Dipterus Devonian Lung Fish Fossil from Scotland

Dipterus valenciennesi

Infraphylum Gnathostomata, Superclass Osteichthyes, Class Sarcopterygii, Subclass Dipnoi, Family Dipteridae

Geological Time: Middle Devonian (385 Million Years Old)

Size: 125 mm

Fossil Site: Achanarras Slate Quarry, Caithness, Scotland

Dipterus valenciennesi Devonian Lung Fish FossilDescription: This is a fine fossil specimen of the first lungfish described in 1828. It is one of the oldest to possess cranial ribs, and is thus believed to have been capable of gulping air, allowing it to extract oxygen directly from the atmosphere. The lungfish arose during the early Devonian, reaching a peak in diversity by the Late Devonian. While all early Dipnooans were marine, all known from the Carboniferous on have been freshwaterLung Fish denizens. A few survive today in Africa, South America, and Australia. The shine to the specimen is the result of cosmine, a layer of shiny bony tissue that consists of an external enameloid layer over a dentine layer. Cosmine is thought to have comprised apart of the skin’s complex vascular system. This cosmine layer was lost in most Dipnoan by the Late Devonian in favor of thinner scales. Interestingly, the deposits of Caithness also hold the remains of Palaeospondlyus, a much smaller fish though by some to be a larval form of Dipterus because of similar cranial structures.

Also see: Sarcopterygii Fish Fossils

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