Australia: The Land Where Time Began

A biography of the Australian continent 

Pituriaspida

Named after a hallucinogenic drug used by Aboriginal People in central Australia, these agnathan fish were distinguished by a long extension of the head shield, the rostrum, similar in appearance to that of a swordfish. They lived in the Middle Devonian, about 390 million years ago. They are known only from a sandstone deposit in the Toko Range in the Georgina Basin of southwestern Queensland. The bony body shield, in the form of a tube covering most of the body, one species having the long rostrum, Pituiraspis doylei, had an appearance somewhat like the Osteostraci. A unique feature of both species was a large opening below the opening for the eyes. The other species, Neeyambaspis enigmatica, had a much shorter rostrum, and the head shield was much shorter. There were openings in the body shield for the pectoral fins, that are believed to have been well-developed, on either side that were protected in the front by bony protrusions. They had a

Based on their appearance, they may be most closely related to the osteostracans or the galeaspids from China. The environment at the time of deposition of the site was marine, deltaic. Other fish present were placoderms. They have been classified as being at the base of the radiation that includes the osteostracans and galeaspids (Young, 1991). According to Long their main feature is a shield that is cephalaspid-like but lacks a nasohypophyseal opening on the dorsal side.

Sources & Further reading

1. John A Long The Rise of Fishes - 500 Million years of Evolution, University of New South Wales Press, 1995
2. Long, John A., 2011, The Rise of Fishes - 500 Million years of Evolution, University of New South Wales Press, 2011

Links

1. Pituriaspida
2. Pituriaspida
3. Pituriaspida

Fish