Monthly Archives: December 2015
During our “time-travel safari” through the Miocene woods and plains of Madrid, many of the herbivores we could come across would look vaguely familiar. Small three-toed horses, deer with simple antlers, running rhinos… all these animals belonged to the same families as their modern counterparts. But one of the ungulates we were likely to encounter was an animal with no living relatives.
Triceromeryx pachecoi, as this creature is named, was built like some sort of stocky deer, but on its head it had three bony appendages: the two smaller ones, placed over the orbits, were ossicones, bony structures similar to those of modern giraffes. The third, larger appendage, was forked and grew directly from the back of the skull. The weaponry of this bizarre animal was completed with a pair of small dagger-like canines protruding beyond the upper lip.
The reconstruction of the life appearance of Triceromeryx pachecoi was one of my first professional challenges as a hopeful young paleoartist, back in the early nineties. Fossil remains of this species were first recognized back in the 1940s at the fossil site of Hidroeléctrica in Madrid, and they were enough to show that it was a pretty weird animal, but they were so fragmentary that reconstructing its life appearance was a tricky business. In fact, the appendages were not found attached to a complete skull, and even the fact that they belonged to the same animal could seem open to question. Fortunately, at about that time discoveries were made in other Spanish fossil sites which added important pieces to the palaeomericid puzzle.
At the site of Els Cassots in Catalonia, paleontologists discovered a complete, crushed skull of a new palaeomericid which they named Ampelomeryx ginsburgi. Although the shape of its appendages was different, having a complete skull further confirmed their arrangement in the animal’s head and provided new information about palaeomericid evolution and function.
Closer to Madrid, a collection of palaeomericid fossils were found at the site of La Retama, in Cuenca. Again, the new fossils were so different from the ones from Madrid and Catalonia that they clearly belonged to a new species, and the shape of the appendage at the back of the skull was probably the weirdest. I was commissioned to create a life reconstruction of the new palaeomericid for the local museum at Cuenca, and even I was surprised at the strange appearance of the creature.
Here is my first reconstruction of the palaeomericid from la Retama, created for the Museum of Cuenca back in 1991. The illustration showed several males in a dispute over a female, reflecting the hypotheses that the appendages were exclusive of the males
When I started working on the reconstruction of Madrid’s T. pachecoi it had seemed a strange enough animal, but the findings of palaeomericid fossils that were taking place were showing the remarkable diversity of this family: almost each new finding corresponded to a new species, each of them wierder than the previous one!
More recently, those palaeomericid fossils keep contributing to our knowledge of that strange family. A recent study has finally given a name to the species from la Retama: Xenokeryx amidalae. A detailed analysis of its anatomy and that of the other palaeomericids has clarified the affinities of the family, which is revealed as closely related to the giraffids, rather than to the American dromomerycids as some previous studies had suggested. You can check the new study here:
Triceromeryx pachecoi was the right size to fit in the diet of the large amphicyonids that were so common in Madrid at the time. Here a nice male has come to a sad end and its remains are disputed by a pair of quarrelsome Amphicyon
The palaeomericids disappeared in the Miocene leaving no living descendants, but they were a succesful and diverse group, with a wide Eurasiatic distribution from Spain to China. We have come a bit closer to understanding their evolution and their place in Nature, but they remain one of the most mysterious ungulate groups and much remains to be known about them. Having worked in their reconstruction since so early in my a career, I find them especially endearing. And certainly, the finding of a complete skull of Madrid’s Triceromeryx pachecoi would be high on my wish list. New Miocene fossil sites keep appearing in Madrid as works uncover sediments here and there. So let us not give up hope!
When you spend time in the African savannah you are surprised to see how relaxed the herbivores can be in the proximity of the big cats. Zebras and antelopes don’t stampede at the mere presence of a lion, but they rather observe it. Information flows in both directions, and the ungulates know how to read the body language of predators. A feline walking casually is no cause of panic, and the potential prey just look at it cautiously until it disappears. And it makes sense, because if zebras had to be in a constant state of panic at the possible presence of a predator, stress would kill them even before the predators would. For us humans as well, irrational fear of predators is probably something that developed once we abandoned our life as hunters-gatherers to become Neolithic farmers. Before that, cautious respect and a keen interest in the predators would be a far more useful attitude than panic.
As a sabertooth freak, I often imagine what it would be like to travel back in time and meet my favourite predators from the past. If I were in a B movie, a succesion of screams and chases would follow, and my survival would depend on being the star of the film or a mere sideshow, so I would really stand little chance of survival! But in the natural world, I should rather try to follow the example of the zebra and read the cat’s body language before running.
To see an adult Amphimachairodus walking your way would be in impressive sight by any standards. Tall as a lion, it would walk with a cat-like supination of the forepaws, although less exaggerated than in a lion: the structure of its elbow and wrist joints tell us that much. Free-swinging shoulder blades would move up and down as the cat stepped towards us. But the animal’s head would be subtly different from any modern cat’s. The face was narrower, with slightly smaller eyes looking less frontally, somehow intermediate between a lion’s and a wolf’s in terms of relative size and position. The muzzle was long and high but also narrow, with blade-like upper canines showing discretely beyond the upper lips.
Reconstruction of Amphimachairodus in frontal view. The animal was as tall as a lion with a distinctly cat-like walk, but it had a peculiar narrow head with a high and narrow muzzle and blade-like upper canines showing beyond the upper lips
Concerning body language, if the cat is walking upright and with a casual cadence, you have reason to think it is just minding its business rather than stalking you. A relaxed mouth further indicates lack of aggression, but ears pointing slightly backwards are less simple to read. In the general context of a relaxed animal they don’t mean much, but it could be the sabertooth is not very happy about something. Better observe it for a few seconds and see what those ears do, but remember that any part of the animal’s body generally works as a part of the whole, and if the cat is in an aggressive mood there will be other signs apart from those ears to show it…
Amphimachairodus lived a little too long ago for our bipedal hominin ancestors to have come across it, but other sabertooths, such as Homotherium and Megantereon, were familiar elements of their world. I am sure that body-language reading was more important than panic as a reaction to their presence. But timing is everything, and surely there was a right time to panic as well!
Some eight million years ago, during the late Miocene, much of Eurasia underwent dramatic environmental changes, with a reduction in the previous expanse of forests and a predominance of open woodlands and savannah-like landscapes. This part of the Miocene period is known in Europe as the Turolian.
The Turolian plains were inhabited by herds of three toed-horses and many kinds of antelopes, which together with a diversity of giraffids, rhinos, and proboscideans, would turn much of the old continent, to our eyes, into a gigantic Serengeti of sorts. That vast array of herbivores was not free of predation, and the lion’s share corresponded to one of the most impressive sabertooth genera ever: Amphimachairodus.
Probably originating in Asia, Amphimachairodus spread like fire across the continents, becoming the dominant large carnivore in Europe and North America and eventually entering Africa and reaching as far South as the Cape province. Nothing could stand in its way. What was the key to such success? A close relative of Machairodus, Amphimachairodus took the adaptations of its older cousin one step further, not only by developing longer, more flattened and more coarsely serrated upper canines, but also by refining the adaptations of its skull, mandible and neck for a super-efficient kind of killing bite. Fully as large as a lion, Amphimachairodus not only had access to very big prey, but it also was dominant over any other predator in its habitat.
A less well known side of the success of Amphimachairodus was diversity. Subtle differences between species are not always easy to tell from the fossil record, but it is obvious that there existed more than one species of this sabertooh genus during the late Miocene. The type species, A. giganteus, was widespread in Eurasia, but others have been desccribed in China, North America and Africa. And with diversity come different adaptations and even behaviours. Populations of A. giganteus living in open environments, in direct competition with clans of the large hyena Adcrocuta, would probably develop some sort of social behaviour in order to defend territory, females, cubs, and kills. But other species within the genus may have led solitary lives in more wooded environments, much like the modern tiger does. Just let us bear in mind that the genus Panthera today includes a diversity of adaptations which we would hardly be able to tell from their bones alone. Lions, tigers, jaguars, leopards, snow leopards, each one has its unique solutions to cope with the challenges of its ecological niche, and so would the sabertooths.
The impressive teeth of Amphimachirodus would give additional intensity to any facial expression. The interplay of the complex facial muscles, for which all cats are notorious, would allow a precise transmission of mood to conspecifics, and why not, to rival species such as the hyaenas. The expression shown in this illustration clearly says “don´t mess with me”!
Fortunately, the fossil record provides more than just skulls to gauge at the adaptations of Amphimachairodus, as we shall see elsewhere.