Therapsids Characteristics | Therapsids Transition to Reptiles and Mammals

Therapsids

What are Therapsids?

Therapsids are a group of extinct mammals that lived from the late Permian to the Early Triassic. They are a group of synapsid animals that includes mammals and their extinct relatives.  The name “therapsid” is derived from the Greek word theras, meaning “wild beast,” and psídēs, meaning “foot.”

They were named after their most distinctive feature, which was a large opening in their skull called the temporal fenestra.

Therapsids are synapsid amniotes. They have a single temporal opening, with the lower jaw being located above it.

Synapsids are an evolutionary grouping of amniotes that includes mammals (including humans) and their extinct relatives, such as pelycosaurs (such as Dimetrodon) and therapsids.

Therapsids were a diverse and successful group in the Permian period but declined as the world changed.  The earliest known members of this group date from around 290 million years ago

The first specimens discovered were found by Sir Richard Owen in 1859, and they were originally classified as reptiles because of this cranial feature.

Later on, it was determined that they are more closely related to mammals than reptiles because of other features such as teeth and limb bones.

Therapsids Characteristics

Therapsids are a subgroup of synapsids that includes mammals and their extinct relatives (mammals, reptiles, and birds.)  The earliest known members of the group appeared in the Late Carboniferous, about 310 million years ago.

They were among the most successful land animals of all time, dominating terrestrial ecosystems for over 100 million years.  Most therapsid fossils have been found in North America and Europe.

They also had a mobile lower jaw that was able to move up and down as well as side-to-side. The skull is composed of two parts: the braincase and the mandible.

They were the dominant land animals in the early Permian period. The name “Therapsid” is derived from two Greek words meaning “beast-footed.”

In addition to having four legs like other synapsids, they have a fifth digit on their hands which became an opposable thumb for grabbing prey.

Therapsids are a group of synapsid tetrapods. They were the dominant land animals, and some even lived in freshwater environments.

The first known members of this group appeared near the end of the Carboniferous period (about 300 million years ago).

Therapsids had large brains, and they may have been warm-blooded or homeothermic because their brains required so much energy to function properly.

Therapsids Transition to Reptiles and Mammals

Animals evolved from their predecessors, the Therapsids, who were knee-high reptiles with small heads. The Therapsids first appeared in the fossil record about 385 million years ago during the Carboniferous period.

This was a time when dinosaurs walked the Earth when reptiles dominated and amphibians ruled.

The Therapsids, like everything else on Earth, evolved from invertebrates called early Paleozoic arthropods. One group of early Paleozoic arthropods, the trilobites, became extinct about 250 million years ago.

The second group of early Paleozoic arthropods, the worm-like ambulocarids, and nectrideans continued to evolve and eventually gave rise to three modern-day mammalian families. These three modern families are called mammals (mammals), insects (insects), and reptiles (reptiles).

The Therapsids (also known as the Insectivora) were the direct ancestors of two families of modern-day mammals: the Soricomorpha and the Talpidae. These two families are called “marsupials,” and they evolved in Australia (primarily) from shrew-like animals called “therian mammals,” which was a popular name for these animals during the 1800s.

Marsupials are well known today for their unique reproductive habits because the female gives birth once and then “abandons” her young to care for themselves.

The Therapsids also evolved into the earliest known American family of reptiles (the Synapsida) called the anomodonts. This family survived on Earth until about 165 million years ago in what is now North America.

The anomodonts were the ancestors of the first true reptiles, which were members of a group called diapsids. The diapsids appeared during the Triassic period and eventually evolved into the dinosaurs, which became extinct at the end of the Mesozoic (Mesozoic) era.

Members of both of these modern-day families, Soricomorpha and Talpidae, are still alive today in different parts of the world. The Soricomorpha family has spread worldwide to become one of the most widespread families of mammals.

Species of the Talpidae family are found in Europe and North America, but they are not very diverse. All known Talpids species are similar to one another (they all have large eyes, large ears, long tails, and claws) and seem to have been in existence since the late Jurassic period.

Why Did the Mammals Take Over from the Reptiles?

The first reptiles probably evolved from amphibians, and some of these early reptiles may have even lived in water.

By contrast, the first mammals–the Permian-era mammals (Mammalia)–were terrestrial. They needed to escape from larger predators on land, and they took over the Earth from reptiles in the form of dinosaurs and other predators soon after their appearance.

The explanation of why the mammals took over from the reptiles has little to do with religion or politics. Still, it is simply based upon scientific observations that relate to animal anatomy and physiology.

The difference between mammals and reptiles is that all reptiles lay eggs, but only a few modern mammals lay eggs. Others give birth to live young.

Mammals are warm-blooded, and most reptiles are cold-blooded (ectotherms). Reptiles have a solid, heavy skeleton in which their bones lock together and are not pliable.

In mammals, most fluids are circulated in the blood. In reptiles, most fluids are circulated inside the body.

The oldest known fossil remains of an elephant-like mammal are called Pakicetus, and this Eocene-era mammal became extinct about 40 million years ago.

Are humans Therapsids?

Therapsids are a group of mammals that includes animals like the cynodonts and therapsids.  The earliest known members of this group date back to about 260 million years ago, during the Permian period.

There is some debate as to whether humans should be considered therapsids because they lack many features typical for this group.

For example, human teeth do not have any canines or incisors, which are common in other mammalian groups.

Scientists believe they may have been the ancestors of humans and other primates.  If this is true, then humans would be considered Therapsids

What did therapsids eat?

Many therapsids have been found, but there is no true answer to what they all ate. Some of them may have been herbivores, while others were omnivores or carnivores. Many of them are thought to have been the ancestors of mammals, such as rodents or primates, and have some similarities between them and those groups.

While there is no true consensus on what the early mammals ate, there is one thing that all of these groups have in common: they were most likely all insectivorous.

Are Therapsids Dinosaurs? (Dinosaurs vs. Therapsids)

Do you know what Therapsids are? They’re not dinosaurs. But they are related. There are three main groups of Therapsids, and they were animals that lived from the Triassic to the end of the Carboniferous era. They shared some traits with dinosaurs and crocodiles, but they are not dinosaurs.

Therapsids had massive jawbones and teeth and had a huge variety of skull shapes. Therapsids could eat meat, unlike most reptiles at the time.

Therapsids also laid eggs, which was uncommon back in their time. Therapsids were carnivores and scavengers, and their hard shell of the back allowed them to operate without skin. They had a diversity of roles, but they were widespread across the world.

Cynodont Therapsids

Cynodont Therapsids are a subgroup of therapsids. They have two tusks on the upper jaw, and they are considered a closer relative to mammals than other Therapsids. Cynodonts were among the first to develop true mammalian characteristics: a single opening for the ear, a lower jaw independent of the upper jaw, and differentiated teeth.

The term “Cynodont” is derived from the Greek words “kyne,” meaning dog, and “odous,” meaning tooth.

Cynodonts are a subgroup of therapsids that evolved from apospondylid ancestors during the Permian period around 295 million years ago. The group was successful for the first few million years of its existence but began to decline in diversity and abundance towards the Triassic period.

Cynodonts first appeared in the Upper Permian Period and were among the fiercest predators on land at that time. They had sharp teeth and powerful forelimbs that they used to grab prey.

Some, like “Kryptops,” had enormous tusks that could be up to 2 meters long. The massive mass of the tooth and the strong jaw muscles were probably adaptations for crushing bark and harder food items. These tusks were also probably used in fights between males for access to mates.

The structure of the upper molar was a development unique to Cynodonts. Instead of closing at the tooth’s apex as in most other Therapsids, the upper molar teeth closed half-way on the buccal side so that the tooth had a double hinge.

This feature was likely an adaptation for shearing food items. The first upper molars of a young are just like those of all other land vertebrates, but as they stop growing and turn inward, they get more specialized. The molars then interlock, and the tooth becomes double-hinged.

As their name suggests, these Therapsids had two tusks on the upper jaw. These tusks were probably used for display, for foraging, and combat with other males. There was more variation in size and shape than seen in true Tusked Mammals such as elephants. Some were large and curved, while others were small and straight.

Therapsid Vs. Synapsids

Therapsids are a group of extinct synapsid animals from the Permian and Triassic periods. On the other hand, Synapsids are a group of extinct mammal-like reptiles from the Carboniferous to Cretaceous periods. Synapsids are animals closely related to mammals and were the dominant land vertebrates during the Triassic period.

One difference between these two is that synapsids have a single temporal opening in their skull behind each eye, while therapsids have two temporal openings on either side of their head. Synapsid skulls can be distinguished from those of other groups by their squarish shape.

Therapsids are a group of synapsid-like animals that lived during the late Permian and early Triassic periods. They were among the first groups of land animals to evolve from an aquatic environment to living on land.

Synapsids, which include mammals, are often considered more closely related to modern reptiles than they are to other types of synapsid-like animals like therapsids.

Therapsid fossils have been found in South Africa, Russia, China, and India, while Synapsid fossils have been found in North America and Europe.

Pelycosaurs and Therapsids

Pearlycosaurs were the first terrestrial vertebrates to evolve, and they are often considered to be the ancestors of mammals.  On the other hand, Therapsids were more closely related to modern-day reptiles than pelycosaurs, but they did have some mammalian features that distinguish them from other early synapsids.

Pearlycosaurs had a lizard-like body with four legs and a long tail; their jaws contained teeth in both upper and lower jaw like modern lizards do, while Therapsids had a larger skull with two rows of teeth on each side of their mouth; these animals also had fewer bones in their limbs compared to pelycosaurs.

Pelycosaurs were the first reptiles, and they had a lizard-like body and therapsids were also reptiles, but they looked more like mammals than lizards.

Pelycosaurs had large, flat heads with eyes on top, while therapsids had smaller skulls and eyes in front.

Pelycosaurs were carnivores, while therapsids were herbivores or omnivores.

Pelycosaurs lived in the Permian period, while therapsids lived in the Triassic period.

Largest Permian Therapsids