How humans colonized the megacontinent of Sahul. What, sir, was in the head of a spinosaurus? Migration of mosquitoes to completely new territories occurs three times faster than previously thought

How humans colonized the megacontinent of Sahul

If you didn’t know what Sahul was, we’ll explain. Sahul was a megacontinent, also known as Meganesia, that existed about 8,000 years ago and included the territories of Australia, Tasmania, New Guinea, as well as the Aru Islands in eastern Indonesia. The problem with this is that, although it has been inhabited for a very long time, no one knows exactly how it happened.

Using a new and extremely interesting approach, several researchers at Flinders University in Australia say they have finally learned how colonization happened and, more importantly, for how long. To do this, they used maps that reproduce the topography of the megacontinent, divided them into zones like a chessboard, and then calculated the best routes that people could take.

Throughout this equation, they also relied on archaeological discoveries, as well as palynological and topographical studies, which showed the ability of certain areas to provide food or sources of drinking water to those early pioneers. Thus, they would identify, at least, a completely unknown route of Homo sapiens in those times.

In short, around 75,000 to 50,000 years ago, the first humans made their way to Sahul, a wave of migration that began in the Timor region. Here he puts us a bit of a comma, given that, also according to relatively recent data, Homo sapiens only left Africa about 60,000 years ago. But, quite likely, the Out of Africa 2 hypothesis still needs some corrections.

Going back to the model proposed by the Australian researchers, New Guinea would have been the first to be settled, followed by Australia, while Tasmania would have been occupied about 10,000 years after people had already settled in Sahul. This whole process would take about ten thousand years, twice as long as a study last year claimed.

Now, in all this research, the first thing that was interesting was the method of approach. One that has not been used before and which, when extrapolated to other continents, can lead to surprising results. Also, it could explain why Australia was colonized millennia before Europe, given the much greater distance between it and Africa. Or like I said, maybe it will at least help us fix the Out of Africa 2 hypothesis.

What, sir, was in the head of a spinosaurus?

As a rule, in the absence of an accident, the head of a spinosaurus contained its brain. The problem is that none of the fossils found in northern Africa (through Egypt, Tunisia or Morocco) have left us any cranial remains that would allow us to form a clear picture of what was going on in his head.

To overcome this shortcoming, an international team of paleontologists focused on two Spinosaurus relatives discovered in England that preserved the cranial features that would allow us to study the brains of these dinosaurs. These are Baryonyx and Ceratosaurus, dinosaurs that lived before Spinosaurus, but which have morphological features found in them, namely an elongated crocodile-shaped skull, which means that they had similar behavior in a semi-aquatic environment.

The aforementioned researchers were able to reconstruct the brains of two dinosaurs on the basis of fossils for the first time and thus find out how they worked. Please, what they found out doesn’t really set us back. Namely, that the olfactory bulbs were not very developed, so they did not differ in smell, as well as vision. The fact that it might have features that indicate adaptation to semi-aquatic life was not reflected in the simulations. In fact, they had the same brain as other predatory dinosaurs that hunted exclusively on land.

Now these researchers did not work in vain either. From their results, we can conclude that there was no need to adapt the brain to a new living environment. Most likely, semi-aquatic life somehow did not affect the evolution of the brain. Simply put, only morphological adaptations were needed. In particular, the elongated skull and snout are much more prominent in the case of Spinosaurus, a possible evolutionary descendant of Baryonyx and Ceratosaurus.

Migration of mosquitoes to completely new territories occurs three times faster than previously thought

Based on data obtained over the past 120 years, biologists from Georgetown University, USA, were able to calculate the rate at which Anopheles mosquitoes, carriers of malaria, are colonizing areas where they were previously absent. And the results of the study, which they published in Biology Letters, are not encouraging at all.

According to American researchers, mosquitoes in the sub-Saharan region moved south about 4.7 kilometers per year, while in mountainous areas they rose about 6.5 meters annually. Initial estimates from 12 years ago showed that with global warming of 1.2 degrees Celsius, they would advance 1.1 kilometers per year, but rise no more than 1.1 meters per year over the same time period.

Most likely, other species also migrate at the same rate, but mosquitoes that carry the parasite that causes malaria are the most dangerous, given the danger they pose to the population.

Meanwhile, authorities in Singapore have begun a program in which they release more than 5 million mosquitoes into the wild each week artificially infected with Wolbachia, a bacteria that blocks the development of eggs. However, it is difficult to believe that African states will be able to implement such a program.

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