Reconstruction of Purussarus neivensis attacking Pericotoxodon platignathus.
Image: Miguel Hernandez.
If the Young-Earth creationist claim that there was no death, suffering or predation before Eve’s supposed ‘sin’ were true, four fossil specimens preserved in museum collections in Colombia should not exist. They are the remains of large herbivorous mammals bearing punctures and other damage attributed to the teeth of a giant crocodylian—and they are between approximately 10.5 and 16 million years old.
In other words, these fossils are not merely the remains of animals that lived and died millions of years before there were humans to commit any biblical ‘sin’. They preserve physical evidence of animals attacking—or, at the very least, feeding upon—other animals in a functioning predator–prey ecosystem more than a thousand times older than the entire universe imagined by Young-Earth creationists.
The evidence is described by Oscar E. Wilson of the University of Helsinki and Jorge W. Moreno-Bernal in a paper recently published in the Journal of Vertebrate Paleontology. The researchers examined four specimens belonging to three species of large, now-extinct South American ungulates from the celebrated La Venta fossil assemblage of Colombia: the toxodontid Pericotoxodon platignathus and the astrapotheres Xenastrapotherium kraglievichi and Granastrapotherium snorki.
The skulls and jaws bear puncture marks and, in some cases, substantial deformation caused by a powerful bite. From the size and shape of the marks, together with the force apparently needed to produce the damage, Wilson and Moreno-Bernal identify the most likely culprit as Purussaurus neivensis, an enormous relative of modern caimans that may have reached about seven metres in length and weighed approximately 1,800 kilograms.
Middle Miocene South America contained an ecosystem unlike anything living today. The continent’s long geographical isolation had allowed native mammals—including toxodontids, astrapotheres, ground sloths and glyptodonts—to diversify independently. Around the immense tropical wetlands lived giant snakes, flightless predatory ‘terror birds’, terrestrial crocodyliforms and several kinds of aquatic crocodylian. Because large mammalian carnivores were comparatively scarce, reptiles such as Purussaurus occupied the major apex-predator niches.
Earlier studies had inferred this ecological role from the animals’ size, anatomy and the composition of the La Venta fauna. The newly reported bite marks provide direct physical evidence that giant crocodylians interacted with—and probably preyed upon—some of the ecosystem’s largest herbivorous mammals. Purussaurus may therefore have helped to regulate herbivore populations, much as large predators influence prey populations in modern ecosystems.
For creationists, the problem could hardly be clearer. These animals lived, competed, killed, fed, reproduced and became extinct millions of years before any known hominin existed, let alone the mythical couple blamed in Genesis for introducing death into the world. Even if an individual bite mark resulted from scavenging rather than an actual attack, that alternative still requires a dead animal, a flesh-eating crocodylian and an established ecological system based partly upon the consumption of carcasses. It offers no refuge for the claim that the pre-Fall world was free from death and carnivory.
Nor can a recent global flood explain a geographically distinctive Miocene fauna preserved within its wider geological and evolutionary setting. A single catastrophic event cannot manufacture an ancient South American ecosystem populated by related lineages with coherent histories of evolution, geographical isolation and extinction. It cannot make tooth punctures correspond to the anatomy of an appropriate contemporary predator, or place the resulting fossils consistently within millions of years of sedimentary history.
La Venta^ A Miocene World of Giant Predators and Prey. The La Venta fossil sites lie in what is now the Tatacoa Desert of south-western Colombia. During the Middle Miocene, however, this was not a desert but a warm, humid landscape of rivers, floodplains, forests and extensive wetlands connected with the great aquatic systems of western Amazonia.
Most of the celebrated La Venta fauna comes from the La Victoria and Villavieja formations of the Honda Group and dates from approximately 13.5 to 11.5 million years ago. Some older museum specimens cannot be assigned so precisely to individual rock layers, which accounts for the broader age range of 10.5–16 million years given for the fossils examined in the new study.
Because South America remained geographically isolated for much of the Cenozoic, its animals followed distinctive evolutionary paths. La Venta preserves an extraordinary mixture of freshwater fish, turtles, snakes, crocodylians, flightless predatory birds, marsupials, primates, rodents, ground sloths, glyptodonts and several groups of native South American ungulates. Many belonged to evolutionary lineages with no living representatives.
The animals identified in the study
- Purussaurus neivensis was a giant member of Caimaninae, the evolutionary group containing modern caimans. It may have reached approximately seven metres in length and weighed about 1,800 kilograms. Its massive skull, broad snout, robust teeth and powerful jaws made it capable of attacking animals weighing more than a tonne. The new evidence suggests that it occupied an apex-predator role and may have helped to regulate populations of large herbivores.
- Pericotoxodon platignathus was a large, heavily built member of the Toxodontidae, within the extinct mammalian order Notoungulata. Toxodontids are sometimes compared superficially with rhinoceroses or hippopotamuses, but they followed their own South American evolutionary history and were not simply ancient versions of either.
- Xenastrapotherium kraglievichi and Granastrapotherium snorki belonged to another extinct order of native South American mammals, the Astrapotheria. They were large, robust herbivores with prominent canine tusks. Their skull anatomy suggests that at least some astrapotheres may have possessed a short, muscular proboscis, although its precise form cannot be known from the fossilised bones alone.
The resemblance of these animals to elephants, rhinoceroses or hippopotamuses should not be mistaken for close relationship. Similar ecological pressures can produce similar body forms independently in different evolutionary lineages—a process known as convergent evolution.
How can a fossil bite reveal its predator?
Bite marks are examples of trace fossils: preserved evidence of an organism’s activity rather than part of the organism itself. Palaeontologists identify and interpret them by examining several kinds of evidence together:
- Shape and cross-section: pointed, rounded or blade-like teeth leave characteristically different pits, punctures, scores and grooves.
- Size and spacing: the diameter and arrangement of marks can be compared with the teeth and jaws of predators known from the same deposits.
- Depth and deformation: deep punctures, crushed bone and distortion around a mark indicate the amount and direction of force applied.
- Position on the skeleton: marks on the skull, jaws, limbs or other parts of the body may provide clues to how the animal was seized or consumed.
- Possible predators: researchers consider which carnivores lived at the same time, possessed suitably shaped teeth and were large enough to produce the observed damage.
- Evidence of healing: new bone growth around an injury shows that the victim survived for some time after being bitten. An unhealed mark could have been inflicted during a fatal attack or while a predator was feeding upon an already dead animal.
The marks described in the new study include deep, rounded punctures and substantial deformation of the skulls and jaws. Their dimensions, shape and inferred force are consistent with the large, rounded teeth and immensely powerful bite of Purussaurus.
It is not always possible to distinguish conclusively between predation and scavenging from an unhealed bite mark alone. Nevertheless, either interpretation records a trophic interaction: a giant carnivorous crocodylian biting and consuming a dead or dying herbivorous mammal millions of years before humans existed.
Creationists are therefore left with their customary dilemma. They can accept the evidence that predation and death were natural features of ecosystems millions of years before humans evolved, in which case the biblical Fall cannot have introduced them; or they can insist that Purussaurus was deliberately designed with immensely powerful jaws and teeth for seizing and crushing other animals. The latter merely replaces evolution with the actions of a designer responsible for suffering and violent death long before the alleged offence for which that suffering was supposedly imposed.
The paper in the Journal of Vertebrate Paleontology was accompanied by a University of Helsinki news release:
Giant crocodylians dominated the food chain in Miocene South America
Purussaurus neivensis, a seven-metre-long, 1,800-kilogram giant, may even have influenced the size of herbivore populations, fossil evidence suggests.
South America during the Miocene was a frightening place. More than ten million years ago, a vast lake covered much of the continent, home to giant turtles and crocodylians.
On the lake's shores hunted a wide range of predators, including anacondas, saber-toothed mammals, flightless "terror birds" and sebecids — terrestrial relatives of crocodylians.
A recent study shows that crocodylians were in fact the most significant group of predators in this habitat.
There was so much prey available that mammalian predators couldn't have eaten it all. Our new study shows that crocodylians in particular were the region's most important predators, especially when it came to hunting large prey.
Dr. Oscar Wilson, lead author
Department of Geosciences and Geography
University of Helsinki, Helsinki, Finland.
Bite traces reveal the predator
On the lake's shores lived a great variety of herbivores: giant ground sloths, glyptodonts — relatives of armadillos — and several groups of ungulates, such as astrapotheres ("lightning beasts") and toxodontids. The ungulates of this era could weigh well over a tonne.
But the predators were giants too. The largest predator of the time was a seven-metre-long, 1,800-kilogram crocodylian, Purussaurus neivensis, a relative of modern caimans. At the top of the food chain, it may even have influenced the size of herbivore populations, the new study suggests.
The research is based on the analysis of fossils held in museum collections. Bite and tooth marks left by predators on herbivore fossils are the only direct evidence of interactions between species. The fossils examined were between 10.5 and 16 million years old.
The frequency of marks likely made by Purussaurus suggests that it was an important predator in these tropical ecosystem.
Dr. Oscar Wilson.
The study was published in Journal of Vertebrate Paleontology.
Skull of Pericotoxodon platignathus showing the puncture mark likely made by Purussaurus neivensis
Jawbone of Xenastrapotherium kraglievichi that features marks of both predation by Purussaruus neivensis and possible scavenging by Langstonia huilensis.
Publication:
What Wilson and Moreno-Bernal have recovered from these museum specimens is more than evidence of a very large caiman biting some very large herbivores. The punctures and crushed bone preserve part of an ancient ecological relationship: predators exploiting prey in a tropical South American wetland millions of years before humans appeared.
Whether every mark represents the attack that killed the animal or, in some cases, feeding upon an existing carcass does not rescue creationist mythology. Predation requires animals to suffer and die; scavenging requires animals to be dead already. Either interpretation is incompatible with the claim that animal death entered the world because of an offence supposedly committed by the first humans.
The chronology alone is fatal to that claim. These animals lived between approximately 10.5 and 16 million years ago, long before any known hominin and more than a thousand times earlier than the date at which Young-Earth creationists imagine their universe was created. Eve could no more have caused the death of these animals than she could have caused the formation of the rocks in which their remains were preserved. Creationism has cause following effect by millions of years.
A global flood provides no escape. The La Venta fossils form part of a geographically and geologically coherent Miocene fauna containing organisms with established evolutionary relationships, ecological specialisations and wider histories of geographical distribution. Declaring all of them victims of a recent flood does not explain that evidence; it merely requires the ages, geology, biogeography, comparative anatomy and taphonomy to be dismissed simultaneously because they contradict a predetermined conclusion.
The evidence is equally troublesome for intelligent-design claims. Purussaurus possessed a massive skull, strong jaws and robust teeth capable of puncturing and deforming the bones of large mammals. These were effective adaptations for acquiring meat in a competitive ecosystem. If they were deliberately designed, then their purpose was to enable one sentient animal to seize, injure and consume another. That is not evidence of benevolent design but of the cruelty and suffering that creationists insist their designer intentionally introduced into nature.
Evolution requires no such moral contortions. South America’s prolonged isolation allowed distinctive herbivores and predators to diversify, while ecological opportunities enabled giant crocodylians to occupy niches filled elsewhere by large mammalian carnivores. Species evolved, interacted and became extinct as environments changed. The La Venta fossils fit naturally into that evidence-based history without requiring magic, a mythical ancestral offence or a planet-wide act of divine destruction.
As usual, the researchers show no sign of abandoning evolutionary biology because their discovery supposedly presents some insurmountable problem for it. On the contrary, evolutionary history, comparative anatomy, geology and ecology provide the framework within which the evidence makes sense. The problem belongs entirely to creationism: the bones record death in the wrong place, predation at the wrong time and an ancient world that had already been evolving for millions of years before creationists believe their god created anything.
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