Masiakasaurus

## MasiakasaurusVicious Lizard

* Adult
* Juvenile

* Known for forward-projecting, heterodont teeth
* Took 8 - 10 years to grow

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***Masiakasaurus*** (Vicious Lizard, named after the Malagasy word for vicious) is a genus of noasaurid theropod dinosaur that lived in the Maevarano Formation, Madagascar, 70 - 66 million years ago, during the Maastrichtian stage of the Late Cretaceous Period.

## Description

### Size and Physique

***“ Masiakasaurus. A hunter, and one particularly well-adapted for catching burrowing prey. With its long neck and narrow head, it can investigate any hole that might contain a meal. ”***

― **David Attenborough**, *Islands*
Like most noasaurids, *Masiakasaurus* is a fairly small theropod dinosaur reaching around 1.8 - 2.1 meters (6 feet - 6 feet, 10 inches) long and weighing 20 kg (44.1 pounds). The animal took around 8 - 10 years to reach maturity and grow to the size of a large dog, a rate 40% slower than other non-avian theropod dinosaurs of similar size, but 40% faster than crocodylians. Animals found in impoverished environments tend to grow slower in order to reduce the cost of maintaining and nourishing themselves. Having lived in the semi-arid and seasonally stressful environment of the Maevarano Formation (which can, in turn, result in a scarcity of food, water, and various other resources), *Masiakasaurus* likely evolved slow growth for similar reasons.

The neck of *Masiakasaurus* is relatively narrow, with the stout neck vertebrae, hollowed out like most other abelisauroids, giving *Masiakasaurus* a stiff neck that is held almost horizontally, as opposed to the necks of other theropods, which are significantly curved in an "S" shape.

### Dentition

***“ This is Masiakasaurus. A female, six feet long, and she has a mouthful of needle-sharp teeth, just what you need to deal with awkward, multi-legged prey. ”***

― **David Attenborough**, *Freshwater*
The most distinctive characteristic of *Masiakasaurus* is its procumbent (forward-projecting) front teeth, which are heterodont (come in different shapes). The first four dentary teeth of the lower jaw are long, spoon-shaped, and project forward, with the first tooth angled only 10 degrees above the horizontal. These teeth also possess hooked edges with weak serrations, though the teeth at the back of jaw are more significantly serrated. These indicate that the back teeth were suited for cutting and slicing like other carnivorous dinosaurs, while the more unusual front teeth were meant for gripping small prey, not for tearing larger food apart. These teeth are believed to be adaptations for a specialist diet which includes fish and other small prey, vertebrates (like *Adalatherium*, which it attempted to hunt in Islands) and invertebrates (like crabs, which it is shown feeding on in Freshwater) alike.

### Arms

As a noasaurid, *Masiakasaurus* has longer arms than its abelisaurid cousins, and likely also has a same large hooked claw on the first finger of each hand, though the only evidence of this is that, in *Masiakasaurus*, the finger bone just before the supposed massive claw is similar in appearance to that of its relative, *Noasaurus*, which does indeed possess this enlarged sickle claw. However, the show does not depict *Masiakasaurus* with any enlarged claws on its hands.

### Prehistoric Planet's Depiction

*Main: *Masiakasaurus* on Prehistoric Planet*

Main: *Masiakasaurus* on Prehistoric Planet

On Prehistoric Planet, *Masiakasaurus* is shown to have a countershaded skin color (which aids in camouflaging it from prey and predators alike), with a black back running down in vertical stripes over an otherwise yellowish-brown (green in juveniles) body. The forward-projecting front teeth are covered up with lips, and there is a slight coat of feathers on the animal's back.

*Masiakasaurus* first appears in the fifth segment of Freshwater, where a family visits the shoal of a river to feast on crabs, though one juvenile gets caught and eaten by a *Beelzebufo*. The fourth segment of Islands also shows the vulnerability of the adults when one *Masiakasaurus* gets ambushed by a *Madtsoia* while looking for prey. *Masiakasaurus* also briefly appears in the third segment of Swamps, where an adult rushes alongside a river revived by rains, but gets scared off by a large male *Beelzebufo*.

## Habitat

*Main: Maevarano Formation*

Main: Maevarano Formation

***“ As river water flows downstream, it scours out billions of tonnes of sand and gravel, and even shifts great boulders. The finer sediments may be transported for hundreds of miles, but as the river broadens, it slows, and as a consequence, it begins to drop some of its load. And animals whose ancestors lived in the sea begin to appear. Crabs. In some places, there may be dozens per square meter. ”***

― **David Attenborough**, *Freshwater*
*Masiakasaurus* lived 70 - 66 million years ago in the Maevarano Formation in the Mahajanga Province of Madagascar. The Maevarano Formation is recognized as an alluvial plain where the discharge of rivers fluctuate. The area is also believed to have had reddish soil, with floodplains that supported vegetation able to grow in the relatively dry climate. The region, at times semi-arid (like it is today), at times undergoing strong dry and wet seasons, was eventually claimed by rising sea levels that pushed the shoreline back. This may or may not have been the result of the Cretaceous-Paleogene Extinction Event, a catastrophe that wiped out three-quarters of life on Earth.

***“ In Northern Madagascar, conditions are already changing. The first rain in months is reviving the parched land. As pools and channels refill, the animals return. ”***

― **David Attenborough**, *Swamps*
On Prehistoric Planet, *Masiakasaurus* is shown to inhabits riversides, taking advantage of crabs as seen in Freshwater, as well as the water itself, as seen when it is one of the first to arrive to the river formed again by the rains, taking a drink from the returning water in Swamps. As seen in Islands, however, *Masiakasaurus* is not averse to looking for food in more arid, rocky areas, using its narrow head and neck to investigate for food in holes in the environment.

## Behavior

***“ Crabs may have hard shells, but they're full of protein. Too good an opportunity to miss, and not only for her. She has three young, only four inches tall, and not quite ready to take on large crabs... but some youngsters develop hunting instincts early. ”***

― **David Attenborough**, *Freshwater*
*Masiakasaurus* is shown to be opportunistic, like most predators. It lives by the river shoal to hunt crabs in Freshwater, looks for food by checking holes in the rocks in Islands, and is one of the first to take advantage of the rainy season in Swamps, coming to a newly-formed river to drink. The female *Masiakasaurus* in Freshwater is also shown raising her three children alone (much like *Kuru kulla* and *Nanuqsaurus*, which are also depicted with the juveniles being raised by their mothers only), feeding them her leftovers and even calling one of her children out of concern of them straying too far.

One juvenile *Masiakasaurus* is shown to have developed hunting instincts early, going after crabs small enough to swallow whole. However, this results in less cautiousness, which in turn leads to the juvenile getting caught and eaten by a *Beelzebufo*, scaring its two other siblings into hiding behind their mother. This lack of cautiousness also extends to some adults, with one being unwary of being hunted itself while hunting for food, ending up with it getting attacked and killed by a *Madtsoia*. The adults themselves are also not averse to being afraid, with the mother *Masiakasaurus* not going after the *Beelzebufo* in Freshwater (it would also have been a waste of effort to attack given how her chick was already eaten anyway, and her surviving chicks are behind her, with all of them out of reach of the toad). *Beelzebufo* also proved that it could frighten off adult *Masiakasaurus* too close to it in Swamps given how it is still big enough to eat even them.

## References

1. ↑ 1.0 1.1 1.2 A bizarre predatory dinosaur from the Late Cretaceous of Madagascar
2. ↑ 2.0 2.1 The osteology of Masiakasaurus knopfleri, a small abelisauroid (Dinosauria: Theropoda) from the Late Cretaceous of Madagascar
3. ↑ 3.0 3.1 Bone histology confirms determinate growth and small body size in the noasaurid theropod Masiakasaurus knopfleri