More “skulls on my desk”

Some years ago, I wrote about the skulls on my desk, asserting that any scientist worth their salt should have at least one. My skulls, however—six of them until recently, are not just “ordinary” modern human skulls (much as I would love to have one), but rather replicas of famous fossil hominid skulls and crania. It has been a while since I’ve added to my collection, but Santa was good to me this past Christmas, bringing me a replica of the “La Chapelle-aux-Saints 1” skull of Homo neanderthalensis, and for today’s birthday my wife gave me a replica of the “Toumaï” cranium of Sahelanthropus tchadensis.

Homo neanderthalensis “La Chapelle-aux-Saints 1”

The “La Chapelle-aux-Saints 1” skull was discovered in 1908 in La Chapelle-aux-Saints, France and is thought to be about 50,000–60,000 years old. It was the most complete Neanderthal skull at the time it was discovered and had a brain capacity exceeding 1600 cc—more than most modern humans. Unfortunately, initial reconstructions of Neanderthal anatomy based on la Chapelle-aux-Saints material depicted the species with thrust-forward skulls, stooped posture, bent hips and knees, and a divergent big toe—reinforcing existing synonymy of the term “Neanderthal” with brutality and savagery. The errors were eventually corrected, but only after decades had passed, and even today this unfair characterization lingers still among the general public.

This particular individual was a male, probably around 40 years of age at the time of his death, and in poor health. He had lost most of his teeth and was suffering from resorption of bone in the mandible and arthritis. This has been widely cited as an example of Neanderthal altruism, since with most of his teeth missing he would have been unable to process his own food. Later studies, however, have shown that the La Chapelle-aux-Saints 1 individual still had enough teeth in place to chew his own food, although perhaps with some difficulty (Tappen 1985).

Sahelanthropus tchadensis “Toumaï”

Sahelanthropus tchadensis was formally described in 2002 based on cranial remains of at least six individuals dated to about 6–7 million years ago during the Miocene epoch. “Toumaï” is the most complete of all the cranial remains, although it was crushed and badly deformed. To date, all the fossils found of Sahelanthropus have come from a small area of northern Chad.

The age of Sahelanthropus puts it around the time of the human-chimpanzee last common ancestor (HCLCA). At the time it was described, only cranial fragments were included in the original description, and the position of the opening for the spinal chord was used to infer that the species walked upright. However, a femur was also found alongside the cranium but was placed with animal bones and excluded from the original analysis. Later analysis of the femur concluded that Sahelanthropus was not bipedal (Macchiarelli et al. 2020), putting its status as a possible relative of the HCLCA into doubt. One alternative possibility that has been raised is that Sahelanthropus is not ancestral to either humans or chimpanzees, but rather to gorillas—a no less significant possibility since fossils attributed to the presumed gorilla lineage at this time consist only of teeth dating to about 10 million years ago.

Literature Cited

Macchiarelli, R., A. Bergeret-Medina, D. Marchi & B. Wood. 2020. Nature and relationships of Sahelanthropus tchadensis. Journal of Human Evolution 149:102898. doi:10.1016/j.jhevol.2020.102898

Tappen, N. C. 1985. The dentition of the “Old Man” of La Chapelle-aux-Saints and inferences concerning Neanderthal behavior. American Journal of Physical Anthropology 67(1):43–50. doi:10.1002/ajpa.1330670106

©️ Ted C. MacRae 2022

2 thoughts on “More “skulls on my desk”

  1. There is nothing like having a skull around to help your mind muse & meander in interesting ways
    For example, you might recall the “Alas, poor Yorick, I knew him ….” scene from Hamlet?
    Ofelia’s grave is being dug — Hamlet doesn’t yet know she is a dead.
    And Yorick’s skull is incidentally unearthed — he was the court jester in Hamlet’s childhood.
    It’s an odd kind of graveyard — maybe a tiny bit like the La Brea Tar Pits?
    This leads to Hamlet & Laertes fighting in Ophelia’s grave.
    But what do we remember?
    That … skull.

    There is just nothing like having a skull around for a thinking cap.
    Decades ago my sweet wife got me a cast of a Smilodon californicus skull for X-mas from Skullduggery.
    [We opted for the bone-white version — the tar-stained one did not appeal.]
    You lean back from your tray of specimens, or your microscope, or book — & your eye goes to that bone.
    Sometimes, like the bard’s gravedigger, you might actually handle the skull in question.
    I still do that with my Smilodon skull.
    The mandible is attached to the skull by a wire on each side — so you can rotate it & think about its bite.
    Never, not once, could I make myself believe this beast could saber-stab, & bite to kill.
    The sabers are so thin side-to-side — even a desperately-thrashing smallish antelope could snap one of them off.
    Reluctantly, after years of puzzlement, I concluded that Smilodon was a … scavenger.
    Supporting evidence for a scavenging niche for Smilodon from the La Brea Tar Pits includes, & perhaps for saber-tooths elsewhere —
    1] the many broken-&-then-healed Smilodon bones are tantamount to proof of sociality …
    2] Smilodon’s short tail suggests a non-coursing creature …
    3] Smilodon’s low-slung weight suggests an unusual life style for a supposed pure predator …
    4] also, the taller-but-actually lighter American lion, Panthera atrox, shows up with Smilodon in the La Brea Tar Pits …
    5] suggesting a non-hunting-to-kill niche for Smilodon …
    6] Smilodon’s reduced dentition suggests a special diet not requiring a lot of bone-crushing …
    7] the huge sabers perhaps served as belly-openers, a Pleistocene switchblade …
    8] the enlarged front dew-claws might have served to help hold open the belly, providing tension, as the sabers sliced downward …
    9] a large clan of Smilodons might have needed a few days to consume all of the soft organ-tissues …
    10] perhaps the hyenas & lions might have evolved a habit of patience while awaiting their own feast, as we see in the guild of American vultures …
    11] the seemingly over-developed neck-to-skull muscles of Smilodon suggest the cat used its weight to zip open the carcasses of the behemoths

    About this time, 1980, I saw an article in Natural History magazine about the King Vulture, Sarcorhamphus papa.
    A large mammal dies in the forest, & the Cathartes vultures [1 to 3 species] smell it & form a “kettle” high in the sky.
    Black Vultures, Coragyps atratus, can’t smell the corpse, but they see the gyre of Cathartes & join the circling kettle.
    Together, they seem to attract the King Vultures.
    This mostly snow-white, bird, perhaps as a mated pair, shows up at the carcass & the darker vultures stand aside.
    This amazing ability to await your turn supports the idea of a guild, with participants evolving to play their roles in adaptive relations with multiple players.
    The King Vultures OPEN the carcass, feed to satiation on the innards, & waddle aside.
    Then, the other, lesser, vultures can mob the opened & perhaps still-cooling carcass.
    The importance of a carcass-opener for the cadavers of behemoths flashed like a bulb in my little brain.
    From there, it was an easy step to realize that Smilodon was perhaps a highly-specialized carcass opener & viscera consumer.
    What a … gross, ghastly, gut-gobbling disappointment for our authorities of the Pleistocene scene!
    Perhaps their minds can’t go there — partly because of the hold our prejudices have on our own noble evolution?
    Might the descent of Smilodon from its pedestal of prime predator threaten — unconsciously — our own place on our own pedestal of Man-the-Mighty Hunter?

    Let’s take a peek back, to our continent of origin.
    There we were on the Pleistocene African savanna in our clans of 150-or-so folks [Dunbar’s Number].
    Our look-outs espy a circling “kettle” of vultures way off high in the sky.
    These birds are announcing the demise of a behemoth so huge that nothing could kill it — not even us.
    But it could not live forever, & one day it took its last step.
    Excitement rouses out entire clan, & we gather up our portables & babies & hie ourselves toward the dark gyre.
    We arrive with our clubs & spears & pouches of rocks for throwing.
    Perhaps a clan of African saber-tooths has also arrived.
    Perhaps we arrive with torches, & set the grass & forbs afire.
    We drive off the saber-tooths & lions & hyenas.
    There is no mammalian defense against thrown stones — if there are enough throwers & enough stones.
    The huge beast is moaning its last, virtually begging for release from its torment.
    With our sharp wooden lances, we pierce its abdomen, probing for the vital spots.
    Then, in moments, mercy embraces the stilling behemoth.
    And then, with our Clovis points, we begin the blessed dismemberment.
    I think that was our Pleistocene economic model — the top scavenger in Africa.
    And we took that successful model with us all over the world — including those American tar pits.

    We should all emulate Ted MacRae & keep some bones about — especially skulls from our past.

    • Hi Scott – thanks for the thoughtful and probative contribution to the subject. How I would love to add a Smilodon skull to my bookshelf! You lay out a well-reasoned argument for Smilodon as a scavenger – similar to the idea that T. rex also may have been a scavenger rather than a top predator. As for Pleistocene man being a scavenger, I can accept it as at least a part of its strategy, but the megafaunal extinctions around the globe that seem to coincide precisely with the first appearance of modern humans leaves little doubt in my mind that they were primarily hunters—their ability to kill with coordinated hunting outpacing the replacement capabilities of these large mammals.

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