Ahl al Oughlam
Ahl al Oughlam is a very important paleontological site in Africa . It is located just outside the eastern outskirts of Casablanca , 2.6 kilometers from Tit Mellil in Morocco . The first finds were made in 1985 in a former quarry, and systematic excavations have been taking place since 1989. The age of the site is given as about 2.5 million years, this corresponds to the beginning of the Gelasian , the highest stage of the Pliocene . Around 80 vertebrate species have been discovered so far, mainly mammals (including primates , but not hominids ) and birds . Ahl al Oughlam is thus the richest vertebrate site in North Africa .
Geological and geomorphological framework
The area surrounding Casablanca consists of folded Paleozoic basement mountains - Central Cambrian slate, greywacke and quartzite. This basement is known as the coastal meseta and structurally belongs to the Moroccan meseta . It only appears sporadically to the surface, mostly it is covered by neogene formations.
The meseta is characterized by the relative stability that this crustal area experienced after the completion of the Variscan mountain formation - in contrast to the neighboring atlas. In the period that followed, the meseta was gradually eroded into a uniform hull surface and, from the Neogene, was then covered by several transgression cycles of the Atlantic. The first and at the same time most important of these cycles took place in the Tortonian (Miocene), the second with the onset of the Gelasium - it bears the local name "Moghrebian".
Ahl al Oughlam belongs to the third cycle, the “Messaoudium”. When the sea receded, a coast-parallel dune series with a layer of scree at the base formed. The actual body of sand had meanwhile solidified into sand-lime brick . In this solidified sediment body there were karstification phenomena and crevices; the latter became the undoing of a rich fauna.
In the Pleistocene (Quaternary) there are five more dunes towards the Atlantic. It should be noted that these transgression and regression cycles coincide quite well with the interglacial and ice ages .
Ahl al Oughlam is around 6.2 kilometers from the Atlantic and is 108 meters above sea level. The coastal meseta has therefore shown strong emergence tendencies since the Neogene with the formation of large abrasion terraces .
fauna
The most common finds among the vertebrates were clearly made in the class of mammals :
Primates (Primates)
- Macaca sp. - macaques
- Theropithecus atlanticus - baboon
Rodents (Rodentia)
- Gerbillus bibersoni - gerbil
- Hystrix sp. - porcupine
- Irhoudia sp. - Comb finger style
- Mus haouzi - species of mouse
- Paraethomys chikeri - extinct species of mouse, related to the lava mice
- Praomys skouri oughlamensis - African soft rat
Hare-like (Lagomorpha)
- Lepus sp. - Real bunny
- Prolagus - Pika
- Serengetilagus - extinct species of hare
Insect eater (Eulipotyphla)
- Episoriculus maghrebiensis - species of shrew
- Erinaceus sp. - Small ear hedgehog
- Suncus barbarus - thick-tailed shrew
Bats (chiroptera)
- Emballonura - smooth-nosed free tail type
- Lasionycteris - silver haired bat
- Myotis - mouse-eared bat
- Rhinolophus sp. - horseshoe bat
Predators (Carnivora)
- Acinonyx aicha - extinct species of cheetah
- Alachtherium africanum - extinct species of walrus
- Canis aureus - golden jackal
- Chasmaporthetes nitidula darelbeidae - extinct species of hyena
- Crocuta dbaa - spotted hyena
- Dinofelis sp. - "Dread Cat"
- Genetta sp. - Gorse cat
- Herpestes abdelalii - extinct species of mongoose
- Homotherium sp. - extinct saber-toothed cat
- Hyaenictitherium barbarum - extinct species of hyena
- Ichneumia nims - mongoose species
- Lutra fatimazohrae - species of otter
- Lynx sp. - Lynx
- Mellivora sp. - honey badger
- Nyctereutes abdeslami - raccoon dog
- Panthera pardus - leopard
- Pliocrocuta perrieri latidens - extinct species of hyena
- Poecilictis lybica minor - Libyan striped weasel
- Prepoecilogale sp. - Bandiltisart
- Ursus sp. - bear
- Viverra leakeyi - extinct species of civet
- Vulpes sp. - Fox
Unpaired ungulate (Perissodactyla)
- Ceratotherium sp. - white rhinoceros
- Hipparion pomeli - extinct genus of horses
Artiodactyla (Artiodactyla)
- Beatragus antiquus remotus - species of antelope
- Camelus sp. - Old World Camel
- Gazella psolea - extinct species of gazelle
- Gazella thomasi - extinct species of gazelle
- Kobus barbarus - waterbuck species
- Kolpochoerus phacochoeroides - extinct species of bush pig
- Parmularius atlanticus - extinct hartebeest species
- Sivatherium maurusium - cattle giraffe
- Tragelaphus sp. - Antelope species
Whales (cetacea)
- Delphinus sp. - Common dolphin
- Kogia sp. - Pygmy sperm whale
Russell animals (Proboscidea)
- Anancus sp. - extinct species of proboscis
- Palaeoloxodon recki - extinct species of elephant
In addition to mammals, birds are the most common animal group with 20 species, followed by reptiles with 15 species and amphibians with 3 species. In addition, countless isolated fish remains have been found.
What is striking is the large number of predators among the mammals - they obviously had their shelter in caves and crevices of the dunes.
The fauna shows overall echoes of East African sites (e.g. Omo ), but there are also southern European influences.
The remains of a walrus and a horned cattle giraffe are curious .
literature
- S. Bailon: Amphibians et Reptiles du Pliocène terminal de Ahl al Oughlam. (Casablanca, Maroc) . In: Géodiversitas 22, 2000, 4, ISSN 1280-9659 , pp. 539-558.
- D. Geraads: Rongeurs et Insectivores du Pliocène final de Ahl al Oughlam, Casablanca, Maroc . In: Géobios 28, 1995, 1, ISSN 0016-6995 , pp. 99-115.
- D. Geraads: Carnivores du Pliocène terminal de Ahl al Oughlam. (Casablanca, Maroc) . In: Géobios 30, 1997, 1, ISSN 0016-6995 , pp. 127-164.
- André Michard: Eléments de Géologie Marocaine . Editions du Service Géologique du Maroc, Rabat 1976, ( Notes et memoires du Service Geologique 252).
Web links
- Ahl al Oughlam excavations on ivry.cnrs.fr (English) ( Memento from March 27, 2008 in the Internet Archive )
Coordinates: 33 ° 34 ′ 5.6 " N , 7 ° 30 ′ 42.7" W.