Category: science illustration

Colobomycter

Colobomycter pholeter, a parareptile from the Early Permian of Oklahoma, USA (~289 mya). Although known only from partial skull fossils, its full size was probably around 30cm long (1′).

It had huge fangs at the front of its jaws, along with a few other enlarged teeth further back, all with serrated edges that show it was clearly a predator. What exactly it was feeding on with this unusual tooth arrangement is unknown – but proposed ideas include piercing through hard-shelled arthropods, or stabbing into smaller vertebrate prey.

Waharoa

Waharoa ruwhenua, a whale from the Late Oligocene of New Zealand (~27-25 mya). Part of an early branch of the baleen whale lineage, it’s known from partial remains of an adult and a couple of juveniles and would have reached a full size of about 6m long (19′8″).

It had an unusually long flattened snout, with its nostrils further forward than modern whales, and only had baleen in the back half of its mouth – an interesting comparison to the intermixed teeth-and-baleen of some other early mysticetes. It’s not clear whether it had any vestigial teeth in the front of its jaws, although a single possible tooth has been found associated with its close relative Tokarahia.

The rather delicate nature of Waharoa’s jawbones suggests it wasn’t capable of rapid lunges at swarms of its small prey, instead probably using slow-cruising surface skim-feeding similar to modern right whales.

Bulbasaurus

Who’s that synapsid?

It’s Bulbasaurus phylloxyron!

This creature was a member of the dicynodonts, a group of herbivorous mammal-relatives with beaks and protruding tusks. Its fossils are known from the Late Permian of South Africa, about 259-254 million years ago, and it would have been roughly the size of a cat, around 60cm long (2′).

It wasn’t officially named after the pokémon character Bulbasaur, but instead in reference to the bulbous bosses on its snout. But combined with how the species name “phylloxyron” means “leaf razor”, it doesn’t seem to entirely be a coincidence.

Pisanosaurus

Pisanosaurus mertii from the Late Triassic of Argentina (~228-216 mya).

Known only from a partial skull and a few pieces of its skeleton, this 1m long animal (3′3″) is usually considered to the be the earliest known member of the ornithischian dinosaurs – but some recent studies have thrown that into question, suggesting that it might not even be a dinosaur at all.

Instead it may have been a member of the silesaurids, Triassic dinosauriforms that were close cousins to the dinosaurs but not quite true members of the group. Small and lightly-built, silesaurids had long front limbs and may have been at least partially quadrupedal, and some showed evidence of herbivory with beaks at the tips of their snouts.

Of course, if the “oldest ornithischian” is actually a silesaurid, we’re left with no fossil record at all for ornithischians until the start of the Jurassic. And that brings back up the controversial question of where they actually originated…

Halszkaraptor

Halszkaraptor escuilliei, a dromaeosaurid (“raptor”) dinosaur from the Late Cretaceous of Mongolia (~75-71 mya). It’s known from a single near-complete skeleton and would have been about the size of a modern mallard duck, around 60cm long (2′).

It had some very odd features for a raptor, with many small sharp backwards-pointing teeth, crocodile-like sensory pits on its snout, a long flexible neck, small flipper-like arms, a relatively short tail, and a more upright body posture than its other relatives. All these traits together suggest it may have been semi-aquatic, which is a pretty big deal since the only other group of non-avian dinosaurs known to have developed adaptations for life in the water were the spinosaurids.

The fossil was originally illegally excavated by fossil poachers and was owned by private collectors for several years, but it has now been returned to science and is due to be repatriated to Mongolia. With its odd anatomy and the exact origin of the specimen being unknown, there’s some skepticism about whether Halszkaraptor represents a genuine animal or an elaborate fake chimera – but synchrotron scans of the fossil and its similarity to previously-discovered more fragmentary short-armed raptors like Mahakala suggest that it is real, and it really is that weird.

Orthrozanclus

Orthrozanclus elongata, from the mid-Cambrian of China. Only about 2cm long (~0.8″), this tiny creature was covered in both long spines and extensive armor – with tile-like scales on its back, overlapping dagger-shaped plates around its sides, and a small shell on its head.

It’s the second species of Orthrozanclus to be discovered, extending the genus’ range about 10 million years older than the Canadian O. reburrus.

Although it would have been a member of the Lophotrochozoa (the group that contains modern molluscs, annelid worms, and brachiopods), its exact evolutionary relationships are still uncertain. It might have been a transitional form between Wiwaxia and the halkieriids, or it could be closer related to the brachiopods.

Bunostegos

Bunostegos akokanensis, from the Late Permian of Niger (~260 mya). About 2.5m long (8′2″), similar in size to a modern cow, it was a member of a group known as the pareiasaurs – stocky herbivorous reptile-relatives with osteoderm armor in their skin and knobbly bony nodules on their skulls.

The anatomy of its limb bones suggest it walked fully upright, with its legs held vertically under its body. This sort of posture has independently evolved multiple times in different tetrapod lineages, but Bunostegos is one of the earliest known examples.

Thoatherium

While this animal might look like some sort of deer or horse, it was actually only distantly related to any modern hoofed mammals.

This is Thoatherium from the Early Miocene (~17-16 mya) of Argentina. About 70cm long (2′3″), it was related to the weird llama-like Macrauchenia and was part of an extinct group of ungulates (the Meridiungulata) which evolved during South America’s time as an isolated island continent.

It was adapted for fast running, with long legs and only a single horse-like hoof on each foot – but it was even more one-toed than modern horses are, having no remaining “splint bones” from vestigial side toes.

Jamaican flightless ibis

The Jamaican ibis (Xenicibis xympithecus) was a bird unique to the Caribbean island of Jamaica. One of only two known types of completely flightless ibises, it was similar in size to a chicken – probably around 75cm long (2′5″) and weighing 2kg (4.4 lbs).

It had some incredibly unusual wing anatomy, with strengthened bones, a proportionally short forearm, and the “hand” section modified into a thick club-like shape. Some remains show evidence of blunt-force injuries, suggesting these birds fought each other by swinging around their heavy wings like baseball bats.

Its bones have found in several cave deposits which are difficult to accurately date, but are likely to be somewhere between 10,000 and 2,200 years old. It’s unclear whether Xenicibis was still around when humans first colonized the island, but if so it was probably driven to extinction soon after.

Shringasaurus

Shringasaurus indicus, an archosauromorph reptile from the Middle Triassic of India (~247-242 mya). About 3-4m long (9′10″-13′1″), it was part of a group known as the allokotosaurs, specialized herbivores with lizard-like bodies, and was related to the strange long-beaked Teraterpeton.

Partial remains of about seven different Shringasaurus individuals of varying ages have been found, with several of them having large curving horns over their eyes convergently similar to those of the later ceratopsids. A couple of adult specimens lack horns entirely, suggesting the feature was sexually dimorphic with only the males developing ornamentation – a very rare arrangement among archosauromorphs, but similar to some horned mammals.