Table 1. Summary of specimens used in the training set. F:AMNH refers to the Frick collections of the AMNH; UCMP is the University of California Museum of Paleontology collections. "Hemiauchenia" minima and H. edensis were reassigned by Webb et al. (2008) from Procamelus (Frick, 1921). "H." minima was suggested to be different enough from H. vera that it should have its own generic identification (Webb et al., 1981). Pleiolama vera was reassigned from Hemiauchenia by Webb and Meachen (2004).

 

Taxon

Location

Collection

n

Aepycamelus

Mixon's Bone Bed, Levy Co., FL

F:AMNH

48

Megatylopus

Guymon, Texas Co., OK

F:AMNH

23

Procamelus

Blackhawk Ranch, Contra Costa Co., CA

UCMP

6

Alforjas

Guymon, Texas Co., OK

F:AMNH

24

"Hemiauchenia" minima

Mixon's Bone Bed, Levy Co., FL

F:AMNH

66

Hemiauchenia edensis

Mt. Eden, Riverside Co., CA

UCMP

5

Pleiolama

Edison Quarry, Sherman Co., KS

F:AMNH

9

 

TABLE 2. Eigenvalues, percent of variance explained by each Principal Component, and eigenvectors for the PCA.

 
PC Eigenvalue % Var LM TD TI TP LL WD WI LI
1 7.8266 97.833 0.35543 0.34588 0.35451 0.35269 0.35615 0.35455 0.35353 0.35558
2 0.074 0.925 -0.1783 0.92393 0.00152 -0.14375 -0.13798 -0.14678 -0.078 -0.21732
3 0.0362 0.453 0.07511 -0.00481 0.26301 0.66134 0.04432 -0.41203 -0.55816 -0.06719
4 0.0249 0.311 -0.44952 -0.08602 0.10998 0.49714 -0.30148 0.12993 0.50994 -0.40433
5 0.0177 0.222 0.02768 0.1323 -0.8413 0.40319 0.02876 0.28418 -0.13635 0.10589
6 0.012 0.149 0.27374 0.01073 -0.2905 0.05553 0.19248 -0.72612 0.52138 -0.03666
7 0.005 0.062 0.73846 0.00216 0.01329 0.00588 -0.564 0.14335 0.00295 -0.3403
8 0.0036 0.045 -0.11462 0.04095 0.02661 0.06888 -0.63662 -0.19375 0.0832 0.728

 

TABLE 3. Tukey HSD results for first three PC axes. Taxa not connected by the same letter are significantly different.

 

Taxon

PC1

PC2

PC3

Aepycamelus major

A

       

A

 

A

B

 

Alforjas

 

B

       

B

A

 

C

Megatylopus

   

C

   

A

B

 

B

 

Procamelus

     

D

 

A

B

   

C

Pleiolama vera

       

E

A

 

A

B

 

"Hemiauchenia" minima

       

E

A

 

A

B

 

Hemiauchenia edensis

       

E

A

B

A

B

C


TABLE 4. Discriminant function analysis results for training set. Known identity in rows, predicted identity in columns. Correct identifications are in bold, with the number correct followed by the percent correct in parentheses. Incorrect identifications are in blue. The last row represents Mahalanobis distance cutoffs for predictions on unknowns.

 
Full dataset Aepycamelus major Alforjas Megatylopus Procamelus Pleiolama vera "Hemiauchenia" minima H. edensis Totals
Aepycamelus major 44 (92%)   4         48
Alforjas   22 (92%)     1 1   24
Megatylopus 1   22 (96%)         23
Procamelus       6 (100%)       6
Pleiolama vera     8 (89%)   1 9
"Hemiauchenia" minima   5 52 (79%)   66
Hemiauchenia edensis   1 1 3 (60%) 5
Mahalanobis cutoff 15.10 6.72 10.78 11.02 2.54 4.86 3.20  
Genus level Aepycamelus Alforjas Megatylopus Procamelus Pleiolama "Hemiauchenia" Totals  
Aepycamelus 44 (92%)   4       48  
Alforjas   22 (92%)     1 1 24  
Megatylopus 2   21 (88%)       23  
Procamelus       6 (100%)     6  
Pleiolama         8 (89%) 1 9  
Hemiauchenia         7 64 (90%) 71  
Mahalanobis cutoff 15.12 6.68 10.80 11.08 2.56 5.46    
Lumped "Hemiauchenia" Aepycamelus Alforjas Megatylopus Procamelus "Hemiauchenia" Totals    
Aepycamelus 44 (92%)   4     48    
Alforjas   23 (96%)     1 24    
Megatylopus 1   22 (96)     23    
Procamelus       6 (100%)   6    
Hemiauchenia         80 (100%) 80    
Mahalanobis cutoff 15.08 6.64 10.76 11.12 5.18    

 

TABLE 5. As for Table 4, but reflecting leave-one-out jackknife verification.

 
Full dataset Aepycamelus major Alforjas Megatylopus Procamelus Pleiolama vera "Hemiauchenia" minima H. edensis Totals
Aepycamelus major 44 (92%)   4         48
Alforjas   22 (92%)     1 1   24
Megatylopus 2   21 (91%)         23
Procamelus       6 (100%)       6
Pleiolama vera         8 (89%)   1 9
"Hemiauchenia" minima         5 52 (79%) 9 66
Hemiauchenia edensis         1 3 1 (20%) 5
Genus level Aepycamelus Alforjas Megatylopus Procamelus Pleiolama "Hemiauchenia" Totals  
Aepycamelus 44 (92%)   4       48  
Alforjas   22 (92%)     1 1 24  
Megatylopus 2   21 (91%)       23  
Procamelus       6 (100%)     6  
Pleiolama         8 (89%) 1 9  
"Hemiauchenia"         9 62 (87%) 71  
Lumped "Hemiauchenia" Aepycamelus Alforjas Megatylopus Procamelus "Hemiauchenia" Totals    
Aepycamelus 44 (92%)   4     48    
Alforjas   23 (96%)     1 24    
Megatylopus 2   21 (91%)     23    
Procamelus       6 (100%)   6    
"Hemiauchenia"   1     79 (99%) 80    

 

 

TABLE 6. Taxonomic assignments of Thousand Creek unknown camel astragali from each of the three discriminant analyses, accompanied by probability (p) and Mahalanobis Distance. Bold name indicates acceptable identification, while a blue name indicates a rejected identification on the basis of probability (<0.5) or Mahalanobis distance too great. Probabilities and distances are similarly bold or blue to indicate acceptance or rejection. The secondary predictions are listed for each analysis, along with their probabilities and distances; no second prediction is listed if all had p<0.01.

 
   

Full Dataset

Genus level

Loc. No

Spec. No.

Prediction

p

Dist

2nd. Pred.

p

Dist

Prediction

p

Dist

2nd

p

Dist.

2744

70461

A. major

0.95

30.6

Megatylopus

0.05

36.4

Aepycamelus

0.94

30.7

Megatylopus

0.06

36.3

V6570

164715

Alforjas

0.63

20.3

Procamelus

0.35

21.5

Alforjas

0.63

20.3

Procamelus

0.34

21.6

2744

70463

Alforjas

0.75

6.7

Procamelus

0.14

10.1

Alforjas

0.77

6.6

Procamelus

0.13

10.2

2744

164708

Alforjas

0.94

12.6

Procamelus

0.05

18.4

Alforjas

0.94

12.7

Procamelus

0.06

18.1

2744

164707

Megatylopus

0.50

12.4

Procamelus

0.50

12.4

Megatylopus

0.52

12.3

Procamelus

0.48

12.5

V78053

164712

Megatylopus

0.88

27.4

Procamelus

0.08

32.3

Megatylopus

0.86

27.0

Procamelus

0.11

31.2

V99410

158359

Megatylopus

1.00

31.6

     

Megatylopus

1.00

31.7

     

V6570

31379

Procamelus

0.76

19.7

Alforjas

0.23

22.0

Procamelus

0.74

19.8

Megatylopus

0.01

28.9

2744

164709

Procamelus

0.94

14.2

Megatylopus

0.06

19.7

Procamelus

0.94

14.3

Megatylopus

0.06

19.7

1101

70346

Procamelus

0.94

19.8

Megatylopus

0.05

25.5

Procamelus

0.95

19.7

Megatylopus

0.05

25.6

2744

164728

Procamelus

0.96

7.9

Alforjas

0.04

14.1

Procamelus

0.95

7.9

Alforjas

0.05

14.0

V78050

164713

Procamelus

0.98

29.6

Megatylopus

0.01

38.3

Procamelus

0.98

29.7

Megatylopus

0.01

38.5

V99448

157285

Procamelus

0.99

6.1

     

Procamelus

0.99

6.1

     

2744

164725

P. vera

0.32

13.3

Alforjas

0.30

13.4

Pleiolama

0.36

13.4

Alforjas

0.35

13.4

2739

164726

P. vera

0.47

13.5

H. edensis

0.38

13.9

Pleiolama

0.74

13.5

"Hemiauchenia"

0.26

15.6

2744

70464

P. vera

0.49

13.7

"H." minima

0.33

14.5

Pleiolama

0.53

13.7

"Hemiauchenia"

0.32

14.7

V91097

164774

P. vera

0.51

3.7

Alforjas

0.23

5.3

Pleiolama

0.57

3.7

Alforjas

0.26

5.3

V99410

158358

P. vera

0.72

6.6

"H." minima

0.16

9.6

Pleiolama

0.77

6.6

"Hemiauchenia"

0.17

9.6

V69107

164714

"H." minima

0.45

11.6

H. edensis

0.35

12.1

"Hemiauchenia"

0.70

11.5

Pleiolama

0.30

13.2

V78061

164716

"H." minima

0.46

4.4

H. edensis

0.44

4.6

"Hemiauchenia"

0.83

4.3

Pleiolama

0.15

7.8

1100

35633

"H." minima

0.48

3.2

H. edensis

0.42

3.5

"Hemiauchenia"

0.84

3.1

Pleiolama

0.15

6.5

V69106

164720

"H." minima

0.54

4.7

H. edensis

0.43

5.2

"Hemiauchenia"

0.96

4.6

Pleiolama

0.04

11.2

V6570

164727

"H." minima

0.55

2.0

H. edensis

0.27

3.5

"Hemiauchenia"

0.76

2.0

Pleiolama

0.24

4.3

V69106

164721

"H." minima

0.55

7.6

H. edensis

0.42

8.1

"Hemiauchenia"

0.96

7.5

Pleiolama

0.04

14.0

V99414

158399

"H." minima

0.58

2.6

H. edensis

0.34

3.7

"Hemiauchenia"

0.88

2.5

Pleiolama

0.12

6.5

V99448

157286

"H." minima

0.70

2.2

H. edensis

0.15

5.3

"Hemiauchenia"

0.81

2.3

Pleiolama

0.16

5.6

2744

164724

"H." minima

0.70

3.2

H. edensis

0.21

5.6

"Hemiauchenia"

0.88

3.2

Pleiolama

0.09

7.8

V69106

164723

"H." minima

0.81

4.4

H. edensis

0.14

7.9

"Hemiauchenia"

0.94

4.5

Pleiolama

0.06

10.0

V78075

164755

H. edensis

0.37

7.2

"H." minima

0.34

7.4

"Hemiauchenia"

0.56

7.3

Pleiolama

0.44

7.7

V69114

164718

H. edensis

0.37

15.2

"H." minima

0.16

16.9

Alforjas

0.54

15.3

"Hemiauchenia"

0.28

16.6

V69106

84648

H. edensis

0.51

13.8

"H." minima

0.35

14.5

"Hemiauchenia"

0.74

14.3

Pleiolama

0.26

16.4

V99414

157206

H. edensis

0.56

9.8

"H." minima

0.30

11.1

"Hemiauchenia"

0.71

10.8

Pleiolama

0.29

12.7

V99451

153817

H. edensis

0.57

7.8

"H." minima

0.42

8.4

"Hemiauchenia"

0.97

8.2

Pleiolama

0.03

15.3

V69106

164719

H. edensis

0.72

6.6

"H." minima

0.17

9.5

"Hemiauchenia"

0.64

9.1

Pleiolama

0.36

10.3

2741

70417

H. edensis

0.75

14.2

"H." minima

0.24

16.5

"Hemiauchenia"

0.98

16.2

Pleiolama

0.02

23.5

2739

70390

H. edensis

0.79

16.7

"H." minima

0.19

19.6

"Hemiauchenia"

0.91

19.2

Pleiolama

0.07

24.2

 

TABLE 6 continued.

 

Lumped "Hemiauchenia"

Prediction

p

Dist.

2nd

p

Dist

Aepycamelus

0.96

30.3

Megatylopus

0.04

36.5

Alforjas

0.69

19.8

Procamelus

0.31

21.4

Alforjas

0.80

6.7

Procamelus

0.14

10.1

Alforjas

0.94

12.3

Procamelus

0.05

18.1

Procamelus

0.50

11.7

Megatylopus

0.50

11.7

Megatylopus

0.75

27.0

Procamelus

0.17

29.9

Megatylopus

1.00

31.8

     

Procamelus

0.71

19.7

Alforjas

0.28

21.6

Procamelus

0.96

13.1

Megatylopus

0.04

19.4

Procamelus

0.91

19.6

Megatylopus

0.09

24.3

Procamelus

0.95

8.0

Alforjas

0.05

14.0

Procamelus

0.96

29.7

Megatylopus

0.03

36.8

Procamelus

0.99

6.1

Alforjas

0.01

16.0

"Hemiauchenia"

0.50

13.4

Alforjas

0.49

13.5

"Hemiauchenia"

0.98

14.9

Alforjas

0.02

23.2

"Hemiauchenia"

0.75

14.2

Alforjas

0.24

16.4

Alforjas

0.50

5.3

"Hemiauchenia"

0.50

5.3

"Hemiauchenia"

0.82

8.7

Alforjas

0.18

11.7

"Hemiauchenia"

1.00

11.4

     

"Hemiauchenia"

0.98

4.4

Alforjas

0.02

11.8

"Hemiauchenia"

0.99

3.2

     

"Hemiauchenia"

1.00

4.9

     

"Hemiauchenia"

1.00

1.9

     

"Hemiauchenia"

1.00

7.8

     

"Hemiauchenia"

0.99

2.7

     

"Hemiauchenia"

0.96

2.4

Alforjas

0.04

8.6

"Hemiauchenia"

0.96

3.4

Alforjas

0.04

10.0

"Hemiauchenia"

1.00

4.7

     

"Hemiauchenia"

0.99

7.0

     

Alforjas

0.64

15.3

"Hemiauchenia"

0.36

16.5

"Hemiauchenia"

1.00

14.3

     

"Hemiauchenia"

1.00

10.8

     

"Hemiauchenia"

1.00

8.5

     

"Hemiauchenia"

1.00

8.9

     

"Hemiauchenia"

1.00

16.5

     

"Hemiauchenia"

0.97

19.5

Alforjas

0.03

26.8