History of the early Catarrhini Lecture 6

Question 1

___________ exhibit bilophodonty

Answer 1

Cercopithecoids exhibit bilophodonty

Question 2

What foramen have catarrhines lost that most mammals have?

Answer 2

The entepicondylar foramen. It is a little hole near the distal part of the formen that blood vessels and nerves go through.

Question 3

Describe propliopithecids.

Answer 3

Stem catarrhines

They have a ring-like ectotympanic (which is primitive) and an entepicondylar foramen (unlike catarrhines)

1) Oligocene
2) Fayum
3) 4-6.7kg

4) Examples:
Propliopithecus
Aegyptopithecus

5) H shaped pterion (catarrhine condition)
6) 2 premolars (catarrhine condition)
7) Postcrania suggest it was a slow, arboreal, quadruped

Question 4

Describe Pliopithecids

Answer 4

1) Miocene of Europe. Asia and Africa

2) Examples:
Dionysopithecus, Anapithecus, lomorupithecus

Question 5

Describe Lomorupithecus.

Answer 5

1) Uganda
2) Miocene
3) About 19.5 million years ago
4) They have a mid-nasal premaxilla-maxilla structure (primitive condition)
5) Projecting nasals (not hominoid)

Stem catarrhine

Question 6

How does the premaxilla-maxilla structure differ in apes and old world monkeys?

Answer 6

In apes it hits the nasal bone.

In old world monkeys it hits the frontal bone.

Question 7

Describe Pliopithecus.

Answer 7

1) Europe
2) Middle Miocene (16-9 mya)
3) About 10kg
4) 2 premolars
5) Has a lingual cingulum
6) Incomplete tubular ectotympanic (could be a morphocline)
7) Entepicondylar foramen present

Question 8

Describe Laccopithecus.

Answer 8

1) Late Miocene in China
2) 12kg
3) Similar teeth to Pliopithecus
4) Dimorphic canines (polygynous)
5) Small orbits = diurnal
6) Low, rounded cusps = primarily frugivorous (supplementing diet with leaves due to large size)

Question 9

Describe Saadanius hijazensis.

Answer 9

1) Late Oligocene, Saudi Arabia
2) 29-28 mya
3) 15-20kg
4) Tubular ectotympanic present
5) two premolars

Question 10

Give an example of a morphocline.

Answer 10

Ectotympanics:

1) Ring-like (Aegyptopithecus)
2) Partial tubular (Pliopithecus)

3) Complete tubular
(Saadanius)

Question 11

Describe the teeth of cercopithecoids.

Answer 11

Cercopithecoids have crests on both sides of the teeth. These crests form the slicing actions. They have lost the back cusp (hypoconulid) on M1 and M2, on the third molar they have a big hypoconulid. They have a derived dentition.

Question 12

Describe the postcrania of cercopithecoids.

Answer 12

Cerco retain the monkey-like body. Primitive postcrania. They have longer legs for leaping. They have a tail. Intermembral index below 100.
They have a few charactersistics of postcrania that seem a bit derived; joint of limbs seem to be narrow (subtle one).

Question 13

Describe postcrania of hominoids.

Answer 13

Homonoids have an intermembral index above 100, so their arms on average are longer than their legs (for hanging from branches). Shape of bones different so that they can hold their arms above their heads. They have lost their tails.

Question 14

Describe Victoriapithecus

Answer 14

1) Early Miocene, Kenya, Libya, Uganda and Egypt
2) 7-25kg
3) Partial bilophodonty
4) Facial morphology resembles cercopithecines

Question 15

Explain possible morphoclines in Victoriapithecus.

Answer 15

1) Has partial or lost crista oblique (variable in this animal) This is a morphocline because there is no crista obliqua in extant cercopithecoids
2) The presence of the hypoconulid is variable in Victoriapithecus and they aren’t present at all in extant cercopithecoids
3) Cusps go from middle to the side and Victoriapithecus appears to be pretty much half way between these conditions
4) Victoriapithecus has lost the maxillary sinus

Stem cercopithecoid

Question 16

Hominoids have retained the condition of having ____________ _______ but cercopithecoids have lost it (which is a derived characteristic)

Answer 16

Hominoids have retained condition of having maxillary sinus but cercopithecoids have lost it (which is a derived characteristic).

Macaques have maxillary sinuses but it looks like they have regained them (lost and then regained).

Question 17

Describe the brains of Victoriapithecus.

Answer 17

1) brain = 35.6 cc
2) brain is smaller than in extant catarrhines (also seen in Aegyptopithecus)
3) Olfactory bulb similar to to extant streps (again also seen in Aegyptopithecus) Ancestral condition.

Question 18

Describe Theropithecus.

Answer 18

1) Plio-Pleistocene; Africa and India
2) Open environments
3) Widespread
4) They were terrestrial. Lots of OW monkeys are at least partially terrestrial. Not seen in NW monkeys.
5) Larger than extant species (could be due to Pleistocene megafauna extinction)
6) No maxillary sinuses

Question 19

Describe Libypithecus

Answer 19

1) Late Miocene, Egypt
2) Colobine teeth
3) Considered stem colobine
4) face resembles cercopithecines and Victoriapithecus (longer snout and narrow interorbital septum like cercopithecoids whereas colobines have a wide interorbital septum).

Question 20

Describe Mesopithecus

Answer 20

1) Late Miocene-Pliocene, Europe

2) Partially terrestrial (short thumb and phalanges)

Question 21

Almost all forms of extinct colobines were _____ but extant forms are ________.

Answer 21

Almost all of the extinct colobines are terrestrial but extant forms are arboreal.

Question 22

Why were extinct colobines a lot bigger than extant colobines?

Answer 22

They didn’t live in the rainforest. If you live in the open you get bigger to protect you from predation.