St. Helena Petrel
| St. Helena Petrel | ||||||||||
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| Systematics | ||||||||||
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| Scientific name | ||||||||||
| Bulweria bifax | ||||||||||
| Olson , 1975 |
The St. Helena Petrel ( Bulweria bifax ) is an extinct seabird from the family of the Petrels (Procellariidae). It was endemic to the island of St. Helena . The species name bifax means "two-faced" and refers to the fact that the fossil material has similarities with both the genus Bulweria and the genus Pterodroma .
features
The holotype is an almost complete tarsometatarsus , which was discovered in June 1971 by Storrs Lovejoy Olson in the Pleistocene deposits in the Aeolian calcareous sand near Sugerloaf Hill. The total length of the tarsometatarsus is 24.9 mm, the width through the joint roller (trochlea) 4.7 mm, the depth through the joint roller 3.5 mm, the shaft width at the center 2.3 mm, the shaft height at the center 2.0 mm . The color of the bone is white with dark wave markings. The as paratypes material marked that in some cases already in 1963 by Philip Ashmole was discovered, comprises a series of humerus , ulna , radii , Carpometacarpi , coracoid , femur , Tibiotarsi and Tarsometarsi . The St. Helena petrel was similar in size to the Jouanin petrel ( Bulweria fallax ), which reached a body length of 31 cm. The tibiotarsus is relatively short and heavy. The tarsometatarsus is characteristic of the genus Bulweria , but the wing elements are shorter and heavier than the Jouanin petrel. The relatively long and thin humerus bones distinguish Bulweria bifax from the genus Pterodrama , especially the Cook petrel ( Pterodroma cooki ), the Steijneger petrel ( Pterodroma longirostris ) and the white- wing petrel ( Pterodroma leucoptera ), in which the humerus bones are short and heavy.
die out
The decline of the St. Helena petrel is reflected in the diminishing presence of subfossil material in the younger deposit layers. This led Storrs L. Olson to the assumption that the St. Helena petrel probably only died out in the Holocene , when the settlement of St. Helena began around 1502.
literature
- Storrs L. Olson : Paleornithology of St. Helena Island, South Atlantic Ocean. In: Smithsonian Contributions to Paleobiology No. 23, 1975
- Julian Pender Hume , Michael Walters: Extinct Birds . A&C Black, London 2012. ISBN 140815725X .
Web links
- Bulweria bifax inthe IUCN 2016 Red List of Threatened Species . Posted by: BirdLife International, 2016. Retrieved January 7, 2017.