Genome Biology, can be found online at www.oxfordjournals.org]]>
PLOS ONE. Despite living many thousands of miles away from each other, both South American and India gavialoids developed the same distinctive widely separated and protruding eyes. It is a mystery that has puzzled scientists for years, complicated by the fact that the fossil record for crocodylian evolution is far from complete. By analysing the fossilised remains of an extinct, 13 million year old crocodilian from the Amazon known as Gryposuchus pachakamue, the authors of the study believe they have solved the mystery surrounding the evolution of the Indian and South American gavialoids. Their conclusion is that the shared features were the result of parallel evolution. The study was performed by Rodolfo Salas-Gismondi from the University de Montpellier, France, with the assistance of his colleagues John J. Flynn, Patrice Baby, Julia V. Tejada-Lara, Julien Claude and Pierre-Olivier Antoine. Gavialoids are a diverse group of long snouted crocodilian species. Most members of the group have long since gone extinct, with the exception of Gavialis gangeticus, an Indian gharial which inhabits the northern river systems of the sub-continent and feasts on fish. Remains of the Gryposuchus pachakamue were excavated from a region of the Amazon in Peru. Salas-Gismondi’s team named the creature after Pachakamue, a Pre-Columbian storyteller god thought to have held secrets about the origins of life in South America. The name has proven surprisingly appropriate considering the insights the remains have revealed. Gryphosuchus pachakamue lived during the Middle Miocene, and is the oldest known South American gavialoid. The remains used in the study were found in the Pebas Formation, a region dominated by swampy waterways during the time the creature was alive, a fact which suggests G.pachakamue was a river dweller like later gavialoids. Significantly, the creature had telescoped eyes, although only slightly. After phylogenetic and morphometric analysis of the ‘storyteller’ crocodile, the team concluded it was the ancestor from which other South American gavialoids evolved their telescopic eyes. Significantly, this shows that the South American crocodiles developed their distinctive eyes in parallel with the Indian species. Such parallel evolution of course has precedent, most explicitly in the development of mammals on the earth’s different continents, which often evolved remarkably similar characteristics despite living thousands of miles from each other. It is a process which can clearly be seen in the likes of the European and the Tasmaninan wolf; and the European sabre-toothed tiger and the South American marsupial sabre-tooth. This parallel evolution is usually the result of creatures from similar lineages responding to similar challenges in similar ways. In the case of the gavialoids, it seems the progression to river dwelling necessitated their distinctive eyes, likely allowing them to hunt fish more effectively in these habitats. For more information: www.plos.org Image courtesy of D. De Francesci]]>
Ancient Nasca World: New Insights from Science and Archaeology. ]]>
Archaeology in Bulgaria website. Sexaginta Prista, which translates to “port of the sixty ships” in Latin, was a major city within Moesia Inferior, the Late Antiquity province that bordered on so-called “barbarian” regions along the Lower Danube. The fortress city itself was one of several frontier fortifications known as the Limes Moesiae, designed to keep these barbarian forces at bay; the 20-meter long fragment of wall most recently discovered, which would have been part of the southern wall of the ancient Roman city, has been dated back to the fourth century CE. The importance of the find was reinforced in a press release from the museum. The museum stated that the remarkably high levels of preservation had made it possible to compare the Sexaginta Prista fortification system to other cities in the surrounding regions over the past several years. These other finds include the ancient Roman cities of Trimamium and Iatrus, the museum added. In addition to the wall – an invaluable find in and of itself – museum archaeologists also found coins and ceramic vessels that span the centuries between Late Antiquity and the eleventh century CE, otherwise known as the Early Middle Ages. Discoveries include coins from the Early Byzantine and Late Roman periods as well as later pottery fragments that have been dated to well after the transformation of Sexanginta Prista to the settlement that would one day become known as Ruse. Additionally, evidence of coins dating to the fifteenth through the nineteenth centuries, the time of the Ottoman Empire, have also been discovered. All told, some 300 coins, all from varying historical periods, have been excavated during the effort to study the ancient Roman wall fragment. Meanwhile, the dig itself was a historic event. The rescue excavations were noteworthy in that they marked the first time in the history of Ruse that an archaeological dig had occurred on private property. At the same time, the Roman roots of the Bulgarian city aren’t even the true beginning of the story of Ruse. Sexaginta Prista itself, which existed in the northwestern region of modern Ruse alongside the Danube, was erected on the ruins of an ancient Thracian settlement thought to date back to as early as the third century BCE. ]]>
Homo genus. “Over the last four million years, brain size and body size increased substantially in our human ancestors,” Mark Grabowski with the American Museum of Natural History and author of the paper is quoted as saying in a press release from the museum, “This observation has led to numerous hypotheses attempting to explain why observed changes occurred, but these typically make the assumption that brain and body size evolution are the products of separate natural selection forces.” That’s the very assumption now being questioned. There is significant evidence showing that the genetic variations (evolution’s kick starter) in some traits are a result of genes which are also causing simultaneous variations in other traits – leading to the conclusion that the natural selection experienced by either trait causes a correlated response in the unselected trait. For example, consider an elephant’s leg bone; as the bone grows longer, it also grows wider. If you used artificial selection to produce an elephant that was tall, it’s likely the elephant’s legs would also get wider as they get longer. This effect, in part, is because of shared genetic variations (co variations) among the traits of the leg bone. Likewise, researchers set out to investigate this type of genetic relationship between a human’s brain size and their body size and its impact, if any, on our evolution. Using the patterns of brain-size and body-size covariations from an assortment of modern humans and primates, researchers created several different models to examine exactly how these underlying genetic interactions and their associated selection pressures affected the evolution of our lineage. For the first time the findings demonstrate that the strong selection pressure to increase only brain size had a significant role in increasing body size at the same time, throughout our evolution. The phenomenon alone may also have been responsible for a major increase that occurred in both traits when our human ancestors (like Australopithecus) transitioned to Homo erectus. Selection undoubtedly played a role in fine tuning the physical changes inherent to bigger body size, this research suggests however, it was not the driving force and evolutionary models pertaining to Homo origins should be reconsidered. To put it another way, all of the scientific ideas and research done to explain why, over time, humans evolved bigger bodies may be moot; body size simply got pulled along with brain size. The work was published in the journal Current Anthropology.]]>
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Did Neanderthals Brush Their Teeth?
Antiquity, has discovered evidence of non-edible material in Neanderthal teeth. It is a remarkable find, one which opens up a host of possibilities concerning what Neanderthals did with their teeth: did they use their mouths as a third hand, or are the non-edible materials evidence that Neanderthals were concerned with dental hygiene? Most estimates suggest that Neanderthals first came on the scene between 300,000 and 250,000 years ago. By around 32,000 years ago they had been rendered completely extinct. They are often portrayed as being less intelligent, and uncivilised when compared to humans, however, new studies, including this latest one by Anita Radinia, Stephen Buckleya, Antonio Rosasa, Almudena Estalrricha, Marco de la Rasillaa and Karen Hardy; are increasingly bringing this assumption into question. For their research, the team led by Hardy from the Catalan Institution for Research and Advanced Studies extracted chemical compounds and micro fossils embedded in the teeth of Neanderthals from the 49,000 year old El Sidrón site in Spain. It was a unique approach to the still relatively new use of dental calculus (tartar) in archaeological study. Dental calculus is a hard substance that builds up on a creature’s teeth when they are not cleaned properly. For a long time archaeologists considered it nothing more than a waste product, and scrubbed it off of fossils. Over the last decade however, it’s been realised calculus actually contains a wealth of information, particularly when it comes to diet reconstruction of ancient populations. Hardy’s team discovered traces of conifer wood from a non-edible part of the trees in the molar of one adult Neanderthal. According to the study, the substance with no nutritional value could not have been confused with an edible part of a conifer – meaning it’s presence was certainly not connected to the Neanderthal’s diet. The study, published in the April edition of Antiquity, points out that associated dental wear suggests the teeth were being used for non-dietary functions, supporting the idea the piece of conifer had become embedded in the molar because the animal was using its mouth as a third hand. However, there are several other possible explanations. A study from 2013 revealed evidence from a 1.8 million year old Homo Erectus fossil discovered in Georgia that the creature had used something resembling a tooth pick to clean its teeth. Another study published earlier this year in the Journal of Human Evolution suggested that Neanderthals had healthier teeth than modern human hunter gatherers, a result of them cleaning their teeth. Taking these two studies into consideration, the piece of conifer wood in the El Sidrón Neanderthal’s teeth could have been linked to dental hygiene. Hardy et al’s study shows that a wealth of new insights into the lives of Neanderthals and ancient humans can be gained by studying dental calculus. The ambiguity surrounding their discovery serves as a reminder of just how much there is to learn about how our extinct cousins lived. For more information: journals.cambridge.org Image courtesy of Wikimedia Commons user: Rept0n1x]]>
American Association of Physical Anthropologists, researchers presented the results of their ongoing examination and testing of the girl’s remains and the objects found buried with her. The incomplete and poorly preserved skeletal remains belong to a young woman determined to have been between 17 and 25 years old (radiocarbon testing of the fabric and tooth show she was born around the year 900 CE and the time of her death was sometime around the year 920 CE). Based on the chemical analysis of one of her teeth, the Woman in Blue moved from the British Isles or Scandinavia to Iceland when she was between five and ten years old, a fact indicated by her change in diet from mostly land animals and plants to one that included a large amount of seafood and fish. It’s unclear if the young woman was a Viking or Northern European, although she was dressed in traditional Viking garb which had been made with Icelandic wool and dyed blue using herbs that were probably brought to Iceland from abroad. The indigo blue plant-based dye is typical of female Viking garments. Buried along with her were an extravagant pearl necklace and two oval Scandinavian brooches made with a copper alloy. Amazingly, a piece of her skin had been preserved underneath one of the Scandinavian brooches which had been pressed against the young woman’s body at the time of her burial. The skin has allowed researchers to determine, among other things, her age and origin. Iceland’s history starts with Viking explorers (and their slaves) settling there in the ninth century – Iceland remained uninhabited even after western Europe had long-been settled. These first permanent settlers and the vast majority of the settlers (but not all) who arrived in Iceland over the following decades were Norwegian. The traditional story for this Norwegian exodus is that it was instigated by people escaping the overly strict rule of then Norwegian king Haraldr Hárfagri (Harold the Fair-haired). Alternatively, people may have simply been leaving Norway because of overcrowding in the western fjords. Seagoing Vikings from Norway, Denmark, and Sweden arrived and settled in several different countries, Iceland being one of them between the year 700 CE and the year 1100 CE, supporting the possibility the “Woman in Blue” came with the Vikings to Iceland. Skin and bone remains from the Woman in Blue were inadvertently stained green by the preservation solution used in the jars they were stored in. These items were transferred recently into jars containing a light paraffin oil in order to maintain their preserved state without staining them further. DNA from the young women is currently being studied by a team of researchers led by Joe and Jakob Walser, both with the University of Iceland in Reykjavik.]]>