The genus Crocodylus contains roughly of half of modern crocodilian species and the vast majority
of true crocodiles. While most of the species contained in Crocodylus are still alive today,
some of the most impressive are now extinct. Among these were Crocodylus anthropophagus and
Crocodylus thorbjarnarsoni. Collectively referred to as the Paleoafrican crocodiles, these two large
crocodiles were each other’s closet relatives, and were the most dangerous predators in Africa
when humanity’s ancestors roamed the prehistoric savannahs. Crocodylus anthropophagus’s species
name means “human eater”, in reference to how the bones of early hominids bear its bite marks.
Crocodylus thorbjarnarsoni, sometimes called Thorbjarnarson's crocodile, is named in reference
to a much more positive interaction between crocodilians and hominids. Its name is in
honor of the late Dr. John Thorbjarnarson, who played a major role in crocodilian research and
conservation, and is one of the reasons so many of the other species of Crocodylus are still alive
today. Fossils of Thorbjarnarson's crocodile are found in the Turkana Basin in Kenya and Ethiopia.
Its oldest fossils are about 5 to 4.2 million years old while the most recent are about 2
million years old, after the beginning of the ice ages. Crocodylus anthropophagus has
only been found at the Olduvai Gorge in Tanzania and lived from 2.5 million to 1.8 million years
ago. Since it is difficult to impossible to tell fragmentary fossils of Crocodylus anthropophagus,
Thorbjarnarson's crocodile, or the Nile crocodile apart from each other,
the range of both of the Paleoafrican crocodiles was almost certainly much larger.
Both Paleoafrican crocodiles were larger than the Nile crocodile, which is the largest crocodilian
in Africa today. Crocodylus anthropophagus was over 5 meters long. However, it was smaller than
male saltwater crocodiles, who grow to about 6 meters long and are the largest living reptiles.
While Thorbjarnarson's crocodile is mostly known from skulls, it is estimated to have been between
6.2 to 6.5 meters long. However, the calculations used have often underestimated the size of large
crocodilians. A length of 7.5 meters is more likely and a length over 8 meters is considered
very much possible. While Thorbjarnarson's crocodile still wasn’t as large as the more
famous giants such as Deinosuchus and Purussaurus, it was at least the largest species of Crocodylus.
There was one true crocodile that may have been larger, Euthecodon. Euthecodon actually
lived in Africa at roughly the same time as the Paleoafrican crocodiles. However, it had the
teeth and slender snout of a piscivore, or fish eater. Therefore, even though it was smaller,
an adult Crocodylus thorbjarnarsoni outmatched Euthecodon and any other predator in its native
environment. One of the features that unites the Paleoafrican crocodiles is their nostrils.
While they were at the top of the skull like in other crocodilians, they pointed forward rather
than up. More noticeably, the skulls of the Paleoafrican crocodiles were very broad and,
by crocodilian standards, deep. Thorbjarnarson's crocodile took this to an even greater extreme
than Crocodylus anthropophagus. One of the larger skulls required four people to carry it.
Crocodylus anthropophagus had triangular, horn-like projections above its ears. These
were extensions of the squamosal bone of the skull. Thorbjarnarson's crocodile also had
squamosal horns, although they were smaller. Their purpose was to attract mates and scare off rivals.
This is not just speculation because squamosal horns are also present in some other species,
such as the Siamese crocodile. One of the most prominent examples is the extinct Voay robustus,
who was in Madagascar when the Paleoafrican crocodiles were alive.
The African ice age savannahs the Paleoafrican crocodiles inhabited were both familiar, but not
quite the same as today. While many modern species were present, such as leopards and the African
elephant, there were also other extinct species, such as Deinotherium and the Sivatherium.
Of course, their most famous contemporaries were humanities ancestors and close relatives.
The hominid bones with clear Crocodylus anthropophagus bite marks are from Homo
habilis and a bone that is either from Homo habilis or the more robust Paranthropus. Given
the size of the crocodilians, it is thought that those who left the bite marks were juveniles,
since fully grown adult could have simply swallowed them whole. However, given their
large size, the Paleoafrican crocodiles likely focused on megafauna, with humanity’s ancestors
being one of the rarer components of their diet. Before the Paleoafrican crocodiles were recognized
as distinct species, their fossils were actually thought to be those of Nile crocodiles or their
direct ancestors. This was in part because most of the scientists who found them were mammal experts,
usually looking for the bones of hominids. Though the Paleoafrican crocodiles are no longer thought
to be the ancestors of the Nile crocodile, or any living species, their legacy does extend to the
present day in another way. While the dragons of most myths were based on a variety of creature,
crocodilians are thought to have been the template. While more modern species likely
inspired the myths, it was the primal fear that evolved in response to the crocodilians of Africa
that caused them to make such an impact. Of these, the Paleoafrican crocodiles were the largest
and most dangerous. Therefore, while Crocodylus anthropophagus and Crocodylus thorbjarnarsoni
are now extinction, their legacy lives on in the fiction of the descendants of their
prey. Thank you for watching. Also, a thank you to Siridhean for suggesting the topic of this video.
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