|ID||Michel: 789-792, Bl. 22 Scott: Stanley Gibbons: Yvert: UPU: N/A Category: pF|
|Stamps in set||5 (4 + Block)|
Geochelone stromeri, |
80 c., Diamantornis wardi (eggs),
90 c., Prohyrax hendeyi (skull),
1.20 N$., Crocodylus lloydi (skull),
Block, 80 c., Diamantornis wardi
|Size (width x height)|
|Perforation||13.75 x 14.25|
|40c Geochelone stromeri
In the Lower Miocene period 19 to 20 million years ago, the coastal region of southern Namibia was inhabited by giant tortoises, first described in 1926 as Geochelone stromeri. In 1992, the first complete carapaces of this species were found during diamond mining operations at Auchas in the Orange River valley 50 kilometres upstream from Oranjemund. The tortoises are associated with fossil mammals and plants that indicate that the area enjoyed a subtropical climate at the
time that they lived, in stark contrast to the extremely arid conditions that prevail there today. The specimen depicted on the stamp is almost half a metre long and 25 centimetres high, an is thus much larger than any tortoise living in southern Namibia today.
|80c Diamantornis wardi|
Fossilised eggsehll fragments have been known to occur in the Sperrgebiet (forbidden territory) for many years, but it was only in 1992 that the first complete eggs were foun y the Namibia Palaeontology Expedition at Ftooilepel. At this site 30 kilometres north of Auchas Mine is an extensive cliff of hardened sand dunes 120 metres thick which contain abundant fossil mammals as well as eggshells dating from about 16 to 17 million years ago. The eggs of Diamantornis wardi (Wards
Diamod Bird) are one and a half times as voluminous as those of the living ostrich (1,8 liters as opposed to 1,2 litres) and the shell is much thicker (3 to 4 millimetres verus 1,2 millimetres), suggesting that the birds that laid them were appreciably larger than the living ostrich.
|90c Prohyrax hendeyi
At Arrisdrift, 35 kilometres upstream from Oranjemund, numerous fossils were found in an abandoned channel of the Orange River during diamond prospecting activities. The commonest mammals found at the site, dating from 17,5 million years ago, were large dassies (hyraxes) the size of Dorper sheep. In 1976, a particularly finely preserved skull was found and this formed the basis for the reconstruction depicted on the stamp. These dassies probably lived in herds along the floodplain of the proto-Orange River, much as the springbok today. At that time, the environment in the Orange River valley would have been considerably more luxuriant than it is today. Apart from dassies, Arrisdrift has yielded many other species of mammals ranging in size from mice to elephants.
N$1,20 Crocodylus lloydi
In contrast to the arid situation prevailing today in the lower Orange River valley, the environment was probably subtropical and the vegetation more luxuriant during the Middle Miocene period 17,5 million years ago. At Arrisdrift, many fossilised crocodile bones and teeth have been excavated which indicate that the climate was on average warmer then than it is now. The discovery of the complete skull and jaws of the Crocodylus I/oydi revealed its similarity in shape and size to the Nile crocodile, the modern distribution of which is restricted to the tropics and subtropics. Many of the fossil mammal bones at Arrisdrift show evidence of having been bitten by crocodile, which must have been one of the major predators in the valley.
|FDC (inside text of the FDC is here)|
Latest update 19.11.2017
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