27 November 2014

Well Known Ice Age Beasts

CollectA Megacerops
The fact that Megacerops is so well known that there are a fair number of popular outlets that enhance its popular culture reach. There are toys and references in books, though not in many younger reader books that show up online, and we know it has appeared in documentaries. The only terrible thing about all of this popular culture referencing is that sometimes the lineage of Megacerops still gets confused, lost, or ignored. Many people do not realize that these animals are not exactly and not exactly horses but are related to both; they are more closely related to horses we know. This is very important to note, especially since Kenneth Branagh specifically relates this information to the audience in the Walking With Series. Hopefully we will all remember that in the future since it has been mentioned so much this week.

26 November 2014

Ribs and Noses

©Dmitry Bogdanov
Megacerops is, as we have seen, very open faced, skeletally, on the rostral end of the animal. In life, of course, this is not the case at all. That open area is filled with the nasal sinuses and conchae that would have been required by the animal to detect smells sufficiently and to warm the air that it breathed. In colder times of the year this was obviously of great import as cold air in the lungs brings the temperature of the body core down; though being such a large animal to begin with breathing cold air was probably not very dangerous to the temperature of the animal. More interesting topics abound in that nasal area of the skull. We have noted the horns and how they could be used in combat at a pinch, but were they actually of any use? Fossils indicate that damage to the ribs of some larger males could only have been inflicted by other members of the species during ramming contests with the horns. These fractures did not heal properly, if at all, because of the large movements occurring during breathing.

25 November 2014

1905, A Big Year

1905 was a big year for Megacerops. Richard S. Lull, of the Massachusetts Agricultural College (presently UMass Amherst), published his description and plates of a fossil he named Megacerops tyleri in the Journal of Geology for the first time. Thirty five years before that the genus Megacerops was originally named and described by Joseph Leidy. Osborn discussed Leidy's description in his 1902 discussion on the Oligocene titanotheres. Either way, Lull's plates depict a skull and forelimb of the animal, far more than Leidy had in his initial descriptions. Prior to this, in the same compile volume, Lull detailed the restoration of the animal. This restoration was effected in clay and features a photograph of the skull, as opposed to the line drawings in the plates of the description. Papers and studies continue to be published, of course. The last well detailed description of a new specimen that I would recommend reading was published in 1995 in the Journal of Paleontology and introduced the new species Megacerops kuwagatarhinus from the White River beds of Montana.

24 November 2014

Brontotherium Walking

Walking with Beasts features a battle that is pretty interesting to watch. The confrontation is between Brontotherium (as they are calling it in the show) and Andrewsarchus, an animal known from an enormous solitary skull and thought to be related to pig-like omnivores and potentially whales as well. Regardless, the fight alone can be seen here, with background on Brontotherium. The entire episode is hosted on a different site. However, it may be worth watching to see what other information the BBC presented on these two animals and the other animals that lived at the same time.

23 November 2014

Megacerops For Kids

Megacerops, under either that name or Brontotherium is a popular fossil mammal. Multiple sites exist that host lists or paragraphs of facts. About continues to use the more popular Brontotherium on their site while Planet Dinosaur acknowledges the switch, somewhat begrudgingly since they use both names on the title of the page. Brontotheres as a group are addressed on a page dedicated to the fossils of the White River Badlands rather than any single genus in the group. This wider angle approach is good at times and is helpful for viewing all of the animals related to this animal rather than just looking at our target animal. It is always good to look at the bigger picture once in a while.

22 November 2014

What Is on Your Nose?

Menodus (junior synonym to Megacerops),
Field Museum, Chicago.
Megacerops has a pair of horn-like protuberances on the rostral end of the skull. In the mounted specimen from the Field Museum, shown here, those protuberances appear smaller than they are often illustrated. The nostrils do not appear, in this specimen, to be completely formed as external foramina, as one would expect. The nares are actually present in the concavity ventral to the the twin horns of the face. The nasal bones appear to extend over the premaxillae between the horns but do not recurve to meet the premaxillae at the chin. As expected in the list of rhinoceros-like traits, the optic foramina are small, relative to the entire skull, and offset laterally so that the animal most likely did not have a great deal of binocular vision. Not having depth perception, we can probably safely surmise that Megacerops was not adept at detecting predators visually. To make up for that deficit we can assume that the powers of smell and hearing may have been more sensitive in Megacerops (there may be more definitive answers that I have not found quite yet). Conversely, mixed herds and even the addition of non-mammalian (i.e. bird) members of the community may have aided in predator awareness, meaning that none of the senses would have had to have been highly adapted toward sensing predators. Either way, the horns on the face of Megacerops are not used for the purpose of combat primarily. As skeletal elements, a broken horn would be tremendously detrimental to the health of the animal. Such a danger would cause the animals to use their horns, both males and females possessed them, as a last resort in protecting themselves. The horns would have served to intimidate as much as the sheer size of the animal itself.

21 November 2014

Rhinos or Horses?

Though not a rhinoceros and much more closely related to horses, Megacerops was a very rhinoceros-like relative of horses and is therefore a bit confusing on first glance. Known more popularly as Brontotherium, Megacerops Leidy 1870 was far larger than any modern horse or rhinoceros. Its distinctive look, two large bony protuberances above its nose, make it look slightly more like a rhinoceros, but are significantly different from any known rhinoceros horn as well. The use of these protuberances is well documented, as we shall discuss. This animal is yet another North American Eocene mammal.
Robert Bruce Horsfall, 1913