paleoween – Nix Illustration

Garamaudo

Garamaudo bauciensis was a mosasaur that lived during the Late Cretaceous, about 84 million years ago, inhabiting freshwater lakes and marshes in what is now southeastern France.

Its genus name comes from the Provençal expression “gara au maudo”, meaning “beware the cursed one”, referring to an aquatic serpentine monster of local legend.

Around 2.5m long (~8’2″), Garamaudo was a fairly “primitive” mosasaur, with limb anatomy closer to the legs of terrestrial lizards than the paddle-like flippers of later forms. It had increased bone density that would have helped control its buoyancy and aided it in diving — but this also would have made it unable to move around on land due to the increased fragility of its heavier bones.

It probably swam with an eel-like motion and may not have been particularly speedy or maneuverable, possibly relying on ambush predation to capture its prey.

It would have been one of the largest aquatic predators in its ecosystem, living alongside gars, turtles, small crocodilians, and some of the last known freshwater coelacanths.

Gargoyleosaurus

Gargoyleosaurus parkpinorum was a very early ankylosaur that lived in what is now Wyoming, USA, during the Late Jurassic, about 154-150 million years ago.

Known from a partial skeleton — including much of its armor preserved in place — it was a fairly small ankylosaur, around 3.5m long (~11’6″). Its head was proportionally small, its snout was rather narrow, and unlike later members of the group it still had teeth in the front of its jaws.

It would have inhabited the warm and semi-arid “Jurassic savanna” environment of western North America, feeding on vegetation along river flood plains and sharing its ecosystem with more famous dinosaurs such as Stegosaurus, Diplodocus, and Allosaurus.

Alienacanthus

Alienacanthus malkowskii was a placoderm armored fish that lived in the seas covering what is now Europe and northern Africa during the late Devonian, about 365 million years ago.

First discovered in the 1950s, this species was originally known only from some strange elongated bony elements that were interpreted as fin spines. But more recent finds of near-complete skull material revealed a surprise — the “spines” were actually this animal’s extremely elongated lower jaw!

Around 2.5m long (~8’2″), it was probably a streamlined open ocean swimmer that may have used its bizarre underbite similarly to the snouts of modern billfish, slashing at and stunning soft-bodied prey.

Ogresuchus

Ogresuchus furatus was a small crocodyliform that lived during the Late Cretaceous, about 66 million years ago, in what is now Catalonia, Spain.

It was originally classified as a sebecid, which would have made it the earliest known member of that family, but a more recent analysis suggests it was probably instead an atoposaurid.

Around 1m long (~3’3″), it was a lightly-built generalist predator that would have fed on invertebrates and small vertebrates — possibly even including sauropod hatchlings, since its fossil remains were discovered in a titanosaur nesting site.

Styxosaurus

Styxosaurus snowii here was one of the largest known elasmosaurids, named after the mythological river separating the worlds of the living and the dead.

Reaching around 11m long (36′), with half of that being entirely neck, it lived during the late Cretaceous period about 83-80 million years ago in what is now the American Midwest – a region that at the time was submerged under a large inland sea.

With pointy interlocking teeth in its proportionally tiny head, Styxosaurus would have fed on slippery aquatic animals like fish and cephalopods, possibly using its long neck to get up close to its targets while the bulk of its body remained out of sight in dark murky waters. Large numbers of gastroliths found in the stomach regions of some specimens would have been used to grind up the hard parts of prey items after they were swallowed whole.

Phiomicetus

Named after the canine-headed Ancient Egyptian god, Phiomicetus anubis is the first fossil cetacean to discovered, described, and named entirely by a team of Arab paleontologists.

Living during the mid-Eocene, about 43 million years ago, in a shallow sea-covered region that is now part of Egypt‘s Western Desert, Phiomicetus was an early protocetid – an amphibious foot-powered swimmer, at a transitional point in the evolution of whales from deer-like terrestrial animals to fully aquatic screaming torpedoes.

About 3m long (~10′), it had large jaw muscles and sharp teeth with wear patterns that suggest it was a raptorial hunter grabbing and snapping at prey with powerful bites. It would have probably tackled fairly big prey compared to other protocetids, hunting things like large fish, turtles, and even smaller whales in an ecological role similar to that of modern orcas.

Along with the distantly-related long-snouted Rayanistes it’s one of the earliest known whales from Africa, giving us further glimpses at a time period when early cetaceans were first dispersing out from the South Asian subcontinent via the ancient Tethys Sea.

Joermungandr

Named after a legendary Scandinavian serpent, Joermungandr bolti here was a recumbisrostran “microsaur” – part of a group of animals that were traditionally considered to be lepospondyl amphibians, but more recently have been proposed to in fact be a lineage of early reptiles.

Discovered in the Mazon Creek fossil beds in Illinois, USA, this species dates to the late Carboniferous period around 310 million years ago. A single near-complete specimen about 5cm long (~2″) preserves impressions of the body outline and numerous tiny scales, giving us a pretty good idea of what it looked like in life.

Joermungandr had a long streamlined tubular body with small limbs and a short tapering tail, and a stubby snout with fused bones heavily reinforcing its skull. Along with microscopic ridges on its body scales that resemble the dirt-repelling scales of some modern reptiles, this combination of features suggest it was a headfirst burrower that wriggled its way through soil with snakelike motions.

Spectrovenator

(This is a couple of days late for Halloween, but since this October saw the description of a new dinosaur species with a particularly spooky name, I couldn’t resist putting it into the schedule anyway.)

Spectrovenator ragei was an early member of the abelisaurid lineage, living in southeastern Brazil during the Early Cretaceous, about 120 million years ago. It was one of the smallest known abelisaurids, measuring just 2m long (6’6″), and lacked a lot of the skull specializations seen in larger-bodied Late Cretaceous forms like Carnotaurus, suggesting it was more of a generalist predator.

Its genus name translates to “ghost hunter” due to it being found underneath the fossil remains of another dinosaur entirely – a “ghost” unexpectedly appearing when the specimen was being prepared – but it’s extra appropriate since it also helps to fill in a rather sizeable ghost lineage in the fossil record of abelisaurids.

Anzu

Named after the mythological bird-like Anzû – and also nicknamed “the chicken from hell” – Anzu wyliei was one of the larger known oviraptorosaurs, measuring about 3m long (9’10”).

Its fossils are some of the most complete for a North American member of this dinosaur group, with four different specimens representing about 80% of the whole skeleton.

Living right at the end of the Cretaceous, about 66 million years ago in North Dakota and South Dakota, USA, Anzu inhabited the ancient floodplains of Hell Creek and appears to have been a fairly fast-moving omnivorous generalist. It had a large crest on its head made of rather fragile thin-walled bone, which may have been used for display or sound amplification similar to the casque of modern cassowaries.

Some of the fossil specimens also show evidence of healed injuries, including a broken rib and an arthritic toe.

Kerberos

Named after the mythical dog Cerberus, Kerberos langebadreae was a member of an early group of carnivorous placental mammals known as hyainailourids.

These large-headed predators were part of the hyaenodont lineage, evolutionary cousins to modern carnivorans that convergently developed similar shearing carnassial teeth in their jaws. Hyainailourids originated in Africa during the late Paleocene or early Eocene, and repeatedly dispersed into Eurasia and North America before eventually going extinct in the mid-Miocene.

Kerberos was one of the earliest of its kind known from Europe, living in Southern France during the mid-Eocene about 41-38 million years ago. It was close in size to a small American black bear, standing around 65cm tall at the shoulder (2’2″), not nearly as large as some of its later relatives but still making it one of the biggest carnivorous mammals in Europe at the time.

It was a heavily-built animal with a fully plantigrade posture, and would have been an active apex predator hunting similarly-sized early ungulates. While it wasn’t anatomically specialized for fast running it didn’t really need to be – it’s important to remember that modern bears have a similar chunky flat-footed build and yet can move surprisingly quickly.

Its incredibly powerful jaw muscles and premolar teeth adapted for bone-cracking also suggest it ate like a hyena, efficiently consuming entire carcasses.