genus of fishes (fossil)

Panderichthys is a genus of extinct sarcopterygian (lobe-finned fish). It lived in the late Devonian period, about 380 mya. Possible tetrapod tracks dating back to before the appearance of Panderichthys in the fossil record were found. This suggests that Panderichthys is not a direct ancestor of tetrapods. It shows the traits which evolved during the fish-tetrapod evolution.[1][2]

Temporal range: Late Devonian,
380 mya
Skull cast, Musee d'Histoire Naturelle, Lille
Scientific classification Edit this classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Clade: Elpistostegalia
Family: Panderichthyidae
Vorobyeva, 1968
Genus: Panderichthys
Gross, 1941
Type species
Panderichthys rhombolepis
Gross, 1941
  • P. stolbovi? Vorobyeva, 1960
  • P. rhombolepis Gross, 1941

Decreased oxygen in the atmosphere would have caused the oxygen concentrations in water to decrease. This would have caused any aquatic animal which could breathe air to have an advantage, and be more likely to thrive.

In addition to its ability to swim in water, Panderichthys could also breathe air. Its strong pectoral fins might allow it to prop up its head in shallow water and take a breath.

Description change

Panderichthys is a 1.5–2 m (4 ft 11 in–6 ft 7 in) long fish with a large tetrapod-like head that is flattened, narrow at the snout and wide in the back.

In January 2010, Nature reported well-preserved and "securely dated" tetrapod tracks from Polish marine tidal flat sediments approximately 397 million years old. These fossil tracks suggest that a group of two meter long tetrapods lived in the fully marine intertidal or lagoonal areas on the south coast of Laurussia. This implies that Panderichthys is not a transitional fossil and represents its own adaptive morphology. Therefore, Panderichthys can only be a "late-surviving relic", showing traits that evolved during the transition from fish-like creatures to tetrapods, but whose date does not reflect that transition. The tracks "force a radical reassessment of the timing, ecology and environmental setting of the fish–tetrapod transition, as well as the completeness of the body fossil record".

References change

  1. Niedzwiedzki, G., Szrek, P., Narkiewicz, K., Narkiewicz, M and Ahlberg, P., Nature 463(7227):43–48, 2010, Tetrapod trackways from the early Middle Devonian period of Poland, 7 January 2010.
  2. Clack, Jennifer A. "Devonian climate change, breathing, and the origin of the tetrapod stem group." Integrative and Comparative Biology 47.4 (2007): 510-523.