Plio-Pleistocene Hominids

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ANT 3514- Introduction to Biological Anthropology

Plio-Pleistocene Hominids

Lab 5, Week of 6/06/05

The focus of this lab is gracile and robust Australopithecines and “early Homo”. As such, we will be comparing specimens of the subfamily Australopithecinae with those of the early members of the subfamily Homininae. The genus Homo emerges approximately 2.4 m.y.a., and as we will see these fossils possess both ancestral and derived morphological traits.
STATION 1: Gracile vs. Robust “Australopithecines”
This station focuses on the similarities and differences between the gracile and the robust Australopithecines. At this station you will find:

  • Composite cranium of Australopithecus afarensis

  • 2 crania of Paranthropus robustus (A6, A28)

  • a mandible of Paranthropus boisei (“Peninj”)

  • 2 crania of P. boisei (KNM-ER 406 and OH 5)

  • a cranium of Paranthropus aethiopicus (KNM-WT 17000 – “The Black Skull”)

The subfamily Australopithecinae (the Australopithecines) contains a gracile group and a robust group. These groups are differentiated based on differences in their cranial morphology. (Their postcrania do not necessarily conform to a “gracile vs. robust” distinction.)

(in class) Complete the following table comparing the crania of these different australopithecines:

A. afarensis

P. robustus

P. boisei

P. aethiopicus

Cranial cresting (sagittal and nuchal)

Degree of Prognathism

Degree of Post-Orbital Constriction

Size of anterior vs. posterior teeth

Overall Robusticity

(rank 1=most robust, 4=least)

(at home) What do the cranio-dental differences between the species noted above suggest to you about the subsistence strategies of robust and gracile Australopithecines?

STATION 2: Australopith Mandibular Anatomy
(in class) Compare the mandibles of each species:

A. afarensis

P. boisei

Pan troglodytes

H. sapiens

Dental Arcade Shape (rectangular vs. U-shaped vs. parabolic)

Canine Size (small vs. large)

P3 form (1 or 2 cusps)

Presence/Absence of Chin

STATION 3: Gracile Australopithecines and Homo

The focus of this station is to compare the differences between the gracile australopithecines and Homo habilis. At this station you will find:

  • a cranium of (A73)

  • a cranium of Homo habilis (KNM-ER 1813)

  • A. africanus foot

  • femur of H. sp. (KNM-ER 1481)

  • articulated foot and a femur of a chimpanzee

  • human femur

(in class) List any post-cranial features from the H. habilis foot and H. sp femur that indicate bipedality. Use human and chimpanzee material for reference.

(in class) Complete the following table regarding the similarities and differences between the H. habilis and A. africanus crania:

A. africanus

H. habilis

Cranial Vault Height

(short vs. tall)

Overall Robusticity

(most vs. least)

Degree of Prognathism

Shape of Face/ Zygomatics

(flared vs. non-flared; broad vs. narrow; tall vs. short)

Dental Arcade Shape

(U-shaped vs. parabolic)

(at home) Can A. africanus conceivably be ancestral to H. habilis? Why or why not? Include morphological (from the specimens) as well as temporal and geographic elements in your answer.

STATION 4: Robust australopithecines and Homo
The focus of this station is to compare the crania of the robust australopithecines and early Homo. At this station there is:

  • crania of P. boisei (A27, A30)

  • a cranium of Homo habilis (OH 24)

  • a cranium of Homo rudolfensis (KNM-ER 1470)

(in class) List all significant differences between the crania of the robust australopithecine to that of H. habilis and H. rudolfensis .

(in class) Compare the crania of H. habilis and H. rudolfensis. What differences are apparent? What similarities are apparent?
(at home) Based on morphological and temporal comparisons, can P. boisei, or any of the robusts be ancestral to genus Homo?

(at home) P. boisei males were roughly twice as large as females, while H. rudolfensis males were only about 25% larger than females. How might social behavior differ between these species? Why might it be different? Are there any modern primates with which you could draw analogies?

STATION 5: Early Homo versus modern Homo sapiens
(in class) Compare the crania of these species and record the relative differences revealed in your observations on the table below:

Homo rudolfensis

African Homo erectus (H. ergaster)

Homo sapiens

Supraorbital Torus

Degree of Prognathism

Cranial Capacity

Morphology of Face (Size and Shape)

Occipital Area (Torus)

Overall Shape of

Cranial Vault

(at home) Some scientists have argued that H. habilis and H. rudolfensis are one species. Do you think there is good reason to separate these skulls into two species or should they be collapsed into a single species? Explain your reasoning.

STATION 6: Homo ergaster vs. Homo erectus

(in class) Compare Homo erectus and Homo ergaster. Complete the table:

Homo erectus (Sangiran 17)

Homo ergaster (KNM-ER 3733)

- long and low vault, receding frontal “squama”

- angulation at rear of skull with a “transverse” occipital torus present

- large supraorbital torus

- high, rounded orbits

- strong alveolar prognathism

- canine fossa absent

STATION 7: Homo neanderthalensis
(in class) Compare the “classic” Neanderthal features with the anatomically modern human from Cro-Magnon (France).

Homo neanderthalensis

Homo sapiens

Skull vault

(long vs. short; high vs. low)

Presence/Absence of occipital bun

Supraorbital torus

Eye orbits


Nasal area


Degree of Prognathism

Presence/Absence of canine fossa

Retromolar gap


Presence/Absence of chin

(at home) What about these features (and other anatomical features) suggest the Neanderthals were adapted to the cold?

STATION 8: Hominid femora

(in class) Three femora are present at this station. Match each with the correct taxa listed below. List at list one trait that indicated the femur belong to that particular taxa.
Early Homo


Homo sapiens
(at home) What might account for these differences in the femora?

STATION 9: Stone Tool Industries

Before you are three reproductions of stone tools that date from approximately 2.4 to 30 kya. These tools are of the Olduwan, Acheulian, and Mousterian industries. Olduwan tools have traditionally been associated with H. habilis, Acheulian tools with H. erectus, and Mousterian tools with Archaic H. sapiens. Examine the tools and sketch them. Briefly describe how each was used

The Hominid Family Tree up to H. erectus

  1. Based on your comparisons above, sketch out a rough “family tree” that includes all the australopithcines you know, as well as, early Homo and H. erectus. Since there is no universal answer, be sure to defend your sketch with insights and observations about derived traits, time scales, geographic location, etc. that you learned in lab or in the text. A well-defended answer will receive full credit even if there are a few errors. A time scale has been drawn to get you started.

1 mya

2 mya

3 mya

4 mya

Complete the following table.

Transitional Hominids


Date Range

Cranial Capacity


Geographic Distribution

Homo habilis

Homo rudolfensis

Homo ergaster

Homo erectus

Homo heidelbergensis

Homo neanderthalensis

Reading Questions

1. Based on modern analysis of the fossils, what conclusions have been reached about the anatomy and lifestyle of Gigantopithecus? How might humans have contributed to its eventual extinction? (Ch. 21- Ciochon)

2. According to Leonard, what is the common thread for all the traits that are uniquely human? (Ch. 22)

3. What conclusions about human speech did Cartmill and colleagues arrive at by looking at the hypoglossal canal? (Ch. 24)

4. What can we infer about interaction between H. sapiens and archaic hominids based on DNA evidence? (#33)

5. Describe the two basic models of human evolution: the regional-continuity (multiregional) model and the out-of-Africa model. What are the data Cartmill mentions that support and that argue against the latter model? (#32)

Terminology Issues: As you are all now well aware, things change quickly in the field of paleoanthropology! This includes various issues in terminology.

Homo erectus v. Homo ergasterFossils attributed to these groups span a wide geographic range and an enormous span of time. In addition, the fossils include a wide range of anatomical variability. As such, many researchers (the “splitters”) claim the group should be divided into two. Since the first finds attributed to this group came from Asia, “splitters” feel that the name Homo erectus should be reserved for those fossils more closely associated with the Asian finds in geographic distribution, time range, and anatomical features. The other fossils (those from Africa) should therefore be given a new designation of Homo ergaster. Not all researchers agree, however. The “lumpers” feel that the anatomical variability found among these specimens falls in line with their wide geographic distribution, and therefore only the name Homo erectus should be retained. The author of your textbook, Bernard Campbell, is a lumper (at least concerning Homo erectus). Therefore, keeping in line with the text, those specimens originating from Africa will be denoted as “African Homo erectus (Homo ergaster).”

Homo neanderthalensis v. Homo sapiens neanderthalensisIt is now generally agreed by most researchers that Neanderthals are a separate species of the genus Homo. However, you should be aware that Neaderthals are sometimes (depending on what you are reading and the publish date) referred to as Homo sapiens neanderthalensis, denoting a subspecies designation within the species Homo sapiens. Keeping in line with the text, Neanderthals will be denoted as Homo neanderthalensis (or simply Neanderthals).

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