Véra Eisenmann

Skull proportions, excluding the size of the preorbital â€˜bar' (32) : Unclassified

2010-05-31T21:18:03Z

Unclassified.
Five skulls remain unclassified using this kind of ratio diagram (Unclassified 1).
Unclassified fragments. Fifteen other skulls were too fragmentary to be studied by this kind of ratio diagram (Unclassified 2).

- Ratio diagrams, 8 variables

Skull proportions, excluding the size of the preorbital â€˜bar' (32) : Miohippus & Mesohippus

2010-05-31T21:13:52Z

- Ratio diagrams, 8 variables

Skull proportions, excluding the size of the preorbital â€˜bar' (32) : Hypo, Mega, & Parahippus

2010-05-31T21:10:55Z

- Ratio diagrams, 8 variables

Skull proportions, excluding the size of the preorbital â€˜bar' (32) : Dinohippus & Pliohippus

2010-05-31T21:04:54Z

Dinohippus and Pliohippus
Dinohippus 11724, 87201, and Pliohippus 12998 have similar proportions (Dino-Plio 1) but only the last one has a well developped POF.
Five other skulls are all different (Dino-Plio 2).

- Ratio diagrams, 8 variables

Skull proportions, excluding the size of the preorbital â€˜bar' (32) : Group B

2010-05-31T20:24:55Z

Group B.
B-1. Thirteen skulls referrable to Cormohipparion B, differ from the group A mostly by their longer naso-incisival notches. They tend also to have longer muzzles and shorter palates.
B-2. Two skulls are similar but quite smaller.
B-3. Five skulls have a long muzzle.
B-4. One skull (74400 from MacAdams) has a wide muzzle.
B-5. Three skulls, with very wide muzzles, belong in Group B.

- Ratio diagrams, 8 variables

Skull proportions, excluding the size of the preorbital â€˜bar' (32) : Group A

2010-05-31T20:15:18Z

Group A.

A-1 : Height adult skulls and two juveniles may be easily referred to Cormohipparion A. They are characterized by relatively long palates (2), wide muzzles 15), and short naso-incisival notches (NNI=30).

A-2 : Sixteen skulls are similar but smaller, and have a deeper naso-incisival notch.

A-3. Twenty one differ from the 16 precedent mainly by a smaller anterior ocular line and a shorter naso-incisival notch.

A-4. Six skulls are close to the precedent 21, but have the deepest naso-incisival notches.

A-5. Two are very small : Sheep Creek 69700 and Jonas Wilson 70108.

A-6. In this group of 10 specimens, palate and P2-M3 are long.

A-7. The palate seems especially long in the skull 613-150 from June Q. and in specimen 10864 from Leptarchus Q. referred to Neohipparion.

A-8. A wide muzzle characterizes three specimens.

A-10. Unclassified A. The last ratio diagram shows 6 skulls that could not be placed in any of the previous groups but all with short naso-incisival notches - a group A character. Most have wide muzzles, but not as wide as in Morph 8.

Skull proportions, excluding the size of the preorbital â€˜bar' (32) : Lakotahippus s.l.

2010-05-31T19:26:47Z

As the variation is the largest for measures of the fossa, especially its distance from the orbit ('bar' : mesure 32), I have drawn separate ratio digrams for other dimensions : 5=post-palatal length ; 23=anterior ocular line ; 2=palatal length ; 1=muzzle length ; 15=maximal muzzle breadth ; 9=P2-M3 length ; 30=length of the naso-incisival notch ; 31=length of the cheek. The reference is the skull FAM 60300 of Lakotahippus (Tables 1 doc2262 and 2 doc2265).

Lakotahippus, Lakotahippus-like, and Group A-morph 9 skulls.

There are only two skulls (7269 from John Day, referred to Kalobatippus ; and 10828, referred to Protohippus or Neohipparion) that somehow resemble the reference Lakotahippus 60300 from Ash Hollow (Lakotalike).
All other have much shorter naso-incisival notches and/or longer cheeks ; they evidently belong to Group A. They form the morph 9 of Group A (A-9).