees are closely related to California red woods.

There are a lot of interesting microhabitats within a cypress-tupelo swamp.  Areas flooded in shallow water provide homes for fish, reptiles, amphibians, crayfish, and aquatic insects and spiders.

Flooded land in the cypress-tupelo swamp.

Fallen hollow logs and standing snags provide dens from everything from bats and possums to snakes and birds.

This hollow log is a possum mansion.

This standing snag could be hiding bats or flying squirrels.

When the water recedes lush grass and bamboo cane grow.  I can just imagine such Pleistocene mammals as long-horned bison, horses, and mammoths feeding in these grassy glades which often come about when a mighty old tree topples over allowing more light to reach the forest floor.

Note the grassy glade in the background.  There is plenty of grass and cane for a small population of bison and horses in the Congaree.  Too bad they’ve been extirpated.  The only big game left is deer and feral hogs.

A stand of cane.

When the mighty behemonths do topple over, their roots rip caverns in the forest floor.  Those often fill with water forming deep pools that are free of fish.  Amphibians can breed here without fish preying on their eggs and tadpoles.

Upturned tree root.

Pool formed in a hole from where a tree toppled over.

Beech–Fagus grandifolia

Beech tree canopy

Beech grows on sites that are near water but normally stay high and dry.  I love beech, and I wish I lived in a forest of these beautiful trees.  Their bark is white, the leaves turn a lovely yellow in fall, and they produce delicious little nuts.  Beech trees were common in the south during certain climatic stages of the Pleistocene, and as I mentioned in my blog entry “Pleistocene Passenger Pigeon Populations,” I think it’s a clue that passenger pigeon populations skyrocketed when beech was common because beech can grow and spread from sprouts.  The absence of passenger pigeons feeding allows more oak acorns to survive, and oaks outcompete beech.

The Congaree Swamp is probably as old as the Okefenokee Swamp

No studies on the age of the Congaree Swamp have been conducted as far as I know, but I assume it formed about the same time as the Okefenokee which became a swamp between 7,000-8,000 years ago following the final dissolution of the Canadian glacial Lake Agassiz when the water table rose all across the continent.  Throughout much of the Pleistocene, the region around the Congaree River was likely a mixture of upland oak and pine forests and savannahs with only scattered marshes perhaps near creeks and beaver ponds.  Particularly dry climatic stages even hosted oak scrub and sand dune environments.  It’s possible this region has repeatedly converted and re-converted to swamps with every full blown interglacial.

A comparison between my 1988 trip to the Congaree with my experience in 2011

The park system has considerably upgraded the facilities since I was here last in 1988.  Then, there was a gravel parking lot, and nothing else other than some gray paint marks on trees to demarcate the trails.  I hiked by myself in late July and was impressed with the giant trees.  This was before 1989 when Hurricane Hugo flattened many of the trees, but even then there were quite a few felled trees.  I saw a deer resting on a log, a scarlet king snake, and about a billion orb-weaving spiders that built webs across the entire trail at about 1 foot intervals.  After about 5 hours of enjoying nature, I became paranoid that I didn’t know what trail I was on, and I began jogging because I didn’t want to get lost in the park after dark–I feared the potential threat from feral hogs and rabid raccoons.  I didn’t see a single person while I was there until I got back to my car and met a park ranger.

Today, the Harry Hampton Visitor center is located at the entrance of the park.  It’s an air conditioned haven with clean lavatories.  Though the park is still not crowded, we did cross paths with many people.  Moreover, there is a pleasant 2.4 mile boardwalk which made the park accessible for us because my wife is wheelchair bound.

The lower boardwalk goes through a cypress-tupelo swamp.  The upper boardwalk goes through a bottomland forest dominated by sweetgum, loblolly pine, red maple, river birch, and ash.  I only saw a few oaks here–water, swamp chestnut, and willow; though in other areas of the park they’re more common.  Holly trees are common in the understory, and there are occasional patches of palmetto.  I saw no paw paw trees here, but I remember there were many on the trails.

The trails are now color coded, so there is little danger of becoming confused as to which trail one is on as I did 23 years ago.  The paint marks are on trees for the hiker to follow.

Little Kettle Creek–The only Pleistocene Fossil Site in the Piedmont Region of Southeastern North America

Little Kettle Creek excites me because it is the closest Pleistocene fossil site to where I live.  It is the only known Ice Age fossil site in the entire piedmont region.  Bogue Chitto Creek in Alabama is in the northern coastal plain, and Ladds in north Georgia is in the southern ridge and valley, so there are other fossil sites close to this geographic region, but Little Kettle Creek is the only one actually in it.  Its discovery 40 years ago sparked hopes that it would lead to discoveries of more sites in the region but that hasn’t happened.  But I believe it can’t be the only one and some day I hope to find another piedmont fossil site.

The word, kettle, is a derivative of kittle which is an archaic word for fish trap.  In the days before supermarkets Indians and early pioneers likely laced the creek with fish traps for  easy suppers while they were busy clearing land and working in the fields.  A Revolutionary War battle fought here demoralized the British, so the area has plenty of interesting history, despite being off the beaten path–the county population is a mere ~10,000 and early town leaders rejected the development of railroad lines through here because they considered trains “faddish, noisy, and dirty.”  Eventually, railroad lines were built, but by then, the rest of the state had passed this county by.

Location of the Little Kettle Creek fossil site.  From a copy of the below referenced paper.

A photo of Little Kettle Creek on property for sale.  This photo is probably a few hundred yards downstream from the fossil site.  Fossils were found in sediment accumulated behind granite dikes like those seen in this photo.

I found land for sale near this site.  For $235,000 one can buy 65.12 acres of nice timber land where he/she can hunt deer and dove, fish the creek, and prospect for fossils and artifacts.  However, the only building on the site is an ancient barn.  It may be heaven for me, but my wife doesn’t appreciate the lack of amenities.

Most of the fossils were discovered in an accumulation of sediment trapped behind a granite dike similar to those shown in the photo above.  The son of the then property owner discovered a partial mastodon tooth 100 yards downstream from the dike but all but one other specimen were found behind the natural rock dike.  The whole area is underlain by pre-Cambrian age granite which is eroding at different rates.  This accounts for the uneven distribution of the granite outcroppings.  Pleistocene sediment overlays this.  I’ve thought about this for a long time and believe the creek must cut through a large undiscovered Pleistocene deposit farther upstream from the site.  The fossils washed downstream (and may still be periodically washing into the same dike) to become lodged behind the rocky impediments.

Dr. Voorhies and his students scoured the area for fossils and found specimens of 7 species.  Here’s the list.

–a vertebrae and pectoral fins that compare favorably to a channel catfish

–2 cheek teeth of a southern bog lemming, a species that no longer occurs south of Kentucky

–a tooth that compares favorably to the red backed vole, a species that no longer occurs south of extreme northeast Georgia in the mountains

–2 partial teeth of a mastodon

–a partial mammoth tooth

–teeth, metacarpals, and phalanxes from bison

–teeth and metatarsals from white tailed deer

The catfish bones show growth rings similar in size to those from fish that live in midwestern states where fish stop growing in the winter.  Fish in modern day southeastern states don’t show these size growth rings.  That means the climate at the time these fossils were living creatures must have included colder winters than those of today in this region.

I’m planning a trip early this summer to visit Wilkes County.  In addition to the fossil site, the Revolutionary War monument is worth seeing, and I’m curious as to whether I can find William Bartram’s “Great Buffalo Lick,” which reportedly an historian has determined is nearby.  Of course, I’ll recount the day trip on this blog.

References:

Voorhies, M.R.

“Pleistocene Vertebrates with Boreal Affinities in the Georgia Piedmont”

Quaternary Research (4) 85-93 1974

CSI: Pleistocene Alaska

“Science” programs on cable networks are often idiotic.  I suppose the television producers want to boost ratings and make their presentation dramatic for entertainment value.  But for those of us who know a good bit more about the subject than the average couch potato, these programs are laughable.  I think it was the History Channel that featured a special about the Pleistocene megafauna that concluded the beasts became extinct because of global warming.  The imbecilic producers actually showed computer images of the beasts dropping dead due to a heat wave.  They made no mention of overhunting by humans which is a much more plausible cause of extinction.  Instead, they wanted to jump on the bandwagon of global warming phobia, unware that all of these “Ice Age” species survived the Sangamonian Interglacial which was on average warmer than present day temperatures.

Another program about megafauna extinction (either on Discovery or PBS) did give equal time to overkill, climate change, hyperdisease, and comet impact.  The latter two, in my opinion, are crackpot theories.  While it is clear that an extraterrestrial impact probably led to the extinction of the dinosaurs, the evidence that a comet caused the recent megafauna extinction event is not at all convincing.  Supposedly, the comet hit a glacier–explaining why there’s no impact crater.  The theory is on shaky legs to start, if it’s proponents have to make an excuse for the lack of a smoking gun.  Other independent scientists have been unable to replicate their findings, perhaps relegating the comet impact theory to the trash can of illogical ideas.  When interviewed for the above mentioned program, one of the comet impact proponents made an astoundingly illogical comment.  He stated that the overkill theory didn’t make sense to him because he couldn’t believe humans could kill every last individual of a species.

His statement demonstrates a remarkable ignorance of basic ecology.  Humans would not have to kill every last individual of a species to render it extinct.  All wild species of animals already have high rates of natural mortality.  Let’s take the mastodon for example.  Mastodons had a long lifespan and low birthrate.  Saber-tooths and scimitar-toothed cats caused a certain amount of mortality.  Diseases, such as tuberculosis, took a percentage more.  Accidents (falling into quagmires, males killing each other in battles for mates, etc.) took a toll as well.  But this was mortality the mastodon birthrate could keep up with, and they maintained their existence for millions of years.  However, the addition of human hunting was a variable that increased a mortality rate that exceeded their birthrate.   So man + natural mortality = extinction.  Remove man from the equation and it would be natural mortality = a still extant species.

In my opinion overhunting by man is the only cause of the demise of the Pleistocene megafauna.  There is no other logical solution to this mystery. But I don’t agree with Paul Martin’s blitzkrieg model of extinction.  I believe the process took thousands of years rather than hundreds.  A recent study supports my belief in a protracted overkill scenario.

Researchers taking cores of permafrost in Alaska’s north slope.  There is forensic evidence of extinct Pleistocene megafauna in some of these cores.  This forensic evidence dates thousands of years later than the most recent dated fossil evidence of these species.  That means these animals lived more recently than previously thought.  Photo from google images.

A group of scientists led by James Halle examined cores of permafrost found in Alaska.  They were looking for megafauna DNA.    The cores were dated using carbon dating and optically stimulated luminescence (see  http://crustal.usgs.gov/laboratories/luminescence_dating/technique.htmlxplanation for an explanation of OSL dating).  The dates of the cores with the megafauna DNA ranged from 11,000 to 8,000 years old.  This sediment is more recent than the youngest known dated megafauna fossils from the interior of Alaska.  (A population of dwarf mammoths is known to have survived on the Pribiloff Islands until ~4000 BP.)  These cores harbored DNA from mammoth, horse, bison, moose, and snowshoe hare.  This DNA is referred to as sedaDNA and comes from hair, feces, and urine.  It proves the existence of these species in the environment, even though they left no fossil evidence from this time period.  The mammoth DNA is 2600 years younger than the youngest known mammoth fossil from the interior of Alaska; the horse DNA is 3700 years younger than the youngest known horse fossil from this region.  Using sedaDNA is uniquely possible in Alaska, thanks to permafrost conditions, and it’s a technique probably not possible anywhere else. 

The scientists concluded that the continued existence of megafauna until ~7500 BP rules out climate change, the blitzkrieg model of overhunting, comet impact, and hyperdisease as the ultimate causes of megafauna extinction, though they do concede that anyone of these factors could’ve caused an initial population collapse.  Curiously, they made no mention of a protracted overkill model of extinction, which in my opinion this study strongly supports.

It occurs to me that previously disregarded recent dates of megafauna fossils my not be in error.  For example the Devil’s Den fossil site in Levy County, Florida yields remains of Jefferson’s ground sloth, dire wolf, Florida spectacled bear, southeastern lemming, saber-tooth cat, mastodon, horse, and flat headed peccary.  The fossils from this site were radiocarbon dated to be 7,000-8,000 years old–several thousand years later than when scientists believe these species became extinct.  Therefore, scientists disregard these dates as inaccurate due to some kind of contamination or obsolete carbon dating techniques.  I suggest scientists redate these fossils, as well as those from other sites with unusually young dates, using the more updated and improved methods of carbon dating.  It seems likely the Pleistocene megafauna may have survived in southeastern North America for several thousand years longer than previously thought.

References

Halle, James et. al.

“Ancient DNA reveals late survival of mammoth and horse in interior Alaska”

http://www.pnas.org/content/early/2009/12/16/0912510106.full.pdf

www.devilsden.com/

Top Ten Pleistocene Animals I would bring back to the Present, if I could

(Warning: I’m jumping on my soapbox for this blog entry.)

Merry Christmas?  I say bah humbug!  Christmas is an ancient pagan holiday celebrating the winter solstice–the shortest day of the year–with a festival of artificial lights.  The Romans knew how to party, and they turned this festival into a drunken orgy known as Saturnalia.  They gave toys to their kids to distract them, so the children wouldn’t be aware that their parents were engaged in a little joyful wife and servant swapping.  The Catholic Church gained political power in the 4th century, but the hierarchy was unable to stop the alcoholic sex-crazed fun.  Instead, they incorporated the holiday and falsely claimed it to be the birthday of Jesus, the invisible Jewish rabbi who the psychotic founders of Christianity believed was the son of God, after God supposedly deposited his sperm into Mary’s vagina without breaking her hymen.

Pious Christians tried to break the real spirit of what the winter solstice should be about, but they haven’t ruined it nearly as much as the oppressive rulers of today’s American society have.  Big corporations and monstrous merchants have transmogrified this glorified sex orgy into a psychological compulsion for working class people to waste money on a bunch of junk they don’t need, so that wealth is transferred from the poor to greedy merchants.  Clueless economists make the ridiculous claim that this is good for the economy.  In reality it’s only beneficial for credit card-owning banks who for the rest of the year use this expensive spending orgy to drain working class people’s money, like vampires sucking the blood of sheep.

I’m not interested in material objects, but I do have a Christmas wish that a magic Santa could transport live specimens of extinct Pleistocene animals to the present so scientists could study the beasts, and zoos could display them.  Here’s my top ten wish list:

Photo of a replica skeleton of Ermeotherium that I took at the Skidaway Island museum.

1. Eremotherium laurillardi–a giant ground sloth.  There’s nothing like this beast living today.  Diminutive South American tree sloths are the closest living relative, but c’mon, there’s just no comparison.  This massive beast lived on Georgia’s coastal plain until about 30,000 years ago which is the time the last glacial maximum began.  The climate became too cold for them in North America, but they persisted in South America until about 11,000 years ago.

2. Smilodon fatalis–the saber-toothed cat.  There’s nothing like this alive today either.  Maybe we could lead a horse or cow into its cage and solve the mystery, once and for all, how it killed its prey.

3. Glyptotherium floridanum–Glyptodont.  A mammal built like a turtle and the size and shape of a Volkswagon.  Who wouldn’t want to see this in person?

4. Mammut americanum–Mastodon.  I’d pick mastodon over mammoth.  Mammoths are closely related to extant living Asiatic elephants, but mastodons were much more primitive and were related to an ancient order close to the evolutionary foundation of elephant-like animals.

5. Megalonyx jeffersonii–Jefferson’s ground sloth  This was a smaller ground sloth about the size of an ox.  For ecological reasons I believe this was the most common kind of ground sloth found in Georgia during most of the Pleistocene.  It preferred forested environments and was better adapted to colder temperatures, living as far north as Canada.

6.  Glossotherium harlani–Harlan’s ground sloth. Co-existed with Jefferson’s ground sloth, but apparently preferred open meadows as opposed to the forested conditions frequented by the other.

7. Mammuthus colombi–Columbian mammoth.  An elephant adapted for living in a temperate region.  Definitely unique enough to make my Christmas wish list.

8. Dinobastis serum–Scimitar-toothed cat.  Not as famous as Smilodon but equally as fascinating.  Got to give it the edge over other mammals left off the top ten list such as the Pleistocene vampire bats, extinct javelinas, and extinct llamas.  Though interesting, those other species do have similar living relatives, but there are no species of fanged cats left on the planet.

9. Terratornis sp.–The terratorn.  It’s a condor with a 14 foot wingspan.

10. Hesperotestudo crassicutata–This giant tortoise lived on Georgia’s coastal plain during warm interglacials and interstadials.  It grew as big as modern day Galapagos Island tortoises, but was closely related to extant gopher tortoises.

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The nature lover in me did get a real gift this year in time for Christmas.  The state of Georgia is going to purchase 15 square miles of Oaky Woods in Houston County.  Currently, it’s being managed as a wildlife management area, but real estate developers were threatening to destroy it.  Oaky Woods is a unique wilderness.  It’s the last stand of the black bear in the piedmont region of Georgia, and it’s home to 4 state record trees.  The landscape consists of mature stands of mixed pine and oak as well as rare remnants of blackbelt prairie, a probable relic habitat dating back to the Pleistocene.  Moreover, there is some good fossil-hunting ground there.  Eocene marine fossils are commonly found on this piece of land.

See www.saveoakywoods.com

Augusta radio talk show host, Austin Rhodes, suggested I go live in a tree when I brought this subject up on the Augusta Chronicle message board.  What a jerk!  The site is now protected, however, no thanks to shmucks like him.

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My next entry will be about ice berg keel scours off the coast of South Carolina. 

Cool.

Shit-eating Sharks and Fish of the Cretaceous

To keep abreast of the latest paleontological finds in Georgia, I often check the Georgia Journal of Science.  The March 2010 volume has a couple of fascinating articles.  The first is “Coprolites of Deinosuchus: Late Cretaceous Estuarine Crocodylian Feces from West Georgia,” by Samantha Harrell and David Schwimmer.

Deinosuchus rugosus may have been the most powerful predator to ever live in what’s now Georgia.  This monstrous crocodylian grew to 36 feet long, weighed 12,000 pounds, and had a bite force of 13,000 newtons, perhaps the hardest bite of any land animal to ever live.  It dominated the salt marshes of Cretaceous North America (salt marshes were the most widespread ecotone of its time) even seizing and killing dinosaurs such as hadrosaurs and tyrannosaurs.  Its most common prey, however, were turtles that it crushed in its deadly jaws.  It survived as a species from 84 million to 77 million years BP, and left many fossils on the West Georgia/East Alabama border along Hanahatchee Creek near Columbus.  It was neither alligator nor crocodile but is thought to be related to an ancestor of the former.  Dr. Schwimmer, a professor from Columbus College, has been studying dinosaurs in Georgia for almost 30 years, and he wrote an excellent book devoted to the ecology of this fearsome creature.

Part of the dust cover of Dr. Schwimmer’s excellent book about Deinosuchus.

Dr. Schwimmer and Samantha Harrell now believe they’ve identified coprolites originally excreted by Deinosuchus which they found associated with its fossils in west Georgia. 

Picture of Deinosuchus coprolites from Dr. Schwimmer’s book.

Surprisingly, fossil shark and fish teeth are occasionally found on the outside of these coprolites.  These are not interpeted to have been prey of Deinosuchus.  Instead, the scientists believe it’s evidence that the sharks and fish were feeding on its feces.  It’s thought that the strong digestive juices would’ve destroyed and rendered unrecognizable the shark’s teeth, if they had been eaten by Deinosuchus, but the ones they found are identifiable as those from crow sharks (Squalicorax) http://www.oceansofkansas.com/sharks/Kansas/s-kaup1.jpg , an extinct scavenging species.  See the link for a picture of a crow shark’s tooth.  Other crocodylian coprolites discovered in Georgia are thought to belong to another extinct crocodylian–Borealosuchus.

Coprophagy, or the eating of feces, is not that unusual in the animal world.  Box turtles eat deer feces.  Crows and ravens eat crap of all kinds.  Dogs fed dry dog food crave their own feces.  Rabbits and rats must reconsume their own feces for nutrient extraction.  Foals must consume the mama horse’s feces in order to obtain the bacteria they need to digest the plants they will eat as adults.  Some snails depend entirely on fish feces.  And many insects such as butterflies and dung beetles are all attracted to shit…like flies, as the old cliche` goes.

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The second interesting article from the March volume of the GJS is a “Preliminary Description of Pleistocene Rodents from Clark Quarry, Brunswick, Georgia,” by Ray Cornay and A.J. Mead who is from Georgia College in Milledgeville.  Clark Quarry is a productive fossil site, yielding adult and juvenile mammoth skeletons, the complete skull of a long-horned bison which I discussed in an earlier blog entry, and many other large and small mammal, bird, reptile, amphibian, and fish fossils.  Here’s the list of rodents found at this fossil site:

Woodchuck–Marmota monax

Bog lemming–Synaptomys cooperi

Capybara–Hydrochoeris holmesi

Florida or round-tailed muskrat–Neofiber alleni

Rice rat–Oryzomys palustris

Cotton rat–Sigmodon hispidus

Harvest mouse–Reithrodontomys

The first two species on this list no longer range this far south.

Current range of the woodchuck.  This map is a little off.  I’ve seen woodchucks in Lafayette, Georgia.  Notice how far south Clark Quarry is compared to this species’ present range.

Current range of the bog lemming.

The Florida muskrat ranges just a little south of Brunswick today by only a few miles.  This species was more widespread during the Pleistocene, but today is restricted to Florida and extreme south Georgia.  Rice rats, cotton rats, and harvest mice still live in the region.  The species of capybara found as fossil specimens here is, of course, extinct.

The presence of woodchucks and bog lemmings is evidence of much cooler summers than those of today’s south Georgia, but the other species indicate winters at least as mild as those of today.  Scientists believe a warm thermal enclave existed near the south Atlantic coast during the Ice Age, and many believe temperatures were more equable.  I think temperatures were more equable during some climate phases of the Ice Age, but not all the time.

Woodchucks and bog lemmings both prefer to inhabit meadow/forest edge habitat which was probably a predominant ecotone of the late Pleistocene southeastern coastal plain where a mixture of open forests, prairie and wetlands existed rather unlike the closed canopy forests of today.  Fire, megafauna grazing, passenger pigeon mast consumption, locust infestations, and rapid climate fluctuations created a dynamic habitat where the ratio of woodlands to grasslands waxed and waned.  Florida muskrats (which aren’t closely related to the common muskrat–Ondatra) like open marshes, and capybaras thrive in flooded grasslands, so I believe wet prairies must have been one of the common environments in this region during the late Pleistocene.