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Wadi Al-Hitan, Egypt

In the desolate desert 150 kilometers southwest of Cairo there is a fearsome arid valley (wadi) of cliffs, carved buttes, and sandblasted erratic boulders.  The bleached landscape has an otherworldly emptiness as though it were located on a lifeless alien planet, though if you look closely, the desert is filled with austere furtive life like dorcas gazelles, tiny sand colored lizards, cobras, scorpions, and fennec foxes. The name of the place is even more otherworldly—“Wadi Al-Hitan” which is Arabic for “valley of the whales” and although the great smooth rocks buckling out of the sand might momentarily be taken for the backs of huge whales, the utter absence of the ocean (or of water of any kind) makes the name seem fanciful. The nearby Mount Garet Gohannam (which means mountain of hell because of the way it glows like flames at sunset) seems to be more aptly named.

Whale fossil at Wadi Al-Hitan

However the name of Wadi Al-Hitan is remarkably literal–for the valley contains the remains of hundreds of huge ancient cetaceans which died in the Eocene and were fossilized in the yellowish sandstone.  Forty million years ago the valley was a marine lagoon.  Although the remains of numerous sirenians, sawfish, sharks, rays, sea turtles, marine crocodiles, sea snakes, and even swamp dwelling moeritheriums have been discovered in the wadi, the valley takes its name from the most spectacular and numerous fossils which belong to four different species of primitive whales.  The most commonly discovered fossils belong to Dorudon, which was 3-5 meters long (9-15 feet) and fed on fish and mollusks, and to Basilosaurus, which was 15-22 meter (50-72 foot) and fed on everything else in the ocean.

Basilosaurus was first discovered in Louisiana in the early 19th century.  Its immense size and serpentine form initially convinced naturalists that it was a marine reptile and they misnamed the creature Basilosaurus (which means “king lizard”).  The mistake soon became obvious and Basilosaurus was classified among the Archaeoceti, a paraphyletic suborder of the cetaceans, however the giant kept its dinosaur name.  Different species of Basilosaurus flourished in oceans worldwide during the wet, tropical Eocene and, even though they were obviously very adept at ocean living (indeed rising to the top of the food chain) the creatures betray vestiges of terrestrial living which modern whales have entirely dispensed with. Not only do Basilosaurus fossils have teeth and jaws which retain reatures from their artiodactyl ancestors, they also have tiny vestigial back legs a mere half meter in length (which would scarely help a 22 meter animal get around).  Additionally Basilosaurus was different from modern whales in that it probably moved with eel-like horizontal thrashing of its long tail (modern whales move their flukes vertically).  Basilosaurus probably did not dive very deeply, but moved about near the surface of the oceans hunting for smaller marine animals.

Basilosaurus from “Life in the Ancient Seas Exhibit” at the Smithsonian Institution, National Museum of Natural History

Although Wadi Al-Hitan was discovered by Europeans in 1902-1903, some archaeologists and anthropologists have speculated that it was known long before that and have been irresistibly drawn towards comparing basilosaurus with the giant crocodiles and earth spanning serpent gods which populate ancient Egyptian cosmology.

Detail from painting (Life in the Ancient Seas Exhibit: Smithsonian Institution, National Museum of Natural History)

Andrewsarchus Skull at the American Museum of Natural History

In the summer of 1923, Kan Chuen Pao unearthed an enormous skull from the baking Gobi desert of Mongolia.  Pao was a member of a paleontology expedition led by Roy Chapman Andrews, a world famous explorer, adventurer, and naturalist who, during the course of his career, rose from being a janitor at the American Museum of Natural History to being its director.  The skull they found was an enigma—the creature was a mammal with immensely powerful jaws but blunt peg-like teeth. No substantial bones were found other than the skull sans jaw (nor have any further specimens ever been discovered). The skull was discovered in sediments deposited during the late Eocene, the sweltering summer epoch when most extant mammalian orders evolved, so it is probably 36 to 40 odd million years old.  Andrews was immediately of the opinion that it was a huge carnivore, but what sort of creature was it really?

A toothy hairy model of Andrewsarchus

The creature was named Andrewsarchus mongoliensis in honor of Adrews and his expedition.  Andrewsarchus may have been the largest mammalian carnivore ever (although short faced bears might have been larger).  The one skull, currently in New York, measures 83 cm (33 inches) long and 56 cm (22 inches)wide–which suggests the animal may have been 3.4 meters (11 feet) long and nearly 2 meters (6 feet) tall at the shoulders.  Such a creature could weigh more than 1000 kg (2200 lb).

A drawing of Andrewsarchus with a large ninja to explain scale (Picture Credit: Everything Dinosaur)

But Adrewsarchus may not have been a carnivore:  ever since the beginning of the jazz age, Paleontologists have argued about the monster’s diet.  Andrewsarchus lived along the coast of the eastern Tethys Ocean, a sea which was dried out and destroyed when the Indian subcontinent barreled into Asia during the late Eocene/Early Oligocene.

A Delightful Andrewsarchus model/toy produced by Bullyland

Some scientists believe the creature was a hunter which captured the giant land animals of the time. Other scientists believe the animal was a scavenger which lived on the rotting carcasses of primitive whales and beached sea turtles.  Another group feels that the creature fed on huge beds of shellfish, and a final school holds that the animal was even larger than believed and was at least part-herbivore!

An unpainted model of an athletic hunting Andrewsarchus (as envisioned by Paleocraft)

The taxonomy of Andrewsarchus is equally confusing.  The great skull was initially classified as a giant creodont (an extinct order of alpha-predators which share an ancestor with today’s carnivore).  The first scientific paper about the creature by great paleontologist and…um, eugenicist, Henry Fairfield Osborn, states, “An outline sketch of the skull was sent in a letter to the Museum, from which Dr. W. D. Matthew immediately observed its real affinity to the primitive Creodonta of the family Mesonychidae.”

Later scientists have been less certain about lots of things than Osborn was and Andrewsarchus’ place in the mammalian family is now unclear.  A consensus is emerging that the great creature shared common ancestors with the artiodactyls (like hippos, deer, and pigs).  Perhaps its heritage provides insights into the link between the artiodactyls and their close (yet oh so distant) cousins the whales.

A digital Andrewsarchus pensively gnawing a bone beside the Eastern Tethys (from BBC’s “Walking with Beasts”)

Whatever the case is, these giant hoofed creatures with their immense powerful maws must have been amazing and terrifying to behold.  Their fate seems to have been sealed as the Tethys closed and the Gobi basin dried out, but, whenever I think of the harrowing deserts of Mongolia and China, I imagine their fearsome toothy spirits towering over the other strange ghosts of that haunted place.

An Iridescent Wasp on a Linen Tablecloth

Today I would like to start a brand new animal category concerning the most gifted of the social insects, the superorder Hymenoptera, which consists of wasps, bees, ants and sawflies (along with some other oddballs which are less frequently mentioned).  Hymenoptera are arguably among the most successful creatures on the planet.  Their behavior can be almost embarrassingly humanlike and they are famous for building elaborate constructions, going to war, taking slaves, farming fungi, and crafting rigid city-like social hierarchies. However, of all life forms on earth, the hymenoptera are some of the most vividly alien: cuttlefish do seem downright cuddly when compared to the horrifying digger wasps.   A sociologist could happily draw parallels between a bee hive and a city until he looked at the details of bee reproduction, at which point he would probably break down and weep.

The Hymenoptera are not as ancient as either the mollusks or the mammals (if it is fair to compare an order with a phylum or a class).  They originated in the Triassic and did not develop the successful social organization which is now such a defining feature until the late Cretaceous.   The first hymenopterans were the xylidae, a family of sawflies with a minimal presence on earth today but with a long pedigree. These first sawflies fed on the pollen and buds of the conifer stands beneath which the first dinosaurs developed (and under the roots of which the first mammals cowered).  The rise of the flowering plants in the Cretaceous led to a leap-forward for these pollen-eaters: complex flowers then evolved in tandem with the hymenopterans. It was also during the Cretaceous that the ants and termites split from the vespoid wasps.  The earliest honey bees of the familiar genus Apis evolved at the end of the Eocene bt they were preceded by all sorts of hymenopteran pollinators.

A Sawfly Fossil (Hymenoptera: Symphyta)

I mentioned above that, for all of their familiarity to us, the Hymenoptera are disturbingly alien.  In fact as I have been writing this comparatively tame post, a dreadful sense of formication has stolen over me and I find myself brushing phantom ants from my limbs and feeling the terrible pang of yellowjacket stings from childhood.  The hymenoptera are frequently the basis of the extraterrestrial enemies in science fiction.  Although people are occasionally stung to death by wasps or ripped apart from within by driver ants, it is something larger and less tangible which makes the hymenoptera such reliable villains. I have watched the soldier bees snip the wings off of wasps trying to invade my grandfather’s bee hive and then toss the invaders’ writhing bodies from the painted ledge—all while a river of worker bees went out and came back laden with pollen.  There is an alarming touch of civilization to these social insects: a hint that they are utilizing the same kinds of organization and communication which have made humans such a success.  And, in fact, the social insects are a huge success—ants alone are estimated to constitute a substantial portion of the animal biomass of earth (to say nothing of termites, bees, wasps and the rest).

Yellow Jackets on a Coke Can (photo by the fearless Alan Cressler)

Of course this success has broad ramifications. The hymenoptera are everywhere in nature and they also play a huge part of human culture. Indeed the very name of this blog is a play on words between my surname and the noble art of aviculture.  Without the bees, we would not have much in the way of fruit or vegetables.  Not only would this be a disaster for human farming—just contemplate how many other creatures rely on those fruit!  Similarly the ants bulwark an entire portion of the ecosystem by scavenging the tidbits out of fields and forests.  Writing about the hymenoptera may be an itchy, antsy business but it is a well-merited study.  This group of insects is pivotal to life on dry-land as we know it.  The biblical promised land was one of milk and honey.  There would be no milk without mammals, but there would be no honey (and precious few mammals) without the hymenoptera.

A beekeeper completely covered with swarming honey bees in a “bee man” cantest in China

Obdurodon--A Miocene Platypus which flourished 15 to 20 million years ago

Ferrebeekeeper has an abiding interest in monotremes including both the poisonous platypus and the enigmatic echidnas (with their advanced frontal cortex).  But sadly that is about it as far as it goes for the extant egg-laying mammals: there are only two living families of monotremes (with a scanty total of five species split between them).  To learn more about these animals one must turn to paleontology.  Unfortunately even in the fossil record, monotremes are extremely rare.

Based on genetic evidence, biologists believe that the first monotremes made their advent in the history of life about 220 million years ago during the Triassic era; however the earliest known fossil monotreme so far discovered was a fossil jaw from the early Cretacious era about 120 million years ago.  The bones belonged to Steropodon galmani, which seems to have been a beaked swimmer about 50 cm (20 inches) long which lived in Australia.  Steropodon was apparently a giant among Cretacious mammals–most of which seem to have been shrew-sized (so as to better avoid attention from their contemporaries, the dinosaurs). Reconstructions of Steropodon all seem to resemble the platypus, and most paleantologists would probably concede that it was a sort of platypus—as apparently were other Mesozoic fossil monotremes such as  Kollikodon and Teinolophos (platypuses and these platypus-like forbears are called the Ornithorhynchida).  During the Cretaceous era, the land which is now Australia was in the South Polar regions of the world (approximately where Antarctica is today).  Although temperatures were much warmer during the Cretaceous, monotremes must still have been able to deal with terrible cold: it is believed that the extremely efficient temperature control and the deep hibernation mechanism which these animals continue to display first evolved during that time.

An artist's reconstruction of Steropodon

The only monotreme fossil which was not found in Australia was from another platypus-like creature named Monotrematus sudamericanum.  The creature’s remains were found in a Patagonian rock formation from the Paleocene era (the era just after the fall of the dinosaurs). Monotremes probably flourished across South America and Antarctica, as well as on Australia, but evidence is still scarce. There are most likely many interesting monotreme fossils throughout Antarctica, but, for some reason, paleontologists have not yet discovered them. Additionally, unlike the marsupials (which still quietly flourish throughout South America), the poor monotremes were wiped out on that continent.

Another artist's vision of Steropodon galmani--Notice how peeved the poor creature looks!

Last week I wrote about the Eocene era and the great proliferation of mammalian types which took place during that warm and fecund time.  Although most families of mammals alive today first appeared on the scene during the Eocene, obviously the monotremes were already incredibly ancient.  The Eocene does however seem to have been significant time for the monotreme order: the aquatic platypuses were apparently the ancestral monotremes, and echidnas (the Tachyglossidae) probably split off from them during the Eocene.  Unfortunately we have no Eocene monotreme fossils so this conclusion is based on genetic evidence and on the suffusion of Miocene monotremes which include representatives of both Ornithorhynchida and  Tachyglossidae.  Some of these latter creatures are spectacular, like Zaglossus hacketti the giant echidna from the Pleistocene which was about the size of a ram! As Australia dried up so did the monotremes and now there is only one species of platypus left…

The Giant Echidna (Zaglossus hacketti) which lived until 20,000 years ago...

Well, that’s a cursory history of the monotremes based on what we know.  I wish I could tell you more but unfortunately there is no fossil evidence concerning the first half of the order.  Sometimes I like to imagine the first monotremes—which were probably clunky, furry platypus-looking characters with an extra hint of iguana thrown in. These creatures fished in the alien rivers of the Triassic world in a time when dinosaurs and pterosaurs were also still evolving.

The Eocene (Illustration by Bob Hynes for the Smithsonian Institution)

The Eocene epoch (which lasted from 56 million ago to 34 million years ago) was hot!  Temperate forests ran all the way to the poles.  Steamy tropical jungles grew in the latitude where Maine is now and the equatorial regions of earth were (probably) sweltering. Tropical reefs formed in the coastal waters around a heavily forested and ice-free Antarctica. Since there was not year-round ice at each pole, the sea levels were much higher.

A Global Map of the Early Eocene (map by Dr. Ron Blakey)

The Eocene was a time when most of the contemporary mammalian orders first appeared.  The earliest artiodactyls, perissodactyls, rodents, bats, probiscideans, sirenians, and primates all originated during this time.  Of course mammals were not the only story: the Eocene was also a time of great diversification for birds and many familiar orders of avians developed then.  Reptiles begin to put the setbacks which marked the end of the Cretaceous behind them and several giant new species emerged including an immense tropical ur-python and a host of crocodiles and turtles. It is harrowing to think that the first wee dawn horses and cute little early atiodactyls were forced to contend with a 13 meter long super snakes and giant crocodilians (which flourished in the great hot swamps of Alaska), but such is the case.

Titanboa with Ancient Crocodilian (painting by Jason Bourque)

The high temperatures of the Eocene are perplexing to scientists.  By contrast, the temperatures of the Paleocene (which was the first era of the Cenezoic and had directly preceded the Eocene) were much more temperate. In fact the temperature spike of 56 million years ago seems to have ended the Paleocene and brought about the diversification of Eocene life.  The rapid warming is known as the Palaeocene-Eocene thermal maximum and scientists have been vigorously debating what caused the climate change.  An immense amount of carbon seems to have entered the atmosphere at this time, which in turn led to greenhouse warming.  It remains controversial as to how such a large quantity of carbon got into the atmosphere.  Comet/meteorite impact, massive peat fires, and volcanic activity have been suggested as triggers, however supporting evidence is lacking.  The release of globally significant quantities of hydrocarbons–which had been trapped in undersea clathrates seems like a more feasible hypothesis, as does the idea that the earth’s orbit brought the planet closer to the sun for a time.

Phenacodus, a goat-sized grazer of the Eocene era (painting by Heinrich Harder)

The end of the Eocene was also linked to the carbon cycle.  Reduced carbon dioxide in the atmosphere seems to have led to global cooling and newly evolved varieties of grasses began to invade large swaths of the world.  Additionally two massive meteor strikes in Siberia and Maryland combined with substantial volcanic activity to finish off the long hot summer. But during the Oligocene, the era which followed the Eocene, the world was a much more familiar place inhabited by orders of animals which are still here with us today (or are us–since primates first evolved during the Eocene).

Yesterday, if you read the post concerning pikas, you probably found yourself wondering why pikas are found throughout the highlands of North America, Europe, and Asia but do not dwell in the rocky scree of Africa and the Middle East.  As it turns out, another animal grazes the arid mountain lands in those areas.  Although superficially this furry herbivore seems to share many features with the pika, it is a very different sort of creature with an entirely different (and rather grand) history.

A Rock Hyrax near Capetown, South Africa

I’m writing about the hyrax, a tiny tusked grazing creature with certain anachronistic features of earlier mammals (such as an unique dentition and poorly developed internal temperature regulation ).  Hyraxes are the only living members of the family Procaviidae, itself the only extant family of the order Hyracoidea.  Hyracoids are rare and unusual today, found only in niche ecosystems, but 40 million years ago they were among the dominant grazers in Africa.  We’ll get back to the paleontological history of the hyrax family at the end of the article, but for now here’s an overview of the living hyraxes.

Hyraxes (photo by Vladimir Danilov)

Found in rocky and mountainous area of the Sahara and the Middle East, hyraxes are equipped with sweat glands on the tough rubbery pads of their feet.  This helps them keep cool and gives them traction on the steep cliffs where they dwell.  Additionally they have sophisticated kidneys which help minimize water consumption in their arid rocky homes.  Among the small mammals, Hyraxes, uniquely, possess multi-chambered stomachs capable of digesting plant materials and fibers.  Their complicated digestive apparatus makes use of numerous symbiotic bacteria to absorb the nutrients out of the coarse shrubs and weeds they eat.  Unlike cows and other artiodactyl ruminants, hydraxes do not chew a cud–however their aggressive tusk gnashing was mistaken for cud-chewing by biblical law-givers so um, I guess they are (incorrectly) not kosher according to Deuteronomy.

A Family of Rock Hyraxes (Procavia capensis)

Hyraxes are small animals but they have long lives, elaborate social networks, and surprisingly capacious memories (at least according to zoologists and neurophysiologists).  I have watched them at the Bronx zoo where they live in an enclosure filled with baboons and ibexes: it is intriguing to see how their miniature society copes with these large aggressive neighbors.  The hyrax colony has all sorts of rules and communication protocols dealing with sentries, foragers, and communal huddling for warmth.  Their elaborate social behavior (quite lacking in yesterday’s pikas and tomorrow’s groundhogs) makes sense when one looks at their relatives.

A Painting of Arsinotheriums by Heinrich Harder

As I noted above the Hyracoids were a very diverse and widespread taxonomic order in Africa during the Eocene and Oligocene epochs (55 to 34 million years ago). To quote the McGraw-Hill Encyclopedia of Science and Technology,  “the early hyracoids ranged from animals as small as rabbits to ones as large as modern Sumatran rhinoceroses. The fossil skeletons of the early hyracoids indicate that some species were active runners and leapers, while others were heavy, piglike quadrupeds.”  In fact these hyracoids, or their immediate ancestors, seem to have been the basal group (which is to say the progenitors) of the paenungulates.  DNA sequencing and the fossil record both give compelling evidence for this relationship.  This means that the long ago ancestors of the hyraxes–which looked much like today’s hyraxes–were also the grandfather species for the mighty proboscideans—the towering mammoths, the mighty gomphotheres, the mastodons, and the ingenious elephants.  Not only that, the early hydracods were also ancestors to the desmostylians, the embrithopods (like the pictured Arsinoitherium), and the gentle sirenians such as dugongs and manatees.  When you look at a hyrax you are not looking a tusked groundhog, but at a sophisticated social animal with some giant successful cousins.

A (Proboscidean-centric) Portion of the Paenungulata Clade

Catfish are an ancient order of fish.  Fossilized catfish from the Cretaceous period have been discovered–which means catfish coexisted with dinosaurs (and survived the cataclysm which wiped those great reptiles from the earth).  The fossil specimens pictured here are from the Green River formation, an Eocene era Lagerstätten in Wyoming, Colorado, and Utah.  They are from approximately 48 million years ago.  These catfish lived in Lake Gosiute a large lake abounding with fish including freshwater stingrays, paddlefish, trout, perch, gars, suckers, mooneyes, bowfins, and great shoals of herring-like Knightia (a fish well known to fossil collectors and rock store owners).  The catfish are discovered in what were the depths of the lake, where they could avoid the sinister Borealosuchus, an extinct crocodile which thrived in the warmer climate of the Eocene.

Astephus antiquus

Another specimen of Astephus antiquus

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