Research published in Royal Society journal Biology Letters reveals that scientists have uncovered what they believe to be the ‘youngest’ dinosaur fossil known to science.
Image: Royal Society
The fossil, found in the famous Hell’s Creek formation in the US, could help to settle one of the longest running controversies in modern palaeontology – were the dinosaurs wiped out suddenly by a catastrophic impact, or did they die out gradually over many centuries?
Most scientists agree that the evidence points towards there being a huge asteroid impact on Earth at the end of the Cretaceous period, a time referred to as the ‘Cretaceous-Tertiary’ (K-T) boundary. However, palaeontologists disagree as to whether it was this catastrophic impact that killed off the dinosaurs, or whether they were killed off gradually thousands of years before the impact.
So far, advocates of the gradual extinction theory have pointed towards an area directly beneath the K-T boundary which lacks fossils as evidence for a gradual extinction – this is the so-called “three metre gap”. However, the new fossil – a horn fragment belonging to a ceratopsian dinosaur like Triceratops – was found just 13cm under the K-T boundary, which suggests that in fact there were dinosaurs alive much later than previously thought, and lending support to the idea that it was the asteroid which killed off the dinosaurs.
Image: Wikipedia
The researchers stress that although their work lends support to the asteroid extinction theory, there is still a considerable area devoid of fossils in this region, and more fieldwork and analysis is required to settle the question once and for all.
Image: Wikipedia
Triceratops ( /traɪˈsɛrətɒps/ try-serr-ə-tops) is a genus of herbivorous ceratopsid dinosaur which lived during the late Maastrichtian stage of the Late Cretaceous Period, around 68 to 65 million years ago (Mya) in what is now North America. It was one of the last dinosaur genera to appear before the great Cretaceous–Tertiary extinction event.
Bearing a large bony frill and three horns on its large four-legged body, and conjuring similarities with the modern rhinoceros, Triceratops is one of the most recognizable of all dinosaurs and the best known ceratopsid. It shared the landscape with and was preyed upon by the fearsome Tyrannosaurus,[2] though it is less certain that the two did battle in the manner often depicted in traditional museum displays and popular images.
The exact placement of the Triceratops genus within the ceratopsid group has been debated by paleontologists. Two species, T. horridus and T. prorsus, are considered valid although many other species have been named. Recent research suggests that the contemporaneous Torosaurus, a ceratopsid long regarded as a separate genus, actually represents Triceratops in its mature form.
Image: Wikipedia
Triceratops has been documented by numerous remains collected since the genus was first described in 1889, including at least one complete individual skeleton. Paleontologist John Scannella observed: "It is hard to walk out into the Hell Creek Formation and not stumble upon a triceratops weathering out of a hillside." Forty-seven complete or partial skulls were discovered in just that area during the decade 2000–2010. Specimens representing life stages from hatchling to adult have been found.
The function of the frills and three distinctive facial horns has long inspired debate. Traditionally these have been viewed as defensive weapons against predators. More recent theories, noting the presence of blood vessels in the skull bones of ceratopsids, find it more probable that these features were primarily used in identification, courtship and dominance displays, much like the antlers and horns of modern reindeer, mountain goats, or rhinoceros beetles. The theory finds additional support if Torosaurus represents the mature form of Triceratops, as this would mean the frill also developed holes (fenestrae) as individuals reached maturity, rendering the structure more useful for display than defense.
Triceratops is the best known genus of the Ceratopsidae, a family of large North American horned dinosaurs. The exact location of Triceratops among the ceratopsians has been debated over the years. Confusion stemmed mainly from the combination of short, solid frills (similar to that of Centrosaurinae), and the long brow horns (more akin to Ceratopsinae, also known as Chasmosaurinae). In the first overview of horned dinosaurs, R. S. Lull hypothesized two lineages, one of Monoclonius and Centrosaurus leading to Triceratops, the other with Ceratops and Torosaurus, making Triceratops a centrosaurine as the group is understood today. Later revisions supported this view, formally describing the first, short-frilled group as Centrosaurinae (including Triceratops), and the second, long-frilled group as Chasmosaurinae.
Sources: Royal Society/Wikipedia
The fossil, found in the famous Hell’s Creek formation in the US, could help to settle one of the longest running controversies in modern palaeontology – were the dinosaurs wiped out suddenly by a catastrophic impact, or did they die out gradually over many centuries?
Most scientists agree that the evidence points towards there being a huge asteroid impact on Earth at the end of the Cretaceous period, a time referred to as the ‘Cretaceous-Tertiary’ (K-T) boundary. However, palaeontologists disagree as to whether it was this catastrophic impact that killed off the dinosaurs, or whether they were killed off gradually thousands of years before the impact.
So far, advocates of the gradual extinction theory have pointed towards an area directly beneath the K-T boundary which lacks fossils as evidence for a gradual extinction – this is the so-called “three metre gap”. However, the new fossil – a horn fragment belonging to a ceratopsian dinosaur like Triceratops – was found just 13cm under the K-T boundary, which suggests that in fact there were dinosaurs alive much later than previously thought, and lending support to the idea that it was the asteroid which killed off the dinosaurs.
Triceratops
The researchers stress that although their work lends support to the asteroid extinction theory, there is still a considerable area devoid of fossils in this region, and more fieldwork and analysis is required to settle the question once and for all.
Triceratops ( /traɪˈsɛrətɒps/ try-serr-ə-tops) is a genus of herbivorous ceratopsid dinosaur which lived during the late Maastrichtian stage of the Late Cretaceous Period, around 68 to 65 million years ago (Mya) in what is now North America. It was one of the last dinosaur genera to appear before the great Cretaceous–Tertiary extinction event.
Bearing a large bony frill and three horns on its large four-legged body, and conjuring similarities with the modern rhinoceros, Triceratops is one of the most recognizable of all dinosaurs and the best known ceratopsid. It shared the landscape with and was preyed upon by the fearsome Tyrannosaurus,[2] though it is less certain that the two did battle in the manner often depicted in traditional museum displays and popular images.
The exact placement of the Triceratops genus within the ceratopsid group has been debated by paleontologists. Two species, T. horridus and T. prorsus, are considered valid although many other species have been named. Recent research suggests that the contemporaneous Torosaurus, a ceratopsid long regarded as a separate genus, actually represents Triceratops in its mature form.
Triceratops has been documented by numerous remains collected since the genus was first described in 1889, including at least one complete individual skeleton. Paleontologist John Scannella observed: "It is hard to walk out into the Hell Creek Formation and not stumble upon a triceratops weathering out of a hillside." Forty-seven complete or partial skulls were discovered in just that area during the decade 2000–2010. Specimens representing life stages from hatchling to adult have been found.
The function of the frills and three distinctive facial horns has long inspired debate. Traditionally these have been viewed as defensive weapons against predators. More recent theories, noting the presence of blood vessels in the skull bones of ceratopsids, find it more probable that these features were primarily used in identification, courtship and dominance displays, much like the antlers and horns of modern reindeer, mountain goats, or rhinoceros beetles. The theory finds additional support if Torosaurus represents the mature form of Triceratops, as this would mean the frill also developed holes (fenestrae) as individuals reached maturity, rendering the structure more useful for display than defense.
Triceratops is the best known genus of the Ceratopsidae, a family of large North American horned dinosaurs. The exact location of Triceratops among the ceratopsians has been debated over the years. Confusion stemmed mainly from the combination of short, solid frills (similar to that of Centrosaurinae), and the long brow horns (more akin to Ceratopsinae, also known as Chasmosaurinae). In the first overview of horned dinosaurs, R. S. Lull hypothesized two lineages, one of Monoclonius and Centrosaurus leading to Triceratops, the other with Ceratops and Torosaurus, making Triceratops a centrosaurine as the group is understood today. Later revisions supported this view, formally describing the first, short-frilled group as Centrosaurinae (including Triceratops), and the second, long-frilled group as Chasmosaurinae.
Sources: Royal Society/Wikipedia
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