Nix Illustration – Paleontology and science illustration, and feathering ALL the dinosaurs

Featured

Hello there!

Welcome to the ~~long-overdue~~ new version of Nix Illustration!

Pardon our dust – we’re still working on getting everything properly set up here, and also gradually importing in multiple years’ worth of archived content from tumblr.

Please note that unless otherwise stated, all original non-commissioned work here is published here under a Creative Commons Attribution-NonCommercial license (CC BY-NC 4.0) – you are welcome to use images for non-profit , educational, or personal purposes, provided you credit me and give proper attribution.

Please contact via email (mail@nixillustration.com) to inquire about commercial image licensing or custom commission work.

In the meantime, you can find more complete selections of work at any of these places:
Tumblr | Twitter | Patreon

Current archive status:
–posts from pre-2018 still in progress

Mosura

Mosura fentoni was a small radiodont living during the mid-Cambrian, about 508 million years ago, in near-equatorial shallow marine waters covering what is now western Canada.

Sixty specimens have been discovered in the Burgess Shale fossil deposits, ranging from 1.5cm long juveniles (~0.6″) to 6cm long adults (~2.4″), giving us a detailed look at Mosura’s anatomy and life history. It had three eyes – two on the sides of its head on short stalks and one in the middle of its face – and a pair of grasping frontal appendages each with six long sickle-shaped spines.

Unusually for a radiodont its body was divided into distinct regions: a four-segment neck, a six-segment mesotrunk with large swimming flaps, and an abdomen-like posterotrunk with up to at least sixteen segments (fewer in juveniles), all bearing gills along their undersides.

Its vaguely moth-like shape led to it being nicknamed “sea-moth” by field collectors, and inspired its genus name – “Mosura” is the Japanese name of the fictional giant kaiju moth-monster Mothra.

With a very high proportion of respiratory surface area for its size, Mosura was probably an active and agile fast-swimming predator, possibly living in low-oxygen waters around the outer continental shelf. Its wide oval central eye may have helped it stay orientated during rapid maneuvers, keeping track of the horizon line similar to the median eyes of modern dragonflies.

Shishania

Shishania aculeata lived during the mid-Cambrian, around 512 million years ago, in shallow tropical waters covering what is now southwestern China.

Up to about 6cm in length (~2.4″), its spine-covered body was initially thought to be an early mollusc, but the discovery of more specimens has resulted in a new interpretation: instead of a slug-like creature, the fossils of Shishania might instead represent a flattened and ruptured chancelloriid.

Chancelloriids were an enigmatic group of Cambrian animals that had hollow bag-like bodies armored with numerous sharp star-shaped spines. They were historically classified as sponges due to their similar body plan and immobile filter-feeding lifestyle, and they’ve also been proposed to be relatives of halkieriid molluscs due to similarities in the microscopic structure of their spines – but currently it seems most likely that chancelloriids were actually their own separate lineage of early animals, closer related to eumetazoans than to sponges.

Shishania had much simpler spines than other chancelloriids, so it may represent an early stage of the evolution of these animals’ armor, showing that these structures were developed from scratch rather than adapted from a pre-existing ancestral feature.

Thrinacodus gracia

Thrinacodus gracia* was a stem–elasmobranch – a cartilaginous fish related to modern sharks and rays – living in what is now Montana, USA during the mid-Carboniferous around 324 million years ago.

* previously known as Thrinacoselache gracia

Although the cartilaginous skeletons of chondrichthyans rarely preserve, the exceptional preservation conditions of the Bear Gulch Limestone fossil deposits mean we do actually have full-body soft tissue impressions of this species. It was about 1m long (3’3″) with an unusually slender eel-like body, a pointed snout, no dorsal fins, and an elongated tapering tail.

Preserved gut contents show that Thrinacodus gracia preyed on shrimp-like crustaceans and smaller cartilaginous fish such as Falcatus and Harpagofututor. It would have inhabited a shallow tropical bay environment, and may have had a similar sort of lifestyle to the modern eels it resembled, hiding in crevices or burrowing into sediment and ambushing passing prey.

Dinosorex

Dinosorex, the “terror shrew”, was a genus of eulipotyphlan mammal found across much of Europe for most of the Miocene, ranging from about 23 to 9 million years ago. Part of a family of stem-shrews known as heterosoricids, it was larger than most of its living relatives – probably around 15-20cm long (6-8″) – and inhabited subtropical swampy forest environments.

Dinosorex kaelini here was one of the later species in this lineage, living in what is now Switzerland around 12-10.5 million years ago.

It had massive incisor teeth at the front of its jaws and crushing teeth further back, specialized for grabbing, immobilizing, and cracking open prey like hard-shelled invertebrates. Similar to some modern shrews the tips of these teeth were also reinforced with iron in their enamel, which would have given them a striking dark red coloration.

But while Dinosorex was quite abundant and successful during its time, it seems to have had such a specific ecological preference that it couldn’t adapt when the climate shifted towards the end of the Miocene. Drier conditions and more open savannas quickly took over, and the terror shrews disappeared along with the lush humid forests they were so dependent on.

Hwiccewyrm

Hwiccewyrm trispiculum lived during the late Triassic, around 208-202 million years ago, in what is now England. It was one of the last known members of the procolophonid family, a lineage of small stocky lizard-like animals that had been widespread and abundant earlier in the Triassic.

(Traditionally procolophonids are classified as parareptiles, but some recent studies suggest this group is paraphyletic or polyphyletic, with some “parareptiles” potentially nesting within the diapsids instead.)

Measuring around 30cm long (~1′), Hwiccewyrm had wide flaring cheek bones ornamented with large spines, and like some other procolophonids it may also have had bony scute armor on its body. Its large blunt teeth suggest it was feeding on particularly tough foods such as fibrous vegetation or hard-shelled invertebrates.

Solenochilus

The distinctive pinhole eyes, leathery hood, and numerous tentacles of modern nautiluses were traditionally thought to represent the “primitive” ancestral state of early shelled cephalopods – but genetic studies have found that that nautiluses actually secondarily lost the genes for building lensed eyes, and their embryological development shows the initial formation of ten arm buds (similar to those of coeloids) with their hood appearing to be created via fusing some of the many tentacles that form later.

There’s a Cretaceous nautilidan fossil that preserves soft tissue impressions of what appear to be pinhole eyes and possibly a remnant of a hood, so we know these modern-style nautilus features were well-established by the late Mesozoic. But for much more ancient Paleozoic members of the lineage… we can potentially get more speculative.

So, here’s an example reconstructed with un-nautilus-like soft parts.

Solenochilus springeri was a nautilidan that lived during the Late Carboniferous, around 320 million years ago, in shallow tropical marine waters covering what is now Arkansas, USA.

Up to about 20cm in diameter, (~8″), its shell featured long sideways spines which may have served as a defense against predators – or possibly as a display feature since they only developed upon reaching maturity.

Mexidracon

Mexidracon longimanus was an ornithomimid dinosaur that lived during the late Cretaceous, about 72 million years ago, in what is now northern Mexico.

It was a fairly small ornithomimid at around 2.5-3m long (~8-10′), and its leg proportions suggest it was less specialized for fast running than some of its other relatives. But its most unique feature was its hands, with extremely elongated metacarpal bones – giving it palms that were longer than its upper arm!

It’s unclear what the function of these unusual limbs was. Possibly they gave Mexidracon extra reach to hook its claws onto foliage and pull it within reach of its head, in a similar manner to ground sloths, chalicotheres, and therizinosaurs.

April Fools 2025: When Pterosaurs Were Swimming Gryphons

When it was first described by Cosimo Alessandro Collini in 1784, Pterodactylus wasn’t originally interpreted as a flying reptile. The idea that species could go completely extinct wasn’t fully understood yet, so fossils were assumed to represent things that still existed somewhere in distant unexplored regions. And so, since the oceans seemed like the best place for undiscovered animals to hide, this strange little creature was initially speculated to be aquatic.

Although it was soon properly recognized as a flying animal with some surprisingly mammal-like early reconstructions, the aquatic idea persisted until at least 1830 when Johann Georg Wagler published a restoration of Pterodactylus with huge membranous paddle-like flippers. He even grouped pterosaurs together with ichthyosaurs, plesiosaurs, and monotremes in a proposed vertebrate class called “Gryphi” (literally “gryphons“) and considered them all to be transitional between birds and mammals.

Wagler’s whole classification system seems esoteric and improbable by modern standards, but it’s a fascinating look at a pre-Darwinian “chain of being” sort of mindset where all organisms were thought to exist in a fixed hierarchy with pre-set roles.

Incamys

Incamys bolivianus was a caviomorph rodent representing an early member of the chinchillid family, with its closest modern relatives being chinchillas and viscachas.

Living in what is now Bolivia and Argentina during the late Oligocene about 27 million years ago, it inhabited an arid open grassland at a time when the area’s climate had drastically cooled due to the formation of the Antarctic Circumpolar Current.

It’s estimated to have been similar in size to a large modern chinchilla – weighing around 700g (~1lb 8oz) and measuring about 25-30cm long not including the tail (~10-12″).

An endocast of the shape of its brain from a near-complete fossil skull shows that it had a well-developed sense of hearing, particularly in vocalization processing, suggesting it may have been a social animal living in groups communicating with complex calls similar to modern chinchillids. It was probably a ground-dweller less agile than its modern relatives, but still capable of fast movements.

Rhyniella

Rhyniella praecursor was an early springtail that lived during the early Devonian, about 410-400 million years ago, in what is now Scotland. Discovered in the exceptionally well-preserved Rhynie chert fossil site, it’s one of the earliest known hexapods.

It was around 2mm long (~0.08″) and closely resembled some of its modern relatives – with distinctive anatomical features like a collophore and a furca – showing that springtails were already well-established in such an early terrestrial ecosystem.

It probably had a similar sort of ecological role to modern springtails, too, being involved in the breaking down of organic matter and the formation of soils.