The Page-Ladson Site in Northwest Florida

November 19, 2018

I wrote a new blog article about this last night, but then realized I’d already written an article about this subject. I’m re-running this article this week because I don’t have time to write another one before the holidays. Happy Thanksgiving.

GeorgiaBeforePeople

During the late Pleistocene sea level contracted because much of earth’s atmosphere was locked in glacial ice.  The land area of what today is Florida doubled in size, and shorelines extended 50-100 miles west into the Gulf of Mexico.  The water table fell and many present day small rivers did not yet exist.  Instead, the land was pockmarked with many spring-fed ponds that attracted herds of megafauna and other wildlife.  The basal chemistry of these waters preserved bones and organic matter, and later when water tables rose, the Aucilla River began flowing and it covered these ponds with sediment.  The Aucilla River flows over 4 known Pleistocene pond sites–Page-Ladson, Latvis-Simpson, Sloth Hole, and Little River Quarry.  These sites contain deep layers of mastodon dung deposits.  Bones and artifacts are often mixed with the ancient piles of turds, and tracks are also visible where mastodons stepped on their own shit.  Scientists…

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Ants, Flies, and Trillium

November 12, 2018

Woodland herbs in the trillium family have evolved interesting traits that lure insects into helping them reproduce.  The trillium family belongs to the lily plant order, and it includes 45 species and 5 hybrids found in North America and Asia.  More species live in North America and the center of trillium evolutionary origin is probably the southern Appalachians.  Species of trillium were likely widespread in the tropical to temperate forests that occurred across both continents during the Miocene over 5 million years ago.   This is likely when trillium evolved a dependent relationship with bees, ants, and flies.  Some species of trillium, such as the great white (Trillium grandiflorum) produce flowers that attract bees and wasps with a sweet smell.  But others, such as the inaptly named little sweet betsy (T. cunacateum), have flowers that smell like rotting meat, and the red color looks like flesh, so they attract flies.  These flying insects help pollinate the trillium plants.

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Little sweet betsy–more accurately known as bloody butcher because they smell like rotting meat. The flesh color and carrion smell of the flowers attract flies, and in turn the flies pollinate the flowers.

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By contrast the flowers of the great white trillium smell sweet and attract bees and wasps for pollination help.

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Ants disperse trillium seeds throughout the forest.  Aphaenogaster picca is an example of an ant species that mostly preys on termites but takes advantage of the passive trillium seeds when they have a chance.

Trillium produce a fruit with over a dozen fat covered seeds that attract ants.  This layer of fat is known as the elaiosome, and it surrounds a hard seed.  The ants carry the fat rich seeds back to their nest, but discard the hard seeds after consuming the nutritious coating.  This helps spread the species throughout the environment. Most of the species of ants that consume trillium seeds normally prey on termites, worms, and grubs–the trillium seeds are an easier meal that puts up no resistance.  Plants that depend upon ants to disperse their seeds are called myrmecochorous.

For years many scientists were mystified at how trillium and other plant species so rapidly recolonized land formerly covered by glaciers. This is known as Reid’s paradox defined as the unexplained mystery of how some plant species apparently recolonized post glacial habitats faster than their modern dispersal rates suggest.  It is mathematically impossible for ants to have dispersed trillium across New England and parts of Canada in less than 10,000 years. However, scientists recently discovered deer feces containing viable trillium seeds.  Apparently, white tail deer eat trillium fruit and spread the seeds into new territory.  This would answer Reid’s paradox.  However, high populations of white tail deer can be detrimental to trillium populations.  Trillium plants are perennials, capable of surviving from the same root for up to 25 years, but repeated deer consumption of the leaves can kill the plant.  Deer also choose to eat the largest trillium plants, thus selecting for smaller and less productive individual trillium plants.  I hypothesize extinct tapirs and possibly long-nosed peccaries also fed upon and dispersed trillium during the Pleistocene.

The relict trillium (T. reliquum) is known from just 50 sites along the fall line, mostly in Georgia. A genetic study determined this species survived in 2 different Pleistocene refuges during Ice Ages when much of the landscape became desert like.  There is actually greater genetic diversity on the eastern and western parts of its range rather than in the central part.

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The relict trillium, also known as the Confederate wake robin.  It is an ancient species that became rare because of Ice Ages.

References:

Gonzalez, E.; and J.L. Hamrick

“Distribution of Genetic Diversity among Disjunct Populations of the Rare Forest Understory T. reliquum”

Heredity 95 2005

Velland, Mark; et. al.

“Dispersal of Trillium Seeds by Deer: Implications for Long Distance Migration of Forrest Herbs”

Ecology 84 (4) 2003

ABC Bears

November 5, 2018

During the Ice Age the coast of southeast Alaska was studded with ice floes and perfect habitat for seals and polar bears.  The interior of Alaska was mostly grassy steppe, the preferred habitat of brown bears.  About 16,700 years ago the icy habitat along the southeast coast of Alaska began to melt and polar bear populations became stranded on Admiralty, Baranet, and Chichagof Islands; also known as the ABC islands.  Here, the habitat began to become more favorable for grizzly bears, and young males looking for new territory not already occupied by adult males colonized the islands.  A genetic study of 1 specimen from this island group determined these colonizing male brown bears mated with female polar bears, creating an hybrid population  (Ursus arctos x U. maritimus).  Gradually, the population of brown bears swamped the DNA of this region, so today polar bear DNA makes up just 6% of their X  chromosome (the female chromosome is XX; the male is normally XY).  Polar bear DNA has also been found in specimens of the extinct Irish brown bear.  DNA evidence suggests polar bears diverged from brown bears about 4 million years ago, but there has been periodic hybridization in regions where the 2 species overlap.

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Location of the ABC islands.

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Top 2 photos are polar bear/brown bear hybrids in captivity.  Bottom right is a polar bear; bottom left a brown bear.  The 2 species rarely do hybridize in the wild.

A few months ago, Discovery Channel aired a program about the ABC bears that I lambasted in this blog article https://markgelbart.wordpress.com/2018/06/04/the-fear-island-special-that-aired-on-animal-planet-last-night-was-full-of-shit/ .  Previously, Discovery Channel has aired programs about Bigfoot, mermaids, and the extant existence of a 60 foot long extinct species of shark.  I assumed this program was completely bad pseudo-science, but 1 of my readers alerted me to the scientific merits of this program and also informed me that I wrongly assumed the ABC islands were the same as the Kodiak islands.  The Kodiak islands are on the other side of the Gulf of Alaska, so I errored geographically by hundreds of miles.  And the expedition on this program did have scientific merit because they were seeking just the 2nd DNA sample from an ABC bear.  However, I still think this program was full of shit…just not as full of shit as I initially assumed.  Here is why I stand by my first opinion:

1. The participants acted as if they were the first researchers to ever obtain DNA evidence from a bear on the island, though a study of 1 specimen had already been published.  They already had a good idea what they were going to find, and it was not a great mystery as they promoted.

2. The Indian guide claimed he saw 6 bears ceremonially bury another dead bear.  What unscientific bull crap.

3. I don’t buy the size estimate claim.  It was based on an up close trail cam photo.  Weigh it or just shut up.

Reference:

Cahill, J; et. al.

“Genetic Evidence for Island Populations Conversion Resolves Conflicting Theories of Polar Bear Evolution”

PLOS Genetics 2013

 

Terrifying Trench Warfare Caused the Flu Pandemic of 1918

October 29, 2018

Halloween scares are silly compared to the real world.  The universe is a really scary place, considering the potential for random disasters that could wipe out life on earth or at least a large segment of it.  Supernovas, asteroid impacts, tsunamis, and tornadoes are far scarier than a kid wearing a mask.  The other day I saw my cat terrorizing and killing a baby squirrel, and I thought to myself how harsh the universe can be for living organisms.   That particular animal never had a chance.  One would think humans would always be comforting and helpful to each other because the universe is so unforgiving.  History shows just the opposite is often true.  Humans kill other humans–a behavioral trait inherited from their evolutionary ancestors.  During the 20th century this frightening trait was illustrated in 2 world wars that left 67 million people dead.

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No man’s land on a battlefield in France during WWI.  Imagine being ordered to cross this into an hail of burning steel.

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Before the widespread strategic use of tanks trench warfare resulted in years of bloody stalemate on the Western front during WWI.

World War II caused more deaths than WWI, but battles in the earlier conflict were bloodier.  Men fought in static lines of trenches before the widespread use of tanks.  During WWII mobile tank warfare led to breakthroughs when many army divisions could be surrounded and thousands of troops would be forced to surrender.  Being in a prisoner of war camp sucked, but it was better than death.  But during WWI generals tried to break through enemy trench lines by bum-rushing opposing trenches with a mass of soldiers.  It was like forcing living human flesh through a meat grinder.  At the sound of a whistle 20 year old men were ordered to run across a devastated landscape known as “no man’s land.”  They ran into machine gun fire, artillery barrages, minefields, barbed wire, and poison gas.  Men were slaughtered and these attacks frequently failed.  Death notices were sent to thousands of families, following these futile offensives.  Just think how terrifying it was for these young men to know they were facing near certain death at the sound of a whistle.

The short lifespan of troops participating in trench warfare selected for an unusual strain of virus.  Most influenza viruses are not that deadly because if the host dies rapidly, fewer virus spores will survive to infect other hosts.  But hosts were dying rapidly in WWI trenches, and a virulent strain of virus, known as the Spanish flu, was just as likely to infect other hosts as the less virulent strains.  The virus began to spread in the spring of 1918.  Demobilization during the fall of 1918 when soldiers rejoined the civilian world caused a surge in the pandemic.  The Spanish flu continued to afflict the populations through the winter of 1919.  Scientists estimate this influenza virus killed 50-100 million people–probably more than both world wars combined.  It infected 25% of the world population and had a mortality rate of 5%-10% (most influenza viruses have a mortality rate of .1%).  Healthy people in their  20’s and 30’s suffered an higher mortality rate than the elderly who are usually more vulnerable to flu epidemics.  Scientists think this flu strain was different from the initial flu strain this generation first encountered during the 1890’s, and their imprinted immune systems were maladapted for it.

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Spanish flu virus.

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The Spanish flu virus may have killed up to 100 million people.

I’m not afraid of vampires, werewolves, and witches; but the possibility of global war and disease pandemics are much more frightening to contemplate.

Reference:

unnamed author

“A Deadly Touch of Flu”

The Economist September 29, 2018

Peccary Cave in Arkansas

October 21, 2018

Perhaps the best site for Pleistocene fossils in Arkansas is Peccary Cave located in Newton County.  The site was first excavated in 1960s, and a follow-up expedition prospected for fossils again in the early 1990s.  The fossil remains of at least 51 species of mammals have been found here. 4000 specimens of a minimum of 64 individual flat-headed peccaries (Platygonus compressus) were discovered in the cave, hence the name.  The bones of other extinct species excavated from the cave include mammoth, mastodon, bison (Bison antiquus), stag-moose, helmeted musk-ox, tapir, beautiful armadillo, and dire wolf.  There are also remains of extralimital species found here that no longer occur in the region–grizzly bear, pine marten, porcupine, heather vole, and numerous other rodents and insectivores of northern affinities.  Plenty of species still found in the region are represented in the cave as well such as beaver, otter, muskrat, raccoon, coyote, gray fox, opossum, and either mule or white-tailed deer. Reptile and amphibian specimens have been excavated from the cave along with a few human-made artifacts of unknown cultural origin.

Map of Arkansas highlighting Newton County

Newton County, location of Peccary Cave.  

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Illustration of the flat-headed peccary.  Peccaries didn’t use Peccary Cave as a den.  Instead, they either fell inside or their bones were washed into the cave when the nearby creek flooded.  Birds of prey dropped or defecated smaller animals into the cave from overhanging trees.

The fossils represent several different climate phases.  The lowest level contains fossils over 22,000 calendar years BP, a climate phase that includes a weak interstadial and the following early glacial maximum.  Mixed Ice Age woodlands of spruce, pine, and hardwoods interspersed with prairies predominated.  7 different species of squirrels lived in the region then, showing how many diverse habitats occurred here.  Red squirrels and least chipmunks, now absent from the region, preferred spruce forests; gray squirrels, fox squirrels, and southern flying squirrels occur in temperate hardwood forests; woodchucks like meadows; and 13-lined ground squirrels require tree-less plains.  The author of the study discussed below thinks the following glacial maximum caused the entire Missouri Plateau to become inhospitable desert because there are few fossils from the site, dating to between 21,000 calendar years ago-15,000 calendar years BP.  Undoubtedly, the region became more arid during this climate phase, and desert scrub grassland likely predominated, but I think there are alternative explanations for the lack of fossils during this time period here: a) the cave entrance may have become closed and/or b) the barren landscape allowed animals to see the trap entrance and avoid it whereas before it was hidden by thick vegetation and animals frequently fell inside.  Without overhanging limbs there was no perch for birds of prey to drop of defecate the remains of their meals.  Moreover, the nearby creek dried up, so there were no floods to wash fossils into the cave.

The upper level of sediment represents a warm dry interstadial post 15,000 calendar years BP when the region was dominated by grassland.  Bison fossils appear during this phase, and toad fossils outnumber frog bones.  Toads can survive better than frogs in more arid climates.

Kurt Wilson wrote his PHD thesis about the peccary and dire wolf bones found in Peccary Cave.  His paper has interesting information, but it is incompletely researched, and his conclusions are logically flawed.  He believes flat-headed peccaries were always an uncommon species.  Part of his reason for this assertion is based on his incorrect observation that “the southeast is virtually devoid of records (of flat-headed peccaries), except for a dozen localities in Florida.”  Wilson is unaware of 2 sites in north Georgia (Yarbrough Cave and Ladds) and 1 site in coastal South Carolina where fossil remains of flat-headed peccaries have been found.  It is also illogical to assume a species was absent from a region based on its absence in the fossil record.  Large areas of the southeast are devoid of fossils because the local geology is not conducive to fossil preservation, not because animals didn’t live there in the past.

Wilson concludes flat-headed peccaries became extinct due to climate change based on 4 lines of evidence that are easily debunked.

1. He dismisses overhunting by humans as a cause of flat-headed peccary extinction when he regurgitates the tired old claim of Meltzer and Grayson (an archaeologist and anthropologist…not paleoecologists) that there isn’t enough archaeological evidence of human interaction (kill sites) with this species.  I consider this reasoning absurd in the extreme.  99.999…etc% of animals that ever lived on earth left no fossil evidence whatsoever.  It has always seemed unreasonable to me to expect the remains of the final populations of a species that overlapped with man for less than 2000 years to be preserved in the fossil record.  The chances of this happening are tiny.  I’ve noticed Grayson’s recent book published in 2016 is frequently being cited in new papers about Pleistocene vertebrates.  Grayson was blatantly dishonest in this book in the way he characterized a study that rules out climate change models of extinction.  (See: https://markgelbart.wordpress.com/2017/01/23/donald-graysons-disingenous-case-against-overkill/ ) Grayson lied and he knows he lied.

2. Wilson assumes flat-headed peccaries became extinct in this region about 22,000 calendar years BP because their remains don’t occur in cave sediment after this date.  (When Wilson writes of extinction in his paper he means regional disappearance or extirpation because he’s aware terminal dates for this species in other regions are 11,000 calendar years ago.  Nevertheless, he clumsily never makes this distinction in his paper.)  He asserts peccaries became extinct here because the climate became too arid for them.  Again, he is basing his assertion on the dubious assumption that the absence of evidence is evidence of absence.  I think flat-headed peccaries were probably even more abundant during the arid climate phase because they were anatomically well-adapted to dry dusty environments.  Flat-headed peccaries had extensive structures in their nasal passages that helped filter dust.  Wilson must be unaware there are at least 9 fossil sites where herds of flat-headed peccaries were buried during sandstorms.  (See: https://markgelbart.wordpress.com/2013/03/10/when-sand-dunes-buried-herds-of-flat-headed-peccaries/ ) This suggests they were common in desert environments.  Flat-headed peccaries may have avoided falling in Peccary Cave after 22,000 calendar years BP because the area around the entrance to the cave was barren and not hidden by vegetation.  None happened to fall in the cave after this date, but that doesn’t mean they didn’t still occur in the region.  Other fossil sites in the region yield the remains of horses, but not a single horse fossil has been found in Peccary Cave.  Horses were likely another abundant species in the region that just happened to never fall in or enter Peccary Cave.

3. Wilson did a stable isotope analysis of 2 flat-headed peccary teeth and concluded they fed upon just a few leguminous plant species, so they became extinct when these limited number of plant species disappeared from the region.  I don’t believe the entire dietary breadth of a species can be determined from such a small sample size.  Moreover, 1 study suggests stable isotope analysis is not at all reliable.  (See: https://markgelbart.wordpress.com/2016/06/24/trust-the-coprolites-not-the-stable-isotope-analysis/ )  Scientists compared the results of a stable isotope analysis of moa bones with actual fossil droppings.  The stable isotope analysis was wrong.  Flat-headed peccary teeth were built to eat grass and tough vegetation.  A species that survived millions of years of climate change didn’t exclusively feed upon just a few species of leguminous plants.

4. Wilson asserts flat-headed peccaries were uncommon and thus vulnerable to extinction.  However, a new genetic study of 12 flat-headed peccary individuals from Sheridan Cave, Ohio, dating to just before their extinction revealed populations of this species were diverse and expanding.  This suggests flat-headed peccaries were common, adaptable, and had a wide geographical distribution until the species’ demise.

Peccary Cave has yielded a wealth of information for paleoecologists, and I’m shocked at how little research has been published about this site.  I’ve been able to find about half a dozen research papers.  There hasn’t been a scientific excavation of the site since 1993, though amateurs are currently pillaging it.  Most of the specimens from this site have not yet been described in the scientific literature, and they are not listed on the paleobiology database. An early report of the site mentions the existence of peccary “droppings.”  Yet, nobody has studied the coprolites (please email me if I’m wrong)–an outrageous oversight.  We could actually find out what flat-headed peccaries ate, instead of guessing based on stable isotope analysis.  I’m not sure the coprolites were even collected and stored in a museum.  There should be hundreds of published papers about this site, not just a paltry 6.  I’ve come across other understudied fossil sites and collections in my research, but this site might possible be the most underappreciated.

References:

Bell, Kenneth; and Lee Davis

“Sinkhole Excavations in Peccary Cave, Newton County, Arkansas”

Arkansas Academy of Science 47(30) 1993

Davis, Lee

“Biostratigraphy of Peccary Cave, Newton, County, Arkansas”

Arkansas Academy of Science 1969

Perry, Tahlia; et. al.

“Ancient DNA Analysis of the Extinct North American Flat-headed Peccary (Platygonus compressus)”

Molecular Phylogenetics and Evolution 2017

Wilson, Kurt

“Late Pleistocene Extinction of the Flat-headed Peccary on the Ozark Plateau: Paleozoological Insights from Peccary Cave”

Iowa State Graduate Thesis 2017

 

 

 

Pleistocene Pine Voles (Pitymys pinetorum)

October 16, 2018

Evolutionary biologists like to study rodent fossils.  Rodents occur in high population numbers, and their rapid generational turnover means evolutionary change occurs faster than with larger slower breeding animals.  Scientists recently studied pine vole teeth from 2 caves in Kentucky and 1 cave in Georgia that date to the last Ice Age and compared them with modern day pine vole teeth.  Pine vole teeth from Hilltop and Cutoff Caves in Kentucky date to about 30,000 years ago, and the pine vole teeth from Yarbrough Cave in Georgia date to about 23,000 years ago.  Pine voles are still a common species, occurring all across eastern North America.  Despite their name, they prefer living in moist deciduous forests where they tunnel under tree roots and feed on roots, seeds, fruit, fungus, and insects.  Their fossorial existence keeps them safe from owls and hawks, though snakes can enter their burrows.  Pine voles are considered arvicolid rodents because their teeth cusps are in the shape of alternating triangles.  Other common arvicolid rodents include meadow voles, lemmings, muskrats, and cotton rats.

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Pine voles weigh just an ounce.  They mostly live underground but occasionally venture to the surface.

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Pine vole range.  Pine vole is a misnomer.  They prefer moist deciduous woods, not pine forests.  Nobody knows why the common name is pine vole.

The pine vole teeth from the Kentucky Caves show the pine voles living then were the same size as modern day pine voles living in the region.  However, pine voles living in north Georgia during the Ice Age were larger than modern day Georgia pine voles and about the same size as northern pine voles.  Scientists believe this was in response to colder temperatures.  Bergmann’s rule states that animals living in colder climates generally grow to a larger size because they are better able to retain body heat.  The authors of this study can’t determine whether this large size was the result of inbreeding with northern populations of larger pine voles that colonized the region or natural selection of the local population.

Reference:

Martin, Robert; and K. O’Bryan

“Size and Shape Variation in the Late Pleistocene Pine Vole (Mammalia: Arvicolidae: Pitymys Pinetorum) First Lower Molars from 3 Caves in Kentucky and Georgia”

Paludicola September 2014

A New Study of the Looper Collection

October 9, 2018

Between 1989-1995 Lonnie and Freida Looper hunted for fossils on 19 different gravel bars along the Mississippi River during droughts when the bars became exposed.  These gravel bars are located between Helena, Arkansas and Greenville, Mississippi.  Thousands of years ago, the bones were quickly buried when glacial meltwater pulses flooded the Mississippi River Valley.  The Mississippi River erodes this Pleistocene-aged sediment and deposits the soil and bones on the gravel bars.  For years the Looper family sold replicas of their specimens, but they donated most of the actual specimens to Delta State University.  I don’t think they still sell the replicas, though the Looper’s website remains on the internet.  The Looper family discovered over 550 specimens including 27 species.  A comprehensive study of their collection wasn’t published until 2017.

 

 

 

 

 

 

The Looper family found this Jefferson’s ground sloth claw on a Mississippi River gravel bar exposed during a drought.

During most of the late Pleistocene the Mississippi River entered the Mississippi River Valley through 3 gaps, but all of these flooded following the collapse of the ice dam that unleashed the waters of Lake Agassiz about 12,900 years ago.  Before this the Mississippi River didn’t meander broadly like it does today.  Instead, it was a series of braided channels clogged with sandbars because the water table was much lower then.  Cold glacial meltwater pulses caused cool microclimates within the valley that favored mixed Ice Age woodlands of pine, spruce, ash, aspen, oak, hickory, willow, tamarack, herbs, and grass.  Frequently flooded bottomlands and abandoned dried-out channels hosted alder thickets with beech, walnut, tulip, willow, and grass.  Spruce and jack pine dominated drier upland sites.  These were the types of habitats that supported the animal life represented in the Looper collection.  Some of the species they found were not known to have occurred within the Mississippi River Valley including paleolama, stag-moose, helmeted musk-ox, giant short-faced bear, and manatee.

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Map of the Mississippi River Valley in relation to the ice sheet during the Last Glacial Maximum. This map doesn’t represent the land area that occupied the continental shelf then.

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The Mississippi River resembled this modern day braided river during the Ice Age.

Paleolama mirifica was a species known from the coastal plains of South Carolina and Georgia, and throughout Florida; so the specimen found by the Looper family was a first for the region and evidence for a greater range than was previously known. The manatee was likely an accidental migrant that may have perished because it failed to go south during cool weather.  Manatees can’t survive in water temperatures below 68 degrees F.  The Looper family also collected bones of mammoth, mastodon, bison, white-tailed deer, long-nosed peccary, 2 species of extinct tapir, horse, beaver, giant beaver, Jefferson’s ground sloth, dire wolf, raccoon, black bear, giant tortoise, snapping turtle, soft-shelled turtle, unidentified bird, small-mouth buffalo fish, and flat-headed catfish.  Bones of bison and deer were the most common.

Nina Baghai-Riding, the lead author of this new study, thinks the Mississippi River Valley may have been a migratory corridor for some species.  Cool microclimates along the river may have attracted fauna of northern affinities.  Rivers are also rich in food resources as well because a greater quantity and quality of vegetation can grow in more irrigated environments.  The superior feeding opportunity attracted megafauna as well.

Reference:

Baghai-Riding, Nina; and D. Hunley, C. Beck, and E. Blackwell

“Late Pleistocene Megafauna from Mississippi Alluvium Plain Gravel Bars”

Paludicola December 2017

file:///C:/Users/Owner/AppData/Local/Packages/Microsoft.MicrosoftEdge_8wekyb3d8bbwe/TempState/Downloads/Baghai-RidingLatePleistocenegravelbarpaper%20(3).pdf

 

How far South did the Extinct Stag-Moose (Cervalces scotti) Range During the Late Pleistocene?

October 2, 2018

A species of extinct deer, slightly larger than a modern day moose (Alces alces), occurred south of the ice sheets during the late Pleistocene.  It is alternatively known as stag-moose or elk-moose, but its scientific name is Cervalces scotti. This giant deer had the long nose of a moose, though its antlers were more like those of an elk.  However, it shared a closer common ancestor with the former.  They inhabited wetlands surrounded by mixed forests dominated by spruce but with significant elements of pine and hardwoods.  Like modern day moose, they fed upon aquatic plants during summer and twigs during winter.  Mastodons occupied a similar habitat and fed on the same foods, so the 2 species often co-occurred together.

Evidence from the fossil record suggests stag-moose were particularly abundant in midwestern bogs left by retreating glaciers.  Stag-moose bones are quite commonly found in Ohio, Indiana, Illinois, and New York.  Surprisingly, they occurred even farther south with isolated fossil remains having been discovered in Virginia, Arkansas, Mississippi, and South Carolina.  The stag-moose remains found in Desha and Philips County, Arkansas and Rosedale, Mississippi are at 34 degrees latitude.  These consist of antler fragments and a jawbone with a tooth.  The stag-moose specimen from Charleston, South Carolina (just a tooth) occurred at 32 degrees latitude.  This is probably close to the southern limits of its former range because stag-moose remains are completely absent from sites in fossil rich Florida.

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Artist’s depiction of the stag-moose.  They were huge. That is a lot of venison.

A stag-moose skeleton found in Chippewa Lake, Medina, Ohio had 1 bone that had attached sediment filled with pollen representing the type of environment it lived in.  The pollen included fir, maple, alder, aspen, birch, hickory, hackberry, hazelnut, ironwood, pine, oak, basswood, elm, spruce, cedar, ragweed, grass, and cattail.  Spruce pollen made up 60% of the total.  It seems likely the type of environment favored by the stag-moose, as far south as Charleston, South Carolina, included various compositional ratios of these species.  I hypothesize stag-moose occurred in the mid-south during cool moist interstadials rather than the coldest driest stages of Ice Ages.  Wetlands would’ve been more common during these climatic phases.  Full blown glacial maximums restricted stag-moose habitat because desert scrub and grassland habitat expanded then.

Although there is no supporting archaeological evidence, I think overhunting by humans caused the extinction of the stag-moose.  Man colonized North America when ice sheets covered most of Canada, thus restricting stag-moose to more temperate regions where humans became common enough to impact their populations.  When the glaciers began to recede, optimal stag-moose habitat increased, but humans had already decimated their populations into extinction.  Modern day moose crossed the Bering land bridge, and ecologically replaced the stag-moose and were able to survive in northern latitudes where human populations remained too scarce to overhunt them.

Reference:

Mcdonald, Greg; R. Glotchober

“Partial Skeleton of an Elk-Moose, Cervalces scotti, from Chippewa Lake, Medina County Ohio”

Research Paper 2017

Were Beringian Wolves Blonde?

September 25, 2018

An extinct ecomorph of the gray wolf (Canis lupus) roamed North America from Beringia to at least as far south as Wyoming during the Late Pleistocene. (See: https://markgelbart.wordpress.com/2016/05/30/beringian-wolves-an-extinct-ecomorph-of-canis-lupus-lived-as-far-south-as-wyoming/ ) Beringia included the unglaciated region of Alaska, the Yukon, and the Bering Strait located north of the Ice Sheet that covered most of Canada then.  The Bering Strait emerged above sea level during Ice Ages.  An ecomorph is the regional variation of a species that differs morphologically from other populations of the same species.  Beringian wolves had bodies closely resembling those of gray wolves, but their teeth and jaws were larger and more robust like those of the extinct dire wolf (C. dirus).  Paleontologists interpret the larger teeth and jaws as an adaptation for preying and scavenging on megafauna.  Isotopic evidence of Beringian wolf bones does suggest they fed upon mammoths, horse, bison, musk-ox, and caribou.  Beringian wolves were not ancestral to modern day Alaskan gray wolves, but they do share a common ancestor.  Genetic evidence suggests Beringian wolves diverged from wolves found in northern China and Mongolia today about 28,000 years ago.  Present day Alaskan wolves descend from a different population of wolves than the Beringian wolves which became extinct about 7500 years ago.

Map showing location of sites where Beringian wolf bones have been discovered and the proposed route from Beringia to Wyoming.  I hypothesize they occurred as far south as the southern Appalachians.

I hypothesize Beringian wolves were an hybrid species originated when gray wolves interbred with dire wolves.  This hypothesis will be possible to test when scientists are able to extract DNA from a dire wolf fossil.  There are thousands of dire wolf specimens from the La Brae Tar Pits, but the tar in the bones prevents DNA extraction.  Many specimens of dire wolf have been found in Florida as well, but humid conditions here cause DNA to deteriorate.  I also hypothesize Beringian wolves were more widespread than the fossil record indicates.  Over much of the continent fossil evidence of canids consists of isolated teeth and bones difficult for scientists to differentiate between gray wolf, Beringian wolf, dire wolf, and even large Pleistocene coyote.  For example 1 wolf tooth found at Ladds Cave in north Georgia was identified as belonging to a gray wolf by 1 paleontologist, but another scientist ruled it fell within the size range of a dire wolf.  Maybe this specimen came from a Beringian wolf.

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80,000 year old mummified wolf pup found in a Yukon gold mine.  Note the coat color.  It’s is a brownish blonde.

During June of 2016 gold miners discovered the mummified remains of a wolf pup.  As the photo shows, it was perfectly preserved.  Carbon dating of the specimen indicated it was older than 50,000 years–the upper limit of carbon dating.  However, the specimen was associated with volcanic ash dated to about 80,000 years BP.  This predates the 28,000 year old divergence between Mongolian wolves and Beringian wolves, so it will be interesting to learn how this specimen relates to later populations of wolves.  Julie Meachen of Des Moines University will lead a study of the pup.

The coat color of this specimen surprises me.  Of all the speculative illustrations of Pleistocene wolves none depict a golden, blonde, or tawny colored coat.  This specimen appears to have a coat color similar to a lion but a little darker.  Perhaps preservation in permafrost for so long changed the original color of the coat but suppose this was the color.  The coat color likely resembled the landscape background of its habitat.  Patches of yellow grass interspersed with bare dirt predominated in Beringia and much of North America during Ice Age stadials when precipitation was scarce and temperatures dropped.  It’s possible packs of yellow dire wolf/gray wolf hybrids lived throughout parts of North America for thousands of years.

In Defense of House Sparrows

September 18, 2018

Jessica Neal and Virginie Rolland, scientists from Arkansas State, published a paper in Southeastern Naturalist about their research of bluebird nesting boxes, and they mentioned “euthanizing” non-native house sparrow nestlings that they found occupying the nest boxes intended for bluebirds.  This irritates me for several reasons.  I hate the use of the word, euthanize, because it was used to sanitize what they actually did.  They killed helpless baby birds.  Many people kill house sparrows because this species outcompetes native birds such as bluebirds, swallows, woodpeckers, and unestablished purple martins.  It is too bad these species may be in decline, but when she killed the house sparrows that were occupying that site there were then fewer  birds occupying that area.  Bluebirds probably weren’t going to return to that site during that nesting season, and there is no guarantee they ever will.  Without the house sparrows there was less avifauna for bird watchers to enjoy.  I also don’t like the way they played God by deciding which species they wanted to live there.  Some may say humans already decided to play God by introducing house sparrows to North America in 1852 when ironically they were brought to New York to control native linden moths.  I reject this argument.  Humans shouldn’t pick an animal to introduce, then decide they don’t want it any more and try to eradicate it.  Not only are humans playing God, they are playing a fickle God in this case.  Not even the worst Old Testament version of God was this monstrous.

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House sparrows are a commensal species with humans.

I love house sparrows because they thrive where few other birds can.  Every grocery store shopping center hosts a colony of house sparrows, and they often live in the patio section of big chain lawn and garden centers.  This habitat is completely unsuitable for native songbirds.  The only other bird species I see in suburban parking lots are city pigeons (also non-native) and ring-billed gulls during winter.  But house sparrows are abundant in these otherwise barren urban environments where they feast on discarded junk foods and fill the atmosphere with their delightful singing.

The house sparrow (Passer domesticus) originated in the Middle East having evolved from P. predomesticus following the development of agriculture.  Fossil remains of P. predomesticus have been unearthed from Qumm-Quatufa Cave in Israel that date to the mid-Pleistocene.  House sparrows may have already been a commensal species with archaic humans, hanging around their garbage middens.  Late Pleistocene remains have also been discovered from Kebara Cave in Israel.  Genetic evidence suggests P. predomestica diverged from the Spanish sparrow (P. hispaniolensis) about 100,000 years ago.  Another genetic study suggests P. domesticus evolved larger skulls and an improved ability to digest starch 11,000 years ago–the dawn of the agricultural era.  The larger skulls helped them crack human-grown grains, and the improved ability to digest starch let them survive on an heavy diet of wheat, rye, and oats.  They became less dependent upon insects than their wildest remaining subspecies P. domesticus bactranius. Unfortunately for other songbirds, their larger skulls gave them greater biting and piercing force, and this allows house sparrows to outcompete them.

House sparrows followed humans throughout Europe and Asia where they continued to feast on grain spillage and nest on housing structures.  This close association with humans let house sparrows conquer the world wherever humans became established.  House sparrows were formerly even more abundant when the horse and buggy were the most common mode of transportation.  In addition to excess grain spillage house sparrows ate the undigested grains in horse manure.  But the introduction of the automobile dealt a little setback to house sparrow populations, reducing the amount of grain and manure in the environment.  Nevertheless, a trip to the local grocery store is all it takes to see them.

References:

Schans, Franke

“How the Sparrow Made Its Home with Humans”

Science August 24, 2018

Neal, Jessica; and Virginie Rolland

“A Potential Case of Brood Parasitism by Eastern Bluebirds on House Sparrows”

Southeastern Naturalist (14) 2 2015