Tydea septentrionalis
| Tydea septentrionalis | ||||||||||||
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| Temporal occurrence | ||||||||||||
| Oligocene ( Rupelian ) | ||||||||||||
| 30–31 million years | ||||||||||||
| Locations | ||||||||||||
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| Systematics | ||||||||||||
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| Scientific name of the genus | ||||||||||||
| Tydea | ||||||||||||
| Mayr & Smith , 2012 | ||||||||||||
| Scientific name of the species | ||||||||||||
| Tydea septentrionalis | ||||||||||||
| Mayr & Smith, 2012 |
Tydea septentrionalis is an extinct species of albatrosses (Diomedeidae) from the early Oligocene (about 30-31 mya ). The only representative of the genus Tydea reached about the size of a black- browed albatross ( Thalassarche melanophris ) and is the earliest known representative of its family . The animals lived in the area of the North Sea coast and probably had a similar way of life as today's albatrosses. Although Tydea shows strong bone structure similarities to their present-day relatives, they lack derived traitsas the basal line of the family. The fact that the genus occurs in the North Atlantic shows that in the Oligocene, unlike today, the albatrosses were not restricted to the Pacific and the southern hemisphere.
features
Only fragmentary bones of the flight apparatus and the shoulder girdle have survived from Tydea septentrionalis . They do not allow any conclusions to be drawn about the exact dimensions of the birds, but have dimensions similar to those of the black- browed albatross ( Thalassarche melanophris ), which has a maximum span of 245 cm, a body length of around 80 cm and a weight of 2.9-4.6 kg reached. Both in size and in general morphology , Tydea largely corresponded to today's representatives of the Diomedeidae.
Sites and fossil material
The known fossil material from Tydea comes from a single individual and includes pieces of the humeri , a carpometacarpus , an ulna , the raven and fork bones, and a shoulder blade . They come from the Belgian Boom Formation , a clay formation from the Rupelian , the lower stage of the Oligocene . They were salvaged in 1903 by Georges Hasse from a clay brick pit near Terhagen . Your find layer, the so-called Terhagen-Putte transition, is rich in organic material and has been dated to 30–31 million years ago.
Way of life
The site of T. septentrionalis was during his lifetime on the south coast of the North Sea , then a golf of the Atlantic , that of Great Britain , Scandinavia and the uplands was flanked southern Germany. The parallels in size and physique between Tydea and Quaternary albatrosses suggest a similar way of life: Today's members of the family feed on fish and squids , which they catch in low flight from the surface of the water. In doing so, they take advantage of the winds over the sea; many albatross species occur in the area of influence of far-reaching airflow systems such as the Humboldt or Benguela currents . This suggests the possibility that a similar air flow existed over the Oligocene North Sea, while the North Atlantic today has no comparable system and albatrosses are restricted to the southern hemisphere and the North Pacific.
Taxonomy and systematics
Although the holotype of Tydea (inventory number IRSNB was Av 94 am) discovered in the early 20th century, it remained more than 100 years undescribed in the magazines of the Muséum des Sciences naturelles de Belgique in Brussels . It was not until 2012 that the German palaeontologist Gerald Mayr and his Belgian colleague Thierry Smith described the fossil fragments as a new species Tydea septentrionalis in a monotypical genus. The genus name Tydea is derived from Tydeus , the father of Diomedes in Greek mythology , to whom the modern genus of albatross Diomedea is based. Mayr and Smith chose the specific epithet septentrionalis ( Latin "septem" for seven and "triones" for the plow ox, so the big wagon only visible from the northern hemisphere ) to underline the North Atlantic origin of the species.
Both its dimensions and several typical fine features of the bone structure clearly identify T. septentrionalis as an albatross, according to Mayr and Smith. According to the authors, this makes him the earliest safe representative of this family. The lack of some autapomorphies typical of today's albatrosses suggests that the genus Tydea is a basal line of the family Diomedeidae, which is opposite to today's representatives.
swell
literature
- Hemmo A. Abels, Stefaan Van Simaeys, Frits J. Hilgen, Ellen De Man, and Noël Vandenberghe: Obliquity-dominated Glacio-eustatic Sea Level Change in the Early Oligocene: Evidence from the Shallow Marine Siliciclastic Rupelian Stratotype (Boom Formation, Belgium) . In: Terra Nova 19, 2007. doi : 10.1111 / j.1365-3121.2006.00716.x , pp. 65-73. ( Full text ; PDF; 1.8 MB)
- Gerald Mayr, Thierry Smith: A Fossil Albatross from the Early Oligocene of the North Sea Basin. In: The Auk 129 (1), 2012. doi : 10.1525 / auk.2011.11192 , pp. 87-95. ( Full text ; PDF; 451 kB)