Early American Hyrax Bones Wrongly Attributed To Protorohippus?

[tailormane]

The hyrax skeleton is remarkably similar to the protorohippus skeleton. Both have simple tapir-like teeth and four front toes and three rear toes. It's possible that some of these finds were in fact early hyrax which have been wrongly attributed to the protorohippus imo. Mystery three toed tracks have been found all over North America. Is there a clever species of modern hyrax which is able to stay undetected from science?

[Auspex]

...Is there a clever species of modern hyrax which is able to stay undetected from science?

One cannot prove a negative, but suffice it to say that any creature leaving tracks "all over North America" would be known.

[mikeymig]

I have a few Hyrax skulls in my collection because they look just like mini Rhino skulls (I love Rhinos). Hyrax is somewhat related to the elephant and share a common ancestor somewhere in Africa where both species live today. The family got as far as Asia a few million years ago then died out soon after that. It would be cool if Hyrax made it to NA but with nothing to hold onto like a single tooth, it’s not likely.

Convergent evolution is cool.

[Boesse]

Mammal paleontologists are some of the most anal-retentive researchers out there with respect to dental features - while early horses and hyraxes look "kinda" similar, their teeth (including the molars) are pretty distinctly different. The incisors of these taxa are completely different, for one, let alone general skull shape. Horses and hyraxes belong to completely different parts of the mammalian tree (Laurasiatheria, and Afrotheria, respectively) and a mistake of this magnitude would have been detected by mammal paleontologists much earlier (i.e. probably over a century ago).

Bobby

[tailormane]

One cannot prove a negative, but suffice it to say that any creature leaving tracks "all over North America" would be known.

That's why we have a subject called cryptozoology. They are known, just not caught.

[tailormane]

I have a few Hyrax skulls in my collection because they look just like mini Rhino skulls (I love Rhinos). Hyrax is somewhat related to the elephant and share a common ancestor somewhere in Africa where both species live today. The family got as far as Asia a few million years ago then died out soon after that. It would be cool if Hyrax made it to NA but with nothing to hold onto like a single tooth, it’s not likely.

Convergent evolution is cool.

Thanks for the reply mikey.

[tailormane]

Mammal paleontologists are some of the most anal-retentive researchers out there with respect to dental features - while early horses and hyraxes look "kinda" similar, their teeth (including the molars) are pretty distinctly different. The incisors of these taxa are completely different, for one, let alone general skull shape. Horses and hyraxes belong to completely different parts of the mammalian tree (Laurasiatheria, and Afrotheria, respectively) and a mistake of this magnitude would have been detected by mammal paleontologists much earlier (i.e. probably over a century ago).

Bobby

Okay, you've convinced me that it's probably not a hyrax species, but the protorohippus *could* have evolved into a non-equine species too imo. The fossils shown in the OP could be an early ancestor of the horse *and* the mystery tree-hugger. One stood on it's hind legs to browse the bushes and trees, whilst the other lowered it's head and benefited from grazing the grasses. See attached. Only one small step from being a browser to a secretive tree-hopper.

[Auspex]

That's why we have a subject called cryptozoology. They are known, just not caught.

I am familiar with the subject of cryptozoology, and the speculative musings it generates on many internet forums. Here we also speculate on possibly unknowable creatures, but of the prehistoric kind, and with the purpose of considering relationships between well documented but long extinct species.

[tracer]

i found bigfoot by walking in circles

[Boesse]

No offense, but trying to advance an argument that some kind of ancient horse that evolved into a somehow arboreal modern para-hyrax which we haven't discovered is much more difficult to argue than there being bigfoot or chupacabras. At least "legends" of those critters already exist, as stupid as they are. When new species of terrestrial mammals are found today, they are typically never novel - they are usually species within already known genera, or new subspecies. At that, they are typically never large animals either (i.e. they are typically small taxa, under 10 lbs or so), because the larger taxa typically have larger ranges and are therefore easier to identify.

Bobby

[tailormane]

Okay, I appreciate that you're all familiar with the amateur nobody trying to tie up fossils with modern day mystery animals. I'll try to get to the nub of what I'm on about though:

(i) Quote: "Indeed, its first and correct scientific name, Hyracotherium, was coined because it was believed to be related to the hyrax. A later name for the same ancestor, Eohippus, was used because the fossils were first discovered in deposits from the Eocene epoch. (Hippus coming from the Greek for horse.)" Why is the idea of a common ancestor for both the protorohippus and the hyrax so 'impossible' for palentologists?

(ii) I assume that it's because of the split of the American continent from Africa which is perceived to be too early for a common ancestor to have existed. Ergo, convergent evolution?

(iii) The dating of the continental split is based on the speed of continental drift, amongst other things, I presume. But this movement of the plates is still an enigma. Newton's and Einstein's laws are under immediate threat. It's these which underpin our understanding of how the internal workings of the planet operate. These could soon easily change. It's possible that the plates accelerate and are only presently moving at such a low speed for example.

(iv) btw, Where is the fossil of the protorohippus ancestor and where is the fossil of the hyrax ancestor of the same period?

Thanks for taking your time in considering the musings of an absolute beginner..Maybe the continents were connected for longer than realised and that there is a common ancestor of the NA protorohippus and the African hyrax?

Edited October 29, 2011 by tailormane

[Auspex]

(iii) The dating of the continental split is based on the speed of continental drift, amongst other things, I presume. But this movement of the plates is still an enigma. Newton's and Einstein's laws are under immediate threat. It's these which underpin our understanding of how the internal workings of the planet operate. These could soon easily change. It's possible that the plates accelerate and are only presently moving at such a low speed for example.

The timing of the tectonic rifting of the Atlantic takes into account both the shifts in magnetic polarity of the rocks in the mid-Atlantic ridge and the changes in the stratigraphic sequence of the opposite sides. The estimate is well refined and self-confirming.

This data is based on observation and study of the world at large scales, and the idea that "Newton's and Einstein's laws are under immediate threat" is popular hyperbole, insomuch as may be applied to anything outside of subatomic physics.

[siteseer]

Boesse answered this by noting the groups, but put plainly, Protorohippus originated in Asia/North America during the Paleocene-Eocene transition when those continents were connected by a land bridge while hyraxes are from Africa (earliest known fossils date back to the Late Eocene). Protorohippus was an early horse belonging to a mammal order quite separate from hyraxes. In fact, hyraxes are much more closely-related to elephants and dugongs than they are to horses (evidence based on fossils, DNA, and probably blood-testing as well). They are related to horses in that they are both mammals but their common ancestor may be more ancient than Tyrannosaurus.

Actually, as I understand it, Hyracotherium was not named because an ancestral relationship was indicated. It was based on recalling some modern analogue, some familiar face, to provide a quick six-syllable description of it. Also, the name, "Eohippus," means "dawn horse" or "early horse," a reference to the fact that it is an ancestor of the horse - not that it came from the Eocene, though it did live during the Early Eocene.

(i) Quote: "Indeed, its first and correct scientific name, Hyracotherium, was coined because it was believed to be related to the hyrax. A later name for the same ancestor, Eohippus, was used because the fossils were first discovered in deposits from the Eocene epoch. (Hippus coming from the Greek for horse.)" Why is the idea of a common ancestor for both the protorohippus and the hyrax so 'impossible' for palentologists?

[tailormane]

Auspex:

it's worth remembering that science doesn't have a working explanation for the irregular movement of the plates. I saw a programme on it.

Siteseer:

you said "They are related to horses in that they are both mammals but their common ancestor may be more ancient than Tyrannosaurus" which I found very interesting. Could you expand on this some more for me please?

[Boesse]

If your citation for "we don't understand plate tectonics, so it must be wrong!" is a soundbite on a TV show, then you don't have a leg to stand on. People say all sorts of weird snarge on TV (like the pyramids in Egypt and Mexico and Macchu Picchu were built by aliens, and the aliens taught the Romans, and all sorts of other bull). When there's a show on TV dedicated to promoting ancient alien pseudoscience, everything on the telly becomes un-citable.

I can vouch for everything that Auspex and Siteseer stated above are correct and generally widely held ideas within the field.

Bobby

[tailormane]

Thanks for the advice but the main point stands: science doesn't know why the plumes are so irregular. Simulation experiments show that they *should be* evenly distributed and equal strength.

[Auspex]

Thanks for the advice but the main point stands: science doesn't know why the plumes are so irregular. Simulation experiments show that they *should be* evenly distributed and equal strength.

Plumes?

[siteseer]

Protorohippus and other recognized early perissodactyls are found in Early Eocene rocks and their apparent ancestors, the phenacodontids (a family included within a loosely-classified order of early ungulates) lived during the Middle-Late Paleocene (some representatives survived into the Middle Eocene). However, the fossil trail grows cold before the Middle Paleocene. Early Paleocene mammals are mostly represented by isolated teeth and jaw sections and the groups represented tend to be a mix of survivors from the Cretaceous and some descendant groups that existed only during the Paleocene. Only a few that would be identified as early ungulates (or other groups better-known from the Eocene) and their teeth are different enough from those of later groups that it is not possible to determine degrees of relatedness to those groups. Furthermore, Paleocene land mammal occurrences are relatively rare worldwide with Early Paleocene ones especially so.

The earliest hyrax-like mammal (hyracoid) comes from the Early Eocene of some parts of North Africa with no confirmed ancestral group, though it must be said that phenacodontids have been proposed as a possibility. Phenacodontids are best known from North America and rare in Eurasia with a possible Early Eocene relative (Seggeurius) in North Africa based on some lower teeth. Perissodactyls and hyracoids might be more closely related to the extent that they diverged from separate branches of that family tree but more complete remains would be needed to confirm that.

If the proposed North African phenacodontid turns out to be just a form similar to but not directly related to established phenacodontids, then hyracoids would be difficult to trace back into the Paleocene or earlier as much of North Africa during that time (and into the Cretaceous) was submerged by the Tethys Sea. As far as I know, Paleocene and Eocene land mammal deposits are rare anywhere in Africa.

The earliest-known relatives of ungulates may be the zhelestids, known from jaws and teeth from the Late Cretaceous of Asia, North America, and Europe, though they have not been accepted as such by all mammal researchers. Bones reported to be associated with zhelestid teeth were being studied as of a few years ago so the closeness of their relationship to ungulates could be clarified soon. These mammals date back 85 million years which predates the oldest known Tyrannosaurus fossils by about 15 million years.

I have an interest in Early Cenozoic mammals but I am far from being informed on the latest findings regarding phenacodontids, their proposed relatives, and other research pertinent to their study. The information provided may be 5-10 years out-of-date so I would welcome comments from others providing updates or pointing out inaccuracies.

Siteseer:

you said "They are related to horses in that they are both mammals but their common ancestor may be more ancient than Tyrannosaurus" which I found very interesting. Could you expand on this some more for me please?