Fossil Afrotheria

Proboscidea

Fossil members of the Proboscidea and Tubulidentata are discussed here in detail

 

Order: Proboscidea

The earliest known member of the Proboscidea is a primitive elephant called Phosphatherium. It was a dwarf elephant in comparison with the 3 species that survive today, weighing only 15 kg and measuring 60 cm high at the shoulder. The Proboscidea appeared in the Paleocene, between 65 and 53 mya. Later species increased in size and diversity, evolving straight column-like legs and a variety of tusks in their upper and lower jaws, plus an elongated snout that led to the trunk.

Moeritherium is also one of the most primitive elephants. It occupied Africa throughout the Eocene where it inhabited lakes and rivers, similar to the modern hippopotamus. The skull indicates that it had an enlarged snout, but it cannot be certain whether this developed into an actual trunk based purely on fossil material. Its body was bulky, with short legs that had not yet developed into the more column-like leg structure of modern elephants. Although the incisors were enlarged to form tusks, they were so small that they barely protruded from the mouth.

A later of primitive proboscideans called the Phomia roamed northern Africa during the Oligocene (33.7-23.5 mya). They were larger than Moeritherium with larger more prominent tusks and a longer snout, or short trunk. They were about the size of a modern horse, with a shorter neck and a bigger skull than modern elephants. Later still, were a group called the gomphotheres. This group were almost world wide throughout the Miocene and Pliocene (23.5-1.75 mya) where they inhabited marshes, grasslands and forests. Species such as Gomphotherium was around the same size as the modern Asian elephant and unlike its predecessors, had a long trunk and large tusks in both their top and lower jaws, thought to be used for fighting and display. As with modern elephants, the tusks were larger in males than females.

Mammoths are the most widely known prehistoric proboscideans and lived from the Pleistocene to around 4000 years ago. There were eight species, including both the largest proboscideans to have ever lived. The smallest mammoths were a dwarf species that were actually the last group of mammoths to become extinct, on Wrangel Island north of Siberia. Mammoth DNA discovered in 1994 has proved that they were almost identical to living elephant species. The woolly mammoth (Mammuthus primigenius) inhabited the freezing grasslands of the Ice Age and thus had thick shaggy coats. Frozen mammoths have been found on which the hair measured up to 90 cm in length. Apart from their woolly coat, mammoths differ from modern elephants in that they had a large domed skull that developed in adolescence, huge, curving tusks and very short tails, probably due to vulnerability to frost bite. Similar to African elephant species, both male and female mammoths had tusks, thought to be used for defence, fighting for dominance, display and for gathering food.


Mammoth tusk Mammoth molar
Bristol University Museum, UK Bristol University Museum, UK

(Click on the images above to larger pictures)

 


Mammoth tusk
Bristol University Museum, UK

 

 

Example species:

Primitive elephant
Moeritherium

Length: 3 m
Region: Northern Africa
Time: Eocene and Oligocene (53-23.5 mya)
Status: Extinct

 

Primitive elephant
Platybelodon

Height: 3 m at the shoulder
Region: North America, Africa, Asia and Europe
Time: Miocene and Pliocene (23.5-1.75 mya)
Status: Extinct

 

Mammoth
Mammuthus primigenius

Height: 3.3 m at the shoulder
Region: North America, Europe and Asia
Time: Pleistocene (1.75 mya to 4 kya)
Status: Extinct

 

 

Order: Tubulidentata

Ectoconus ahs been proposed by some as the ancestor of the aardvark, despite it looking morphologically very different. Ectoconus was approximately the same size and weight as the modern aardvark and had the same curved spine. However, skeletal remains do not show that Ectoconus had neither the elongated snout nor large powerful claws for digging, both of which are characteristics of the aardvark.

 

Example species:

Aardvark
Ectonus

Length: 1.5 m
Region: North America and possibly Asia
Time: Tertiary (65-1.75 mya)
Status: Extinct


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Author: Emma-Louise Nicholls
Last updated: 20th November 2005
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Websites produced by students on the MSc Palaeobiology programme in the Department of Earth Sciences at the University of Bristol for academic year 2005-6