Many vertebrate fossils look familiar, even to laymen. The average man on the street could identify the complete reconstructed skull of a Smilodon. Other relatively common fossils are so easily recognizable that the amateur novice fossil collector can quickly learn to ID them. It’s not hard to discern the difference between a mammoth and mastodon tooth, and after a little practice the difference between a horse and tapir tooth is quite apparent. Size alone makes bones such as a femur of a proboscidean distinguishable from that of a bison. But the chances are just as likely that a fossil collector will stumble upon a bone so odd it creates a mystery. The hyoid bone is one example that without consulting a book, I’d never be able to identify.
A comparison of hyoid bones from 3 closely related species of proboscideans–Africans elephants, Indian elephants, and Columbian mammoths. The hyoid bone is the tongue bone.
A Neanderthal hyoid bone. About a dozen muscles including the tongue are attached to it. It’s more often found with one of the ends broken off.
Who besides a medical doctor or trained vertebrate paleontologist would have thought this bone rests a few inches above the pharynx? Usually, only half of this u-shaped bone is found, and it resembles an erect penis. A dozen muscles are attached to this bone including the tongue, so in laymen’s terms it can be known as the tongue bone. Howler monkeys may have the largest hyoid bones in the animal kingdom. It makes the area below their chins ovoid in shape, and it aids the high volume of their howls.
Howler monkeys have big hyoid bones. Situated above the pharynx, it contributes to the monkey’s ability to loudly vocalize.
Other odd fossils may be hard to ID, simply because they’re so nondescript.
Woolly Mammoth heel bone (Calcaneum).
The calcaneum or heel bone looks like an uninteresting rock. In the living animal it’s attached by ligaments and tendons to the astralagus or ankle bone which is much more interesting to examine.
Camel astralagus or ankle bone.
Many fossils are unusual due to morphology.
Giant ground sloth bone with a puncture mark made by a big cat of some kind.
The above fossil is interesting because of the cat canine puncture mark on it. A big cat either killed this baby ground sloth or scavenged it. Cats eat fresh kills far more often than they scavenge. It seems likely the cat killed this unfortunate animal. How did it get past the mother ground sloth? Adult ground sloths were much larger than any cat species, and had claws and armoured hides under thick fur. I’m sure the mother wouldn’t give up their offspring without a fight. Perhaps, the young sloth wandered too far from the protective vicinity of its mother. Which species of cat did the damage? I say jaguar, but the scientists who examined the specimen believe it was a scimitar tooth (Dinobastis serum). Jaguars have a more powerful bite and their canine can easily puncture bone. The fanged cats didn’t have as powerful a bite–I’m not sure it would’ve punctured bone. But if it is from the scimitar-tooth, we are looking at the results of a confrontation between 2 extinct mammals never to be seen again.
Many vertebrate bones also show evidence of invertebrate activity. A fossil collector gave me a piece of a dugong bone with holes made by burrowing clams. (See http://markgelbart.wordpress.com/2010/04/ It’s the third article down in the April 2010 archives.) Terrestrial vertebrate bones occasionally have holes made by burrowing beatles. Vertebrate bones with this kind of morphology are evidence the fossils rested on top of the ground or within topsoil for years.
Smilodon Vertebrae fused together from arthritis.
The photo above shows that a tough old Smilodon, aged enough to develop arthritis, still survived for years despite its ailment. A high incidence of severe injuries occurred among the population of saber-tooths that left specimens found in the La Brea tar pits. Apparently, these big cats wrestled large, heavy-bodied prey to the ground before killing the beast by slicing through the soft throat with their fangs. They often suffered the kinds of injuries a human might get from lifting too much weight. But they survived these debilitating injuries, suggesting to some scientists that they lived in prides and took care of each other. However, other scientists think they were not social animals for 2 reasons: they have relatively small brains compared to those of lions, and the vast majority of cat species are solitary. I agree with the those who think Smilodon was a solitary species. I think saber-tooths could survive serious injuries because even a partially crippled one was more than a match for most other carnivores, and they could drive them from their kills, not unlike the way Clint Eastwood chased away young punks in his movie, El Camino.