Morocco boasts a rich marine ecosystem, home to a variety of fascinating creatures, including sharks. While the country is known for its terrestrial wildlife, its coastal waters also harbor diverse marine life, including various shark species. This article explores the sharks found in Moroccan waters and delves into the region's ancient marine history, revealing extinct species like the unique Xenodens.
Ancient Marine Reptiles of Morocco
66 million years ago, during the late Cretaceous period, shallow seas covered northern Morocco, reaching inland to the Sahara's edge. These waters teemed with an extraordinary variety of marine reptiles, including mosasaurs, plesiosaurs, and giant marine turtles. This era represents one of the most diverse Mesozoic marine faunas known, even containing some surprising dinosaur discoveries.
Amidst this rich marine life, new species continue to emerge. One notable example is Xenodens, a unique mosasaur species unlike any other reptile previously discovered. This small mosasaur possessed bladelike teeth arranged edge to edge, forming a cutting surface similar to certain sharks. It appears that mosasaurs were still diversifying just before the Chicxulub asteroid impact that marked the end of the Cretaceous period, but this diversification was not enough to save them from extinction.
It seems that just before the Chicxulub asteroid impact that ended the Cretaceous, mosasaurs were still diversifying- but that wasn’t enough to save them.
The new species, named Xenodens, is unlike any mosasaur (or reptile) we’ve seen before. It had bladelike teeth packed edge to edge to make a cutting surface, like certain sharks.
Read also: Our Stay at DoubleTree Sharks Bay
The teeth of Xenodens aren’t like anything we’ve seen in mosasaurs before, or lizards. For that matter, I’ve struggled to find anything like them in any other reptile.
Recently it has been alleged that Xenodens is a composite. This is not true; having personally prepared not one but two Xenodens specimens showing its unusual anatomy, I can confirm its authenticity. CT scanning is scheduled and we have no doubt will verify the animal.
The giant Mosasaurus was a fish eater, adapted to dive deep in search of large prey, like a sperm whale. Halisaurus, a little mosasaur with lots of small, sharp teeth, probably hunted small fish like a porpoise or a seal. Globidens evolved short, blunt teeth, which are variously shaped like marbles, acorns, or buttons, depending on the species. These teeth were specialized to crush mollusks, like a sea otter or a walrus. And the monstrous Prognathodon had teeth shaped like those of a killer whale- it was an apex predator, eating fish, plesiosaurs, marine turtles… and other mosasaurs.
Morocco’s Ancient Shark Teeth 🦈 | Megalodon & Prehistoric Fossils Unearthed
The Evolution and Specialization of Mosasaurs
Mosasaurs, marine reptiles from the age of dinosaurs, were not dinosaurs themselves but lizards, possibly related to monitor lizards and snakes. They first invaded the seas 100 million years ago, initially small and confined to shallow, nearshore environments.
Around 94 million years ago, a mass extinction occurred at the end of the Cenomanian period, likely caused by a volcanic eruption. This event, known as the Cenomanian-Turonian extinction, led to widespread low oxygen conditions in marine ecosystems. Ichthyosaurs and other marine species went extinct, paving the way for mosasaurs to evolve and take their place. They rapidly became more specialized for marine life, growing much larger and developing flipper-like limbs and a fluked tail.
Read also: Identifying Sharks in Egypt
Imagine a Komodo dragon crossed with a shark, and stretched out to 12 meters or more, and that’s a mosasaur. They evolved the ability to exploit the open seas and the deep ocean. Probably, like modern elephant seals and sperm whales, mosasaurs were able to dive thousands of feet in search of prey.
Mosasaurs were one of just a handful of tetrapod lineages (whales, sea cows, modern sea snakes, the extinct palaeophiid sea snakes, plesiosaurs and ichthyosaurs) to become fully specialized for a marine existence, neither needing to return to land, nor able to.
By the end of the Cretaceous period, 30 million years after their initial appearance, mosasaurs had diversified to exploit a huge range of niches.
Xenodens: A Shark-Like Mosasaur
The teeth of Xenodens are unique among mosasaurs and lizards, resembling those of dogfish and sleeper sharks. These sharks use their tooth arrangements to slice meat, allowing them to cut large fish into bite-sized pieces or scavenge from large carcasses.
By analogy with dogfish, Xenodens may have done something similar with its teeth. Our best guess is that the specialized teeth served to allow it to cut large fish into bite-sized pieces. Perhaps they could also scavenge from large carcasses, as dogfish and sleepers sometimes do, although we can’t rule out other feeding strategies or other prey.
Read also: Facts About South African Sharks
Xenodens could probably take a huge range of foods, like modern dogfish, but the key purpose of those bladelike teeth was probably to let the animal take much larger prey than it otherwise could have.
Xenodens was a very small mosasaur- about the size of a small porpoise (it’s not impossible we’ll eventually find larger individuals- juvenile mosasaurs are common in the fauna, and the specimen may not be full grown- but it probably didn’t get that big, since its relatives were also small). So these bladelike teeth let it to punch above its weight and eat large things despite its diminutive size, occupying a niche that’s distinct from anything any other mosasaur does.
So what's it all mean? Xenodens is one more piece of evidence showing that the very end of the Cretaceous, the late Maastrichtian, was a time of high diversity.
Lower jaws of the dogfish Squalus acanthias. Courtesy Ross Robertson, STRI.
Morocco's Diverse Mosasaur Fauna
Over the past two decades, research in Morocco has revealed an astonishingly diverse mosasaur fauna dating back 66 million years. This fauna existed just before the Cretaceous-Paleogene (K-Pg) boundary, immediately before the Chicxulub asteroid impact that wiped out dinosaurs and most other life on Earth. Morocco provides a glimpse into a marine ecosystem just before this catastrophic event, showcasing an incredible array of species.
It’s been suggested that marine ecosystems were stressed before the asteroid hit, and low in diversity. This, the story goes, made them vulnerable to disruption. But that’s not at all what we see. Diversity was as high as it had ever been in the marine ecosystem. There were a huge range of mosasaurs; there are more mosasaurs in the late Maastrichtian than at any time in their history. There were also plesiosaurs, giant marine turtles, and a remarkable diversity of bony fish (like the huge, saber-toothed Enchodus) and sharks.
All these animals- mosasaurs, plesiosaurs, big fish- lie at the top of the food chain- so their diversity implies a high diversity and abundance of prey items, things like small fish, squid, ammonites, crustaceans, clams, snails, and so on.
Modern Shark Species
While the ancient seas of Morocco were home to unique mosasaurs like Xenodens, the region's modern waters also host a variety of shark species. Some notable examples include:
- Shortfin Mako Sharks: These sharks have pointed snouts, long gill slits, blue/gray backs, light metallic blue sides, and white undersides.
- Scalloped Hammerhead Sharks: These moderately large sharks have a global distribution and are distinguished by their "hammer-shaped" head.
- Atlantic Blacktip Sharks: These sharks grow quickly and can reach up to 6 feet in length.
- Various Angelshark Species: Including the Argentine angelshark, common angelshark, sawback angelshark, smoothback angelshark, and spiny angelshark.
- Other Cartilaginous Fish: Such as the daggernose shark, narrownose smoothhound, and striped smoothhound.
Conservation and Threats to Moroccan Wildlife
Morocco's diverse ecosystems are protected through national parks, national reserves, sanctuaries, and other nature and wildlife areas. However, several threats endanger the country's wildlife, including habitat loss, poaching, and over-hunting.
Common threats are overhunting, poaching, and global warming.
Habitat loss is the result of agricultural expansion and urbanization. As these activities continue to increase in Morocco’s cities and rural areas, natural habitats shrink or become fragmented.
Poaching is an illegal activity that involves hunting animals for their fur or other body parts. This has had a devastating effect on many animal populations in Morocco.
It's important to note that the Barbary lion has been extinct in the wild since the 1920s, and the West African crocodile, also called the desert crocodile or sacred crocodile, once lived in Morocco but is now extinct in the country.
Morocco's National Symbols
The Barbary lion is the official national animal of Morocco and is commonly depicted in clothing featuring the Moroccan flag colors. The Moroccan coat-of-arms also features two lions supporting the shield.
The flag of Morocco is composed of a red field with a black-bordered green pentagram star in the center. It was enacted as the national flag over 100 years ago, on November 17th, 1915. The interconnected green pentagram, which stands for the Seal of Solomon, represents wisdom as well as long life and good health. The red background on the Moroccan flag is meant to represent a strong spiritual connection between God and his followers.
Diversity and Extinction
The high diversity of species in ecosystems might make things more vulnerable to environmental catastrophes because ecosystems pack in a lot of species, at least in part, by having them evolve to be more specialized. Mosasaurs evolved diverse teeth, jaws, bodies and life histories to specialize with different feeding strategies, and different prey- big fish, small fish, mollusks, marine reptiles. They probably specialized in where they fed and lived in space- the upper water column or the ocean depths, coastal shelves or open ocean, tropics or polar latitudes, soforth.
But in specializing, species become dependent on a narrower range of foods and habitats. So specialization makes them vulnerable to a disruption of the food chain, or destruction of habitats. To the extent you rely on one kind of prey, if it becomes rare or goes extinct, you’re vulnerable.
Popular articles:
tags: #Morocco
