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Table 1 Incubation temperatures and sex ratios from wild populations of tuatara. ti = constant incubation temperature, Uti = uncertainty around ti in °C, Ni = number of sexed embryos, Mi and Fi = number of males and females, and Osri = observed male frequency. Numbers of sexed hatchlings from the Little Barrier Island population are included for comparison [10].

From: Support for a rare pattern of temperature-dependent sex determination in archaic reptiles: evidence from two species of tuatara (Sphenodon)

S. guntheri (North Brother I.)

S. punctatus unnamed subsp. (Stephens I.)

S. p. punctatus (Little Barrier I.)

t i

U t i

N i

M i

F i

Osr i

t i

U t i

N i

M i

F i

Osr i

t i

N i

M i

F i

Osr i

18

1

19

0

19

0

18

1

14

0

14

0

18

24

0

24

0

      

18.1

0.1

105

0

105

0

     

18.3

0.1

12

1

11

0.08

           
      

20

1

44

3

41

0.07

     

20.8

0.1

12

3

9

0.25

           
            

21

1

0

1

0

      

21.3

0.1

80

3

77

0.04

     
      

21.5*

0.1

7

0

7

0

     

22

1

5

0

5

0

22

1

30

9

21

0.3

22

14

3

11

0.21

22.1

0.1

14

14

0

1

           
      

22.3

0.1

113

113

0

1

     

23.0

0.1

11

11

0

1

      

23

7

7

0

1

      

24.1*

0.1

8

8

0

1

     
  1. *These eggs were collected from a captive-housed female