October 27, 2016 at 3:33 pm #14799Jeanette PirloKeymaster
This past summer, Erin Petersen Lindberg, a teacher from Santa Cruz, California, discovered a beautifully preserved vertebra of a juvenile gomphothere. It turned out to be the first vertebra of the cervical column, otherwise known as the atlas or C1. The atlas is important to vertebrates because it supports the weight of the cranium and, along with the axis (second vertebra), allows the animal to turn its head.October 27, 2016 at 8:17 pm #14803Lisa LundgrenKeymaster
Neat! Thanks for posting, @jeanette-pirlo. Do humans have an atlas as well? I’m wondering about comparative anatomy now! Like what does a T. rex atlas look like? Or a mammoth’s? Or an alligator’s? Do birds have atlases? I have many questions!October 27, 2016 at 9:10 pm #14804Tynessa MorganParticipant
I need to do comparison pictures for my classroom between the various branches of the elephant family. I use a juvenile dolphin vert in class to compare with humans when I teach anatomy and basic classification.October 27, 2016 at 10:20 pm #14805Jeanette PirloKeymaster
All vertebrates have atlases! The C1 vertebra was thusly named by ancient Greeks because it supports the weight of our cranium (“world”) just like the Titan, Atlas, held up the world.
I would thinking that a mammoth atlas would be similar in design and robustness as that of a Gomphothere since they are related. As for the comparative anatomy of a T-Rex/alligator/bird atlas, I too would like to see examples of them!October 27, 2016 at 10:26 pm #14806Lee ConeParticipant
The first and second cervical vertebrae of all mammals are modified into specific vertebrae called the atlas and axis vertebrae. I have pictured a baleen whale atlas, which measures about 12 inches across. The axis is directly behind it in the picture as it appears in my display case (hence the reflection). The atlas and axis nestle together followed by 5 more cervical vertebrae. The cervical vertebrae, C3-c7, are very thin in the whale, relative to thoracic or lumbar vertebrae, while in the giraffe the same 7 cervical vertebrae are extremely long. The evolutionary difference accounts for the long neck of the giraffe (not more cervical vertebrae). Both have the same number.October 28, 2016 at 11:48 am #14808Eleanor GardnerModerator
For those curious about birds (@llundgren, @jeanette-pirlo) – yes, they do have atlas and axis vertebrae. In fact, birds have more cervical vertebrae than most other animals; for example, a swan has 25 cervical vertebrae, while most mammals only have 7. If you’d like to see a fossilized bird atlas, I’m attaching a figure from Bertelli et al. (2006) showing the atlas of Paraptenodytes antarcticus (a Miocene penguin).
Also, just to clarify Lee’s comment: the majority of all vertebrates have modified first and second cervical vertebrae called the atlas and axis. Fish are known for lacking specialization of the atlas/axis, but all amphibians, reptiles, birds, and mammals have atlas and axis vertebrae. Obviously some groups have a more specialized atlas/axis than others, allowing for unique head movements (like those of owls).
Citation: Bertelli, S., Giannini, N. P., & Ksepka, D. T. (2006). Redescription and phylogenetic position of the early Miocene penguin Paraptenodytes antarcticus from Patagonia. American Museum Novitates, 1-36.
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