This answers a simple question. Why did the crocodile line remain
fairly small? It turns out that they were much bigger previously.
The fossil record also shows that the creatures were also much more
speciated. This begs the question of why the loss of diversity? Is
this part of the die off of the Pleistocene Nonconformity?
I do not think we can blame humanity for any of this. Had we a
successful hunting strategy, it is likely humanity would have driven
all crocs to extinction.
The largest known
true crocodile identified
May 5, 2012
A crocodile large
enough to swallow humans once lived in East Africa, according to a
University of Iowa researcher.
"It’s the
largest known true crocodile,” says Christopher Brochu, associate
professor of geoscience. “It may have exceeded 27 feet in length.
By comparison, the largest recorded Nile crocodile was less than 21
feet, and most are much smaller.”
Brochu’s paper on
the discovery of a new crocodile species was just published in the
May 3 issue of the Journal of Vertebrate Paleontology. The new
species lived between 2 and 4 million years ago in Kenya. It
resembled its living cousin, the Nile crocodile, but was more
massive.
He recognized the new
species from fossils that he examined three years ago at the National
Museum of Kenya in Nairobi. Some were found at sites known for
important human fossil discoveries. “It lived alongside our
ancestors, and it probably ate them,” Brochu says. He explains that
although the fossils contain no evidence of human/reptile
encounters, crocodiles generally eat whatever they can
swallow, and humans of that time period would have stood no more than
four feet tall.
"We don’t
actually have fossil human remains with croc bites, but the crocs
were bigger than today’s crocodiles, and we were smaller, so there
probably wasn’t much biting involved,” Brochu says.
He adds that there
likely would have been ample opportunity for humans to encounter
crocs. That’s because early man, along with other animals, would
have had to seek water at rivers and lakes where crocodiles lie in
wait.
Regarding the name he
gave to the new species, Brochu said there was never a doubt.
The
crocodile Crocodylus thorbjarnarsoni is named after John
Thorbjarnarson, famed crocodile expert and Brochu’s colleague who
died of malaria while in the field several years ago.
“He was a giant in
the field, so it only made sense to name a giant after him,” Brochu
says. “I certainly miss him, and I needed to honor him in some way.
I couldn’t not do it.”
Among the skills
needed for one to discover a new species of crocodile is, apparently,
a keen eye.
Not that the
fossilized crocodile head is small—it took four men to lift it. But
other experts had seen the fossil without realizing it was a new
species. Brochu points out that the Nairobi collection is “beautiful”
and contains many fossils that have been incompletely studied. “So
many discoveries could yet be made,” he says.
In fact, this isn’t
the first time Brochu has made a discovery involving fossils from
eastern Africa. In 2010, he published a paper on his finding a
man-eating horned crocodile from Tanzania named Crocodylus
anthropophagus—a crocodile related to his most recent
discovery.
Brochu says Crocodylus
thorbjarnarsoni is not directly related to the present-day Nile
crocodile. This suggests that the Nile crocodile is a fairly young
species and not an ancient “living fossil,” as many people
believe. “We really don’t know where the Nile crocodile came
from,” Brochu says, “but it only appears after some of these
prehistoric giants died out.”
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