Abelisaurus is a genus of abelisaurid theropod dinosaur from the late cretaceous period(between 83 and 80 million years ago). Abelisaurus comahuensis has a large skull, 85 cm in maximal length, provided with wide lower temporal, antorbital, orbital and nasal fenestrae. With robust cranial roof in the interorbital region and profusely rugose nasals, even with irregular prominences in the form of
small sharp points. It was the bipedal carnivore that probably reached 7 to 9 meters in length. The generic name recognizes Roberto Abel as the discoverer of the specimen and former director of the provincial Museum of Cipolletti in Argentina. genus and species were named and described by Argentine paleontologists Jose Bonaparte and Fernando Novas in 1985, who placed it in the newly-created family Abelisauridae. The one known fossil skull of Abelisaurus is incomplete, especially on the right side. It is also missing most of the palate. Although there are no bony crests or horns, like those found in some other abelisaurids, such as Carnotaurus, rough ridges on the snout and above the eyes might have supported some kind of crest made out of keratin, which would not have become fossilized. There are also very large fenestrae (window-like openings) in the skull, which are found in many dinosaurs and reduce skull weight.
small sharp points. It was the bipedal carnivore that probably reached 7 to 9 meters in length. The generic name recognizes Roberto Abel as the discoverer of the specimen and former director of the provincial Museum of Cipolletti in Argentina. genus and species were named and described by Argentine paleontologists Jose Bonaparte and Fernando Novas in 1985, who placed it in the newly-created family Abelisauridae. The one known fossil skull of Abelisaurus is incomplete, especially on the right side. It is also missing most of the palate. Although there are no bony crests or horns, like those found in some other abelisaurids, such as Carnotaurus, rough ridges on the snout and above the eyes might have supported some kind of crest made out of keratin, which would not have become fossilized. There are also very large fenestrae (window-like openings) in the skull, which are found in many dinosaurs and reduce skull weight.
Abelisaurus comahuensis often found in family groups. However, they live temporarily in solitude when they leave their family to start their own. This neoceratosaurian is recognized by its huge skull, sunken white eyes, ornamented snout, powerful jaws, and boxcutter-like teeth. The ornaments on its head include a series of knob-like horns on its snout, a thick bony ridge over its eyes, and a bright red dewlap on its throat during mating season. Its large head is held by a long and powerful neck, connected to a muscular torso with incredibly tiny and insignificant arms. Its legs are long and powerful yet gracile, showing that this animal was a built runner. Another notable feature of this predator is the scutelike armor covering its body. Sexual dimorphism is highly present in these animals, with females lacking the decorative features of the males, including the knobs and dewlaps. Males are a greyish green with a series of dark stripes running down from its neck to its tail. In mating season, their faces flush reddish with blood. Females are a darker version of this green, with their stripes ranging from an azure blue to a chocolate brown. Battle scars from interspecies rivalry often appear on the heads of males.
The Abelisaurus comahuensis is a pursuit predator, known for recklessly chasing down its quarry, then finishing it with a fatal blow to a soft area, usually the throat. Hunting techniques vary with age, as their size and social unit plays a large role in how they prey. In mated pairs, these abelisaurs would chase and harry large quarry such as small to medium sauropods, biting them until they exhaust from blood loss and collapse. Then one of the theropods would climb onto its back to keep it down while the other chokes it to death with a bite to the throat. In family groups, the technique is almost the same, except the process is quicker because the young are constantly dogging the sauropods during the hunt, nipping at their legs and ankles. Like other abelisaurids, Abelisaurus comahuensis has been known to resort to cannibalism. When these theropods leave their families to live on their own, they are at the great risk of being attacked and eaten by older members of the same species. This is because males are outgoingly territorial when it comes to other males. Sibling rivalry or even just plain food competition are also reasons for this species' cannibalism.
As the wet season begins, loud, throaty vocalizations are heard throughout the rainforests. These calls are the mating calls for females suggesting that they are ready to mate. Females also release a strong scent which attracts several males to the area. As many as 7 males have been seen trailing behind ovulating females. The eager males attempt to impress the female by bobbing their heads, flushing their facial colors, displaying their dewlaps, and emitting low cooing sounds. Then the female judges which one she is most impressed by. If she is equally impressed by a number of males, the males will squabble amongst themselves for the female. The squabbling starts as simple growling and display of ornamentation, which is usually enough to drive off the other competitor(s). However, sometimes the contests can escalate in the form of headbutting and even biting. Death from these fights are not unheard of, but are highly circumstantial.
When a successful male mates with the female, he does not abandon her. Instead, the two form a mated pair, hunting and sleeping together. When the female lays her eggs, usually about 8 to 10, the male hunts solitarily and brings back food for his mate, who tends the nest and later the hatchlings. Sometimes the amount of food the male provides for the female is too meager, and the female ends up eating some of her own eggs or hatchlings. Interestingly, the nesting of Abelisaurus comahuensis corresponds with the nesting of the local sauropods. This is to ensure that their young will have a steady supply of food when they grow up. They lay their eggs a considerable amount of time before the sauropods lay theirs so that their offspring will be at a hunting size while the sauropods are still small. When the young are large enough to hunt, they accompany the adults on their ornithopod or sauropod attacks. Eventually, when the young are large and experienced enough to hunt on their own, usually about age 4 at a length of 6-10 feet, they leave their parents and their nest to live solitarily until they are old enough to mate, which is when they are 8. This is a dangerous time for them, as other carnivores are willing to eat them. After this they mate and keep the cycle going. Mated pairs only rear children once, and after which they hunt for a few more years, until they die at a healthy age of 15.
