Blog 2: non-human primate anatomy lab & blog post

For this assignment, you will study the anatomy of a primate using the KUPRI Digital Morphology Museum (http://www.pri.kyoto-u.ac.jp/dmm/WebGallery/dicom/researcherTop.html). You will collect some measurements and analyze these data in a comparative context. You will then post your results to the blog, and answer some questions about these files. You do not need to use outside resources or references to complete this assignment

This must be posted to the blog no later than 23:59 Friday 14 February!

Instructions – take some measurements!1. Select one of the primate specimens in class.2. Using the viewer’s grid feature, orient the skull so you can measure the maximum width

(in millimeters) across the parietal bones.Width =

a. Estimate the brain size (in terms of volume, cm3) of this specimen using the following equation: brain size = 2.71828[(-4.39926 + 2.25678*ln(W)]. Do not convert your width (W) from mm to cm, keep it in mm! This equation was developed for chimpanzees, so may it or may not give accurate estimates for other species.

Estimated endocranial volume =

3. Measure the maximum diameter of the femur headFemur head diameter (mm) =

a. This can be used to estimate the body mass of the animal using the following equation: body mass = 2.71828[(-5.338 + 2.642*ln(femur head diameter)]. As in the brain size equation above, your final mass (in kg) will be 2.718ln(mass)

Estimated mass =

4. How much of body weight is due to brain size? That is, what is the ratio of brain to body weight, expressed as a percentage? (you can assume that 1 cm3 of brain = 1 gram, or 0.001 kg, although this is not exactly true in reality)

Brain mass / body mass = %5. Measure the maximum length of the limb bones (humerus, radius, femur, and tibia).

Many of the (arm) bones are somewhat curved, so just try to approximate the straight line that gives the maximum length of the bone.

Humerus (mm) = Radius (mm) = Femur (mm) = Tibia (mm) =

6. Use these data to calculate four indices describing the relative lengths of the limbs:a. Intermembral index = (humerus + radius) / (femur + tibia) x 100

b. Humerofemoral index = humerus / femur x 100

c. Brachial index = radius / humerus x 100

d. Crural index = tibia / femur x 100

For your blog postPresent your findings on the blog, providing the following information:

1. The identification number, sex and species of your specimen2. What variables did you examine and why (what will they tell you about this animal)?3. Provide the data you collected for your specimen:

a. Maximum parietal width (W)i. Estimated cranial capacity

b. Femur head diameteri. Estimated body mass

c. How much of the body weight is composed of brain (i.e., brain mass is what percentage of body mass)?

d. Limb lengths (humerus, radius, femur, tibia)e. Indices: intermembral, humerofemoral, brachial and crural

4. Answer the following questions:a. How do your numbers compare to published values (which I have provided at the

end of this handout) for this species?i. If different, speculate why your findings might be different.

b. What do your species’ proportional brain size and limb indices tell you about the animal?

c. What were some difficulties in performing your study?d. What further research questions can you think of based on this study, and how

might you go about addressing them? (provide at least one)

Appendix: published primate body mass and brain sizes

(“index” is the cranial capacity expressed as a percentage of “weight”)

First table: Schultz A. 1941. The relative size of the cranial capacity in Primates. American Journal of Physical Anthropology 28: 273-287.Second table: Aiello L and Dean M. 1990. Human Evolutionary Anatomy. Academic Press.