Level 1 - Absolute Beginner
Scientists find a new animal fossil in China. The animal lived about 165 million years ago, with dinosaurs.
It is called Megacauda sungei. It was about the size of a platypus.
It swam in lakes and rivers. It ate small animals like fish and salamanders.
The fossil has throat bones. They look like the throat bones of many mammals today.
- fossil
- The old remains of a living thing in rock.
- dinosaur
- A very old giant reptile.
- platypus
- A small furry animal that lays eggs and swims.
- swim
- To move through water.
- salamander
- A small animal like a lizard that lives near water.
- throat
- The part inside your neck.
- mammal
- An animal that feeds milk to its babies.
- lake
- A large area of water with land around it.
Level 2 - Elementary
A study in the journal Nature describes a new fossil animal from the Middle Jurassic of Inner Mongolia, China. It is named Megacauda sungei and lived about 165 million years ago, at the time of the dinosaurs.
The animal belonged to a group called docodonts, early relatives of mammals. It weighed about one to two kilograms, about as much as a platypus. Scientists say it is the largest known Jurassic mammaliaform.
It was semiaquatic, so it lived in water and on land. Its tail and legs were good for swimming, and its teeth were made for catching prey. Bones of a salamander were found with the fossil.
The most exciting part is the throat. The fossil keeps the throat bones, and they look like those of living therian mammals, such as kangaroos and humans.
- journal
- A magazine for science studies.
- Jurassic
- A period of time about 200 to 145 million years ago.
- relatives
- Family members or close groups.
- semiaquatic
- Living both in water and on land.
- prey
- An animal that is hunted for food.
- therian
- Belonging to the group that includes marsupials and placental mammals.
- preserve
- To keep in good condition.
- exciting
- Making you feel interested and happy.
Level 3 - Intermediate
A fossil from Inner Mongolia is changing ideas about when a mammal-like throat evolved. In a Nature paper led by Yukun Li and Zhe-Xi Luo, researchers describe Megacauda sungei, a docodont mammaliaform from the Middle Jurassic, roughly 165 million years ago (estimates range from about 168 to 163 million).
At around one to two kilograms, about the size of a modern platypus, it is the largest known Jurassic mammaliaform. Its tail and limbs point to swimming, and its teeth to a predatory diet. Salamander bone fragments in the fossil support this, and the authors suggest it may have sheltered in burrows on land.
The key discovery is anatomical. The specimen preserves the pharynx and hyoid bones, and these resemble those of living therian mammals such as marsupials and placentals. This suggests that the throat structures behind therian-like swallowing, drinking and suckling had already evolved in the common ancestors of docodonts and mammals.
Some coverage goes further and infers a soft palate, which would allow an animal to drink or feed while breathing. Those functional claims are inferences from bones, not observed behaviour, and the authors present them with that caution.
- evolved
- Developed gradually over generations.
- mammaliaform
- An animal close to, or among, early mammals.
- predatory
- Hunting other animals for food.
- burrows
- Holes in the ground used as shelter.
- anatomical
- Related to body structure.
- pharynx
- The part of the throat behind the mouth.
- inference
- A conclusion based on evidence.
- ancestors
- Early forms from which later ones descend.
Level 4 - Advanced
A remarkably well-preserved fossil from Inner Mongolia is forcing a rethink of when the anatomy of a mammalian throat arose. Writing in Nature, Yukun Li, Zhe-Xi Luo and colleagues describe Megacauda sungei, a docodont mammaliaform from the Middle Jurassic, about 165 million years old by most accounts, though the quoted range runs from roughly 168 to 163 million years.
At one to two kilograms, comparable to a platypus, it is the largest Jurassic mammaliaform yet recorded. The authors read its tail and limbs as adaptations to swimming and its dentition as that of a predator, a reading bolstered by salamander bone fragments within the specimen. They suggest it foraged in water for fish, salamanders and invertebrates while retreating to burrows.
What sets the find apart is soft-tissue-adjacent anatomy that seldom fossilises. The pharyngeal vault and hyoid skeleton resemble those of living therians, implying that the apparatus for therian-style swallowing, drinking and suckling was already present in the common ancestors of docodonts and mammals.
Caution is warranted. Claims about a soft palate or the capacity to suckle are inferences drawn from bone, not observations of behaviour, and press reports differ on details such as the specimen's provenance. Even so, the fossil pushes a key feeding innovation substantially deeper into the age of dinosaurs.
- rethink
- A fresh consideration of an idea.
- adaptations
- Changes that suit an animal to its environment.
- dentition
- The arrangement and type of teeth.
- bolstered
- Strengthened or supported.
- forage
- To search for food.
- invertebrates
- Animals without backbones.
- provenance
- The origin or source of an object.
- innovation
- A new method or feature.
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