How Might Fossil Teeth Reveal An Animal Diet
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These are the abrupt-toothed, ferocious meat-eating dinosaurs of popular imagination – the ultimate predators built purely to kill. Or are they? Collectively known as theropods, they range from bus-sized to chicken-sized, and include the outlandish parrot-faced, feathered, toothless and ostrich-like.
It is estimated that carnivores made up only about one per cent of the dinosaur population. This figure is typical of similar ecosystems today.
Giganotosaurus skeleton (reconstructed bandage). Argentina, Cretaceous, 112-89 meg years ago.
Image: Stuart Humphreys
© Australian Museum
Teeth – all the better to eat with
Teeth of meat-eaters are adapted for killing and eating specific types of animals, such as insects, fish, reptiles and mammals, as each has certain requirements for catching, holding, killing and then eating. We tin can determine the likely diet of a meat-eating dinosaur by making comparisons with living animals.
Which theropods ate flesh?
Velociraptor (and other dromaeosaurs), Allosaurus, Giganotosaurus, Tyrannosaurus, Albertosaurusand Carcharodontosaurus had sharp teeth typical of modern flesh-eaters. They besides had serrations on at least one tooth-border. Serrations help cut through flesh and os by a 'grip and rip' activeness. Different teeth reveal the dissimilar eating styles of flesh-eaters. For instance, Giganotosaurus teeth were quite narrow and long with effective cutting edges for slicing; Allosaurus had relatively curt, small teeth to cope with impacts that may have occurred when attacking large prey; and Tyrannosaurus had teeth that were robust, conical and variable in size to crush bone.
Modern knives provide useful comparisons to mankind-eating teeth. You lot may have noticed how much easier it is to cut meat with a serrated knife rather than a butter knife (and that serrated knives do non require constant sharpening similar other slicing knives). Serrated knives perform well when they are fatigued or pulled across meat. Serrated tyrannosaur teeth likely functioned in a similar manner, with strong neck muscles allowing these animals to tear apart their prey past pulling the teeth backwards through the mankind.
Seize with teeth forces
Tyrannosaurus rex head (model based on skull reconstruction).
Image: Stuart Humphreys
© Australian Museum
Nosotros know the teeth of T. rex were suited to crunching through mankind and bone. But were the jaws and skull capable of such a forceful seize with teeth? Modernistic technology helps provide the answer.
Experts use calculator modelling techniques to analyse anatomical and biomechanical data from skull and muscle tissue. Of great importance are data on how the jaw works, how the muscles and basic contribute to seize with teeth strength, how stress is dispersed through the skull and the ability of the lower jaw to resist angle.
Interestingly, fossil bear witness of a unlike kind supports views of T. rex as a powerful os cruncher. A large 44-cm-long coprolite (fossilised poo) attributed to this species contains many bone fragments – nearly one-half of which are undigested.
Which theropods ate fish?
Suchomimus and Spinosaurus had cone-shaped teeth similar to modern fish-eaters such every bit crocodiles, whose teeth are able to catch and pierce fish that tend to be glace and hard to grasp. Like living crocodiles, their cone-shaped teeth didn't preclude feeding on other organisms. A fossil from Brazil shows a close relative had a more diverse diet – a spinosaurid tooth was discovered embedded in a pterosaur vertebra.
Which theropods ate insects?
Archaeopteryx (a bird, and so a theropod) had the small jaws and sharp teeth characteristic of living insect-eaters. These are useful for piercing tough exoskeletons of insects but can also be used to catch pocket-size lizards, fish and mammals. This is why it is hard to tell the difference betwixt a truthful insect-eater and a small mankind-eater from fossils.
Archaeopteryx skull, reconstructed bandage. F134185. Based on fossils from Germany, Tardily Jurassic, 155-150 million years ago.
Image: Robert Jones
© Australian Museum
The odd ones out
Just when you thought yous could tell a meat-eater by its abrupt teeth and claws! These theropods have unusual features that go far hard to determine what they ate. They include the beaked and toothless oviraptorosaurs, the ostrich-like ornithomimosaurs and the enigmatic therizinosaurs.
- Therizinosaurus cheloniformis is a theropod with an impressive hand claw that looks brutal but was perhaps used for stripping vegetation, or ripping open up termite mounds like echidnas and goannas do today. Therizinosaurus had a large, heavy build which suggests it was quite deadening, and a beak with small teeth.
- Oviraptorosaurs similar Ingenia yanshini were meat-eaters with no teeth. They had relatively large heads with short, deep beaks and jaw muscles powerful plenty to crush bones. They may also have eaten plants, molluscs and eggs.
- Ornithomimus edmontionicus fossils accept been found with some soft tissues of their jaws preserved. These tissues are like those of some living water birds, such as flamingos, that eat by straining nutrient from sediment.
Did you know: Dino klutzes?
Theropods accept the greatest number of limb injuries of all dinosaurs. This does not mean they were the virtually accident prone, simply suggests they led very active lifestyles and that injuries were a big risk to a bipedal hunter.
Source: https://australian.museum/learn/dinosaurs/meat-eating-dinosaurs/
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