rauisuchians

((Decided to sketch out some Godzilla anatomy. This is just a lateral skeletal view, but I’ve scanned it into my computer and plan to add muscles and whatnot later.

Godzilla is difficult to phylogenetically categorize because it has traits of many different groups of animals. The antorbital fenestrae and lateral temporal fenestrae would suggest that it’s a dinosaur, but the temporal orbit is a synapsid trait, and no known genera of animals possess both features (while we’re on the subject of fenestrae, I drew the mandibular fenestra far too large. I’ll fix that later). Godzilla has a fulcrum, or wishbone, which is an advanced archosaurian trait, again suggesting a dinosaurian lineage, but its well-developed gills, highly unusual skull morphology, and lack of any evidence for a perforate acetabulum in the hip exclude this possibility. It is most likely that Godzillaformes were among the earliest reptile lineages to diverge after the emergence of amniotes, and may not even be true reptiles at all.

The rib structure, which is solid, unlike that of most reptiles, which have jointed ribs, is very similar to that of a sperm whale. This rib structure, which probably evolved initially as an adaptation for deep sea diving, apparently allows Godzilla to expand and contract its thoracic cavity with a great degree of freedom, and absorb tremendous pressure without creating stress points and risking damage.

The ilium, which anchors the quadriceps, gluteal complex, and femoral biceps, is highly expanded, and has a unique “flower” shape, owing to the massive muscular anchors it supports. This shape led Dr. Serizawa to name the Godzillasaur specimen discovered in 1999 “Godzillasaurus archithera sakura,” though this has since become a nomen dubium. The acetabulum is oriented downward, as in rauisuchians, rather than laterally, as in dinosaurs and mammals, likely an adaptation for supporting the animal’s tremendous bulk.

The hip, knee, and ankle joints are highly disarticulated, resting on thick shock-absorbing pads, and held in place by the powerful ligaments and muscles at each joint. The ligaments connecting Godzilla’s joints are among the strongest organic soft tissues known to science, and are so durable that several were found to have completely fossilized in the 1999 specimen, though they were not ossified in life. Beneath the metatarsus is another fleshy pad, which directly supports the tibia, as in sauropods and elephants. The pubis (which I also need to redraw a bit) is exceptionally large, and is used to support the animal’s weight when lying down.

Neural projections along much of the spinal column support a massive system of muscles and tendons running from the neck and down much of the tail, which keep the abdomen in an upright position, not unlike the “suspension bridge” arrangement of sauropod dinosaurs.

Although they have mostly been omitted, many of the scutes in Godzilla’s skin are reinforced with osteoderms, the most prominent of which being the three rows of dorsal fins along its back. These fins are not connected to the vertebral column by bone, but by elastic ligament systems, which allow them to flex at the base without breaking. This flexion is not related to any muscle movements, and is therefore involuntary, but it can be observed whenever Godzilla’s body makes a sharp movement or absorbs a great deal of shock.))

In the early to middle Triassic, some archosaur groups developed hip joints that allowed (or required) a more erect gait. This gave them greater stamina, because it avoided Carrier’s constraint, i.e. they could run and breathe easily at the same time. There were two main types of joint which allowed erect legs:

  • The hip sockets faced sideways, but the knobs on the femurs were at right angles to the rest of the femur, which therefore pointed downwards. Dinosaurs evolved from archosaurs with this hip arrangement.
  • The hip sockets faced downwards and the knobs on the femurs were in line with the femur. This “pillar-erect” arrangement appears to have evolved independently in various archosaur lineages, for example it was common in Rauisuchia and also appeared in some aetosaurs.

source

Pisanosaurus mertii

Source: http://upload.wikimedia.org/wikipedia/commons/b/b9/Pisanosaurus.jpg

NamePisanosaurus mertii 

Name Meaning: Merti & Mr. Pisano’s lizard

First Described: 1967

Described By: Casamiquela

ClassificationDinosauria, Ornithischia, Pisanosauridae 

My Twelfth Favorite Dinosaur! 

Oh look another basal dinosaur what a surprise. Pisanosaurus is considered to be the basalmost ornithischian, or at least the basalmost one known to date. It lived between 228 and 216.5 million years ago in the Norian age of the Late Triassic period. It was found in the Ischigualasto Formation in Argentina and it was a small, lightweight, bipedal herbivore about 1 meter long. Its classification has been under a lot of debate but the current consensus is that it is the oldest known ornithischian. It is only known from a single skeleton that is known from a partial skull and some teeth, some vertebrae, and other bones including part of the pubis, allowing for its classification. Given the synapomorphic character of protofeather/feather like integuments it probably was covered with them in at least some parts of its body. It lived in a volcanically active floodplain that was covered with forests and was warm and humid, but subject to seasonal rainfalls. It probably ate the vegetation of the area which consisted of ferns, horsetails, and conifers. Its major predator was probably Herrerasaurus, which was the most common predator in the area. Pisanosaurus lived right alongside therapsids, rhynchosaurus, dicynodonts, traversodontids, rauisuchians, archosaurus, Saurosuchus, and Eoraptor as well as Herrerasaurus. Herbivorous dinosaurs such as Pisanosaurus were definitely in the minority. 

Source: 

https://en.wikipedia.org/wiki/Pisanosaurus

Shout out goes to anonbinarywolf!