Bioanthro Lab Activity: Chimpanzee Developmental Osteology

We’ve just done the first lab activity in my Human Evo Devo course. My current university is young, and so we haven’t yet acquired good skeletal materials for teaching. Fortunately, the good people at Kyoto University’s Primate Research Institute have made a large, open access database of primate CT scans. For this first lab, students compare skeletons of neonate and adult chimpanzees, getting a crash-course in osteology, CT data, growth-related changes,  and chimps.

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Neonatal chimpanzee. Three windows give 2D slices in anatomical planes, while the 4th window contains the reconstructed 3D volume that can be rotated and analyzed.

The activity requires a computer lab with the freeware CT analysis program InVesalius. CT files (dicom stacks) can be downloaded from the KUPRI database, but they are massive (100s of MBs), so I recommend some preprocessing before starting the class. I downloaded the specimens we were to use, opened each one in InVesalius, and saved as an .inv3 file. These are on the order of 50-80 Mb each. With smaller, prepared files, it’s faster and easier for students to download and start using them. While the neonate skeleton was small enough to fit into a single dicom stack, the adult scans were so large that I had to use separate files for the the skull, scapula, pelvis, and limbs (pre-separated on the KUPRI database).

Students examined one neonate and adult, making qualitative observations and taking a few cranial and postcranial measurements on each individual.

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It’s pretty easy to take linear and angular measurements on both the 3D volume and the 2D slices in InVesalius.

One goal of the assignment is to show students how bones change with growth, in terms of both gross anatomy and overall size. By measuring the diaphyseal lengths, they see what limb bones look like with and without epiphyses.

Picture1

Measuring diaphyseal, rather than maximum, lengths. Left figure from Jungers and Susman (1984).

Students examine how much size change occurs between birth and adulthood in chimpanzees. They then compare these skeletal sizes and proportional changes with comparable human data (well, up to age 12), taken from Scheuer and Black (2000). This will help get them started thinking about how postnatal growth might lead to differences between adults of each species, or how developmental modifications effect evolutionary changes.

Here’s the lab activity handout in case you want to use it in your own class: Lab 1 Handout-Chimp Development.

ResearchBlogging.orgReferences

Scheuer L and Black L. 2000. Developmental Juvenile Osteology. Academic Press.

Jungers WL and Susman RL. (1984). Body size and skeletal allometry in African Apes. The Pygmy Chimpanzee: Evolutionary Biology and Behavior, 131-177 DOI: 10.1007/978-1-4757-0082-4_7

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