Characteristics of Protoceratops, the ancestor of Ceratops

More than 70 years ago, in order to search for the fossils and cultural relics left by the earliest ancient humans, the American Museum of Natural History organized a large "Central Asia Expedition" to go deep into China's Inner Mongolia, Gansu and Xinjiang regions, as well as Mongolia. The largest paleontological expedition in history was conducted in the Gobi Desert.

Protoceratops

Although this expedition did not discover the fossils and cultural relics left by the earliest ancient humans that we had high hopes for, it did discover countless important other vertebrate fossils, which greatly enriched our understanding of the history of ancient life.

Protoceratops is one of these "jewels" among many precious discoveries.

Braving the dry and hot winds of the Mongolian Plateau, the expedition team unearthed a large number of complete Protoceratops skulls and skeleton fossils, giving us a full understanding of these oldest ceratopsians. Protoceratops lived 90 million years ago. It was less than 2 meters long and weighed less than 200 kilograms. At the same time, it had not yet grown all kinds of strange horns like the various later ceratopsians. However, the skeletal characteristics and body shape of these "little guys" have shown a series of trends consistent with later ceratopsians, confirming the ancestral status of Protoceratops as the most primitive ceratopsian. For example: They have a large, heavy skull, with the back of the skull forming a wide bony frill that extends over the neck. This broad bony frill is called the cervical scute. In order to reduce unnecessary weight, there are two window-like openings on the neck shield. Like other ceratopsians, Protoceratops had a narrow beak that resembled a parrot's beak. But unlike parrots, Protoceratops had strong jaws with teeth.

Initially, people could not understand the function of Protoceratops' neck shield. Later, after careful anatomical analysis, scientists discovered that the function of this bony frill was mainly to attach the powerful muscle tissue that connects the back of the skull to the lower jaw. This group of muscles is called the temporalis muscle, and its function is to drive the movement of the mandible to complete biting and chewing. Therefore, it can be speculated that Protoceratops and various ceratopsians that appeared later had much more powerful chewing capabilities than other vegetarian dinosaurs, which was obviously an adaptation to the increased proportion of plants with rough fibers in the environment. In addition, the cervical shield of Protoceratops served as an attachment point for the powerful neck muscles that controlled head movement. Of course, the existence of the cervical shield also protects the fatal neck part when attacked by carnivorous dinosaurs, so it is also a protective organ.

Protoceratops has not yet developed the various large horns that later appeared in ceratopsians, but the rudimentary form of such a horn has grown on the upper edge of its snout - a small bone called a nasal horn. Ridges. Some scientists believe that this ridge is found only in males and is used by males to fight for mates.

Protoceratops is one of the best-known species of all dinosaurs, because the material scientists have found about this dinosaur not only includes a large number of individuals representing various stages of growth from birth to adulthood, but also several clutches of egg fossils , some eggs still have partial embryos inside! The shape of this dinosaur egg is similar to that of a lizard, with an oblong shape, larger at one end and smaller at the other. The eggshell is calcareous, with a rough surface and small, zigzag stripes. The accumulation of preserved fossil eggs shows that female Protoceratops laid eggs in the sand, arranging the eggs in several concentric circles, much like how modern turtles lay eggs. The eggs were apparently covered with sand at the time and hatched using the heat of the sun. For modern paleontologists, it is fortunate that some of the eggs laid by this small dinosaur tens of millions of years ago have not yet been hatched. Otherwise, how could we know about these mysterious animals that lived tens of millions of years ago? What about these wonderful behaviors?

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