The North Charleston Mastodon

Construction workers digging a foundation for a building in North Charleston, South Carolina 5 years ago uncovered the remains of a mastodon.  Bones including a partial tusk, femur, vertebrae, jaw, ribs, and feet were excavated.  One scientist also examined the surrounding sediment for pollen and plant remains. Apparently, the site was riverbank, and the mastodon likely was covered in flood-borne sediment.  I hope a paper is published detailing the information yielded by this site.  So far, all the information I can find comes from 2 abstracts that described poster presentations of the find at scientific meetings.  The authors didn’t even put the posters on the internet.

One presentation compared the pollen found here to that from other Pleistocene-aged sites located near the present day coast–St. Catherine’s Island, Reid’s and Bell’s Bluff, and a site along the Georgia-Florida border.  All of these sites were farther inland during Ice Ages.  Like these other sites, the North Charleston locality had a strange admixture of species presently found at higher latitudes with those still found in the region.  Water milfoil, an aquatic plant, occurred here.  This is not surprising because mastodons were semi-aquatic.  Hickory pollen was “unusually” abundant, indicating a moist temperate climate, but the pollen of red pine, a northern species, was found in association with sub-tropical Spanish moss.  Other Pleistocene sites in the region yield hemlock, basswood, and walnut–species no longer found this far south.  However, I’m skeptical about the identification of supposed red pine pollen.  This species currently occurs in New England, a region that was under glacial ice for much of the Ice Age when its range was forced south.  I doubt it occurred as far south as South Carolina though because there are no relic populations in the southeast.  Red pine pollen is distinguished from pollen of southern pines on the basis of size.  Pollen grains under 43 micrometers in size are classified as northern species of pine, while those over 43 micrometers are thought to be from southern pines.  Shortleaf pine is a common southern species of pine whose pollen grains overlap in size with red pine pollen grains.  Moreover, under the atmospheric conditions of low CO2 as occurred during Ice Ages, shortleaf pine pollen grains may have been slightly smaller than those of the present day.  In my opinion they look identical as the below photos show.  I believe pollen classified as red pine in the below reference and several other studies is from shortleaf pine which is still widespread in the region.

Shortleaf pine pollen grains average a “maximum” 50-75 micrometers in size.

Photos of northern species of pine pollen grains including red pine (Pinus resinosa), jack pine, and white pine.  Red pine and white pine pollen grains easily overlap in size with shortleaf pine.  Therefore, I’m not convinced of palynologists’ claim that red pine occurred in the southeast during Ice Ages.

Reference:

Rich, Fred

“The North Charleston Mastodon Site–New Insights Drawn from Paleoecological Synthesis”

The Geological Society of America: Southeastern Section–64th annual meeting

 

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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

The Eurasian Steppe Mammoth (Mammuthus trogontherii) may be the same species as the North American Mammoth (Mammuthus columbi)

Eurasian steppe mammoths crossed the Bering Land Bridge early during the Pleistocene (~1.9 million years BP) and colonized North America.  They ecologically replaced stegomastodons over most of the continent but the ranges of both overlapped in Central America until the late Pleistocene.  Mammoths never colonized South America where stegomastodons continued to flourish until human hunters arrived on the scene.  Mammoths were probably better adapted than stegomastodons to the cooler more temperate climates that occurred over most of North America during the Pleistocene. Stegomastodons should not be confused with the American mastodon (Mammut americana) which co-existed with mammoths across most of North America for almost 2 million years.  They were able to co-exist because these 2 species favored different ecological niches.  Mammoths preferred higher drier grasslands, while mastodons were semi-aquatic denizens of wetlands.

Scientists long assumed mammoths that colonized North America evolved into a different species than Eurasian steppe mammoths.  North American mammoths of the late Pleistocene are given the scientific name Mammuthus columbi and Eurasian steppe mammoths are considered M. trogontherii.  However, a recent study of mammoth teeth determined M. columbi and M. trogontherii should be considered the same species.  The authors of this study think teeth of the Columbian mammoth originally used to compare with the teeth of the Eurasian steppe mammoth were from older individuals, thereby misleading scientists into thinking M. columbi was a different species.  The differences could be explained by normal wear and tear that one would expect from older animals.

2 teeth from a Eurasian steppe mammoth. (On sale for 840 British pounds)

Columbian mammoth tooth.  2 scientists determined from an analysis of teeth that the Columbian mammoth of North America and the Eurasian steppe mammoth were the same species.

Eurasian steppe mammoths evolved into woolly mammoths (M. primigenius) about 370,000 years ago during an harsh Ice Age.  Woolly mammoths also crossed the Bering Land Bridge, and as I mentioned in my previous blog post, hybridized with Columbian mammoths wherever the ranges of the 2 species overlapped.

Reference:

Lister, A. M., and A.V. Scher

“Evolution and Dispersal of Mammoth across the Northern Hemisphere”

Science 2015

The Coats-Hines Pre-Clovis Site in Williamson County, Tennessee

Workers constructing the 13th hole of the Crockett Springs Golf Course in 1977 unearthed mastodon bones.  Paleontologists took note of the discovery and 17 years later when they learned lots adjacent to the golf course were going to be transmogrified into residential housing, they surveyed a nearby drainage ditch and found another partial mastodon skeleton along with fossils of horse, deer, a canid, muskrat, turkey, painted turtle, and frog.  This time they also discovered evidence that attracted archaeologists–10 stone tools and 24 lithic flakes.  The tools included a bifacial knife and hide scrapers made from local Fort Payne chert.  Moreover, there were butcher marks on the mastodon backbone, suggesting these ancient Americans removed the proboscidean’s tenderloin.  The apparently butchered mastodon bone yielded radiocarbon dates translated to ~14,000 calender years BP.  Archaeologists regard this as the pre-Clovis era.

Williamson County, Tennessee. 

Photo of the Nashville Golf and Country Club which was formerly known as the Crockett Springs Golf Course.  I couldn’t find a photo of the 13th hole where the mastodon bones were found.  I don’t know which hole this is.

A 3rd survey of the drainage ditch in 2005 found parts of yet another mastodon, and a few years later in this generous spot they found fragmentary evidence of a large Pleistocene mammal, but it was in such poor condition, it couldn’t be identified.  Underneath this, they recovered a Pleistocene-aged deer antler.  In 2010 the owners of the new house built next to the drainage ditch gave permission to the archaeologists to dig a deep trench in their backyard.  Here, the archaeologists found 1582 fragmented bones of mastodon, deer, turkey, turtle, and frog along with 11 more human made artifacts all located 10 feet below the surface of the yard.

Mastodon bones found in trench.

Mastodons roaming future golf course.

The home owners were nice enough to let archaeologists dig this deep trench in their backyard.  I had a trench like this dug in my backyard a few months ago.  Unfortunately, they didn’t find any fossils.  They were replacing the drainage line for my septic tank.  Cost me $5,000.

Geologists think the Coates-Hines site was an intermittent pond that existed between 22,000 BP-12,000 BP.  A stream periodically became blocked, creating the pond, then on occasion it drained.  I propose beavers were the agent that blocked the stream.  Every so often, predators would kill all the beavers in this locality, and the dam would fall into disuse and break down.  A new population of beavers would recolonize the site, and the cycle would begin anew.  About 12,000 years ago, rain washed soil down the adjacent hillside and buried the old pond site and stream with colluvial sediment.

The ancient beaver pond provided an ideal location for a Paleo-Indian base camp.  The ancient Americans opportunistically ambushed big game that browsed aquatic plants, but they also had easy access to muskrats, turtles, fish, frogs, and edible plants such as cattails.  All the species of fossil animals found at this site are notably edible.

Reference:

Wolf, Aaron; Jesse Tune, and John Broster

“Excavations and Dating of Late Pleistocene and Paleoindian Deposits at the Coats-Hines Site, Williamson County, Tennessee”

Tennessee Archaeology 5 (2) Fall 2011

http://csfa.tamu.edu/cfsa-publications/Tune-TA5-2011.pdf

The Curious Disjunct Range of the Miccosukee Gooseberry (Ribes echineiium)

The Miccosukee Gooseberry grows in just 2 counties hundreds of miles apart.  One population clings to the shoreline of Lake Miccosukee in northwest Florida, and it numbers about 5,000 individuals.  The other population lives in McCormick County, South Carolina near the eastern border of central Georgia 1.5 miles north of Clark Hill Lake.  In this county there are 2 separate populations: 1 group is in Sumter National Forest and the other is located in the Steven’s Creek Heritage Area.  The McCormick County population is estimated to number between 13,000-160,000 bushes.

Leaves, flowers, and twigs of the rare Miccosukee Gooseberry.  I couldn’t find a photo of a whole bush on the web.

I suspect the Miccosukee gooseberry had a wider, more continuous range during the Pleistocene and maybe as recently as the Colonial era.  I hypothesize its decline to relict status is probably tied to the extinctions of the mastodon and the passenger pigeon.  Several clues support my hypothesis.  Notice the remaining populations grow near water.  They grow near the shore of Miccosukee Lake in Florida, and on a steep north-facing slope along Steven’s Creek.  Mastodons were semi-aquatic, and passenger pigeon flocks roosted along water ways.  The surviving colonies are likely remnants of once larger colonies that thrived thanks to the bio-activities of mastodons and passenger pigeons.  Mastodons facilitated the growth of gooseberries by eating branches and leaves of overstory trees, thus allowing more sunlight to reach the low growing bushes which don’t exceed 3 feet in height.  Mastodons helped spread gooseberries by eating the bushes–the pruning caused the plants to spread vegetatively–and by spreading the fruit seeds in their dung.  Passenger pigeon flocks had the same effect.  When the incredibly enormous flocks of passenger pigeons roosted in one area, their dung would cover the ground, killing the trees through overfertilization, and opening the canopy to the benefit of plants such as gooseberry which became one of the first floral species to colonize a pigeon roosting area after the tree kill (pokeberry and ginseng are 2 other plants noted for growing in this type of environment).  Poultry manure also raises the ph level of the soil.  The Miccosukee gooseberry only grows on alkali “sinks.”  The pigeons were also known for berry consumption and were capable of spreading the seed far and wide due to their highly migratory habits (their scientific name is Ectopistes migratorius).

Miccosukee gooseberries have a low germination rate, probably contributing to their relict geographic range.  This species may have been more widespread during the Pleistocene when mastodons roamed the land.  Mastodons helped propagate this species in several ways.  Mastodons ate tree branches, thus allowing more light to reach the low growing gooseberries.  When mastodons ate the gooseberry bushes, it facilitated the growth of clonal colonies which spread via the root system.  The gooseberries may have had a higher germination rate after passing through a mastodon’s digestive tract.

Miccosukee Gooseberries may have also relied on passenger pigeons to spread their seed.  Passenger pigeons carrying gooseberry seed in their gut could spead the species far and wide.  It’s probably no coincidence that the last 2 populations of Miccosukee gooseberries are located in the kind of habitat where massive flocks of pigeons formerly roosted.  The manure from the massive flocks of roosting pigeons raised the ph level of the soil.  This type of gooseberry only grows on soils with a high ph.

Scientists attempting to ensure the survival of this species of gooseberry face some obstacles.  The Miccosukee gooseberry has a low germination rate.  This low germination rate supports my hypothesis that its decline coincides with the extinctions mentioned above.  It’s likely gooseberry seeds need to go through the digestive tract of a mastodon or pigeon to improve germination.  Efforts to transplant and propagate the Miccosukee gooseberry have been a complete failure.  This species has low genetic diversity, but there is a high degree of genetic divergence between the Florida and South Carolina populations, evidence they’ve been isolated from each other for quite some time.  The species wasn’t known to science until 1924, a generation after the extinction of the passenger pigeon.  There’s no telling what its range was during the 19th century.  The South Carolina colony wasn’t discovered until 1957.

The Steven’s Creek population grows under a canopy of oaks, hickories, and beech.  Gooseberries leaf out in November and lose their leaves in mid-summer, thereby taking advantage of the increased sunlight they experience when deciduous trees drop their leaves.  Bumblebees and blueberry bees pollinate the flowers.  One source claims the fruit is delectable but sour; another source says the fruit is of poor quality.  I suspect the latter source is closer to the truth, but I don’t know because I’ve never eaten this variety.

Unlike the Miccosukee gooseberry, the eastern prickly gooseberry is more widespread ranging from the midwest to the southern Appalachians.  Reportedly, they are fairly common on Grassy Mountain in the Cohutta Wilderness Area of north Georgia where they grow on boulderfields in the understory of a birch-maple forest.

The eastern prickly gooseberry (Ribes cynosbati) is common throughout the midwest and as far south as the southern Appalachians.  Reportedly, they are a frequent component of an interesting forest growing on Grassy Mountain within the remote Cohutta Wilderness Area of the Chattahoochee National Forest.  According to Jennifer Moore who wrote her college thesis about the forest on this mountain, the prickly gooseberry grows among the boulderfields on Grassy Mountain.  The name is a misnomer–it hasn’t been grassy for over 100 years since pastoralists abandoned the land, and trees began growing in the absence of livestock grazing and fire.  The boulders are the result of severe Pleistocene freeze and thaw cycles that broke up the rocky mountain surface.  A forest of mountain maple, yellow birch, tulip tree, basswood, and buckeye dominates over a shrub layer consisting of smooth hydrangea, strawberry bush, raspberry, prickly gooseberry, and marginal wood fern.  Windthrows are common here, aiding the growth of the shrubby zone.  Much of the mountain is inaccessible to non-hikers, making it a real destination for people seeking solitude with nature.  Better bring pepper spray–I bet there are lots of bears here.

I’ve never eaten a fresh gooseberry.  They aren’t cultivated in Georgia as far as I know.  I tried growing some a long time ago but the plants croaked in the merciless heat.  The canned ones taste like sweetened okra.  Even canned gooseberries are rare in Augusta–none of the local grocery stores currently carry them.

Here’s a related article on Pleistocene Passenger Pigeon Populations. https://markgelbart.wordpress.com/2010/08/27/pleistocene-passenger-pigeon-populations/

Crappie and mastodon

Crappies and mastodons shared the same habitat.  Crappies are primarily a lake fish, preferring clear still water where they prey on small minnows and insects.  Mastodons often waded into lakes to feed upon submerged aquatic plants.  Perhaps they even aided crappies by forcing minnows away from the cover of underwater vegetation into the open to be picked off by schools of crappie.  Of course, mastodons weren’t as tied to the water as crappies and could travel overland whenever they desired.

Black crappie (Pomoxis nigromaculatus).  A beautiful fish and tasty too.  I once had a fish dinner of bass and crappie.  The bass were meatier, but the crappie were sweeter and better tasting.

Kurt Hamlin, a curator at the Milwaukee Museum, was lucky enough to find fur on a mastodon specimen.  The fur resembled that found on river otters and beavers, so we know mastodons spent a lot of time in the water.

River otter (Lutra canadensis) pelt.  River otter fur is water proof and dries quickly.  Mastodon fur was similar.

Although these two different species shared the same habitat, the fossil remains of mastodon and crappie have been found together at only 1 locality–The Charles Adams Mastodon Site in Livingston County, Michigan.  It was a lake deposit also containing fossils of meadow vole, 1300 snail shells, 500 freshwater clam shells, and bones of white sucker fish.  In Georgia mastodon fossils have also been found associated with fish remains, but not crappie.  An alluvial deposit in Little Kettle Creek contained bones of channel catfish along with mastodon.  The  deposit in Kingston Saltpeter Cave in Bartow County contained over 500 fish bones in addition to a mastodon fossil. Here, predatory birds brought  fish from the nearby Ashpole Creek, a tributary of the Etowah River.  They included gar, pickerel, channel catfish, bullheads, sucker fish, chubsuckers, largemouth bass, and unidentified sunfish.  Coastal fossil sites often have marine species of fish as well as mastodon.

Overall, fish populations during the Pleistocene were much higher than those of today’s waters.  Then the rivers were undammed, unpolluted, and unfished by men.  But in what’s now Georgia crappie populations were probably an exception.  They thrive in modern artificial reservoirs formed behind the numerous hydroelectric dams.  Suitable habitat during the Pleistocene was temporary and sporadic.  Oxbow lakes were plentiful during interstaidals and interglacials.  Cut off channels were common during stadials.  But large lakes akin to modern day reservoirs were nonexistent.  Instead, crappies relied on favorable habitats that constantly changed with the evershifting river patterns.  They can live in rivers where water flow is obstructed and forms pools.  Lower water levels with still channels, and higher water levels with wide bends that form slow moving water both provide favorable habitat.  Crappies could also inhabit large beaver ponds.  But the constantly changing conditions probably made crappie numbers fluctuate much more than they do in today’s reservoirs.

Centrarchid Evolution

An evolutionary tree of the centrarchid family of fishes as proposed by some scientists.

 The centrarchid family of fish includes sunfish, crappie, and bass (though not white bass, striped bass, and sea bass which are in completely different families).  The opportunity for speciation occurs often among this family because populations of fish get isolated when connecting streams run dry or become obstructed.  This makes the centrarchid family an excellent one for evolutionary scientists to study.  Scientists can look at rates of genetic divergence between closely related species and estimate the length of time it has taken since speciation occurred from a mutually ancestral species.  They call this a speciation clock. Many species of centrarchids hybridize but genetic compatibility decreases with time since speciation occurred.  One study found that hybrid embryo viablity declines 3% per million years of separation.

Here’s a list of centrarchid species which are strictly an American family of fish.  Note:  Some scientists recognize 33 species and 7 genera; others recognize 31 species and 9 genera.

Mud sunfish–Acantharchus pomotis

Shadow bass–Amploplites aribmarus

Roanoke bass–A. cavifrons

Ozark Bass–A. constellatus

Rock Bass–A.  rupestris

Sacramento perch–A. choplites

Blackbanded sunfish–Ennearanthus gloriousus

Flier–Centrarchus macropterus

Redbreast Sunfish–Lepomis auridus

Green sunfish–L. cyanellos

Pumpkinseed sunfish–L. gibbosus

Orange spotted sunfish–L. humili

Warmouth–L. gulobus

Bluegill–L. marochirus

Dollar sunfish–L. marginatus

Longear sunfish–L. megalatis

Redear sunfish–L. microlophus

Red spotted sunfish–L. miniatus

Spotted sunfish–L. punctatus

Bantam sunfish–L. symmetricus

Redeye or Coosa Bass–Micropterus coosae

Spotted Bass–Micropterus punctatus

Largemouth Bass–Micropterus salmonoides

Shoal Bass–M. cataractus

Guadalupe bass–M. treculi

White crappie–Pomoxis annularis

Black crappie–P. nigromaculutus

Redeye bass

A redeye bass.

In my blog entry of a few weeks ago about the food I would eat, if I could live in Georgia 36,000 BP, I mentioned smallmouth bass as a fish I might find in my fish traps on the Broad River.  At the time of European colonization of North America smallmouth (aka spotted) bass only occurred in extreme northern Georgia.  It did not naturally occur in the Broad River, though it has since been introduced.  During the Pleistocene, smallmouth bass may have ranged further south, but maybe not.  Instead, redeye bass, a closely related species, did occur on the Broad River.  Redeye bass and smallmouth bass probably evolved from a common ancestor that diverged due to the geographical separation of the watersheds where this common ancestor lived.  So, I believe I would find redeye bass in my Pleistocene fish traps in the Broad River, and probably not smallmouth.

Reference:

Bolnick, Daniel; and Thomas Neal

“Tempo of Hybrid Inviability in Centrachid Fish (Telestei: Centrarchae)”

Evolution 59 (8) Augusts 2005

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.

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.