Panderichthys Rhombolepis

Panderichthys rhombolepis

Panderichthys rhombolepis, 160 cm. 

Supervised by Per Ahlberg NHM Uppsala and Philippe Janvier NHM Paris.

Panderichthys is a genus of extinct lobe-finned fish from the late Devonian period, about 380 Mya. This peculiar fish would grow to 130 cm in length, and lived in marine lagoons on the south coast of Laurussia. They were built for movement in shallow waters, and walked around, using their strong forelimbs. These would also assist them in popping their head out of the water for breathing - Panderichthys has lungs, and breathed air. They could even haul themselves out onto land!

These locomotive abilities resembles more those of tetrapods, than those of fish, and Panderichthys display several of transitional features between these two life forms - it took many intermediate steps from swimming in water to walking on land:

Panderichthys lacked dorsal and anal fins present in fish, and had a tail more like those of early tetrapods than the caudal fins of lobe-finned fish. It also displayed a complex skeletal and muscle structure in their paired fins, features eventually exploited to produce weight-bearing limbs. Its head in shaped similar to that of a tetrapod, but Panderichthys has kept cranial skeletal structures only present in fish. The enlargement of the spiracular chamber itself as well as its opening to the outside suggests that Panderichthys was also part of a transition to an increased capacity for air breathing that was completed in tetrapods.