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Perissodactyls (Talk.Origins)

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Response Article

This article (Perissodactyls (Talk.Origins)) is a rebuttal regarding a supposed transitional form published by the Talk.Origins Archive under the title Transitional Vertebrate Fossils FAQ.


Response to Perissodactyls (horses, tapirs, rhinos)


CreationWiki response: (Talk.Origins quotes in blue)

  • Loxolophus (early Paleocene) -- A primitive condylarth with rather low-crowned molars, probably ancestral to the phenacodontid condylarths.

Loxolophus serves as a starting point with no reference to a proposed ancestor. Also there is no information on much of the skeleton has been found.

  • Tetraclaenodon (mid-Paleocene) -- A more advanced Paleocene condylarth from the phenacodontid family, and almost certainly ancestral to all the perissodactyls (a different order). Long but unspecialized limbs; 5 toes on each foot (#1 and #5 smaller). Slightly more efficient wrist.

Tetraclaenodon is difficult to classify do to insufficient information. No real comparison is made with Loxolophus other than reference to the the first and fifth toes being shorter on Tetraclaenodon. The comment that Tetraclaenodon is "almost certainly ancestral to all the perissodactyls" is a result of their Evolutionary mind set and it assume that the rest of the evidence holds up.

GAP: There are almost no known perissodactyl fossils from the late Paleocene. This is actually a small gap; it's only noticeable because the perissodactyl record is otherwise very complete. Recent discoveries have made clear that the first perissodactyls arose in Asia (a poorly studied continent), so hopefully the ongoing new fossil hunts in Asia will fill this small but frustrating gap. The first clue has already come in:

While this Gap may be small for the alleged Evolutionary time scale, it is significant in questioning the alleged lineage since the gap falls right between 5 toes; and 4 front / 3 hind toes.

  • Radinskya yupingae (late Paleocene, China) -- A recently discovered perissodactyl-like condylarth.

Note the following qoute:

In addition, an enigmatic skull with strikingly perissodactyl-like teeth has recently been described from the late Paleocene of China under the name Radinskya. Although no limb remains are known for Radinskya, this animal presents a plausible alternative for the origin of the odd-toed ungulates. The relationships of Radinskya to other Paleocene mammals are not clear, but it could belong to an endemic Asian family of herbivores called Phenacolophidae - also of uncertain affinities. Paleocene mammals of the world.

So Radinskya is known only from its skull. It is considered ancestral to horses based only on its teeth.

  • Hyracotherium (early Eocene, about 55 Ma; previously "Eohippus") -- The famous "dawn horse", a small, doggish perissodactyl, with an arched back, short neck, omnivore teeth, and short snout. 4 toes in front and 3 behind. Compared to Tetraclaenodon, has longer toes, interlocking ankle bones, and slightly different tooth cusps. Probably evolved from Tetra. in about 4-5 my, perhaps via an Asian species like Radinskya. Note that Hyrac. differed from other early perissodactyls (such as tapir/rhino ancestors) only by small changes in tooth cusps and in body size.
  • Hyracotherium vassacciense (early Eocene) -- The particular species that probably gave rise to the equids.
  • Orohippus (mid-Eocene, ~50 Ma) -- Small, 4/3 toed, developing browser tooth crests.
  • Epihippus (late Eocene, ~45 Ma) -- Small, 4/3 toed, good tooth crests, browser.
  • Epihippus (Duchesnehippus) -- A later subgenus with Mesohippus-like teeth.

Hyracotherium Orohippus, and Epihippus are varieties of the same kind of animal, much like the variety among cat and dogs. They all the a 4 toes one their front feet and 3 toes on the back as well as many other similarities that show them to be the same kind of animal.

  • Mesohippus celer (latest Eocene, 40 Ma) -- Three-toed on all feet, browser, slightly larger
  • Mesohippus westoni (early Oligocene) -- A slightly later, more advanced species.
  • Miohippus assiniboiensis (mid-Oligocene) -- This species split off from early Mesohippus via cladogenetic evolution, after which Miohippus and Mesohippus overlapped for the next 4 my. Distinctly larger, slightly longer skull, facial fossa deeper and more expanded, subtly different ankle joint, variable extra crest on upper cheek teeth. In the early Miocene (24 My) Miohippus began to speciate rapidly. Grasses had just evolved, & teeth began to change accordingly. Legs, etc., started to change for fast running.
  • Kalobatippus (late Oligocene) -- Three-toed browser w/foot intermediate between Mio. & Para.
  • Parahippus (early Miocene, 23 Ma) -- Three-toed browser/grazer, developing "spring foot". Permanent establishment of the extra crest that was so variable in Miohippus. Stronger tooth crests & slightly taller tooth crowns.
  • 'Parahippus' leonensis (mid-Miocene, ~20 Ma) -- Three-toed browser/grazer with the emphasis on grazer. Developing spring-foot & high-crowned teeth.
  • 'Merychippus' gunteri (mid-Miocene, ~18 Ma) -- Three-toed grazer, fully spring-footed with high-crowned teeth.
  • Merychippus primus (mid-Miocene, ~17 Ma) -- Slightly more advanced.
  • Merychippus spp. of mid-late Miocene (16-15 Ma) -- 3-toed grazers, spring-footed, size of small pony. Diversified into all available grazer niches, giving rise to at least 19 successful three-toed grazers. Side toes of varying sizes, very small in some lines. Horsey hoof develops, leg bones fuse. Fully high-crowned teeth with thick cement & same crests as Parahippus. The line that eventually produced Equus developed as follows: M. primus, M. sejunctus, M. isonesus (these last two still had a mix of primitive, hipparion, and equine features), M. intermontanus, M. stylodontus, M. carrizoensis. These last two looked quite horsey, with quite small side toes, and gave rise to a set of larger three-toed and one-toed horses known as the "true equines". Crystal clear, right?

Here we a distinct kind as opposed to Orohippus, Epihippus, and Hyracotherium. They had 4 toes in front and 3 toes in the rear. Mesohippus Miohippus, Kalobatippus, Parahippus, and Merychippus 3 toes on all 4 feet. There is no real evidence of a gradual shift as well as other features in common.

Mesohippus Miohippus, Kalobatippus, Parahippus, and Merychippus are varieties of the same kind of animal, much like the variety among cat and dogs.

Reference: TEXTBOOK FRAUD: Hyracotherium "dawn horse" eohippus, mesohippus, meryhippus

SMALL GAP: It is not known which Merychippus species (stylodontus? carrizoensis?) gave rise to the first Dinohippus species.

That is be cause the answer is that non of them gave rise to Dinohippus. This cap is right were Merychippus' 3 toes would theoretically become Dinohippus' one toe.

  • Dinohippus (late Miocene, 12 Ma) -- One-toed grazer, spring-footed. Very equine feet, teeth, and skull, with straighter teeth & smaller fossae. First was D. spectans, followed by D. interpolatus and D. leidyanus. A slightly later species was D. mexicanus, with even straighter teeth and even smaller fossae.
  • Equus (Plesippus), also called the "E. simplicidens" group (Pliocene, ~4 My) -- Three closely related species of one-toed spring-footed high-crowned grazers. No fossae and very straight teeth. Pony size, fully "horsey" body -- rigid spine, long neck, long legs, fused leg bones with no rotation, long nose, flexible muzzle, deep jaw. The brain was a bit larger than in early Dinohippus. Still had some primitive traits such as simple teeth & slight facial fossae, which later Equus species lost. These "simple Equus" species quickly diversified into at least 12 new species in 4 different groups. During the first major glaciations of the late Pliocene (2.6 Ma), certain Equus species crossed to the Old World. Worldwide, Equus took over the niche of "large coarse-grazing plains runner".
  • Equus (Hippotigris) (Pleistocene) -- Subgenus of modern 1-toed spring-footed grazing zebras.
  • Equus (Equus) (Pleistocene) -- Subgenus of modern 1-toed spring-footed grazing horses & donkeys.

Pliohippus, Dinohippus and Equus are varieties of the horse kind, much like the variety among cat and dogs. There a clear jump from 3 to 1 toe, hardly evidence for evolution.

[note: very rarely a horse is born with small side toes, indicating that some horses retain the genes for side toes.]

Hardly, they are just a result of a horse's normal side plints growing more than they should. This is suposed to be proof of Evolution?

Compare Equus to Hyracotherium and see how much it has changed. If you think of animals as being divided into "kinds", do you think Equus and Hyracotherium can be considered the same "kind"?

Actually Equus and Hyracotherium are two distinct kinds with a third placed between them. They have no real evidence of a relationship. This whole scenario is based comparing teeth and legs between several distinct kinds of animals while ignoring other greater body differences.


The following links give more information on this topic.

Creationist

TEXTBOOK FRAUD: Hyracotherium "dawn horse" eohippus, mesohippus, meryhippus

Horse Evolution evolve eohippus hyracotherium mesohippus merychippus pliohippus equus

Creation Bits Number 24

About the Horse Series?

Non-creationist

Fossil horses and evolution

Tapirs and rhinos:

  • Loxolophus see above
  • Tetraclaenodon, see above
  • Homagalax (early Eocene) -- Very like its sister genus Hyracotherium, but had cross-lophs on teeth. Note that these early perissodactyls differed only in slight details of the teeth.

First off Loxolophus is classified as early Paleocene and Tetraclaenodon is classified as mid-Paleocene with no mention of the late Paleocene gap mentioned above.

All the available information on Homagalax is found on Talk Origins and it clones. If as indicated above Loxolophus and Homagalax differ only in their teeth then Homagalax and Hyracotherium were probably the same kind of animal.

  • Heptodon (late early Eocene) -- A small early tapiroid showing one more tooth cusp change.

While there is not enough information to be certain , but the information available suggests that Heptodon was a small short snout variety of tapirs. The differences between Heptodon and Homagalax are too great to suggest a relationship, particularly given how close they would be in time by evolutionary dating methods.

Reference: The Age of Mammals: Eocene:

Reference: Family Tapiridae (tapirs)

Split into two lineages: 1. Helaletes (mid-Eocene) which had a short proboscis, then Prototapir (late Oligocene), much like modern tapirs but without such a flexible snout, then Miotapirus (early Miocene), an almost- modern tapir with a flexible snout, then Tapirus (Pliocene) the modern tapir.

Helaletes

Prototapir

  • The vary name Prototapir has evolutionary assumptions written all over it, but the above description suggests that Prototapir was simply a variety of the tapir kind.

Miotapirus

  • Based on the above description Miotapirus is clearly a variety of the Tapir kind.

Tapirus

  • Tapirus are the living varietiesof the tapir kind.

Basicaly what Talk Origins is doing here is presenting several varieties of Tapir and then claiming a connetction to another kind for which the evidence is questionable.

2. Hyrachyus (late Eocene), a tapiroid with increased shearing function in its teeth. Led to the late Eocene hyracodontids such as Hyracodon (rhino-tapiroids, or "running rhinos") that show increasing development of high-crowned teeth and larger body size. They led to Caenopus (early Oligocene), a large, hornless, generalized rhino which led to the modern horned rhinos of the Miocene & Pliocene. Our living genera first appear in the Pliocene, about 4 Ma.

Hyrachyus

  • [ Hyrachyus] would seem to be a variety of the Tapir kind.

Hyracodon


Caenopus

  • Caenopus is most likly a hornless variety of rino rhino.

Living genera of Rhino

So it turns out that the main lynch pin in their claim seems to be incomplete and poorly described, there by preventing an objective analysis.

Species-species transitions:

  • Horses: Gingerich (1980) documented speciation from Hyracotherium grangeri to H. aemulor.

No problem these are the same genus.

Prothero & Schoch (1989) mention some intermediate fossils that link late Orohippus to Mesohippus celer.

This is quite vague, as we have seen Evolutionists don't need much to claim a link between two types. It is likely that this claim is based on fragmented fossils and a lot of Evolutionary assumptions. Actually since no details are given by which this claim can be objectively checked this statement is nothing but an Appeal to Authority. Talk Origins is presenting perceived authority's interpretation as fact, without presenting any real evidence.

Even if it is legitimate all it would show is a loss of a toe, which would be a loss of information not new information. Yes it would show that what is currently considered two seperate kinds of animals are actualy one kind, but this has happened before as more information is gathered about similar animals.

MacFadden (1985) has documented numerous smooth transitions among the three-toed horses, particularly among Merychippus and the various hipparions.

These have already been identified as the same kinede of animal so it is not a problem.

Hulbert (in Prothero & Schoch, 1989) showed that Dinohippus smoothly grades into Equus through successive Pliocene strata.

While more information is needed to evaluate this claim, however it not a problem since Dinohippus and Equus have aready been identified as the same kind. The partern could represent post Flood changes in the horse.

Simpson (1961) describes gradual loss of the side toes in Pliohippus through 3 successive strata of the early Pliocene.

First of all even Talk Origins admits that the source of this claim is outdated. Once again rather the presenting checkable evidence Talk Origins is resorting to an Appeal to Authority. Besides Pliohippus is not even in the above list of alleged horse ancestors. Furthermore, Pliohippus was a horse with only hoofed toe. What Simpson is referring to are varieties in the length of the side splits not a loss of toes. This just shows how evolutionary interpretations muck up the waters in this area.

  • Rhinos: Wood (1954) said of the rhino fossils "whenever we do have positive paleontological evidence, the picture is of the most extreme gradualism" (quoted in Gingerich, 1977), and Kurten (1968) describes a smooth transition between Dicerorhinus species.

All that is being presented here are variations with two genera, not a big deal. The reference to "extreme gradualism" assumes the accuracy of Evolutionary dating methods.


This is just a comparison of specific parts of difference kinds of animals while ignoring other differences. The main horse series consist of three distinct kinds of animals with far more differences than depicted above, Talk Origins has added two additional one or two additional kinds of animals; insufficient data is available to tell if it is one or two kinds; with a convenient gap.

When it comes to fossil evidence given is support of evolution this is as good as it gets. Even still munch of it is pure Evolutionary interpretation. Further more as is so often the case there is a gap or questionable fossil at critical links in the chain.


See Also