Every ordinary life will leave extraordinary traces in the world.
An epitaph, a relic, a skeleton or even even a tooth... It seems to be small, but under the CT scan of archaeologists, it can deduce the trivia of the owner's life, which is ordinary and vigorous.
So, as a former overlord of the earth, what traces did the dinosaurs leave behind, so that we can know the bits and pieces of its life?
Of course. There is a special classification of dinosaur fossils called "trace fossils", such as dinosaur footprints, feces, nests, etc. However, although trace fossils are common, they are generally not found at the same time as those eye-catching physical fossils (that is, large dinosaur bones), like scattered unsigned dinosaur suicide notes.
Of course, rare is rare, in the 160 million years of time, dinosaurs still have some traces of fossils and physical fossils buried together. These precious materials for paleontologists to "gossip" about the life history of dinosaurs reveal a vivid and lively other side of dinosaur life for us - perhaps different from the "big guys" in your mind!
Could a TidalAposaurus be a good parent to take care of your baby?
The first to appear is a dinosaur that can dig holes. Their trace fossils come from the late Cretaceous strata of Montana, USA, and are buried about 95 million years ago.
This dinosaur, named oryctodromeus, meaning "digging runner", was a small ornithopod dinosaur that belonged taxonomically to the family Diplodontidae. It was the first dinosaur in history to be shown to be capable of digging holes, as evidenced by its fortified foreak, enlarged shoulder blades, and robust pelvis,[1] a special body structure that exhibited the characteristics of "burrowing". At the same time, it retains sensitive hind limbs, which helps to move quickly or rely on the support of the hind limbs to push up the forelimbs and burrow the snout.
What does the hole dug by the Dragon Look like? Look like this --
Dig the Dragon's Cave | References[1]
As can be seen from the above figure, the sediment filled in the cave and the surrounding rock texture are significantly different, so it can clearly reflect the appearance of the cave. Scientists have noticed that in addition to bending, the cave also has some small branches and exquisite and complex structures.
In this case, the cave dug by the dragon eventually became his own burial place. In the cave, scientists found not only sedimentary fillings, but also skeletal fossils of dipterosaurs, including an adult dinosaur and two juvenile dinosaurs. This shows that in addition to digging holes, the digging dragon may also be a good parent, will protect the young children in the family, and the digging of holes may also be a means of caring for the offspring of the digging dragon, because the cave can help avoid predators. In addition, caves are good for maintaining temperatures and are a good way to adapt to extreme environments such as polar, desert or high mountains.
Excavation Dragon Life Scene Restoration Diagram | dinosaurpictures.org
Oviraptorosaurus: Is it a moral degeneration, or a testimony of maternal love?
The second type of trace fossil we are going to talk about involves a historical injustice.
In 1923, explorer Roy Chapman Andrews discovered a litter of dinosaur eggs in the Gobi Desert. Because there were many protoceras fossils around the time, he mistook the nest for a protoceratops' child, and regarded one of the theropod dinosaurs in the nest as an egg stealer, and named it oviraptor.
Later, more high-precision studies analyzed the embryonic morphology in the eggshell and found that they were not protoceratops, but juvenile oviraptorosaurs. Now we know that the egg thief dragon is not a thief, but the real parent of the nest of eggs [3,4]. Unfortunately, subject to international naming conventions, it is difficult to change the name unless the original namer actively errata, and the original namer is long gone. Therefore, the stigma of the thief who stole the egg dragon is afraid that it cannot be changed, which can really be described as the most wronged dinosaur.
Fossil oviraptorosaurs hatching eggs | References[3]
By the way, this specimen is also a classic case of the coexistence of trace fossils and solid fossils. But what few people know is that the nest of eggs of the oviraptorosaur also helped scientists restore the reproductive process of dinosaurs.
By studying the arrangement of eggs, scientists found that each oviraptorosaur "lays eggs in pairs." That is, each time they lay an egg, one on each side of the fallopian tube. Pairs of eggs are arranged in concentric circles, and when one layer is full, it is stacked up to another layer, up to three layers. After the egg laying is completed, the mother egg stealer dragon will lie on the nest with her hands open, quietly waiting for the birth of a new life. Unfortunately, the oviraptorosaur in the fossil specimen did not wait for the arrival of new life, but instead lost his life and eventually died with his children in the loess.
In addition, fossils of " Plesiosaurus " have been found buried with their eggs. [6] The eggs are inserted straight into the soil and arranged in a significantly different way from those of Oviraptorosaurus. Scientists speculate that the mother of the toothed dragon will squat down when laying the egg, insert the freshly laid egg into the soil and twist the hips so that the egg can be more firmly fixed to the ground.
Sketch of a partially preserved skeleton of a tornadoan and five eggs preserved around it | References[6]
An unforgettable imprint
The two trace fossils introduced earlier exist independently of the physical fossils. However, there is a special type of trace fossils that remain on the surface of physical fossils, such as scars and tooth marks left on the bones of dinosaurs when fighting and preying.
First, let's talk about the star T-Rex that everyone pays the most attention to.
In North America, some Triceratops cervical vertebrae fossils have appeared on the teeth of T. rex. Considering that the Triceratops had the protection of a neck shield, this part was not easy to attack before it was born, so it can be inferred that this Tyrannosaurus rex should have eaten corpses. However, it is too early to assert that T. rex were scavengers, as the Tyrannosaurus rex bite marks on another group of platypus show signs of healing. Of course, the wounds of corpses do not change, and only living dinosaurs have a chance to heal their wounds, indicating that they have survived a terrible "dragon's mouth escape" [7]. It can be seen that Tyrannosaurus rex is "fresh" and "scavenger" all-consuming.
In addition to bullying "vegetarian" dinosaurs, carnivorous dinosaurs occasionally cannibalize.
For example, many tooth marks can be found on majungasaurus excavated from the island of Madagascar, possibly due to the lack of local resources. Although there are also signs of cannibalism, the wounds are mostly in the feet or fingers - it is really difficult to imagine the "lost scene" of the Tyrannosaurus rex biting at the opponent's small short hands or toes during the fight, after all, the fight should be aimed at the key parts of the head and neck, so this should be a case of starving and eating the corpse of a companion [7].
In addition, there are some cannibalistic bite marks on the faces of carnivorous dinosaurs such as Sinraptor, Tyrannosaurus, gorgosaurus and albertosaurus. But the researchers don't feel like they're fighting each other, and more likely fighting over turf.
At the Natural History Museum of Los Angeles County, fossils of Triceratops and T. rex, a pair of "old enemies," are placed together | matthew dillon / wikimedia commons
Of course, some plant-eating dinosaurs are also very aggressive, equipped with many sophisticated equipment to resist carnivorous dinosaurs, such as carnivorous Allosaurus found on the plant-eating Stegosaurus tail sting attack marks. Moreover, "vegetarianism" does not mean that they have a gentle personality, and there have been scars of violent collisions with males of the same kind as the opposite sex on the body of Triceratops and Swollen-headed Dragons, indicating that they may be like today's deer, using specialized weapons such as horns to single out [7,9].
Finally, let's talk about the traces of plant "counter-bite" dinosaurs.
According to Newton's third law of motion, objects must have reacted with the same magnitude when subjected to external forces—when dinosaurs chewed on food, these foods in turn wore out dinosaur teeth. For example, some scholars have used a microscope to observe the teeth of the duck-billed dragon, and speculated that it ate a lot of minerals and siliceous matter in the soil before it died. From this, we also learned that duck-billed dragons looked down like cows and horses for food, rather than looking up and chewing young leaves.
Speaking of which, I suddenly wanted to ask a question -
If humans themselves become fossils in tens of thousands of years, what traces do you hope you will retain to show future generations your life?
Author business card
Author: Liao Junqi
Editors: Kamin, Malt Yang
Typography: Condensed
Source: archosaurmusings.wordpress.com
bibliography:
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[2] osborn, h. f. (1924). three new theropoda, protoceratops zone, central mongolia. american museum novitates, 144, 1-12.
[3] norell, m. a., clark, j. m., chiappe, l. m., &dashzeveg, d. (1995). a nesting dinosaur. nature, 378(6559), 774-776.
[4] dong, z. m., & currie, p. j. (1996). on the discovery of an oviraptorid skeleton on a nest of eggs at bayan mandahu, inner mongolia, people's republic of china. revue canadienne des sciences de la terre, 33(4), 631-636.
[5] varricchio, d.j. (2000). "reproduction and parenting," in paul, g.s. (ed.). the scientific american book of dinosaurs. new york: st. martin's press, pp. 279-293
[6] varricchio, david j., jackson, frankie, borkowski, john j., horner, john r. "nest and egg clutches of the dinosaur troodon formosus and the evolution of avian reproductive traits." "nature" vol. 385:247-250 16 january 1997.
[7] anthony j. martin (2014). dinosaurs without bones.
[8] rogers, raymond r.; krause, david w.; & kristina curry rogers. cannibalism in the madagascan dinosaur majungatholusatopus. nature. 2007, 422 (6931): 515–518.
[9] peterson, j. e., & vittore, c. p. (2012). cranial pathologies in a specimen of pachycephalosaurus. plos one, 7(4), e36227.