Within the Mesozoic Era , three periods marked significant differences in the evolution of our planet: the Triassic , Jurassic, and Cretaceous . At the dividing line between the period preceding the Triassic and the Permian , a global mass extinction event occurred, wiping out 95% of all living species. This meant that the Triassic fauna represented something of a restart for all life on Earth. The few species that managed to survive this mass extinction had to adapt to the new terrestrial and marine conditions.
Therefore, we are going to dedicate this article to telling you everything you need to know about the fauna of the Triassic.
Development of the Triassic flora
Despite this process of mass extinction on a global scale, numerous species were able to adapt to the new ways of life and, little by little, diversify over time. Throughout this period, plants formed vast forests, and it was the dinosaurs that began to dominate the planet. They were animals that dominated virtually all existing habitats on land, air, and sea.
Let's take a brief look at the development of flora during this period. At the beginning of the Triassic, many plants became extinct because environmental conditions were not conducive to their proper development and diversification. Therefore, the plants that survived this period of extinction were able to diversify quite easily, given the much lower level of competition. The plants that survived and diversified in large numbers were primarily those belonging to the gymnosperm group.
These plants are known as naked-seeded plants. Conifers and cycads stand out within this group of plants. Representatives of the ginkgo and fern genera were also quite important. Conifers represented the group of plants with thick, woody, and fairly resistant stems. Their leaves were typically evergreen and monoecious. This meant that both their male and female reproductive organs existed in the same individual.
On the other hand, cycads were plants with a woody stem and no branching. Their leaves were located at the apical end of the plant and were dioecious. This means that male and female individuals exist separately. Ginkgo were quite abundant during this period, and only the Ginkgo biloba species survives today. Finally, ferns were vascular plants that already belonged to the pteridophyte group and possess phloem and xylem.
Development of the Triassic fauna
The most representative fauna of this period was made up of two groups: reptiles and dinosaurs. It was the invertebrates that were able to achieve greater development at the level of the aquatic ecosystem. Some species of reptiles also developed in marine environments and were able to dominate much of the seas.
As for the air, some reptiles began to be observed that had certain adaptations to the present environmental conditions and were able to fly. To do this, they needed various anatomical mutations to adapt their arms and limbs to flight.
We are going to develop in a deeper way all the fauna of the Triassic.
Terrestrial Triassic fauna
Within these ecosystems, several groups of animals with unique characteristics developed: mammalian reptiles and dinosaurs.
Mammalian reptiles
This group became known as therapsids. Physically, these animals resembled a hybrid between a dog and a lizard. Their limbs were quite long in relation to the rest of their bodies, but they had very short tails. Their teeth varied in shape depending on the species' diet. When their diet was primarily herbivorous, their teeth were mainly molars. Molars are more practical for grinding plants. However, if their diet was entirely carnivorous, their canines and carnassial teeth were more developed.
Triassic dinosaurs
Dinosaurs are thought to have appeared during this period. Among the most representative dinosaurs are the prosauropods and theropods. Let's analyze the details.
Prosauropods
These were large animals with long necks. However, their necks were not as long as those of the herbivores that lived during the Jurassic period. Their forelimbs were less developed than their hindlimbs. There were several species within the prosauropods. The most prominent were Mussaurus and Sellosaurus.
Theropods
These were the other dinosaur groups that stood out during this period. They were a group of carnivorous dinosaurs. Their main characteristics included a bipedal gait and poorly developed forelimbs. The size of these species varied depending on the ecosystems in which they were found. As animal evolution preceded a mass extinction, genetic adaptations occurred more rapidly. This is because environments were changing rapidly at that time, as flora also underwent its own development.
Some theropod species were less than a meter long, while others could reach up to 12 meters. Some of the best-known theropod species were the Tawa and the Euroraptor.
Aquatic Triassic fauna
Invertebrates developed primarily within the aquatic environment. These were represented by mollusks, most notably gastropods, bivalves, and cephalopods. Some corals also developed on the seafloor.
Aquatic reptiles also saw significant development during this period. Notosaurs and ichthyosaurs are notable examples. Regarding aerial reptiles, there was also a group that developed remarkably well compared to others. They were able to develop membranes that extended from their torsos to their forelimbs, enabling them to fly. This group included pterosaurs, which were oviparous and had elongated beaks. They were carnivorous.
I hope this information helps you learn more about Triassic fauna.