Beringian Wolves, an Extinct Ecomorph of Canis lupus, Lived as Far South as Wyoming

May 30, 2016

Both dire wolves (Canis dirus) and gray wolves (C. lupus) lived in North America during the late Pleistocene.  The former were far more common than the latter south of the ice sheet that covered most of Canada then.  Gray wolves did occur as far south as California, but were uncommon over much of the continent, possibly because of competition with dire wolves, large Ice Age coyotes (C. latrans), and dholes (Cuon alpinus).  However, in Alaska north of the ice sheet, gray wolves were the only species of large canid.  Scientists refer to this population as Beringian wolves.  Though their size and build was similar to that of the extant gray wolf, they had stronger jaws and more robust teeth.  Paleoecologists assert this powerful bite was an evolved adaptation that allowed them to successfully prey upon large Pleistocene megafauna such as horse, bison, and musk-ox.   Fossils of Beringian wolves range in age from 7500 BP->50,000 BP.  This population of gray wolves became extinct about the same time as the Pleistocene megafauna.  (Evidence from DNA in Alaskan permafrost suggests horses occurred there until ~7500 BP).  Pleistocene Beringian wolves were not ancestral to present day Alaskan gray wolves.  Instead, wolves living in Alaska today descend from wolves that expanded their range north following the dissolution of the ice sheet. (See also: https://markgelbart.wordpress.com/2014/04/11/extinct-pleistocene-ecomorphs-of-the-cougar-puma-concolor-and-the-timber-wolf-canis-lupus/ )

 

Map showing potential migration route for Beringian wolves.

Wolves in Idaho's River of No Return Wilderness Post

I tried to find a photo of exceptionally large gray wolves on google images, but they were all marred with the despicable sadistic hunters who had murdered them.  I hate anyone who would go hunting for wolves.

Wolf fossils found in Natural Trap Cave, Wyoming puzzled scientists for many years because they had features intermediate between gray wolves and dire wolves.  A recent study, using a statistical analysis of anatomical measurements, determined these wolves were Beringian wolves, the same extinct ecomorph that lived in Alaska during the late Pleistocene.  Measurements of the jaws and lower teeth of these Wyoming wolves matched those of Beringian wolves.  The jaws and teeth were smaller on average than those of dire wolves, but larger than those of other populations of gray wolves.  Natural Trap Cave is located exactly south of the ice free corridor that existed between the Cordilleran and Laurentide ice sheets before and after the Last Glacial Maximum.  Beringian wolves followed herds of bison (Bison antiquus) and musk-oxen (Bootherium bombifrons) when they migrated back and forth through the corridor.  The authors of this study predict fossils of Beringian wolves may be found as far west as Oregon and possibly farther east than Indiana.

I hypothesize Beringian wolves were an hybrid species, resulting from crossbreeding between Canis lupus x Canis dirus.  A recent study of mammoth DNA determined that Columbian mammoths (Mammuthus columbi) interbred with woolly mammoths (M. primigenius) where the 2 species ranges overlapped, such as the Great Lakes region.  (See: https://markgelbart.wordpress.com/2016/02/18/the-southern-and-northern-range-limits-of-the-columbian-mammoth-mammuthus-colombi/ ).  This explained why fossils of mammoths from this region showed characteristics intermediate between the 2 species.  The same explanation may hold true for Beringian wolves, though convergent evolution is the alternate hypothesis for their more robust bite.  My hypothesis would be easy to test, if dire wolf DNA were available.  Surprisingly, despite this species’ abundance in the fossil record, dire wolf DNA has never been extracted.  There have been well over a thousand specimens of dire wolves excavated from the La Brea Tar Pits, but the chemical used to remove the tar from the bones also destroys DNA.  The humid environmental conditions in Florida, where dire wolf remains are also abundant, probably degrades DNA, making this another unfit potential source.

I wonder if Beringian wolves ever followed herds of megafauna when they wondered as far south as the southern Appalachians.  A study of Beringian wolf bone chemistry determined bison and musk-oxen were their favorite foods.  As I noted here ( https://markgelbart.wordpress.com/2016/05/16/the-extinct-helmeted-musk-ox-bootherium-bombifrons-and-appalachian-grassy-balds-during-the-pleistocene/  ), I believe the woodland musk-ox was the first species of megafauna to colonize grassy balds.  Maybe gray wolf/dire wolf hybrids followed them.  A wolf tooth found in north Georgia at Ladds has been alternately identified as gray wolf (by Clayton Ray) and dire wolf (by Ronald Nowak).  They could both be right.

References:

Fox-Dobbs, K.; A. Leonard and P. Koch

“Pleistocene Megafauna from Eastern Beringia: Paleoecological and Paleoenvironmental Interpretation of Stable Carbon and Nitrogen Isotope and Radicarbon Records”

Paleogeography, Paleoclimatology, and Paleoecology 2008

Gold, DA; et. al.

“Attempted DNA Extraction from Rancho La Brea Columbian Mammoth (Mammuthus columbi: prospects for Ancient DNA Extraction from Asphalt Deposits”

Ecological Evolution 2014

Leonard, Jennifer; et. al.

“Megafaunal Extinction and the Disappearance of a Specialized Wolf Ecomorph”

Current Biology 17 2007

Meachen, J.; A. Brannick and T. Fry

“Extinct Beringian Wolf Morphology Found in the Continental U.S. has Implications for Wolf Migration and Evolution”

Ecology and Evolution 2016

Gopher Tortoises (Gopherus polyphemus) on Anastasia Island State Park

May 27, 2016

Access to swimming beaches near St. Augustine, Florida is not free, but for only $8 per car, vacationers can enjoy a day at the beach on Anastasia Island State Park.  My daughter and I wandered into the surf there one morning in mid-May (last week as I write this).  We experienced strong currents, sudden deep drop-offs, quicksand, and no lifeguard on duty.

Several boardwalks stretch over protected beach dunes, presenting a view of the part of the island known as “Bird Island. ” I saw some birds but not many…I saw more birds in downtown St. Augustine.  I saw a flock of 12 brown pelicans, a great egret, a red-winged blackbird, cardinals, mourning doves, and city pigeons.    But many of the birds I saw in St. Augustine probably nest in the dunes on Anastasia Island.  I’m sure the ring-billed and laughing gulls and the least turn that I saw on St. Augustine nest here.

We took a stroll around the parking lot, and I was excited to find 2 rare gopher tortoises, a living relative of 2 larger extinct species of Pleistocene tortoises.

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This gopher tortoise was walking by the side of the parking lot in Anastasia Island State Park.

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I saw this smaller gopher tortoise first.  Although I’ve seen gopher tortoise burrows, this was the first time I’d ever seen the actual tortoises.

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Anastasia Beach was not crowded mid-morning in mid May.

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Part of Anastasia Island is known as Bird Island.  The currents are depositing sand on the north end and building it up.  Gulls and terns are probably nesting in these beach dunes.  I saw an adult least tern across the bay in St. Augustine.  It may have hatched on this island.  Sea oats, sea grape, and cactus hold down the dunes.

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A brackish marsh.

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Red-winged blackbird.

The giant southern white butterfly (Ascia monaste) is abundant on Anastasia Island in May.  Larva of this species feed on saltwort and plants from the mustard and cabbage family.

I was too lazy to chase around butterflies , so I ripped off this photo from google images. Giant southern white butterflies were abundant on Anastasia Island.

A brackish lagoon bisects the island and wading birds hunt for fish and shrimp in it.  This state park consists of a variety of habitats–surf, beach dune, brackish marshes, and a kind of stunted maritime forest where live oak, myrtle, bayberry, and cedar grow.  The Ponce de Leon Fountain of Youth Archaeological Park in St. Augustine is in the middle of a more mature maritime forest, and there is a boardwalk over a salt marsh within this park.  I enjoyed excellent birdwatching here and saw great blue heron, great egret, least tern, eastern kingbird, red-breasted merganser, and a white ibis.

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A fish taco at Joe’s Grill on Anastasia Island.  This was the best thing I ate on my vacation.  It’s a soft taco wrapped around a crunchy taco with well seasoned fish, lettuce, cheese, a delicious salsa, and a sauce.  And it only cost $5.25.  Most of the entrees offered on the tourist trap restaurants in St. Augustine cost $28-$40 during supper hours.

St. Augustine is a Tourist Trap

We stayed in the Best Western Bayfront Inn in St. Augustine.  They charged an additional $10 per night for a “self-parking fee.”  Most of the tourist trap restaurants and museums are not handicapped accessible, although Anastasia State Park, administered by the state, does offer free beach wheelchairs.  The restaurants in St. Augustine charge kiss-my-ass prices.  Lunch menus offer the same items for almost half the obscene suppertime prices.  I suggest vacationers stay in the cheaper less crowded hotels on Anastasia Island.  From there it’s a short walk across the drawbridge to the best attractions of St. Augustine–the Castillo de San Marcos and the Ponce de Leon Fountain of Youth Archaeological Park.  The Alligator Farm and Zoological Park is located on Anastasia Island.  I would have liked to have visited this attraction.  They keep every species of crocodilian in the world.  However, my daughter chose the Fountain of Youth and it was cheaper anyway.

 

 

The Castillo de St. Marcos National Monument in St. Augustine, Florida

May 21, 2016

The Timucuan Indians lived in northeastern Florida when Spain established the first European settlement on the North American continent in 1565 at St. Augustine, Florida.  The Timucuans averaged well over a foot taller than the European settlers because of their high protein diet consisting of abundant venison, turkey, fish, shellfish, corn, and beans.  Nevertheless, superior Spanish weaponry and tactics gave the Europeans the upper hand in battle, and an inherited lack of resistance to Old World diseases doomed Native Americans all across the continent because their populations were regularly decimated by fatal illnesses.

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Mock-up of a Timucuan hut at the Ponce de Leon Fountain of Youth Park.

England and Spain competed for control of North and South America during the 17th and 18th centuries.  Spain began building a fort in St. Augustine in 1672 to defend Florida from the Anglo aggressors.  They built the fort using coquina–a fossiliferous sedimentary rock they quarried from nearby Anastasia Island.  Coquina consists of sea shells cemented together.  It’s soft when underground and therefore easy to cut, but it hardens when exposed to air, making it ideal material for repelling cannon balls.  Indian, then African slaves quarried the rock for 20 years, loading the stone on oxcarts that were hauled to barges and shipped across Matanzas Bay to the site of the fort adjacent to St. Augustine.  The fort, known as the Castillo de St. Marcos, took 20 years to complete.  It was never taken in battle, though St. Augustine itself was sacked in 1702.  The siege of the fort failed, and the British withdrew.

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The Castillo de San Marcos.

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The material used to build the fort was coquina, a type of fossil rock.  Note the embedded fossil sea shells in the wall.

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A 400 year old Spanish cannon.  Note the coquina it’s resting upon.

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Cannons on the 2nd story of the fort.  The fort was never taken in battle.

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An old fashioned mortar.

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A moat, now drained, surrounded the fort.  It was probably filled with alligators.  This prevented the use of battering rams that could’ve broke in the door.

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A watchtower with a view across Matanzas Bay.

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View from inside the fort.

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Ponce de Leon discovered this freshwater spring in 1513.  The Spanish established a settlement here because of this convenience.  The water tastes exactly like modern day St. Augustine tap water.  The tap water near south Atlantic states always has a sulfurous aftertaste.

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A cistern used for storing rainwater.  Fresh rain tastes better than the local spring water.

Spain gave Florida and the fort to England in 1765 as part of a peace treaty.  Spain regained control in 1783 after the U.S. kicked England’s butt in the Revolutionary War.  The U.S. bought Florida from Spain in 1821 and gained control of the fort.  The U.S. army used it as a prison for Indians during the Seminole Wars, and late in the 19th century kept Kiowa POWs here.  What a depressing chapter of American history.

The Castillo de San Marcos is a nice spot for bird watching.  The most abundant species are city pigeons, chimney swifts, boat-tailed grackles, mourning doves, and laughing gulls.  The city pigeons might be descended from birds the Spanish brought from Europe to raise as food as early as 1610.  Many of the individuals I saw were big and fat.  Another name for city pigeon is rock dove because they are native to rocky cliffs in Eurasia.  The fort offers ideal habitat for them.  They nest in the crooks and crannies within the fort and have access to seaside foods rich in iodine, an element beneficial for brain development.  People supplement their wild foraging.

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I fed some pigeons a piece of banana bread that fell on the floor.  They are greedy little pigs.

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Boat-tailed grackles are superabundant in north Florida and south Georgia near the coast.

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A snowy egret on the edge of Matanzas Bay.

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Peacocks roam the grounds at the Ponce de Leon Fountain of Youth.

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An immature white ibis.

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A great egret and a great blue heron in the same frame.

While I was inside the fort, 3 wood storks soared overhead but not close enough for me to photograph.  I saw wood storks all 4 days I vacationed in St. Augustine.  I saw 4 species of animals for the first time on this trip–a greenhouse tree frog, gopher tortoises, a least tern, and a loggerhead shrike.  I saw the first 3 in Florida, but I saw the shrike in northern Burke County, Georgia while I was driving home.  It was in someone’s front yard about 10 miles south of my house.

The Extinct Helmeted Musk-ox (Bootherium bombifrons) and Appalachian Grassy Balds during the Pleistocene

May 16, 2016

The tops of some mountains in the southern Appalachians are relatively treeless, resembling a man with a bald spot on his head, hence the name Appalachian bald.  There are 2 types of balds–grassy and heath.  Grassy balds are open environments surrounded by forests of red spruce, yellow birch, red oak, chestnut oak, and buckeye.  Heath balds consist of shrubby plants that prefer acid soils including rhododendron, azalea, and blueberry. Peter Weigl theorizes Appalachian balds are relic communities of ancient origin.  He believes harsh climates during Ice Age glacial maximums killed the trees growing at higher elevations in the southern Appalachians.  Prolonged sub-zero temperatures, frequent ice storms, and windy conditions increased tree mortality.  In some areas grass and in others shrubs took advantage of these sunny environments and became the dominant flora.  This attracted herds of megafauna such as mammoths, bison, and horses.  Their trampling and grazing further favored the dominance of grass and shrubs over trees.  Grass can withstand heavy grazing and rapidly grow back in this cool moist climate, while the toxic leaves of heath shrubs protected them from hungry megaherbivores.  Elk and bison continued grazing on the these mountain meadows until colonial times, keeping them open even as the climate became more favorable for tree growth, and then settlers brought their livestock to the balds  inadvertently maintaining these ancient landscapes.  But since the early 20th century when farmers switched to industrial jobs and stopped using the balds for livestock grazing, trees have been encroaching on them.  Some have disappeared completely, while others are in danger of being overgrown in forest.  Ecologists have recognized balds as unique natural communities and are attempting to save them with a combination of mowing and goat grazing.

Heading up towards Round Bald

Modern ecologists are using goats to help maintain grassy balds.  The helmeted musk-ox was closely related to goats.  I believe the helmeted musk-ox was the most important species of megafauna involved in the maintenance of grassy balds during the Pleistocene.

Peter Weigl notes several lines of evidence supporting his belief that southern Appalachian balds are ancient natural communities originating early during the Pleistocene or before.  There are many endemic species of  plants growing on balds that are found nowhere else.  The process of evolution is slow and it’s unlikely so many different species would have evolved so rapidly.  There are also many disjunct species found more commonly in more northerly latitudes.  They are relics surviving in higher cooler elevations but were once more widespread in the region when overall climates were cooler.  This means these plants have been present here throughout many changes in climate.  There’s no evidence of fire in these cool moist higher elevations, and few fire-adapted species of plants live here. This rules out anthropogenic fire as a mechanism in bald creation. Balds were described before Europeans settled here, and even as late as 1790 only 80 settlers lived in the region–not enough people to have cleared so much land.  Relic and endemic species of small mammals, birds, reptiles, and amphibians are also evidence of ancient origin.  Finally, without regular mowing and grazing, these open environments are converting to forest, suggesting a dependence on megafauna presence.

The Canadian blackberry (Rubus canadensis) is native to high elevations in the southern Appalachians, but it has become a problematic plant on grassy balds.  This plant will encroach on grassy areas, completely taking over.  Trees begin to sprout in the brier patches–the first stage of succession leading to the termination of a grassy bald.  Ecologists use goats (Capra aegagrus) to knock back the Canadian blackberry because they readily feed upon the thorny plants.  Goats are closely related to the extinct helmeted musk-ox.  Upon considering this relationship and the coincidental use of goats in bald maintenance, it occurred to me that the helmeted musk-ox may have been the single most important species of megafauna responsible for the existence of Appalachian balds.  Along with caribou (Rangifer tarandus) and flat-headed peccaries (Platygonnus compressus), they were probably the first large mammals to colonize the higher elevations during the harshest climatic phases of the Ice Ages.  Caribou could survive on lichen, while musk-oxen and flat-headed peccaries could subsist on tougher vegetation.  From fossil coprolites scientists know this species of musk-oxen ate woody vegetation during long winters.  They were hardier than bison, horses, and mammoths.  I think these latter 3 species didn’t move to higher elevation balds until warmer phases of climate.  Though they aren’t picky eaters, they prefer lush grasses over thorny blackberry vines.  It was the musk-oxen and perhaps the flat-headed peccary that consumed the thorny vines which would otherwise eventually crowd out grasses here.

Life size model of the helmeted musk-ox.  This species lived as far south as Louisiana.  I’m not sure how accurate this model is.  Helmeted musk-oxen were taller and less wooly than the extant species of musk-ox. 

Rare endemic species such as the Gray’s lily are evidence that Appalachian grassy balds are of ancient origin.

Fossil evidence of the helmeted musk-ox has yet to be found near the present day location of Appalachian balds.  They may never be found here because the most common fossil sites in this region are caves, and musk-oxen probably didn’t venture into caves where they could get ambushed by predators.  However, bones of this species have been dredged from 2 sites off the coast of North Carolina.  Individual musk-oxen bones have turned up on a North Carolina beach and in a stone quarry near the coast as well.  Skeletal evidence of musk-ox as far south as Louisiana and Mississippi has also been reported.  A line drawn on a map between these far separate locations goes right through the southern Appalachians, so it’s a safe assumption their range included this region, and I’m convinced they played an important role in the origin of grassy balds.

Reference:

Weigl, Peter; and Travis Knowles

“Temperate Mountain Grasslands: A Climate-Herbivore Hypothesis for Origins and Persistence”

Biological Reviews 89 (2) 2013

Irrational Admiration and Hatred

May 10, 2016

I recently read and enjoyed Dispatches from Pluto by Richard Grant, a British writer who details his experience moving from an apartment in New York City to a dilapidated big house in rural Mississippi.  The book is interesting in its description of the many eccentric characters Grant encountered and in its examination of backward race relations in Mississippi.  I’ve lived in Georgia since 1976.  Grant’s description of current racial interactions in Mississippi reminds me of the Georgia I moved to then.  But Georgia has progressed.  Mississippi seems to be 40 years behind Georgia.

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This book is the entertaining true story of a British writer who moves into an old house in rural Mississippi.

Of course, I was interested in Grant’s experiences with the nature of Mississippi, a region mostly consisting of farmland, swamp, forest, and fallow field.  His house is located on an oxbow lake, and the entire region is right in the middle of the Mississippi flyway–an important migratory route for birds.  I expected a fish out of water story, but Grant readily adapted to hunting, despite his supposed reluctance. Note this passage about a dove hunting “party:”

I missed the first three doves that came my way, and hit the fourth.  It fell to the ground still fluttering its wings in a wounded death panic.  I swallowed my horror, and following Mike’s example, I picked it up by the head and twirled it around to break its neck.  Its feathers were so soft, its beauty so ruined by blood and death.

I felt sad, upset, shaky, and proud all at the same time…The doves made such small, fast-moving unpredictable targets, a smudge of gray darting and veering, but I managed to bring down two more, and I started to feel the excitement of it, the quickening of the blood, the total adsorption in which I was trying to do.”

I’m not buying it.  How does an human being go from being “sad and upset” to excited in the space of a few paragraphs?  And why would someone feel proud over killing a small bird with a shotgun?  I think Grant is full of shit here because he was prepared to enjoy killing animals.  I also suspect he wanted to act like an hick in order to shock his pretentious city slicker friends. I’m not against hunting for food, and Grant chose to hunt deer in Mississippi for economic reasons–to put food on the table.  I’m not buying this either.  Deer hunting is not an economical way to put meat on the table.  Rifles cost hundreds of dollars and ammo adds interest to this bad “investment.”  Luckily for Grant, a neighbor loaned him a firearm.  But he still paid over $100 to have his deer processed.  Moreover, the time he spent hunting could have been spent working and making money.

I am opposed to killing animals for the hell of it.  Grant adapted the “killing animals for the hell of it” attitude rather too readily as well.  He slaughters armadillos, mistakenly thinking they are invasive pests.  Some people complain because armadillos dig holes in their yards.  But dogs dig holes in yards, and these same assholes would never think of shooting their dog because it dug an hole in their yard.  I hypothesize 9-banded armadillos are not invasive, but instead are the same species that lived in North America during the Pleistocene.  (See: https://markgelbart.wordpress.com/2012/08/19/is-the-9-banded-armadillo-dasypus-novemcinctus-a-dwarf-mutation-of-the-pleistocene-species-dasypus-bellus/ )  Armadillos are merely recolonizing lost territory.  A study published in the Southeastern Naturalist determined killing armadillos is futile because other armadillos quickly replace the ones that are killed.  So the killing of armadillos serves no purpose.

Another animal that Grant kills for the hell of it is the cottonmouth water moccasin.  He also admits to accidentally killing nonvenomous snakes, an illegal act in most states.  He kills cottonmouths because he believes they are dangerous.  Yet, he allows his large German shepherd to roam the countryside at will where it could potentially encounter and kill a small child.  (Allowing his big dog to run loose is evidence that Grant is an hick at heart.)  This illustrates a common irrationality shared by many people.  (I also had a former neighbor who freaked out about a rattlesnake on one occasion, but he often allowed his pit bull terrier to run loose. What a shmuck.)  People hate and fear snakes, often killing them on sight.  People admire and love dogs.  But fatal dog attacks are more than 10 times as common as fatal snake bites in the U.S.  Dogs have killed an average of 32 people per year over the past 10 years, and 2/3rds of the victims have been children.  By contrast snakes have killed less than 3 people per year over the past decade in this country, and some of these cases were people who unnecessarily handled the snake, including nutty Pentecostals.  (And those religious snake bite victims might have survived if they would have put their faith in doctors instead of God.  They refused medical treatment.)  A number of years ago, a dog ripped off a 10 year old girl’s arm at the shoulder.  The case received national attention.  A few dozen people sent the girl sympathetic get well cards, while she was in the hospital.  Thousands of people sent letters to the dog shelter where the dog was being held, begging the authorities not to euthanize the animal and many offered to retrain it.  Not only do people love dogs and hate snakes, they love dogs more than they care about the well being of other people.  Anybody who lets their big dog run loose is an inconsiderate jerk and should spend time in jail.

Here’s a link to some photos of people who were attacked by dogs.  I don’t want to post them directly on my blog because they are disturbing. http://www.ambrosekane.com/2013/10/25/cops-and-dog-attacks-warning-extremely-graphic/ Note how dogs attack the face.  One photo shows a man with half his face literally torn off.

Rattlesnake (Crotalus horridus).  Venomous snakes are much less dangerous than dogs.

Statistics reveal another example of irrational admiration and hate.   Drunk drivers are reviled, and doctors are greatly admired.  Drunk drivers were responsible for 9,967 deaths in 2014 in the U.S.  But a study published in the Journal of the American Medical Association estimates medical malpractice causes the premature deaths of 225,000 people per year in this country, making it the 3rd leading cause of death after heart disease and cancer.  Another study, this 1 published in the Journal of Patient Safety, estimates medical malpractice is responsible for 440,000 annual deaths in the U.S., and millions more are severely injured each year.  Doctors and hospitals are far more dangerous than drunk drivers.  My wife has been disabled for 21 years because of a medical mistake.  My late father, a physician, always said, “stay away from doctors.”  So when you turn 50 and get that letter from the government urging you to get a colonoscopy, think twice about it.  I will never have that invasive procedure done.  Doctors are scarier than drunk drivers.  The volume of death and suffering they bestow is horrifying.

 

 

 

 

 

 

 

 

Red Rain in India was Caused by a Microorganism from Europe, not Outer Space

May 4, 2016

The Color Out of Space: H.P. Lovecraft One of the first stories I’ve read from Lovecraft. It’s basically about this meteor that falls on some farm property, and everything slowly changes.  While you just chant the whole time “Leave! Move somewhere else!”, they can’t because something bigger is keeping them there. What I really love about Lovecraft is nothing is ever simple and there’s seldom a happy ending.

An unusual meteorological occurrence in India reminds me of my favorite H.P. Lovecraft story–“The Colour out of Space.”

H.P. Lovecraft published the classic science fiction/horror story, “The Colour Out Of Space,” in 1927.  The story is about a meteor that crashes in a farmer’s field and causes strange unnatural changes to all the plants, animals, and people living in the vicinity of the impact zone.   It’s remarkably prescient because the story precedes scientific knowledge of radiation poisoning, and the descriptions of the meteor’s effects bear a resemblance to nuclear fallout, though Lovecraft implies a supernatural explanation.  This work of literature directly influenced the movie, “Five Million Years to Earth,” still often aired on Turner Classic Movies, and Stephen King’s novel The Tommyknockers, his last book written while he was under the influence of cocaine and alcohol.  Some literary analysts make the claim the aliens taking over people’s minds in King’s novel is a metaphor for the drugs taking control of the author before he succumbed to treatment.  (I disagree with Stephen King when he later admitted he thinks this was a bad novel.  I rank it in the upper 25% of his creations.)  Lovecraft’s theme of an alien life form effecting life on earth permeates much of the science fiction/horror genre.  Yet, this idea is not solely confined to the realm of fiction.  Many scientists think life on earth originated in outer space, a concept known as Panspermia.  They believe non-photosynthetic microorganisms, living deep inside meteorites, crash landed on earth and later evolved into all the life forms now existing on the planet.  (The microorganisms would have to have been inside the meteorite because they couldn’t have lived on the surface in space nor could they have survived the friction heat generated by entering earth’s atmosphere.)  Proponents of Panspermia Theory thought they had strong supporting evidence when a strange red rain periodically fell in India for 2 months in 2001.  They examined the rain under a microscope and observed single-celled organisms that appeared to be multiplying but had no apparent DNA.  They assumed the organisms originated in a meteor that broke apart in the atmosphere, releasing the extra-terrestrial spawn.

There have been many incidents of red rain falling in India.  Some scientists proposed this as evidence of  Panspermia.

Genetic tests determined the rain got its color from a species of algae that originated in Austria.

However, a more detailed study of the organisms found in the red rain determined they were a species of algae that lives in symbiosis with a species of European lichen.  A DNA analysis identified the microorganisms as spores of Trentepohlian annulata.  Weather conditions sent airborne spores into clouds blown over the ocean, and they eventually fell as rain on India.  The algae recently colonized lichen growing on Indian rubber trees.  Though this study probably disappoints Panspermia proponents, it does illustrate an amazing case of an organism’s dispersal capability.  The same weather patterns periodically recur–red rain in India has been reported as recently as 2012 and as long ago as 1896.

There may be no hard evidence supporting the Theory of Panspermia, but there is a curious fact about microorganisms in space that lends support to the concept.  Astronauts often discover thick disgusting layers of biofilm growing inside space stations.  The microorganisms were introduced by accidental contamination.   A scientific study showed bacteria reproduce and grow more rapidly in zero gravity conditions, resulting in a greater biomass.  This is especially hazardous for astronauts because the human immune system completely shuts down in zero gravity.  Maybe it’s just a coincidence that simple one-celled organisms thrive in weightless conditions of outer space.  Or maybe they are so well adapted to zero gravity because it is the condition from which they originated.

References:

Bast, Felix; Jackson Adnankunju, and F. Stocker

“European Species of Subaerial Green Algae Trentepohlian annulata (Trentepohliales, Uluphyreae) Caused Blood Rain in Kerala, India”

Journal of Phylogen Evolution Biology Feb 2015

Wouseong, Kim; et. al.

“Spaceflight Promotes Biofilm Formation of Pseudonomous aeriginori

PLOS ONE 2013

Why did the Giant Great White Shark (Carchocles megalodon) Become Extinct?

April 29, 2016

The giant great white shark (Carchocles megalodon) existed as a species from ~23 million years BP until ~2.6 million years BP, and the evidence suggests this 60 foot monster preyed on whales.  It was 1 of the many marine species to become extinct during the late Pliocene.  Scientists believed megalodon was a warm water species and couldn’t survive cooling ocean waters that resulted from the emergence of the landbridge between North and South America.  However, a brand new study determined climate change could not have been the cause of megalodon’s extinction.

The authors of this study mapped out all of the sites where megalodon fossil teeth have been collected along with all fossil shark collection sites where megalodon remains were absent.  They estimated the range of the species over geologic time. Megalodon, though it originated in tropical waters, later expanded its range to waters that are thought to have been quite cold.  During glacial maximums megalodon’s potential habitat range shrank by a mere 2%, while it expanded by 8% during warmer interglacials.  Most of the area where megalodon lived was not “negatively impacted by climate change.”

Populations of C. megalodon over time. From Pimiento et al., 2016.

Map of megalodon fossil collection sites, dated over geological time periods.  From the below referenced paper.

If climate change didn’t snuff out megalodon, what was the cause of its extinction?  The researchers who published this study suggest 2 possible causes: a reduction in whale species diversity, and competition with other predators.  They note a decline in whale species diversity during the end of the Miocene is correlated with an apparent decrease in megalodon’s range distribution.  This seems a plausible explanation.  Many of megalodon’s favorite prey species went extinct, depriving the giant shark of food that it could efficiently feast upon.  I’m not convinced competition with other predators was a factor in megalodon’s extinction.  An extinct predatory species of sperm whale (Livyatan  melvillei) likely fed upon the same prey species as megalodon.  The ancestors of the modern day great white sharks (Carcharodon hubbeli) and killer whales (Orca sp.), also may have shared the same prey items.  However, megalodon co-existed with these species for millions of years, so I have a hard time accepting this explanation.

Size comparison between megalodon, a killer whale, and a human. A pod of killer whales could’ve rubbed out a single megalodon.  Perhaps this was a factor in their extinction.

skeletal reconstruction Livyatan melvillei by Christopher252

An extinct species of predatory sperm whale–Livyatan melvillei–probably competed with megalodon for the same prey.  

The extinction of megalodon may have  shaped the evolution of baleen whales.  Whales no longer had to be agile fast swimmers to escape megalodon, but instead could grow to a great size that enabled them to store food as blubber.  The stored fat helped baleen whales swim long distances to warmer waters for breeding and calving.  Killer whales, their lone remaining non-human predator, are less common in warmer waters, and whale calves have a greater chance of survival there.

Reference:

Pimiento, Catalina; et. al.

“Geographical Distribution Patterns of Carchocles megalodon over time Reveal Clues about Extinction Mechanisms”

Journal of Biogeography March 2016

Pleistocene Cricket Frogs (Acris sp.)

April 25, 2016

Every year, trillions of horny cricket frogs call to each other along the shores of ponds and slow moving streams wherever emergent vegetation grows. ( https://www.youtube.com/watch?v=QQirydJRs7Q )This is an ancient sound of nature.  Many mighty mastodons heard these mating calls, and the small frogs occasionally were forced to jump, barely avoiding the heavy steps of the lumbering giants.  The 2 far different species shared a preference for the same kinds of wetland environments.  Old beaver ponds in the process of succeeding to wet meadows hosted the highest density of mastodons and cricket frogs.  The beavers and mastodons opened the forest canopy allowing sunlight to reach plant growth along the pond margins–ideal hiding spots for cricket frogs.  The seemingly insignificant cricket frogs outlasted the more spectacular mastodons because they are capable of reproducing at a much faster rate.

Despite their annual abundance throughout North America for well over 5 million years, cricket frogs are recorded from just 10 fossil sites.  According to the paleobiology database, the bones of cricket frogs have been identified from 4 sites in Texas, 2 in Nebraska, 2 in Kansas, 1 in Colorado, and 1 in Florida.  Their remains are associated with Miocene fauna (25 million years BP- 5 million years BP) at 3 of the sites, suggesting cricket frogs have been around for quite some time.  The amount of known fossil material for this genus compared with how many individuals lived during each generation is astonishingly low and is yet another example of how incomplete the fossil record can be.

species photo

Southern cricket frog (A. gryllus).  They also come in a green phase with a stripe down their back.

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Pine pollen washed into the pond just in time for the season’s first hatching of tadpoles.  I wonder if the tadpoles feed on the protein rich plant food.  I have seen ducks eating pine pollen.

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During late March pond margins in Georgia are filled with cricket frog tadpoles.  Click to enlarge.

There are 3 species of cricket frogs in the Acris genus: the southern cricket frog (Acris gryllus), the northern cricket frog (A. crepitans), and Blanchard’s cricket frog (A. blanchardi).  Until recently, some taxonomists regarded these as 3 subspecies of the same species, but a study of cricket frog genetics determined there are species level differences between them.  The southern cricket frog ranges on the coastal plain of southeastern North America; the northern cricket frog occurs from the piedmont region north to southern Canada.  Blanchard’s cricket frog lives west of the Mississippi River, excepting 2 counties in Mississippi.  This grand river serves as a barrier to the flow of genes, resulting in speciation among cricket frogs, spiny lizards, rat snakes, shrews, and some species of fish.

The cricket frogs belong to the tree frog family (Hylidae), but their ancestors left the trees and inhabited pond margins instead.  The adults eat insects, but during the tadpole stage, they primarily subsist on algae.  I hypothesize cricket frog tadpoles feed on protein rich pine pollen.  The tadpoles seem most abundant when pollen washes into ponds in early spring.  A diet that includes pollen may increase the rate of tadpole growth and development, improving the odds of surviving to adulthood.  It would be interesting to test this hypothesis.  Southern cricket frogs do breed year round, but there is a peak during spring and a slow down during winter.

Herons take a heavy toll of tadpoles and adults when they swarm near shore, and the frogs often fall prey to bass and catfish when the jump in the water to avoid the long-legged birds.  Cricket frogs survive by constantly breeding, producing more frog than predators can catch and eat.

Reference:

Gamble, Tony; et. al.

“Species Limits and the Phylogeography of North American Cricket Frogs (Acris: Hylidae)”

Molecular Phylogenetics and Evolution 2008

A New Study about the Devil’s Den Site in Florida was Published

April 20, 2016

An unpublished study of radiocarbon dates of extinct Pleistocene megafauna excavated from the Devil’s Den site in Florida produced unusually recent dates.  Specimens from this site were dated to between 7,000 BP-8,000 BP; about 4,000 years after the time most believe these species became extinct. I often wondered why this data seemed to be ignored in the scientific literature and why no one had attempted a follow up study of the specimens from this site.  The specimens were described in 1974, then seemingly forgotten.  (See: https://markgelbart.wordpress.com/2012/07/08/the-devils-den-fossil-site-may-have-been-located-in-one-of-the-last-refuges-of-the-megafauna/ )Finally, several scientists began analyzing the Devil’s Den specimens again, and they just recently published their data in  brand new journal named PaleoAmerica.

Devils Den - Williston, FL

Photo of the Devil’s Den site from inside the sinkhole.

I had wrongly assumed the specimens were radiocarbon dated in 1974, but I learned from reading this study that they were dated in 1961 when radiocarbon dating was primitive and not particularly reliable.  Moreover, the authors of this new study determined radiocarbon dating of these specimens could not be accurate because they didn’t have enough bone collagen left.  They also suggest radiocarbon dating for most Pleistocene-aged specimens found in Florida is not possible because the regional environmental conditions eat away at bone collagen so rapidly.  This poses a problem for scientists who want to know if humans overlapped in time with Pleistocene megafauna in North America.  Surprisingly, there is little direct evidence of this, despite the universal assumption that they did.  Human remains of confirmed Pleistocene age in North America are extremely rare.  However, human bones associated with those of extinct Pleistocene mammals have been found in several sites in Florida including Vero Beach, Warm Mineral Springs, Melbourne, and Devil’s Den.  Though this is suggestive, it’s possible humans buried their dead in the Pleistocene-aged strata, mixing the bones from different time periods.  Scientists need something more definitive than association.  Because radiocarbon dating can’t be used at these sites, the authors of this study decided to try rare earth element analysis on the specimens from Devil’s Den.

Here is an explanation of rare earth element analysis. Rare earth elements (a bit of a misnomer because they’re not particularly rare) include elements on the periodic table numbered 57-71.  They occur in groundwater in certain fixed ratios.  Animals absorb ground water by ingestion and then for thousands of years after they die their bones continue to become saturated with it.  Eventually, the bone reaches a saturation point and won’t take in any more.  The ratio of rare earth elements in that particular fossil becomes fixed.  However, over thousands of years the ratios of rare earth elements in ground water changes.  So an animal that lived 13,000 years ago will have a different ratio of rare earth elements than an animal that lived  200 years ago.

The authors of this study compared the ratios and concentrations of rare earth elements from specimens they categorized into 4 groups.  They analyzed 26 specimens from 5 different individual human skeletons found in the Devil’s Den sinkhole and compared them with the associated bones of extinct Pleistocene fauna, extant fauna thought to be of Pleistocene age, and extant fauna from the modern local environment.  They used specimens of the Florida spectacled bear (Tremarctos floridanus), flat-headed peccary, Jefferson’s ground sloth, mastodon, and muskrat that were found in the sinkhole.  The first 4 of these species are extinct, and this species of muskrat hasn’t occurred in Florida for about 3,000 years.  The extant fauna thought to be of Pleistocene age found in the sinkhole included white-tailed deer, woodrat, striped skunk, gray fox, and gopher.  Local fauna of modern age used in the study were deer, fox squirrel, gray fox, and gopher.  Specimens from 4 of the 5 human skeletons shared similar ratios of rare earth elements with Pleistocene fauna, showing they lived during the same time period.  One of the human skeletons is probably of Holocene age, but this study demonstrates without a doubt that humans overlapped in time with Pleistocene megafauna.

The authors of this study assume 4 of the human remains are older than 13,000 years old, but they have no way of knowing for sure.  The rare earth element analysis shows these individuals lived at the same time as Pleistocene megafauna, and the bones are of great antiquity, but the date of deposition is not known.  As I’ve written previously on this blog, I hypothesize some species of Pleistocene megafauna survived in small relict populations well past their accepted terminal extinction date of ~12,500 BP.  The exact extinction dates of Pleistocene megafauna in Florida will remain a mystery, especially if radiocarbon dating can’t be used.

Reference:

Purdy, Barbara; Kathryn Rohlwing and Bruce Macfadden

“Devil’s Den, Florida Rare Earth Element Analysis Indicates Contemporaneity of Humans and Late Pleistocene Megafauna”

PaleoAmerica 1 (3) 2015

Gavialosuchus americanus

April 14, 2016

The false gharials, a type of crocodylian, were widespread throughout the world during the Miocene between 25 million years BP- 5 million years BP.  They inhabited the coastal regions of Eurasia, and North and Central America when worldwide climate was warmer than it is today.  With their long snouts and rows of sharp teeth, they were well adapted for catching the fish that abounded in salt marshes and saltwater lagoons.  Fossil evidence of false gharials has been found along the eastern seaboard of North America from Florida to as far north as New Jersey.  Gaviolosuchus americanus is the species that lived in eastern North America during the late Miocene, while G. carolinensis occurred here during the Oligocene (33 million years BP- 25 million years BP).  The false gharials likely arose as early as the Eocene.

New Pictures 026

Skeleton of Gavialosuchus carolinensis on display at the Charleston Museum.  This species lived during the Oligocene.

Gavialosuchus americanus Skull

Skull of Gavialosuchus americanus.  Note the long snout.

Some scientists use the scientific name of Thecachampus americanus instead of Gavialosuchus americanus.  Scientific nomenclature is a tedious topic, so I won’t delve too deeply into it on my blog.  The first scientific name ever given to a species holds precedence.  Paleontologists often find fossil material they mistakenly think is from a new species, and they will give it a name.  Later studies then determine the “new” species is actually the same as a species that had already been named.  The older species name is accepted as the correct one.  The dispute between the usage of Gavialosuchus americanus and Thecachampus americanus has yet to be unanimously resolved.

Gavialosuchus americanus was a little larger than the sole surviving species of false gharial–Tomistoma schlegeli.  The extinct species grew to 18 feet, surpassing T. schlegeli by a couple of feet.  T. schlegeli survives today in parts of Malaysia and Indonesia, but they’ve been extirpated from Thailand.  They mostly eat fish but will opportunistically take monkeys, deer, birds, other reptiles, and humans.

Tomistoma schlegelii false gharial LA zoo 03.jpg

The only species of false gharial still extant–Tomistoma shlegeli.  Various species  of false gharials occurred along the coasts  of Eurasia and North America  from the late Eocene to the early Pliocene.

Anatomical studies suggested the false gharials are distantly related to the true gharial (Gaviatis gangetives) of India.   The long narrow snout of the false gharial was considered an example of convergent evolution when unrelated or distantly related organisms evolve the same adaptation to similar environments.  However, a genetic study determined the false gharial and the true gharial are closely related sister species.  The vertebrate zoologists were wrong.

Gavialosuchus americanus co-existed with a species of alligator in North America.  An analysis of chemical isotopes in the bones of both crocodylians suggests they occupied different habitats.  The false gharial of America inhabited saltwater environments and alligators ruled the freshwater lakes and streams.

References:

Harshman, J. ; et. al.

“True and False Gharials: A Nuclear Genophylogeny of Crocodylians”

Systematic Biology 2003

Whiting, Evan; David Steadman, and John Krigbow

“Paleoecology of Miocene Crocodylians in Florida: Insights from Stable Isotope Analysis”

Paleogeography, Paleoclimatology, Paleoecology March 2016


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