Question

1 Examine the Afropithecus head skull, sketch/label and describe. note key features including dentition-describe form and function.

2 Choose one of the modern african apes(extant) to sketch/label and describe. Note key features of the skull, including dentition-describe form and function, diet, habitat, and any notable adaptations of species. Consider the ecology, i.e. how is the species interacting with other species and the environment.

a.Bonobo skull

b.Lowland Gorilla skull

c.Mountain Gorlla skull

Answer 1

Answer 1)

Key features:

Habitat: Jungles of Africa

Historical Epoch: Middle Miocene (17 million years ago)

Size and Weight: About five feet tall and 100 pounds

Diet: Fruits and seeds

Distinguishing Characteristics: Large size; relatively long snout with large teeth

Paleontologists are still trying to sort out the complicated relationships of the early African hominids of the Miocene epoch, which were some of the first true apes on the prehistoric primate evolutionary tree.

Afropithecus, discovered in 1986 by the famous mother-and-son team of Mary and Richard Leakey, testifies to the ongoing confusion: this tree-dwelling ape had some anatomical features in common with the better-known Proconsul, and it also seems to have been closely related to Sivapithecus as well (a genus to which Ramapithecus has now been assigned as a separate species). Unfortunately, Afropithecus isn't as well attested, fossil-wise, as these other hominids; we do know from its scattered teeth that it fed on tough fruits and seeds, and it seems to have walked like a monkey (on four feet) rather than an ape (on two feet, at least some of the time).

The type specimen, KNM-WT 16999 is composed of a long distinct snout, the facial skeleton, frontal, much of the coronal structure, most of the sphenoid, and relatively unworn adult dentition; the right orbit (virtually complete), the right zygomatic, the pterygoid, most of the sphenoid and lesser wings, the maxilla and premaxilla, and adult dentition with procumbent incisors. The surface on the right side maxilla and premaxilla along with the enamel on the right molars has been lost over time and has been replaced with calcite crystals, which only provide the general shape and not the details.

From dentition its known that the palate, which is almost completely calcified, of A. turkanensis, is shallow, long and narrow with tooth rows that converge posteriorly, and it is probably the tooth rows were originally nearly parallel. A. turkanensis had a 6.5mm diastema between its very procumbent second incisor (KNM-WT 16999 had large, broad incisors) and the canine.

Answer 2).Bonobo skull

• The skull is longer than it is broad.
• Brain capacity averages 364 cubic cm.
• The forehead is relatively high.
• The ears are relatively small. As in the other great apes the ears are rounded and hairless.
• For seven individuals, ear height was 55-72 mm and ear width, 38-42 mm.
• There is long hair on the sides of the head.
• "Calvarium rounded, facial skeleton moderately prognathic, orbits frontally directed and surmounted by prominent and confluent supraorbital crests. Small sagittal crest very occasionally seen in large [males] and [females]; nuchal crest absent. Cranial capacity 290-500cc (94 adults). Foramen magnum situated well posteriorly on basis cranii."
• Bonobos have a relatively high and rounded forehead with a small brow ridge; in chimpanzees the forehead is relatively lower and the brow ridge more massive. The vault length, vault height, postorbital breadth and cranial capacity are slightly lower than in Pan troglodytes. Mandibular length and maximum palatal length are lower than in Pan troglodytes, giving a relatively rounded, globular cranium. Dimensions include
  • Vault length 122.8 mm
  • Vault breadth 105.8 mm
  • Vault height 85.4 mm
  • Interorbital breadth 14.5 mm
  • Postorbital breadth 65.6 mm
  • Palatal breadth 51.5 mm
  • Palatal length 58.1 mm
  • Mandibular breadth 93.4 mm
  • Mandibular length 102.4 mm
  • Mandibular height 55.4 mm
  • Cranial capacity 350 cm³.

Dental formula i 2/2, c 1/1, pm 2/2, m 3/3 (x 2, total 32 teeth). There is no sexual dimorphism in tooth size except for slightly longer, broader canine teeth in males. Deciduous dental formula is i2/2, c 1/1, dm 2/2.

Habitat: Congo Basin in Central Africa