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Let’s look back through the mists of time to peak at one of the most mysterious and perplexing of mammals, the desmostylians, the only extinct order of marine mammals (although in dark moments I worry that more are soon to follow). Desmostylians were large quadrupeds adapted to life in the water. They had short tails and mighty limbs. Because of this morphology, taxonomists initially thought that they were cousins of proboscideans and sirenians (elephants and manatees), but the fact that their remains have only been found far from Africa (the origin point of elephants, mammoths, mastodons, and manatees & sea cows) along with perplexingly alien traits has caused a rethink of that hypothesis.
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(Art by Ray Troll fror SMU)

Extant between the late Oligocene and late Miocene, the desmostylians had powerful tusklike cylindrical teeth and dense heavy bones. The smallest (and oldest) were peccary sized creatures whereas the largest grew to the size of medium whales. It seems like desmostylians lived in littoral parts of the ocean—near coasts and shores where they used their pillar like teeth to graze great kelp forests. They scraped or rasped up the kelp and sucked it down their voracious vacuum maws like spaghetti! It must have been an astonishing sight! My favorite marine paleoartist, Ray Troll has made exquisite pictures of these majestic creatures which help us to visualize them. I really hope they looked this funny and friendly (if they were anything like herbivorous manatees, they probably did!).
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(Art by Ray Troll, courtesy SMU)

Speaking of manatees, the gentle sirenians had a hand (or flipper?) in the demise of the poor desmostylians. The dugongs and manatees would never fight anyone or even protect themselves with force—they simply outcompeted the less nimble desmostylians for resources, although one wonders if climate-change and the continuing evolution of different coastal sea plants might also have helped do in the great desmostylians.

A Human Holding a Small Limpet

A Human Holding a Small Limpet

We live on the threshold of an era of stupendous nanomaterials! In the near future, molecules will be engineered to be harder than diamonds or stronger than steel…yet these miracle materials will also be workable and light.

Artist's Conception of a Space Elevator--one of the miracles which should be possible through nanotechnology

Artist’s Conception of a Space Elevator–one of the miracles which should be possible through nanotechnology

Well, at least that’s what they keep telling us. In practice our best nano-materials do not seem capable of besting nature in the truly important categories—like hardness, tensile strength, or elasticity (or, if our synthetic materials are superior, they prove difficult to build into structures which fully exploit their strengths). A case in point comes from the lowly yet resilient limpet. Limpets are marine gastropods (snails) which have shells without visible coils. Actually, the name “limpet” is an informal common name—scientists have a very different way of characterizing these mollusks.

Common limpets (Patella vulgata) adhering to tidal zone rocks

Common limpets (Patella vulgata) adhering to tidal zone rocks

Limpets cling tenaciously to rocks at the tidal line by means of a muscular foot designed to create suction. They also produce an adhesive mucus which helps the foot adhere to whatever surface the limpet wishes to cling to. They carefully scour their ocean rocks for nutritious algae with a radula—a tongue-like rasping organ covered with teeth. Limpets have been of note to humans principally as a metaphor for resilience…or as a nuisance. Yet scientists experimenting on a common limpet, Patella vulgata, found that the little snail’s teeth had greater tensile strength than spider silk. Indeed, limpet teeth are the strongest known material in the natural world and approach the tensile strength of our strongest carbon fibers. With these teeth the little snail can (and does!) chew through rocks.

A (horrifying) microscopic picture of limpet's teeth

A (horrifying) microscopic picture of limpet’s teeth

The secret to the limpet’s mighty teeth is a miracle of molecular design in its own right. The cutting portion of the teeth are composed of fibers of goethite (a sort of iron hydroxide named after the great German poet). These fibers are under 60 nanometers in diameter—a size which allows them to be tremendously strong. The teeth are technically a composite–since the tiny goethite fibers are held together by chitin, a natural polymer (which the exoskeletons of insects are made of).

This evil henchman was the best character.

This evil henchman was the best character.

Technically there are human-created carbon fibers stronger than the astonishing teeth of the limpet, but these fibers can only be utilized in certain configurations and fashions–so the limpets’ teeth are of very real practical interest to materials scientists. Engineers are already working on duplicating the little snail’s teeth for mining and cutting equipment…and for human dental uses. Perhaps we really could someday have some of the powers of Jaws, the lovable hulking henchman from seventies James Bond movies. With our synthetic chompers we could bite through rocks and steel cables. Uh, wouldn’t that be wonderful?

Livyatan Melvillei (image painted by Balazs Petheo)

Livyatan Melvillei (image painted by Balazs Petheo)

Behold the terrifying ocean monster, Livyatan Melvillei! This predatory toothed whale lived 12-13 million years ago during the Miocene epoch and grew to 13.5 to 17.5 meters (45–57 feet) in length. A large adult whale could have weighed up to 50 tons. The extinct megapredator is named for Herman Melville and for the Biblical leviathan (“Livyatan” is from the Hebrew word for Leviathan). The great whale’s family is currently listed as “incertae sedis” which means “status uncertain,” a taxonomical place-holder used when biologists are trying to ascertain a creature’s relationship to other related organisms within a larger order.

Livyatan Melvillei

Livyatan Melvillei with smaller baleen whale

In terms of body size, the modern sperm whale is probably slightly longer and heavier, but the livyatan had stronger jaws and much larger teeth. Paleontologists describe the mighty creature as having “the biggest tetrapod bite ever found,” which is no trivial matter, since the tetrapods include all mammals, reptiles (like dinosaurs), amphibians, and birds. Of course plankton feeders (like blue whales and whale sharks) have larger mouths, but the sperm whale and the livyatan have more powerful maws filled with large sharp teeth. The 36 centimeter (1.2 foot) long teeth of livyatan are the largest known teeth from the animal world which were used for eating (which is to say the tusks of elephants, walruses, Odobenocetops, and narwhals tusks were larger, but were not used for biting into plants or animals).

Livyatan Melvillei biting a smaller baleen whale (painting via dino-rider)

Livyatan Melvillei BITING a smaller baleen whale (painting via dino-rider)

Livyatan Melvillei presumably swam the deep blue ocean hunting for seals, dolphins, baleen whales and whatever other sea creature was large enough to command its attention (giant sharks, huge squid, huge fish, and bizarre giant birds?). Like the sperm whale it seems to have had a spermaceti organ in its head although it is unclear if this was used for echolocation, auditory signaling, or aggressive male sexual display (i.e. head-butting).  It must have been quite a (horrifying) sight to see one of these giant monsters biting apart a 10 meter (33 foot) long baleen whale. Sadly, the ever-changing dynamic of ocean life caused the great toothed whale to go extinct at approximately the same time as megalodon, the largest known shark (which was a contemporary of the great whale).  Numerous websites speculate which great animal would have won an ocean duel–which is foolish, since whales are clever animals and thus the obvious victor.

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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.

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