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Jaw Morphology

All articles tagged with #jaw morphology

Twisted-Jaw Tetrapod from Gondwana Illuminates Early Plant-Eating Life
science-paleontology1 month ago

Twisted-Jaw Tetrapod from Gondwana Illuminates Early Plant-Eating Life

Researchers describe Tanyka amnicola, a 275-million-year-old stem tetrapod known from seven to nine jawbones found in Brazil’s Pedra de Fogo Formation. The jaws are twisted with outward-facing teeth and a denticle-covered inner surface, indicating a grinding mechanism for plant matter and suggesting early herbivory among stem tetrapods. The discovery places this “living fossil” in Gondwana’s Permian ecosystems and helps fill gaps in the fossil record, though the full skeleton remains unknown and may have measured up to about 0.9 meters in length.

Great whites grow bone-cutting teeth with age, revealing a lifelong dietary shift
science3 months ago

Great whites grow bone-cutting teeth with age, revealing a lifelong dietary shift

A study of nearly 100 great white sharks shows their teeth change across the jaw and as they grow: juvenile teeth are slender with cusplets for gripping small prey, but around 3 meters they shed cusplets and develop broader, serrated teeth for slicing; the front teeth are thicker ‘impact’ teeth while upper and lower teeth specialize for slicing and gripping, enabling larger sharks to target marine mammals. Continuous tooth replacement acts like a living record of lifestyle and diet changes, highlighting how the shark’s feeding toolkit adapts across life stages.

Shark jaw shapes reveal habitat-driven evolution.
science3 years ago

Shark jaw shapes reveal habitat-driven evolution.

An international research team led by the University of Vienna investigated how the jaw shape of sharks has changed over the course of evolution. They conclude that in the most widespread shark species, the jaws show relatively little variation in shape over millions of years; most variable jaws were found for deep-sea sharks. The results illustrate the importance of prey, level in the marine webs and habitat in relation to jaw shape diversity among shark species.