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Youngina

life science Maturity 7-9 Next article →

Youngina was an extinct genus of small, lizard-like reptiles.

Youngina capensis
Youngina capensis

These animals lived during the Late Permian period. This was a time long before modern reptiles existed. They are found in the Karoo Supergroup of South Africa. Specifically, they lived in the Cistecephalus and Daptocephalus assemblage zones. Scientists find Youngina very important for understanding evolution. It is a member of the stem-group reptiles. This means it represents an early branch of the reptile family tree.

Youngina Scale
Youngina Scale

To understand Youngina, scientists look closely at its physical structure. The animal was relatively small in size. It had a specific skull length and a total body length.

Youngina skull lateral
Youngina skull lateral

Its anatomy shows a mosaic of different features. A mosaic in biology means it has a mix of traits. Some features are primitive, meaning they are ancestral. Other features are more derived, meaning they are more advanced. These advanced traits are seen in groups called archosauromorphs and lepidosauromorphs. This mix suggests that these traits did not evolve in a single, straight line.

The skull of Youngina provides deep clues about how early reptiles functioned. Researchers have used CT scans to look inside the braincase. These scans allow scientists to see the anatomy in great detail.

Youngina capensis
Youngina capensis

Scientists also study the palate and the mandible, which is the lower jaw. Recent studies of these parts have changed our understanding. New data suggests that Youngina is likely more basal than scientists once thought. In biology, basal means it branched off earlier in the evolutionary history of crown-group reptiles. This helps scientists map the exact timing of reptile evolution.

One important detail involves how the skull moved. Earlier researchers thought the basicranial joints had metakinetic mobility. This would mean the parts of the skull could move against each other. However, newer studies suggest the palatobasal articulation was likely immobile. This means the skull was probably stiff and stable. It functioned similarly to the skull of a modern tuatara. This discovery helps scientists realize that early reptile skulls were not all highly flexible.

The history of Youngina is tied to several important discoveries. Robert Broom discovered the holotype, which included a skull and vertebrae.

Youngina capensis
Youngina capensis

He found these fossils near Nieu-Bethesda in the Cape Colony. Broom published his description of the species, Youngina capensis, in 1914. Later, a scientist named Olsen described another well-preserved skull in 1936. In 1995, Smith and Evans identified a group of small reptiles in siltstone. This group, known as SAM-PK-K7710, was eventually moved to its own species, Scyllacerta creanae, in 2026.

Taxonomy, or the way we classify living things, has changed for Youngina over time.

Hovasaurus BW
Hovasaurus BW

It is currently placed in the family Younginidae. This family contains the earliest diverging members of the Neodiapsida. These animals lived outside of the clade known as Sauria. Sauria is the group that contains all living reptiles and birds. In the past, scientists placed Youngina in a group called Eosuchia. This group included many other reptiles like millerettids and rhynchosaurs. Today, scientists believe Eosuchia was a paraphyletic group. This means the members were not all closely related to one another.

Youngina also relates to other ancient reptiles from different regions. It was once grouped into Younginiformes with reptiles from East Africa and Madagascar.

Hovasaurus BW
Hovasaurus BW

These relatives include animals like Acerosodontosaurus, Kenyasaurus, and Hovasaurus. However, scientists have strongly questioned if this group is monophyletic. Monophyletic means all members share a single common ancestor. Some evidence suggests the group might actually be paraphyletic. Studying these connections helps scientists piece together the complex history of early life on Earth.

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🖼️ Images & Media (16)
File:Youngina skull lateral.png
Youngina skull lateral.png
File:Youngina Scale.svg
Youngina Scale.svg
File:Araeoscelis .sp.png
Araeoscelis .sp.png
File:BolosaurusDB15.jpg
BolosaurusDB15.jpg
File:Carbonodraco lundi.png
Carbonodraco lundi.png
File:Bunostegos akokanensis.jpg
Bunostegos akokanensis.jpg
File:Sclerosaurus1DB.jpg
Sclerosaurus1DB.jpg
File:Mesosaurus BW.jpg
Mesosaurus BW.jpg
File:Orovenator.jpg
Orovenator.jpg
File:Lanthanolania.jpg
Lanthanolania.jpg
File:Youngina capensis.png
Youngina capensis.png
File:Hovasaurus BW.jpg
Hovasaurus BW.jpg

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