When studying vertebrate paleontology, the skeleton is one of the most important, and often the only, clue we have to the appearance of long-extinct animals. In Lower Decks: "Kayshon, His Eyes Uncovered", we were treated to the ghoulish sight of of Spock's skeleton ^1, ^2, courtesy of the remains of his giant clone from TAS: "The Infinite Vulcan." Any dinosaur fan knows that while there's only so much bones can tell you about the living animal, they can still tell quite a story. I am not an expert in anatomy and not a trained paleontologist, but it is my hope that analyzing the remains of Spock the Larger will provide further insight into the anatomical differences between humans and Vulcans. By way of comparison, here is an anatomical diagram of the human skeleton: ^3
Dentition
As near as I can tell, adult Vulcans appear to have 28 teeth to the human's 32, seven on each side ^4, ^5 on top and bottom. (It's possible that Spock could have had his wisdom teeth out, but presumably the clone would have undergone no such procedure, and no empty sockets are in evidence.) Looking closely at the teeth themselves, six molars, four incisors, and four bicuspids per side are in evidence. There is no sign of the canines a human has. This suggests that Vulcans evolved from a herbivorous answer. Could Vulcans' propensity for vegetarianism be a biological imperative rather than a cultural tendency?
Skull
The proportions of the Vulcan skull as depicted in this image compared to the human skull in this image are fairly simpler. The skull, across the zygomatic along the upper corner of the orbit, is 101 pixels wide on the Vulcan as depicted in figure 1 and 75 pixels wide in the human as depicted in figure 3. The height of the skull, respectively, is 173 and 132 pixels. These equal a ratio of 1.71 for the Vulcan and 1.76 for the human. Sufficiently clear side and rear views are unfortunately not available for comparing the approximate circumference of the cranium, but it can be presumed that the Vulcan skull is similar in all dimensions to that of a human, and that their brain would likely be similar size (and thus, similar in proportion to their overall body mass) to that of a human. While brain-body ratio isn't a perfect estimator of intelligence this is certainly consistent with them being comparable to a human in intelligence (but don't let the Vulcans know, they'd surely be insulted.) Vulcan eyes are forward-facing. Binocular vision is unusual in prey species, but as we've established, Vulcans are herbivores. One possibility is that a wide field of vision is not necessary to protect from predators, which would suggest that there are no predators on Vulcan large enough to threaten a man, however the existence of the Le-Matya and the large creature that nearly slew a young Michael Burnham when she camped out in the Forge disproves this hypothesis. On Earth, the only herbivorous animals with forward-facing eyes are found among our primate relatives, who descend from an arboreal ancestor that required depth perception to brachiate. I suggest it is thus likely that Vulcan was once home to vast forests, in the trees of which a distant, pointy-eared ancestor once lived.
Vertebrae
Vulcans are vertebrates, shockingly.
All jokes aside, based on the position of Giant Spock's shoulders, it would appear that Vulcans have only five cervical vertebrae to humans' seven ^6. Fewer than seven vertebrae is uncommon for mammals on Earth-- the only mammals with more or fewer than seven vertebrae are manatees with six, two-toed sloths with five, and three-toed sloths with nine. All other mammals, from mice to gorillas, have seven. It's hard to say what the practical effects of this would be, as the number of bones in the neck don't necessarily tell us much about the flexibility of that neck.
Ribcage
I count seven ribs per side, of which the last two are floating ribs unattached to the sternum ^7. These extend rather further forward than the floating ribs of humans. Like earth's tetrapods, and unlike many fishes, Vulcans have only a single set of ribs. I think the Xiphoid process can be seen through a hole in Giant Spock's shirt. I suspect that Vulcans may have smaller lungs than humans do(an assertion backed up by the anatomical chart in the old Starfleet Medical Reference Manual, where the position of the Vulcan heart and stomach truncate the lungs slightly.) Vulcan is generally said to have a thinner atmosphere than Earth, so we can conclude that Vulcan lungs must be far more efficient than our own.
Hands
This is an interesting one. If you look closely at the bones of the Vulcan hand it appears that they are significantly different from those of a human. The most notable difference is that the Vulcan hand appears to have either an additional phalange, or else they have not one, but two metacarpals per finger-- I think the latter, because it looks like the joint would be about mid-palm on a human to me. ^8 The most likely result is that the Vulcan palm can, perhaps, be folded in the middle. This could potentially jive with our brachiation hypothesis from earlier. However it is worth noting that this adaptation seems to appear only on the right hand (on the audience's left in the image.) Most likely one hand or the other is simply the victim of an animation error, but which one it is, we cannot be absolutely certain of.
Unfortunately, glimpses of the remainder of the skeleton are fragmentary and hard to tell us much, though a generally close resemblance to human anatomy continues to be evident from what we see, which includes part of the left radius, the radius, ulna, and humeral trochlea of the right arm, the right shoulder, some three lumbar vertebrae, a bit of the ilium on both sides, and a glimpse of both knees. However we have sufficient diagnostic material to distinguish fossil remains of H. sapiens and V. eridani despite the otherwise extreme convergence of their physical traits.
Wouldn't prime!Chekov be like 12 around this time frame?