Pituriaspida
| Pituriaspida | ||||||||||||
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Life picture of Pituriaspis doylei |
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| Temporal occurrence | ||||||||||||
| Beginning of the Middle Devonian | ||||||||||||
| 390 million years | ||||||||||||
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| Systematics | ||||||||||||
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| Scientific name | ||||||||||||
| Pituriaspida | ||||||||||||
| Young , 1991 |
The Pituriaspida are an extinct taxon of early, jawless , fish-like vertebrates . They are only known from fossils from a sandstone formation in southwest Queensland in Australia. The group was named after the Aboriginal word pituri , which they use for a plant that contains a narcotic substance used as a drug by the Aborigines . The discovered fossils struck the explorer Gavin Young as so strange that he thought he was hallucinating when he first saw them.
Two species, Neeyambaspis enigmatica and Pituriaspis doylei , have been described . They are the only fossils of jawless fish from the Devonian Mountains of Australia. Only Pituriaspis is well known . The age of both species is given as 390 million years, the beginning of the middle Devonian.
features
Both species had a tubular bony armor around the head and trunk, which was interrupted by a larger opening below the eye socket. Another opening on each side could have provided space for well-developed pectoral fins . These openings were preceded by a sharp bone ridge that may have served to protect the leading edge of the fins. The tank ran out at its front end in a long rostrum . It probably reached back to the anus . It was similar to that of the Osteostraci , but did not have a central nasal opening. The nostril may have been on the underside in front of the mouth opening. Of the two species, the carapace of Neeyambaspis enigmatica was wider and shorter.
Systematics
The Pituriaspida are still less known than other fossil jawless fish. Due to its uniqueness, the taxon is given the rank of a class in the classical system . Gavin Young classified the Pituriaspida basal to the Galeaspida and the Osteostraci.
literature
- John A. Long: The Rise of Fishes . Page 59, The Johns Hopkins University Press, 1995, ISBN 0801849926
Web links
- Janvier, Philippe. 1997: Pituriaspida . Version 01 January 1997, in The Tree of Life Web Project
- Palæos: Pituriaspida