A Rare Fossil Turtle Skull with Shell Anatomy
A NATURALLY RARE FOSSIL TURTLE ANATOMY GENUS + THE TURTLE
A rare side-necked turtle: of the families Bothremydidae, the specimen type locality of this turtle is Oued Zem, near Khouribga, which lies over the Ouled Abdoun Basin phosphate layer. The prehistoric Bothremys turtles are a very distinct species having two nose holes. Bothremys maghrebiana, is found in a Danian marine phosphorite in Beacuteni Mellal-Kheacutenifra Middle Atlas of Morocco. The average elevation of the area around Oued Zem is 800 metres, 2600 feet. The Paleocene or Palaeocene, the "old recent", is a geologic epoch that lasted from about 66 to 56 million years ago. It is the first epoch of the Paleogene Period in the modern Cenozoic Era.
The key elements of this particularly fortuitous rare fossil discovery are the skull, which is in exceedingly good order and the carapace, more commonly termed the shell of the turtle. The carapace having been discovered as almost always is the case with fossil finds, exhumed in pieces and has been reconstructed without the aid of aesthetic fillers. In this way, we see it fragmented. The internal carapace strengthened with resin material enabling transportation. These elements of the once-living turtle have transformed in the phosphatic substances of the early Tertiary fossil layer. In prehistory, this was once a vast ocean environment, a prehistoric seabed which thrived with marine life and now forms part of the subterranean Saharan landscape of Morocco currently mined by the government Office Cherifieacutendes Phosphates Group (OCP).
Genus: Bothremydidae, Bothremys maghrebiana side-neck turtle.
Age: Paleogene, Palocene, Danian, 66,000,000 - 61,700,000.
Origin: Khouribga, Oued Zem, Near Casablanca, Morocco, North Africa.
The fossil layers which are within the vast phosphorite deposits run for approximately one hundred and twenty kilometres northeast of Agadir to the south-east of Casablanca. These deposits contain reserves of around 80,000 million tonnes of phosphate. The mines are among Morocco's most abundant resource, these are mined by the Office Cherifieacuten des Phosphates Group (OCP). The area of the most productive mines of fossils is in the vicinity Khouribga which is the central town of the region at 820 meters altitude on the Ouardigha plateau. The authorities of the French protectorate before Morocco regained independence from France in 1956, established the town in 1923 when they discovered phosphate in the region from the early 20 century the mining of phosphate became Morocco's premier industry. Morocco is among the most prominent exporters in the world of phosphates today.
LOCATION + ORIGIN
The layers of phosphate vary from 1-2 metres thickness, in a sequence of marls, clays and limestones. These belong to the Cretaceous period (135-64 m.y.a) and within the Cretaceous the stages of the Campanian and Maastrichtian age, of around 72-70 million years ago. Extending through to the Eocene period (56-34 m.y.a) in the Ypresian stage of the Eocene about 50 million years ago. The Oulad Abdoun is situated west of the Atlas Mountains; The phosphate deposits encompass approximately 4,500 square km. The Oulad Abdoun is the largest of Morocco's phosphate basins, which include the Ganntour, Meskala, and Oued Eddahab (Laayoune-Baa) basins. Formations are evident in the zone of West and North Africa, Saudi Arabia to East Asia, corresponding to the southern borders of the former Tethys Ocean from the Mesozoic Era (Triassic, Jurassic and Cretaceous periods). Sedimentary phosphorite deposited during sedimentation as a result of the upwelling of nutrient-rich waters coinciding with a Late Cretaceous transgression of the Tethys sea.
Here we see the dorsal view of the skull with its recognisable two prefrontal hole nose anatomy of the premaxilla region, the early turtles at this time were evolving. Here also we can see the large orbits in the inflated parietal area of the protective skull cavity of this vertebrate, which has not suffered for the millions of years underground too badly. The nuchal area where the skull adjoined the carapace is formed of a series of carapacial scute plates along with the complex shell or shield, which is relatively complete, exhibits large scute plates on either side, these the continuing marginals scutes progress around the outer edge of the dorsal carapace. These scute plates were produced from keratin and replaced during the turtle's life. And were evolved from modified bony elements, such as the ribs, parts of the pelvis and other bones found in most reptiles.