Succeeding the Eemian or the Last Interglacial, the Last Glacial period (115, 000 -11, 000 years ago) began. It is a well known fact, that during this time, cave bears (Ursus ex. gr spelaeus) were widespread in Eurasia. This lineage was closely related to recent brown and polar bears. Althought rivaling their extant relatives in terms of dimensions (and on average being heavier), cave bears were specialized herbivores. It can be deduced from numerous factors (isotope analysis, tooth microwear…). There is no doubt they would be a formidable adversary when confronted with our ancestors.
My reconstructions and size chart of several forms of cave bears present in Europe during the Last Glacial.
Cave bears (Ursus ex. gr spelaeus) were very diverse, with different forms living on different localities and having different prefences (altitude and perhaps also plant types..). In central and eastern Europe, Ursus ingressus was one of the largest forms, occupying habitats below the ranges of the smaller, high alpine subspecies such as Ursus spelaeus ladinicus and Ursus spelaeus eremus.
As it has been found, U. ingressus and U. s. eremus were living sympatrically for 15,000 years in Austria, with no apparent interbreeding. This is an evidence, that they must have niche partitioned and were quite different ecologically.
There were also a lot of different forms. For example, the classical Ursus spelaeus spelaeus was found in western Europe.
The brown bears (Ursusarctos) lived alongside cave bears, but were more carnivorous than they are today. This was to avoid competition.
Originally thought to be a wolverine-like animal, (Plesiogulo relative) then viewed as an amphicynodontine ursoid and the third time, we might got it entirely correct… Drassonax harpagops was one of the first definitive ursids (true bear).
Drassonax is a genus with just incomplete remains preserved, like upper maxillary teeth and lower jaws. The only known basal ursoids (ursoids include the Ursidae as well as forms already showing ursid traits but still not belonging to the family) with preserved whole skeletals (therefore giving us much more clues about their anatomy and biology) are Amphicynodon and Eoarctos. Based on dental characteristics, Drassonax appears to be a close relative of the former.
My reconstruction of Drassonaxharpagops, one of the early basal ursids. In life it would resemble a small agile predator like a marten rather than modern bears.
Here is a rough hypothetical sketch of how could the skull of Drassonax look like. The proportions are based off of close relatives such as Amphicynodon and Campylocynodon.
The first true caniforms very likely evolved in North America, as it’s indicated by the oldest and most primitive forms of both arctoids (bear and musteloid ancestors) and cynoids (canids) appearing there as early as in the middle Eocene, and in the case of the first ursoids, the genus Subparictis in the Late Eocene during the Chadronian land mammal age, approximately 38-33 million years ago.
They all started out as largely very active mesocarnivores of rather compact dimensions with adaptations for arboreal or scansorial lifestyle. Drassonax likely possesed great climbing and grasping abilities, also being able to rapidly accelerate. As with its close relative Amphicynodon, it is possible that also Drassonax could reverse its feet, perhaps even up to 180°. This would enable it to descend and ascend trees headfirst.
Perhaps one of the best still-living examples of these small carnivorans that we can compare to our extinct species, in terms of ecology is the enigmatic african palm civet (Nandinia binotata). As well as with others, they resemble the ancestral body plan of the earliest arctoids that all others subsequently evolved from.
Baskin, J. A., and R. H. Tedford. 1996. 24. Small arctoid and feliform carnivorans; pp. 486–497 in D. R. Prothero and R. J. Emry (eds.), The terrestrial Eocene-Oligocene transition in North America, Part II: Common vertebrates of the White River Chronofauna. Cambridge University Press, Cambridge.
The enigmatic and unique molluscivorous carnivoran Kolponomos, has been dubbed by the nickname “the beach bear”. Mostly reconstructed as a true ursid, adapted to live in littoral enviroments, preying on hard-shelled seafood such as molluscs.
But was it really like that? The material of Kolponomos, is well, fragmentary… lacking significant postcranial bones. Althought it is quite likely that it was a littoral molluscivore – judging by the skull and dentition, its ancestry and life appearance remains a bit of a mystery.
Speculative reconstruction of Kolponomos newportensis as a stem-pinniped.
The part of the body we need to focus on is the skull. None of the upper teeth are preserved, but the mandibular are. The large round-shaped teeth are worn out so much so, that the original unworn structure of the cusps (on mostly molars) is not known. This wearage is an evidence for a durophagous lifestyle in a similar manner to the extant sea otter (Enhydra lutris). However, the skull structure of the two is not so similar. Kolponomos had a very pronounced chin that worked like an anchor in aiding to dislodge the clams tightly stucked to the sea floor, by the upper portion of the skull. This is a different strategy, that is not seen in sea otters or in any mammal alive today. In foraging, Kolponomos enhanced mandibular stiffness over mechanical efficiency. The stiffness of the lower jaw is an ursid trait, unlike that of the sea otter which utilizes the mechanical efficiency.
As of now, the phylogenetic position of Kolponomos is uncertain. If it is indeed not a true ursid, it might be a member of the clade Amphicynodontidae. This group contains sort of “intermediate” forms between the terrestrial arctoids and pinnipeds, so called stem-pinnipeds. This does not mean that Kolponomos is ancestral to living seals, but that it represents an offshoot of the numerous stem-pinnipeds that went their own evolutionary path, leaving no descendants in the present day.
Only recently, new light has been shed on the origins of pinnipeds and their relationship to ursoids and musteloids. With a handful of transitional forms being recognized properly. But still, the phylogenetic position of amphicynodontids can vary based on the research. It might be that in future this family will no longer be in use, when all the taxa in it get a proper phylogenetic position (either a stem-pinniped, stem-ursid or a musteloid…)
Quite recently, in 2023, a new species of a large carnivoran from the Late Eocene of Mongolia was described. The only material known of Lonchocyon qiui is sadly quite fragmentary, with only one hemimandible, c1 (canine), p4 (4th premolar) and m1 (carnassial) being present.
The skull and postcranium is based off of other hypercarnivorous arctoids, that show large resemblance in the morphology of the mandible and therefore, occupied similar ecological niche.
Based on the lower jaw alone, it becomes clear, that this species was a hypercarnivore. That is, it obtained more than 70% of its calories by meat, either hunted on its own or scavenged on. This is indicated by the robust canine, deep jaw, sectorial trigonid of m1 (that is, specialized for shearing) and strongly reduced premolars. But, as authors of the paper state, there are several hypercarnivorous arctoids that posses functional non-reduced p4 (opposed to our species).
One characteristic of Lonchocyon that could be considered “primitive” or unspecialized, is the retention of unreduced post-carnassial teeth (m2, m3) which usually do the crushing job in carnivorans. In other carnivoran hypercarnivores, these teeth tend to be strongly reduced.
Taking it all to consideration, L. qiui, could consume both flesh and hard objects like bone.
Here, a hypothetical skull is shown:
Right now, the question remains: Was Lonchocyon an amphicyonid or a true bear of the subfamily hemicyoninae? It’s not known yet. What is known however, is, that it represents an early offshoot of one of these groups, appearing quite early in their history (Late Eocene).
During the cenozoic, the suborder Caniformia has produced several lineages of carnivores, which cannot be compared to any living caniforms, hence, occupied a niche that either today remains vacant or is taken by a non-caniform. Such example would be the amphicyonids (bear-dogs) or the ursids (true bears) of the subfamily hemicyoninae. Contradictory to the name “bear-dog”, later, more specialized amphicyonids (amphicyoninae, thaumastocyoninae..) show a combination of skeletal traits and articulations rather resembling a mix between a bear and a big cat. Having a tendation to become hypercarnivorous, with the ability to deliver powerful, deep canine bite, combined with well developed pronation-supination movement, one would imagine these predators as solitary, ambush hunters and scavengers, much more like big cats and bears than any canid or hyaena. One representative of these robust carnivores is Ammitocyon:
Does this mean that this is exactly how we can imagine Lonchocyon to look like? Perhaps yes. Until more of its material is found and described it’s hard to tell with absolute certainty how exactly L. qiui was built.
This fascinating caniform remain to remind us of our humble knowledge of the history and evolution of the Caniformia clade, that in the past produced one of the most fearsome mammalian land predators that roamed the whole Afroeurasia and North America.
A medium dog-sized carnivore that is able to take down on its own ungulates, survives the harshest winters far north and does not hibernate..
Well, there is an actual animal like that, the wolverine (Gulo gulo).
Wild wolverine in Finland. Image: pixabay
The wolverine is a great example of an opportunistic predator and scavenger. It will feast on anything it stubles on, taking huge advantage of any opportunity given.. While most of the time it’s looking for smaller prey and carrion, it can take down ungulates much larger than itself such as reindeer. It’s also a scavenger, with a very acute sense of smell, capable of detecting carcasses covered up by snow with great accuracy.
With frost and water resistant fur and paws of very large size, that help them to stay on top of deep snow, its anatomy is greatly adjusted to the conditions of arctic and boreal forests.
Its lifestyle and habits are reflected in the skull and dentition. When compared to their closest relatives, it posseses enormously enlarged carnassials (P4 and m1) to crush bones and also, the upper molars are rotated in 90° angle which enables them to tear off frozen solid meat. Overall, the skull looks like that of an absolutely formidable predator.
The wolverine is a member of Mustelidae, that means that it’s basically a giant marten or a weasel rather than a small bear. The members of the weasel family are known to have absolutely enormous capabilities relatively for their body size, which is only confirmed in this species.
To look a little bit at its background and history, among mustelids, the wolverine is most closely related to martens (Martes) and fisher (Pekania). Together forming the subfamily Guloninae. To whose of these is the wolverine more closely related isn’t 100% sure. It’s likely that their common ancestor looked similar to the fisher Pekania occulta.
I had the idea of reconstructing some of its ancestors, or closely related extinct species. What came to my interest, is this fragment of the lower jaw of the ancestor of wolverine, being classified in its own species Gulo schlosseri, from Żabia cave in Poland.
To highlight the proportions and life appearance of this animal with the best possible accuracy, I combined this material with skeleton of modern wolverine, which gave me a good base for my drawing.
With a decent “strolling” pose and proportions, the muscles were added very roughly. I chose it yawning, to show its stunning hypercarnivorous dentition mentioned above.
Since the animal, in life would be all covered in fur, no muscular anatomy would be visible. This has made the job a bit easier. Here’s the outline of it.
Then, the details…
And finally, coloration. Althought color variations in individual wolverines can be suprisingly variable, for this one, I chose more darkly-toned individual. Perhaps, all these populations were darkly colored because of their shared ancestry with the fishers (Pekania)? This is a matter of speculation :).
Here we have it. The reconstruction of Gulo schlosseri, an ancestral wolverine from Early Pleistocene. Acting more or less like its living descendants, it surely would have been an amazing experience encountering one of these in their natural habitat.
Believe it or not, during the early Middle Miocene (here, I focus on roughly 16-14 million years ago, but overall it was for a longer period of time), large parts of Slovakia and Eastern Europe were covered by a massive sea called the Paratethys, with Carpathian mountains being just an archipelago within this massive inland water body!
It was in this setting, where numerous fossils of small-sized earless seals (Phocidae) were discovered. In the outskirts of Bratislava, near the peak of Devínska Kobyla, two species of one of these seals were described. Devinophoca claytoni and D. emryi. Together forming a now completely extinct subfamily Devinophocinae that possessed mixed characteristics with the other extant subfamilies of seals.
Here is shown my reconstruction of D. emryi. It was a seal of rather small size, being close to the Baikal seal. The missing parts of the skeleton and the general appearance is based on bunch of other extant seals such as Phoca, Pusa, Monachus and Neomonachus.
The reconstruction of Devinophoca emryi (skull lenght 11.95 cm)
Althought, it would look a lot like its modern counterparts, D. emryi possesed proportionally smaller skull and longer flippers. The latter might have been an unsuccessful evolutionary adaptadion that led to the eventual demise of this group. It has been suggested that Devinophoca might actually represent a very primitive relict of the common ancestors of other phocid seal species. That would mean that this is how we can imagine some of the first earless seals to look like. It lived in a tropical -subtropical environment of transitional shallow marine waters with coral-reef zones.
A sketch showing a pair of Devinophoca emryi in the Slovakian Central Paratethys.
Seals of the subfamily Phocinae can be divided into 5 exact groups based on morphology and ecology. (Representatives of other subfamilies can also be assigned, but its group can differ based on what criteria are used, as in Medditerrean monk seal (Monachus monachus)). Our seal, Devinophoca emryi, althought not belonging to Phocinae, based on morphology alone, falls exactly into the group 3. It’s reasonable to speculate that it was a bottom feeding seal, preying mostly on invertebrates such as mollusks, crabs, shrimp, amphipods and also fish.
The still-living Ribbon seal also falls into the ecomorphological group 3. Image: Michael Cameron
Devinophoca lived in a tropical-subtropical environment, similar to that of Hawaiian monk seal. Image: Kent Backman
Both species D. emryi and D. claytoni fall into different ecomorphological groups, therefore it is totally possible that they coexisted without any competition and niche overlap (for example hunting in different depths) as it’s also seen in some modern seals.
There is so much that could be additionally said, but for now, my time is up. Hoping to get back to this!
