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TABLE 1. Size measurements (length, width, and thickness) and spiral deviations from all analyzed specimens of the species Laqueus rubellus, Terebratula terebratula, Platystrophia ponderosa, and Pseudoatrypa sp.

Specimen Length (mm) Width (mm) Thickness (mm) Dorsal minima Dorsal maxima Ventral minima Ventral maxima
L. rubellus 1

 

L. rubellus 2

 

L. rubellus 3

 

T. terebratula 1

 

T. terebratula 2

 

T. terebratula 3

 

P. ponderosa 1

 

P. ponderosa 2

 

P. ponderosa 3

 

Pseudoatrypa sp. 1

 

Pseudoatrypa sp. 2

 

Pseudoatrypa sp. 3

23.2

 

29.3

 

27.1

 

47.3

 

38.7

 

40.4

 

23.9

 

35.5

 

26.0

 

19.0

 

21.0

 

19.5

14.8

 

19.0

 

18.0

 

34.0

 

34.2

 

32.0

 

35.0

 

46.0

 

32.4

 

18.0

 

22.0

 

19.6

10.5

 

17.0

 

14.0

 

24.5

 

18.9

 

21.9

 

22.5

 

28.0

 

26.0

 

10.0

 

16.1

 

11.7

4

 

2

 

2

 

5

 

4

 

4

 

2

 

3

 

4

 

N/A

 

N/A

 

N/A

4

 

3

 

3

 

6

 

3

 

4

 

3

 

4

 

5

 

N/A

 

N/A

 

N/A

4

 

3

 

2

 

3

 

4

 

3

 

2

 

4

 

3

 

N/A

 

N/A

 

N/A

4

 

3

 

3

 

4

 

4

 

4

 

2

 

4

 

4

 

N/A

 

N/A

 

N/A

TABLE 2. Spiral output from three specimens of the species Laqueus rubellus. Maximum length is the maximum distance from the posterior to anterior region. Arc length is the maximum distance along the outline of the valve, from the posterior to anterior regions. Spiral axis (a) is the distance between the spiral axis and the first set of coordinates at the umbo. Spiral parameter (k) indicates the shape of the valve, where higher numbers represent flatter valves. Two spirals were fit to these shells, thus there were two spiral axes and parameters. Error is an indicator of how well the spirals fit the biological outline. The error from one spiral fitting was included as a comparison. N is the number of digitized points on the biological outline.

Specimen Length (mm) Arc-length (mm) a1 a2 k1 parameter (spiral angle) k2 parameter (spiral angle) Error: two spirals (mm) Error: one spiral (mm) N
1 Dorsal

 

1 Ventral

 

2 Dorsal

 

2 Ventral

 

3 Dorsal

 

3 Ventral

19.96

 

23.23

 

25.78

 

29.28

 

20.47

 

27.14

23.30

 

29.62

 

35.21

 

37.03

 

26.05

 

32.79

0.40

 

0.99

 

27.03

 

5.17

 

0.95

 

7.29

0.95

 

2.76

 

22.51

 

9.76

 

1.50

 

4.78

1.63 (31.5°)

 

1.20 (39.8°)

 

0.57 (60.3°)

 

0.77 (52.3°)

 

1.08 (42.7°)

 

0.40 (68.4°)

1.24 (38.9°)

 

0.79 (51.6°)

 

0.01 (89.2°)

 

0.45 (65.6°)

 

0.91 (47.7°)

 

0.67 (56.2°)

0.06

 

0.13

 

0.25

 

0.09

 

0.08

 

0.08

0.13

 

0.20

 

0.32

 

0.19

 

0.11

 

0.15

312

 

289

 

385

 

373

 

258

 

400

TABLE 3. Spiral output from three specimens of the species Terebratula terebratula (see caption for Table 2 for definitions and abbreviations).

Specimen Length (mm) Arc-length (mm) a1 a2 k1 parameter (spiral angle) k2 parameter (spiral angle) Error: two spirals (mm) Error: one spiral (mm) N
1 Dorsal

 

1 Ventral

 

2 Dorsal

 

2 Ventral

 

3 Dorsal

 

3 Ventral

39.25

 

47.25

 

33.17

 

38.69

 

34.47

 

40.39

46.41

 

58.04

 

37.80

 

49.52

 

41.09

 

50.50

1.84

 

5.60

 

3.52

 

5.28

 

2.08

 

6.82

2.70

 

6.68

 

1.51

 

2.47

 

0.89

 

15.07

1.40 (35.5°)

 

0.93 (47.0°)

 

1.05 (43.5°)

 

0.66 (56.5°)

 

-1.11 (-42.0°)

 

0.77 (52.4°)

1.19 (40.1°)

 

0.82 (50.8°)

 

1.51 (33.5°)

 

0.97 (45.8°)

 

-1.52 (-33.4°)

 

0.39 (68.6°)

0.12

 

0.08

 

0.14

 

0.11

 

0.14

 

0.09

0.15

 

0.10

 

0.30

 

0.29

 

0.21

 

0.23

514

 

343

 

247

 

459

 

355

 

391

 

TABLE 4. Spiral output from three specimens of the species Platystrophia ponderosa (see caption for Table 2 for definitions and abbreviations).

Specimen
(No./valve)
Length
(mm)
Arc-length
(mm)
a1 a2 k1 parameter
(spiral angle)
k2 parameter
(spiral angle)
Error: two spirals
(mm)
Error: one spiral
(mm)
N
1 Dorsal

 

1 Ventral

 

2 Dorsal

 

2 Ventral

 

3 Dorsal

 

3 Ventral

23.52

 

23.86

 

33.65

 

35.49

 

24.69

 

25.97

37.09

 

37.23

 

50.02

 

49.32

 

42.73

 

43.45

3.15

 

1.41

 

2.75

 

2.01

 

4.66

 

5.02

3.65

 

2.35

 

3.81

 

3.31

 

3.18

 

8.91

0.70 (55.1°)

 

0.80 (51.5°)

 

0.94 (46.9°)

 

0.89 (48.4°)

 

-0.45 (-65.7°)

 

0.51 (62.8°)

0.53 (62.2°)

 

0.63 (57.7°)

 

0.67 (56.1°)

 

0.72 (54.1°)

 

-0.59 (-59.7°)

 

0.29 (74.0°)

0.09

 

0.11

 

0.14

 

0.11

 

0.27

 

0.14

0.10

 

0.16

 

0.16

 

0.17

 

0.29

 

0.21

514

 

492

 

484

 

187

 

524

 

490

TABLE 5. Spiral output from three specimens of the species Pseudoatrypa sp. (see caption for Table 2 for definitions and abbreviations).

Specimen
(No./valve)
Length
(mm)
Arc-length (mm) a1 a2 k1 parameter
(spiral angle)
k2 parameter
(spiral angle)
Error: two spirals
(mm)
Error: one spiral
(mm)
N
1 Dorsal

 

1 Ventral

 

2 Dorsal

 

2 Ventral

 

3 Dorsal

 

3 Ventral

18.60

 

19.02

 

20.52

 

21.03

 

19.38

 

19.54

24.07

 

22.18

 

34.03

 

29.82

 

30.17

 

25.94

4.58

 

8.43

 

5.30

 

16.34

 

3.30

 

10.88

6.27

 

9.63

 

9.26

 

17.65

 

9.32

 

23.04

-0.50 (-63.4°)

 

1.65 (31.3°)

 

0.39 (68.6°)

 

0.10 (84.0°)

 

0.69 (55.5°)

 

0.37 (69.5°)

-0.35 (-71.0°)

 

0.50 (63.4°)

 

0.17 (80.1°)

 

-0.34 (-71.1°)

 

0.23 (76.9°)

 

-0.18 (-79.6°)

0.08

 

0.13

 

0.11

 

0.10

 

0.12

 

0.15

0.10

 

0.16

 

0.15

 

0.16

 

0.22

 

0.22

474

 

438

 

628

 

557

 

497

 

419

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