lab #10 anthropology

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Lab #10 is the online version of Exercise 10 “Comparative Anatomy of the Primate Skull” in the LAVC Anthro 111 Lab Manual for Human Biological Evolution (7th Edition) on pages 91-98.

As you know by now, Primates are an order of mammals with characteristics and behaviors that are different from other mammals including forward-facing eyes (“binocular vision”) with enclosed eye orbits and they have other anatomical adaptations for arboreal living and climbing with hands and/or feet (and sometimes tails) made for grasping. Humans (Homo sapiens) are classified as Primates. Knowing the anatomical differences between humans and non-human primates is an essential research skill that researchers need to identify fossils of our pre-human ancestors. Crime scene investigators like forensic anthropologists also need to know the difference between human and animal bones.

This lab introduces you to the major differences between non-primate animals and primate skulls. And, it goes over the major differences between the skulls of different species of non-human primates and humans from an evolutionary perspective.

The differences have evolved because they were adaptations to different environments and sources of food, which helped the animals’ ancestors survive and reproduce. In other words, “form follows function.” Each anatomical difference has evolved as an adaptation that helped that species survive. If you know about these anatomical differences, you can often infer the behaviors of the animals when they were alive. It is useful to figure out how our now-extinct ancestral species lived and how to tell the differences between ape and hominin fossils by observing the differences in similar extant species.

Some non-primate skulls

alligator skull lateral view with an un-enclosed eye orbit skull of a bobcat with huge canines and narrow meat-eating teeth with un-enclosed eye orbits California sea lion skull, lateral view, with a huge sagittal crest, narrow sharp pointed teeth, and unenclosed eye orbits. Horse skull, lateral view, with wide sharp incisors, tiny canines, and flat and wide molars, and with enclosed eye orbits that are open towards to the posterior.
Alligator skull, lateral view, with an un-enclosed eye orbit and teeth that are the same size and shape Bobcat skull, anterior view, with huge canines and narrow incisors with un-enclosed eye orbits California sea lion skull, lateral view, with a huge sagittal crest, narrow sharp pointed teeth, and unenclosed eye orbits. Horse skull, lateral view, with wide sharp incisors, tiny canines, and flat and wide molars, and with enclosed eye orbits that are open towards to the posterior.

Some primates and their skulls

Three ring-tailed lemurs native to Madagascar tarsier spider monkey semi-brachiating using his prehensile tail Male mandrills displaying their colorful cheek pads and ischial callosities (butt pads) A family of rare mountain gorillas in the wild A family of humans (Jane Goodall, her husband Hugo von Lawick, and their son) in the wild of Serengeti National Park, Tanzania
skull of a ring-tailed lemur with enclosed eye orbit ring of bone that is open towards to posterior of the skull skull of a Haplorrhine sub-order species of Tarsier Anterior view showing partially enclosed eye orbit ring of bone Capuchin Monkey, a New World Monkey/Platyrrhine, skull with an enclosed eye orbit septum place of bone that is closed towards to posterior of the skull and an ear cavity that looks like a pencil erasure indentation Mandrill baboon skull with huge canines and an enclosed eye orbit septum place of bone that is closed towards to posterior of the skull Male Western Lowland gorilla skull with a huge saggital crest of bone on top of the skull and an enclosed eye orbit septum of bone that is closed towards to posterior of the skull human skull, lateral view, with enclosed eye orbits and normal human teeth
Strepsirrhine
(Ring-Tail Lemur)		 Haplorrhine
(Tarsier)		 Haplorrhine > Platyrrhine
(Capuchin Monkey)		 Haplorrhine > Catarrhine >Cercopithecoidea (Mandrill) Haplorrhine > Catarrhine > Hominoidea (Gorilla) Haplorrhine > Catarrhine > Hominoidea (Human)

Above are photographs of different categories of primates. However, the photographs are not accurate portrayals of each primate’s size relative to the other species pictured on this page. For example, a 400-pound adult male Western Lowland Gorilla is just a wee bit larger than a 5-ounce bug-eating tarsier. One pound = 16 ounces.

Resources

  • My lecture slides (saved as a PDF file): 
  • Exercise 10 “Comparative Anatomy of the Primate Skull” (PDF): 
  • Pre-recorded and captioned video lecture “Comparative Anatomy of Primate Skulls”: 

    Notes    :
    (1) Disregard the Lab Manual’s instructions that say “primate number” printed in the lab manual for this online class.
    (2) Use the skull measurements on this Canvas Assignment to complete the exercises. See below.
    (3) You do not need skulls at home to complete these lab exercises.

Directions

Complete the following exercises in the lab manual, using the above resources, according to the directions here for this online class:

  1. Ex. 10.1 “Recognizing the Primate Skull” (pages 91-92) Skip the question at the bottom of page 91.
  2. Ex. 10.2 “Recognizing the Strepsirrhine Skull” (pages 92-93)
  3. Ex. 10.3 “Recognizing the Haplorrhine Skull” (pages 93-94)
  4. Ex. 10.4 “Recognizing the Platyrrhine Skull” (pages 94-95) Skip this exercise.
  5. Ex. 10.5 “Recognizing the Old World Monkey and Ape [Catarrhine] Skull” (page 96) There are no questions to answer. Skip this.
  6. Ex. 10.6 “Comparing the Ape and Human Skulls” (pages 96-97)

    Use the 360° images at the links below to complete the chart on page 97:
    • 360° view of an ape (Chimpanzee (Pan troglodyte)) skull: 
    • 360° view of a human (Combe Capelle 7575 BC (Homo sapiens)) skull: 

    Use the following measurements to calculate the Condylar Index and the Palatal Index for the ape and human skulls:

    1. Ape: Chimpanzee (Pan troglodyte) male skull measurements
      • Cranial Index = cranial breadth/cranial length) x100
      • Chimpanzee cranial breadth = 91
      • Chimpanzee cranial length = 131
      • Condylar Index = Foramen magnum to back of the skull (basion to opisthocranion) / Forman magnum to the front of the skull (basion to prosthion) x 100
        • Chimpanzee basion to opisthocranion = 58
        • Chimpanzee basion to prosthion = 150
      • Palatal Index = Palatal width (two points outside of M2 (subscript)) / Palatal length (Prosthion to point at the midpoint of the line between posterior of M3 (subscript)) x 100
        • Chimpanzee Palatal width = 38.4
        • Chimpanzee Palatal length = 58.8
    2. Human: Human (Homo sapiens) male skull measurements
      1. Cranial Index = cranial breadth/cranial length) x100
        • Human cranial breadth =132
        • Human cranial length = 169
      2. Condylar Index = Foramen magnum to back of the skull (basion to opisthocranion) / Forman magnum to the front of the skull (basion to prosthion) x 100
        • Human basion to opisthocranion = 92
        • Human basion to prosthion = 94
      3. Palatal Index = Palatal width (two points outside of M2 (subscript)) / Palatal length (Prosthion to point at the midpoint of the line between posterior of M3 (subscript)) x 100
        • Human Palatal width = 35.5
        • Human Palatal length = 41.1
  7. Ex. 10.7 “The Primate Skull: A Review” (page 98)
    Complete the chart on page 98.

    Notes: Memorize the meanings of the terms “simian shelf” and “mandibular protuberance” so you can complete the chart correctly:
    • A simian shelf is a shelf of bone on the inside of the anterior of a mandible in non-human primates only. Humans do not have a simian shelf.
    • A mandibular protubrance is chin (aka “mental eminence”). Only anatomically modern humans have chins.

  8. Study Questions: None for this lab. Skip this.

Lab #10 Grading Rubric

2 points: Ex. 10.1 “Recognizing the Primate Skull” (questions in the box on page 92)
(Skip the question at the bottom of page 91.)

2 points: Ex. 10.2 “Recognizing the Strepsirrhine Skull” (questions in the box on page 93)

2 points: Ex. 10.3 “Recognizing the Haplorrhine Skull” (chart on page 94)

2 points: Ex. 10.6 “Comparing the Ape and Human Skulls” (chart on page 97)

2 points for Ex. 10.7 “The Primate Skull: A Review” (chart on page 98)

_+_____________________________________________

10 points: Maximum points possible

Ex. 10 “Primate Skull” key terms to know for Quiz #4

  1. braincase
  2. cranium
  3. external auditory meatus (ear hole located on the temporal bone).
  4. haplorrhine
  5. interorbital breadth (the space between the eye orbits)
  6. mandibular protuberance (aka “mental eminence”)
  7. mandibular symphysis (suture that divides the mandible into left and right halves)
  8. metopic suture (suture that divides the frontal bone into left and right halves)
  9. nuchal crest (crest of bone on the occipital bone on the posterior side of the skull)
  10. olfaction (sense of smell)
  11. orbits (where your eyes go)
  12. postorbital bar (bar of bone around each eye orbit with an opening)
  13. postorbital septum (plate of bone around each eye orbit with no opening)
  14. prognathism (degree of facial protrusion or snout)
  15. sagittal crest (crest of bone along the sagittal suture)
  16. simian shelf (shelf of bone on the mandible posterior to the row of bottom teeth)
  17. strepsirrhine
  18. supraorbital torus (brow ridge of bone over the eye orbits)

lab #10 anthropology

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