Early Anthropoids Lecture 4 Flashcards
Name four anthropoid cranial traits
1) Fused frontal bones
2) Taller face
3) Fused mandibulae
4) Complete postorbital closure
5) No paraconids
On the lower teeth, what have anthropoids lost that tarsiers still retain?
The paraconid.
Why do the upper molars of anthropoids tend to be quite square?
Due to the development of a big hypocone and loss of paraconid
The _______ and ______ are the same height in anthropoids.
The talonid and trigonid are the same height in anthropoids.
The lingual cingulum is a ______ condition.
Lingual cingulum (with cusps in middle of tooth) is a primitive condition Lost lingual cingulum with cusps nearer outside of tooth is derived.
Describe the fossil /Anthrasimias gujaratensis/.
1) Same stratigraphic level as omomyids and adapids
2) Found in Cambay Basin in India
3) Approx. 54-55 mya in early Eocene
4) Potentially earliest anthropoid primate
So splitting events between tarsiers, streps, haps and anthropoids have already happened.
So their common ancestors would be from further back but we don’t have the fossils.
However, due to it being so close to the split, it is unclear if it is related to anthropoids.
The closer you get to a _________ _______, the more similar the animals look so it’s difficult to tell if they’re different species.
The closer you get to a splitting event, the more similar the animals look so it’s difficult to tell if they’re different species.
Describe Eosimias.
1) From the Eocene
2) Found in China
3) Small
4) Anthropoid similarities
Name a difference between Eosimias and anthropoids.
The M3 talonid is much lower than the trigonid and it has a paraconid, unlike anthropoids (so if it is an anthropoid then it is a stem anthropoid)
What is a stem group?
It has some but not all of the characteristics of the crown group
Name a similarity between Eosimias and anthropoids.
They both have an indentation in the facet of the calcaneus.
Describe Proteopithecus.
1) Late Eocene
2) Found at site L41 in Fayum
3) Three premolars
4) Some similarities to platyrrhines
5) 500g
Describe Biretia.
1) Eocene
2) Fayum
3) Has really big orbits which suggests it was nocturnal, whereas most early anthropoids are diurnal.
What traits does Biretia share with anthropoids.
Biretia has square-shaped molars and have lost paraconid and talonid and trigonid are pretty much the same height, (anthropoid traits).
Describe Oligopithecines and name two of them.
Examples: Catopithecus and Oligopithecus
Traits:
1) Two premolars (synapomorphy with catarrhines? Can’t be catarrhine because they are crown anthropoids)
2) Has unfused mandibular symphysis (must be stem anthropoid)
3) Ectotympanic is ring-like and fused to the bulla like in platyrrhines
Why is the loss of the P2 not a synapomorphy of anthropoids?
It has happened convergently in lots of species
Describe Oligocene parapithecids and name two.
Parapithecus and Apidium are examples of Oligocene parapithecids.
Parapithecus had 3 premolars and no permanent incisors.
Apidium had 3 cusped upper premolars with 3 roots (anthropoids today have two roots)
Both have no paraconid and square looking molars.
Describe parapithecid postcrania.
Tibia and fibula are closely approximated (not fused but close together) so it must have been doing quite a lot of leaping.
What feature of Qatrania is anthropoid like?
Trigonid and talonid are the same height
Describe Siamopithecus.
1) Eocene
2) Typically anthropoid teeth
2) Low rounded cusps –> probably eating a lot of fruit
3) Much larger body size (6-7kg)
4) From Thailand
Name three anthropoid traits of Siamopithecus
1) Relatively short face (no snout)
2) Highly convergent and frontated orbits
3) Orbital rim lies well above the alveolar plane
List three non-anthropoid traits of Eosimias
1) Unfused mandibular symphysis
2) P2 is single rooted not double rooted like in extant anthropoids but other stem anthropoids have this condition (Beard et al., 1996)
3) No hypocones in upper molars and they have paraconids
List two anthropoid traits of Eosimias
1) Vertically implanted lower incisors
2) canine morphology similar to anthropoids
