Daily Bulletin


The Conversation

  • Written by The Conversation
imageArtistic reconstruction of two Tiarajudens males during combat in the Permian of southern Brazil.Supplied

New evidence has been provided confirming previous compelling geological findings that today’s continents were once linked in one giant land mass. The evidence has come through the discovery that two fossils, one from South Africa and the other from Brazil, were cousins.

The discovery of a Brazilian plant-eating herbivore fossil in 2008 prompted a restudy of the South African cousin of the same size and with a remarkably similar skull discovered 10 years earlier. These two species from Gondwana – the ancient super continent formed by now separated southern continents such as Africa and South America – show features in their skull and teeth that indicate they were closely related.

Close examination of the two skulls, identified as four-legged or tetrapod animals that date back to a time before dinosaurs existed, revealed two further astonishing facts. The first is that 270 million years ago they were already capable of chewing their food like modern ruminants such as cattle, sheep, goats and deer.

The fossils, which date from what is known as the Middle Permian period, also show that the plant-eating tetrapods had developed two specialisations that they used in combat – a feature typical of today’s cows and deer.

And the most fascinating aspect of all is that these not too distant cousins were found more than 8000 kilometres apart on different modern day continents.

imageThe skulls of Anomocephalus africanus (left) and Tiarajudens eccentricus (right).Supplied.

The deers of yesteryear

Living mammals have a rich history documented by fossils going back 300 million years. Ancestral lineages of mammals were included in a group known as therapsids that flourished during the Permian, which predated the age of dinosaurs, and are exquisitely documented in the Karoo Basin of South Africa.

Plant-eating animals are now far more diverse and abundant than carnivores, a trend that began during the Permian. A particular group called anomodonts can best be described as the “Permian deers”. Besides being plant-eating and the most abundant lineage of the Permian, anomodonts were extremely variable in size. They were also very different in their shapes, particularly the earliest members of the group.

The Brazilian fossil had some unexpected features for a herbivore. Three stand out. The first is that it had occluding teeth that allowed them to chew, or masticate, food – a feature that is a landmark of today’s mammals.

The second is that it had a long outsized blade-like canine (~120 mm long). This shows, for the first time, the presence of saber-tooth in herbivores mammals around 270 million years ago. Saber teeth are found in some great carnivores from the past such as the gorgonopsians or the Smilodon sabre-toothed cat, and other Ice Age cats.

imageThe skull of the Asian water-deer Hydropotes inermis.Provided.

But carnivores do not need to chew their food, so that the Brazilian anomodont had several occluding teeth proved that it was a dedicated herbivore after all.

But the surprises did not end there. Tiarajudens eccentricus, the Brazilian species, show teeth that are commonly located at the margin of the mouth, positioned on a bone of the palate. The novelty is that no other therapsid was known to possess teeth in this bone. In fact no other therapsids are known to have complex, molar-like teeth (molariforms) in the roof of their mouths.

After additional cleaning of the bones of the fossil found in South Africa, called Anomocephalus africanus, it was found it also had molariforms in the palate, identical to those of Tiarajudens. The South African fossil has a complete mandible and its teeth are in contact with the palate, confirming the occlusion between upper and lower teeth. The only apparent difference between the two fossils is the absence of blade-like canines in the African species.

The skull of these cousins are nearly the same size – between 210 and 220 mm. They show a domed profile with a very short snout, large orbits, and temporal opening for chewing muscles about the same size or slightly larger than the eye socket.

The long canine in the Brazilian species is represented in a few living deer such as the Asian water-deer, musk-deer, and muntjacs. In all these cases the enlarged canines are used in male-male visual displays during fighting. The long canine in Tiarajudens eccentricus is being interpreted as an indication of its use in a similar way, representing the oldest evidence of use of canine in a herbivore for male-male fight.

Fernando Abdala receives funding from the National Research Foundation of South Africa.

Juan Carlos Cisneros receives funding from Conselho Nacional de Desenvolvimento Científico e Tecnológico of Brazil.

Authors: The Conversation

Read more http://theconversation.com/ancient-plant-eating-cousins-from-brazil-and-south-africa-are-reunited-43926

Writers Wanted

To learn at home, kids need more than just teaching materials. Their brain must also adapt to the context

arrow_forward

The Conversation
INTERWEBS DIGITAL AGENCY

Politics

Prime Minister's Remarks to Joint Party Room

PRIME MINISTER: Well, it is great to be back in the party room, the joint party room. It’s great to have everybody back here. It’s great to officially welcome Garth who joins us. Welcome, Garth...

Scott Morrison - avatar Scott Morrison

Prime Minister Interview with Ben Fordham, 2GB

BEN FORDHAM: Scott Morrison, good morning to you.    PRIME MINISTER: Good morning, Ben. How are you?    FORDHAM: Good. How many days have you got to go?   PRIME MINISTER: I've got another we...

Scott Morrison - avatar Scott Morrison

Prime Minister Interview with Kieran Gilbert, Sky News

KIERAN GILBERT: Kieran Gilbert here with you and the Prime Minister joins me. Prime Minister, thanks so much for your time.  PRIME MINISTER: G'day Kieran.  GILBERT: An assumption a vaccine is ...

Daily Bulletin - avatar Daily Bulletin

Business News

7 foolproof tips for bidding successfully at a property auction

Auctions can be beneficial for prospective buyers, as they are transparent and fair. If you reach the limit you are willing to pay, you can simply walk away. Another benefit of an auction is tha...

Dominique Grubisa - avatar Dominique Grubisa

Getting Ready to Code? These Popular and Easy Programming Languages Can Get You Started

According to HOLP (History Encyclopedia of Programing Languages), there are more than 8,000 programming languages, some dating as far back as the 18th century. Although there might be as many pr...

News Co - avatar News Co

Avoid These Mistakes When Changing up Your Executive Career

Switching up industries is a valid move at any stage in your career, even if you’re an executive. Doing so at this stage can be a lot more intimidating, however, and it can be quite difficult know...

News Co - avatar News Co



News Co Media Group

Content & Technology Connecting Global Audiences

More Information - Less Opinion