Segisaurus

Type Species: Segisaurus halli

Classification: Dinosauria – Saurischia – Theropoda – Coelophysoidae - Coelophysidae

Time Period: Early Jurassic

Location: North America

Diet: Carnivore

Segisaurus is known from a single sub-adult specimen from Arizona. The specimen discovered was just under three and a half feet long and would’ve stood just over one and a half feet tall at the hips. It was nimble and likely preyed upon insects, lizards, and small mammals (and there’s no reason to think it wouldn’t scavenge when the opportunity presented itself). Segisaurus had a flexible, elongated neck and stout body; its powerful legs were crowned with three-toed feet; and it had a long tail and long forearms. Segisaurus is remarkable for the fact that it seems to have had clavicles, which are unknown in other theropods from that era. This find demonstrates that the clavicle was primitively present in early theropods and reinforces the theory that modern birds are descended from theropod dinosaurs. 

Dracoraptor

Type Species: Dracoraptor hanigani

Classification: Dinosauria - Saurischia – Theropoda - Coelophysoidea

Time Period: Early Jurassic

Location: Wales, United Kingdom

Diet: Carnivore

The ‘Dragon Thief’ lived during the Hettangian stage 201-199 million years ago in what is now Wales in the United Kingdom. It was discovered in 2014 and named in 2016. The fossils discovered indicate Dracoraptor was about seven feet long head-to-tail with a hip height at just over two feet; however, this individual is likely a juvenile, so adults may have grown as long as ten feet. During this point in the Jurassic Period, South Wales was a coastal area dotted with several small islands in a warm, shallow sea. The fossils were recovered from what would’ve been a point offshore, so Dracoraptor had been washed out to see from the northern landmass before being entombed in the seabed. Scientists speculate that this theropod prowled the shorelines, feasting on small vertebrate animals – its teeth were only about a centimeter long – and scavenging when it could. It may have made short hops between islands; on one trip, the discovered Dracoraptor may have been caught in a squall and been drowned before being washed farther out to sea. 

Panguraptor

Type Species: Panguraptor lufengensis

Classification: Dinosauria - Saurischia - Theropoda - Coelophysoidea - Coelophysidae

Time Period: Early Jurassic

Location: China

Diet: Carnivore

Panguraptor – whose name means ‘Chinese plunderer’ – was a coelophysoid theropod from Early Jurassic China. Its remains were found in the Lufeng Formation, which captures snapshots of an alluvial plain of sandstone and mudstone. This was the first coelophysoid dinosaur found on the Asian continent. Being small, it was nowhere near the top of the food chain: its environment was dominated by crocodylomorph predators and the much larger, eighteen-foot theropod Sinosaurus. While Sinosaurus likely preyed upon sauropodomorphs of the area, or even upon smaller ornithischians, Panguraptor likely hunted small animals like lizards and mammals. Undoubtedly it would’ve been an optimistic scavenger, ransacking the bloated corpses left behind by a satisfied Sinosaurus.

Procompsognathus

Type Species: Procompsognathus triassicus

Classification: Dinosauria - Saurischia - Theropoda - Coelophysoidea - Coelophysidae

Time Period: Late Triassic

Location: Germany

Diet: Carnivore

Procompsognathus lived 210 million years ago during the Norian stage of the Late Triassic. Its remains were found in Germany, and it lived in a dry, inland environment. Other dinosaur contemporaries included dubious coelophysoids and the prosauropods Plateosaurus and Efraasia. Procompsognathus was a chicken-sized, lightly-built, bipedal predator that likely fed on insects, lizards, and other small prey. It had long hind legs, short arms, large clawed hands, a stiff tail, and a long, slender snout filled with many small teeth. It grew between 2.5 to 3.5 feet in length and likely weighed just over two pounds. Its tibia was about twenty percent longer than its femur, indicating that it was a fast runner. 

The screenshot above is a cinematic representation of Procompsognathus from the movie The Lost World. In the novels from which the movie was adapted, Procompsognathus carried a sleep-inducing toxin in its saliva. This has no basis in reality, for we cannot uncover any such evidences in fossil remains. However, many reptiles had such weapons, so the hypothetical presence of such abilities isn't without merit in the natural world.

Procompsognathus shouldn’t be confused with Compsognathus: the former lived during the Late Triassic whereas the latter lived during the Late Jurassic. Though they were about the same size, a larger turkey-sized species of Compsognathus has been discovered. The similarity in their names may imply some sort of relationship - "Did the Triassic dinosaur eventually lead to the Jurassic dinosaur?" - but the similarities are symbolic. There's no evidence that Procompsognathus was the genetic forerunner of the later and larger-sized Compsognathus.

Gojirasaurus

Type Species: Gojirasaurus quayi

Classification: Dinosauria - Saurischia - Theropoda - Coelophysoidea

Time Period: Late Triassic

Location: New Mexico

Diet: Carnivore

Gojirasaurus’ name means ‘Godzilla lizard’ and is named after (unsurprisingly) the infamous Japanese monster (Gojira is the Japanese name for Godzilla). One might think, then, that it was discovered in Asia, but its remains were actually uncovered in New Mexico. Why, then, the Japanese connection? The answer is two-fold: first, this predatory theropod was a monster for its time – a ‘Godzilla’, if you will. Second, a theropod dinosaur with the name Godzillasaurus exists in the Heisei era of Godzilla films, and in that continuity is explained to be the un-mutated form of Godzilla; thus the naming of this creature Gojirasaurus is, in essence, a play on Japanese film: “Here is the creature from which Godzilla mutated!” This is why, when searching for images of Gojirasaurus, you’ll come across a lot that have Godzilla’s spinal decorations. Alas, these additions are callbacks to Japanese cinematography rather than deciphered from the fossil record.

a rendition of Gojirasaurus that is heavy on the Godzilla connection

Gojirasaurus lived in the Norian stage of the Late Triassic around 228 to 208 mya. It was one of the largest meat-eating dinosaurs of its time (if not the largest): it dwarfed Liliensternus and grew just shy of the length enjoyed by the early Jurassic Dilophosaurus. Scientists estimate it grew up to eighteen feet long and weighed between 330-440 pounds. Features of the pelvis and ankle suggest to some that the fossil specimen we have is from a juvenile; if that’s the case, an adult Gojirasaurus would’ve grown much larger, perhaps dwarfing even Dilophosaurus and its kin. For this reason it might be considered the ‘Allosaurus’ of its time.

Coelophysis

Type Species: Coelophysis bauri

Classification: Dinosauria - Saurischia - Theropoda - Coelophysoidea - Coelophysidae 

Time Period: Late Triassic to Early Jurassic

Location: Southwestern U.S.A. and Africa

Diet: Carnivore

Coelophysis fossils have been found in the southwestern United States and in South Africa and Zimbabwe. It was a small, slender bipedal carnivore that could grow up to nearly ten feet in length and was about three feet in height at the hips. It appeared in the Upper Triassic of the Norian stage and survived through the Triassic-Jurassic extinction before dwindling to extinction in the Jurassic. Coelophysis probably weighed around forty pounds and was a fast, agile runner. Coelophysis’ anatomy was advanced from that seen in the Carnian-era’s Eoraptor and Herrerasaurus, and the type species (Coelophysis bauri) already had a wishbone (the earliest example in dinosauria, and which would become a central piece of bird anatomy). Coelophysis’ forelimbs were designed for grasping prey. The long tail had an unusual structure within its interlocking prezygapophysis (the ‘pipe-fitting’ of vertebrae) creating a semi-rigid lattice that prevented the rigid tail from moving up and down. Its head was nearly a foot long with large, forward-facing eyes that provided stereoscopic vision and excellent depth perception. Its sclerotic rings indicate that it was a diurnal (it was most active during daytime and likely slept at night). A study of its sclerotic rings further indicate that its vision was far superior to that of lizards and ranked up with those of birds of prey; Coelophysis’ orbital structure closely resembles those of eagles and hawks. It probably had poor night vision.

Gregarious behavior for Coelophysis is hotly debated

Coelophysis’ teeth indicate it was carnivorous: the teeth were blade-like and recurved with sharp, jagged serrations. It likely preyed on small, lizard-like animals, and many scientists believe it could run in packs and coordinate with others of its pack to bring down larger prey; however, because its forelimbs – despite a wide range of motion – were weak, and because its teeth were relatively small, it’s likely that it spent most of its time chasing after small prey. This doesn’t mean, of course, that Coelophysis wasn’t gregarious: the Ghost Ranch bone-bed of New Mexico contains over a thousand of Coelophysis remains, and it may very well  be that Coelophysis ‘flocked’ like modern birds. Another theory is that Coelophysis generally hunted on their own but congregated around watering-holes. It may be the case that Ghost Ranch is the scene of a one-up tragedy: while gathering together to feed on a spawning run of fish before being buried in a catastrophic flash flood. Proponents of gregarious behavior among Coelophysis point to sexual dimorphism as evidence: two ‘morphologies’ of Coelophysis exist, and these may indicate a male or female species. Dimorphism among a species usually indicates gregarious behavior, and a further study of sexual dimorphism among this dinosaur showed that the different morphologies were split close to half-and-half of the population – exactly what you’d expect in a gregarious social hierarchy. A wrench in the theory, however, is the growth rates of Coelophysis: hatchlings grew rapidly during the first year of life and likely reached adulthood by their third birthday. Such fast growth is seen in animals that need to fend for themselves upon birth. A 2009 comparative study between Coelophysis and modern birds and reptiles indicates that Coelophysis laid between 24-26 eggs in each clutch and that parental care was necessary to nurture the relatively small hatchlings during the first year of life. When all these threads come together, there’s no consensus on whether Coelophysis was gregarious – further study (and discoveries) are needed.

a lone Coelophysis on the prowl

Camposaurus

Type Species: Camposaurus arizonensis

Classification: Dinosauria - Saurischia - Theropoda- Coelophysoidea - Coelophysidae 

Time Period: Late Triassic

Location: North America

Diet: Carnivore

Camposaurus emerged in the Norian stage of the Late Triassic of North America. These feisty carnivores belonged to a group of theropods called the coelophysids; these were slender, carnivorous dinosaurs that include Coelophysis, Procompsognathus, and Liliensternus. Some coelophysoids lived in packs, but not necessarily all. They may have had scales, pebbly hides, or even feathers. Camposaurus, as one of the earliest coelophysoids, has been regarded by many paleontologists as the oldest known neotheropod (a group of theropods that emerged during the Upper Triassic and would spawn the dilophosaurs, ceratosaurs, and tetanurans – the latter of which continues to the present day in the form of birds). 

We have only fragmentary remains of this carnivorous dinosaur – mostly partial leg bones – so our knowledge of this creature isn’t spectacular. What is known is that it was small, but not much else. Its classification in the ‘dinosaur family tree’ has been here and there over the years. In 1995 it was considered a Ceratosaur; slightly later it was identified as simply another species of the infamous Coelophysis. In 2011, based upon phylogenic studies, it was distinguished from Coelophysis but only by a hair’s breadth, making them closely related. Because of its close affinity with Coelophysis, scientists guess that Camposaurus may have been a social animal that lived in packs and that it would’ve fed on small mammals, insects, fish, and the plethora of amphibians of the Upper Triassic ecosystems.