The Metopic Suture of Taung

A recent article in PNAS looks at the metopic suture on the Taung endocast. Before discussing the article a few words are in order about the frontal bone.

Interesting Science Picture: Part VII

While we wait for the Science article with the South African hominins, I thought I would mention that other interesting finds have come from Sterkfontein.

Tuesday Paleopathology Blogging: Did STW 431 Have Brucellosis?

I’ve been meaning to mention this ever since the article was published in PLoS One.

Brucellosis is an infectious disease caused by any of several bacilli. It is primarily found in livestock such as cows, horses, pigs, and goats. It has also been found in wild animals such as zebra, eland, waterbuck, and impala. It is primarily transmitted to humans via infected dairy products and meat. In humans the disease appears as a chronic infection of the lungs and recurring fevers. Males are affected more than females. The primary center of skeletal involvement occurs in the spine. Ortner and Putschar define the lesion involved as follows:

The lesion is a lytic cavitation. Grossly and on X-ray, it frequently can be seen penetrating the vertebral end-plate and extending through the nucleus pulposus of the disc into the next vertebral body … The cancellous bone within the focus is destroyed without formation of significant sequestra. The cortex also may be perforated, leading to parosteal abscesses. There is usually very little, if any, reactive bone formation except in the healing phase … In contrast to tuberculosis, which it resembles in several ways, complete collapse of vertebrae with gibbus formation is usually not observed … and paravertebral abscess is rare …

What Did Australopithecus africanus Eat?

Hyenas are amazing animals. It takes a single hyena less than two minutes to consume an entire Thompson’s gazelle. A pack of 21 hyenas was able to polish off a 220 kg zebra and a 150 kg foal in about 30 minutes. An extinct species of borophagine dog (Borophagus) was probably able to accomplish similar feats as well. Borophagines, being descended from canids, retained post-carnassial molars. This pushed the carnassials forward in the jaw and they are located in the region of maximum bite force production and is what allowed them to crack bones efficiently using their carnassials (the carnassials are composed of a blade-like upper fourth premolar and a somewhat blade-like lower first molar). In hyenas, however, post-carnassial molars underwent a reduction and hyenas crack bones between their upper and lower third premolars not with the carnassials, which are behind the region of maximum bite.

Was Australopithecus africanus Hunted By Birds?

According to this story the answer is yes:

A South African anthropologist said Thursday his research into the death nearly 2 million years ago of an ape-man shows human ancestors were hunted by birds.
“These types of discoveries give us real insight into the past lives of these human ancestors, the world they lived in and the things they feared,” Lee Berger, a paleo-anthropologist at Johannesburg’s University of Witwatersrand, said as he presented his conclusions about a mystery that has been debated since the remains of the possible human ancestor known as the Taung child were discovered in 1924.

Apparently:

The Ohio State study determined that eagles would swoop down, pierce monkey skulls with their thumb-like back talons, then hover while their prey died before returning to tear at the skull. Examination of thousands of monkey remains produced a pattern of damage done by birds, including holes and ragged cuts in the shallow bones behind the eye sockets.
Berger went back to the Taung skull, and found traces of the ragged cuts behind the eye sockets. He said none of the researchers who had for decades been debating how the child died had noticed the eye socket damage before.

The study will be published in the AJPA…
My problem with the article is this:

The Taung child’s discovery led to the search for human origins in Africa, instead of in Asia or Europe as once theorized. Researchers regard the fossil of the ape-man, or australopethicus (this should be capitalized – afarensis) africanus, as evidence of the “missing link” in human evolution.

1) Australopithicus africanus is not an “ape-man” it’s a hominin.
2)”Missing link” is a term term used by creationists and scientific illiterates. It has not been used in anthropology in about fifty years…

Dental Microwear Analysis and Australopithecines

This is pretty cool.
Researchers examined several species of monkey teeth in order to determine the microwear patterns produced by a variety of different diets. They then turned their attention to the teeth of Australopithecus africanus and Paranthropus robustus:

The new study by Ungar, Brown, and colleagues suggests that, on average, A. africanus probably ate a greater share of soft and tough foods than P. robustus, which probably ate more hard and brittle foods.

The researchers found, however, that there was substantial overlap between the two species in their dental microwear, and presumably, in their diets.

Both species would probably have preferred to eat easy-to-consume, energy-rich foods, such as fruits, when they were available.

A similar phenomenon can be seen in modern chimpanzees and gorillas that live in the same geographical area. These so-called sympatric animals share food resources much of the year, but differ mostly during times of food scarcity.

At these times, gorillas fall back on tougher foods, such as leaves and stems, because their teeth and guts allow them to do so.

This study tends to confirm the idea that A. africanus and P. robustus were specializing in different diets – although not to the extent one would have thought. Seems like a good example of the competitive exclusion principle.