The findings have been published in the prestigious peer-reviewed journal Nature Communications.
“The study explores the idea that evolution within the group called ‘snakes’ is much more complex than previously thought,” says lead author and professor Michael Caldwell in the Faculty of Science at the University of Alberta. “Importantly, there is now a significant knowledge gap to be bridged by future research as no fossils snakes are known from between 140 to 100 million years ago.”
The oldest known snake, from Southern England, near Kirtlington, Eophis underwoodi, is known only from very fragmentary remains and was a small individual, though it is hard to say how old it was at the time it died. The largest snake, Portugalophis lignites, from coal deposits in Portugal, near Guimarota, was a much bigger individual at nearly a meter or more in length. Several of these ancient snakes (Eophis, Portugalophis and Parviraptor) were living in swampy coastal areas on large island chains in western parts of ancient Europe, while the North American species, Diablophis gilmorei, is found in river deposits from some distance inland in Western Colorado.
This new study makes it clear that the sudden appearance of snakes, some 100 million years ago, reflects a gap in the fossil record, not an explosive radiation of early snakes. From 167 to 100 million years ago, some 70 million years, snakes were radiating and evolving towards the elongate, limb-reduced body plan characterizing the now well known, ~100-90 million year old, marine snakes from the West Bank, Lebanon, and Argentina, that still possess small but well developed rear limbs. As is always the case, the distribution of these newer oldest snakes, and the anatomy of the skull and skeletal elements, makes it clear that even older snake fossils are waiting to be found.
“Based on the new evidence and through comparison to living legless lizards that are not snakes,” explains Caldwell, “the paper explores the novel idea that the evolution of the characteristic snake skull and its parts appeared long before snakes lost their legs.”
He adds that the identification of definitive snake skull features reveals that the fossils, previously associated with other non-snake lizard remains, represents a much earlier time frame for the first appearance of snakes. The concept of how snakes originated and evolved needs to be reassessed in light of this new information, and the unique ideas presented in this paper.
This tattoo is very difficult to make out with the naked eye because his skin has darkened so much over time. The latest sophisticated photographic technology has now enabled tattoos in deeper skin layers to be identified as well.
Oetzi’s discoverers had already noticed his tattoos on the very day they found him, 19th September 1991. Various studies since then have investigated and itemised these skin marks. But now, using a technique which he developed himself, Marco Samadelli, a scientist at the EURAC-Institute for Mummies and the Iceman, has carried out a complete mapping of all the tattoos on the man from the glacier. They are amongst the oldest documented tattoos in the world.
Samadelli photographed the mummy’s body from different angles using a multi-spectral procedure which covered the whole range of wavelengths from infrared to ultraviolet. This allowed tattoos deep in the skin layers and which are no longer recognisable to the human eye to be shown up with great precision. The 61 discovered skin markings on Oetzi’s body consist of lines from 0.7 to 4 centimetres in length, mostly arranged in groups of two, three or four parallel lines, and also include two crosses.
The newly discovered tattoos on the lower right-hand side of the ribcage are striking, because the other markings are mostly found on his lower back and the legs between the knee and the foot. On account of the various locations of the tattoos, some researchers suspected that the marks were part of some therapeutic medical treatment, a kind of acupuncture to relieve pain in the joints. The newly discovered tattoos on the ribcage have now reopened the debate about the role of tattoos in prehistoric times. This investigation has given researchers a new piece to add to the jigsaw puzzle when trying to tease out whether prehistoric tattoos had a therapeutic, symbolic or religious significance.
The multi-spectral photographs were shot in the mummy’s specially refrigerated ‘cell’ in the South Tyrol Museum of Archaeology. “Each shot was taken seven times, using a different wavelength each time. This enabled us to cover the different depths at which the carbon powder used for the tattoos had been deposited. The ultraviolet waves were adequate for the upper skin layers, whilst we resorted to infrared light for the lower layers,” explains Marco Samadelli.
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