Anurognathus

Discovery and Origin of the Name: “Tailless Jaw”

Well-Preserved Fossils and a Connection to Japan

Fossils of Anurognathus were discovered in the same geological strata as Archaeopteryx.
What is remarkable is the excellent condition of the discovered fossils.
Despite being a very small creature, the remains were preserved well enough to retain sufficient features for species identification.
Incidentally, while the discoverer was a German scholar, he is noted as a figure with deep ties to Japan.

Meaning of the Name

The genus name Anurognathus succinctly describes its physical characteristics, meaning “Tailless Jaw.”
As the name suggests, their most defining features were a “short tail” and a “distinctive head”—traits not seen in other pterosaurs of the same lineage at that time.

Taxonomic Paradox: Evolved Tail and Primitive Wrists

The taxonomic position of Anurognathus is highly unique, possessing a blend of features that suggest a transitional phase in evolution.

“Short-tailed” despite being a Rhamphorhynchoid?

Taxonomically, they are included in the “rhamphorhynchoids.”
This group includes Dimorphodon, familiar from the Jurassic Park movie series, and is typically characterized by a “long tail” often tipped with a diamond-shaped vane.

However, despite belonging to this group, Anurognathus has a peculiarly short tail.
This tail characteristic resembled the pygostyle seen in modern birds or the evolved pterosaurs (pterodactyloids) like Pteranodon that would appear much later.

Wrists remain “Primitive”

At first glance, it looks like an evolved pterosaur, but it had not fully evolved.
Its body firmly retained characteristics specific to early pterosaurs like rhamphorhynchoids, such as short carpal (wrist) bones.
In other words, Anurognathus, as the representative of the family Anurognathidae, was a singular existence where primitive features and seemingly evolved traits coexisted.

Bat-like Appearance and Physical Characteristics

Anurognathus was a very small pterosaur.
Its appearance is said to have resembled that of a modern bat.

Size

The body length was only 9 cm, with a wingspan (width with wings spread) of about 0.5 m.

Head

The skull was tall but short from front to back.
The snout was rounded.

Teeth

Small, sharp, pointed teeth grew upright inside its mouth, structured to ensure prey could not escape.

Wings

The wings were long and slender relative to its body length, providing excellent gliding capabilities.

Ecology as an Aerial Hunter

Hunting Insects like a Nightjar

Based on these physical characteristics, Anurognathus is believed to have been an insectivore.
Their hunting style is compared to that of the modern bird, the “Nightjar.”
Utilizing their superior flight capabilities and maneuverability, they would swiftly fly through the air, snatching up other flying insects one after another.

“Maneuverability” over Speed

While their flight capabilities didn’t allow for high maximum speeds, they seemed to specialize in “maneuverability.”
A body with slender wings for gliding combined with a short tail allows for tight turns in mid-air.
This ability likely proved incredibly useful when catching insects, such as moths, that dodge erratically in flight.

In the skies of Jurassic Germany, Anurognathus, with its charmingly small body and unique “tailless” form, played its part in the ecosystem.