TABLE 1. Coefficients of Variation (CV) of OPC values for Hoploscaphites spedeni and H. nebrascensis whole shells and separated body chambers and phragmocones of both sexual dimorphs. Note the higher CV for H. spedeni macroconch body chambers and the much smaller CV for H. nebrascensis macroconch body chambers. This reduction in variation may indicate strong selectivity on the body chamber from H. spedeni to subsequent H. nebrascensis.

 

Species

Dimorph

n

CV Whole Shell
OPC

CV Body Chamber
OPC

CV Phragmocone
OPC

H. spedeni

         
 

macroconch

19

26.58

34.92

26.00

 

microconch

20

24.94

28.61

28.35

H. nebrascensis

         
 

macroconch

5

14.05

11.02

31.7

 

microconch

5

26.16

22.95

38.80

 

TABLE 2. Comparisons and results of the Mann-Whitney U test for equality of median surface-to-planimetric area ratios. Comparisons were made of body chambers and phragmocones between species and dimorphs of Hoploscaphites. Note that whole shell comparisons were not conducted due to the prohibitively large number of cells per raster. Analyses calculated statistically significant differences at the 95% confidence limit between the median area ratios for all specimens compared. Also note that for the H. spedeni macroconch body chambers, the most rotund, ornate specimens did not necessarily have the largest median cell values. This observation suggests that large changes may occur in late ontogenetic stages within this species.

 

Comparisons

Specimen 1 Median Surface-to-Planimetric Area Ratio

Specimen 2 Median Surface-to-Planimetric Area Ratio

U*

p (95%)

H. spedeni macro body chamber:

       

typical vs rotund (ornate)

1.105

1.101

200.95

< 0.01

typical vs compressed (smooth)

1.105

1.056

25.33

< 0.01

         

H. spedeni macro phragmocone:

       

typical vs rotund (ornate)

1.091

1.141

30.81

< 0.01

typical vs compressed (smooth)

1.091

1.092

4.91

< 0.01

         

H. spedeni and H. nebrascensis macro body chamber:

       

rotund H. spedeni vs lowest H. nebrascensis

1.101

1.054

44.61

< 0.01

rotund H. spedeni vs highest H. nebrascensis

1.101

1.089

13.15

< 0.01

         

H. spedeni and H. nebrascensis macro phragmocone:

       

rotund H. spedeni vs lowest H. nebrascensis

1.141

1.070

48.43

< 0.01

rotund H. spedeni vs highest H. nebrascensis

1.141

1.109

23.17

< 0.01

         

H. nebrascensis macro body chamber:

       

lowest vs highest

1.054

1.089

204.08

< 0.01

         

H. nebrascensis macro phragmocone:

       

lowest vs highest

1.070

1.109

9.70

< 0.01

         

H. spedeni micro body chamber:

       

typical vs rotund (ornate)

1.086

1.139

32.68

< 0.01

typical vs compressed (smooth)

1.086

1.059

28.65

< 0.01

         

H. spedeni micro phragmocone:

       

typical vs rotund (ornate)

1.120

1.129

9.56

< 0.01

typical vs compressed (smooth)

1.120

1.092

21.27

< 0.01

         

H. spedeni and H. nebrascensis micro body chamber:

       

rotund H. spedeni vs lowest H. nebrascensis

1.139

1.046

66.41

< 0.01

rotund H. spedeni vs highest H. nebrascensis

1.139

1.100

26.30

< 0.01

         

H. spedeni and H. nebrascensis micro phragmocone:

       

rotund H. spedeni vs lowest H. nebrascensis

1.129

1.073

42.12

< 0.01

rotund H. spedeni vs highest H. nebrascensis

1.129

1.127

7.15

< 0.01

         

H. nebrascensis micro body chamber:

       

lowest vs highest

1.046

1.100

41.50

< 0.01

         

H. nebrascensis micro phragmocone:

       

lowest vs highest

1.073

1.127

33.16

< 0.01