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Table 1 A review of available publications on the most frequently investigated digit ratio (2D:4D) in amphibians, with the main results and additional information. Results for which significant sexual dimorphism in digit ratio was detected are indicated in bold. The effect sizes (to two decimal places) are included in parentheses where reported in parentheses. For values of other digit ratios (2D:3D and 3D:4D) in the common toad Bufo bufo, see Tables 2, 3, and S2

From: Digit ratio in the common toad Bufo bufo: the effects of reduced fingers and of age dependency

Order

Sample size

Adult SVL

Specimen type

2D:4D

References

Family, Species

M

F

FL

FR

BL

BR

 

Anura

 Bufonidae

  Bufo bufoa

158

143

F > M

Live

ns

ns

  

this study

     

(−0.08)

(0.02)

ns

ns

 
     

ns#

M < F#

(− 0.08)

(− 0.01)

this study

     

(0.15)

(−0.53)

   

  Rhinella marina

24

28

F > M

Live

ns

ns

ns

ns

[27]

  R. marina

14

5

F > M

Live

ns

ns

ns

ns

[27]

 Craugastoridae

  Craugastor bransfordii

46

42

F > M

Live

F < M

ns

ns

ns

[26]

     

(0.62)

(0.12)

(0.33)

(0.1)

 

 Dendrobatidae

  Oophaga pumilio

40

44

F = M

Live

ns

ns

F < M

F < M

[25]

  O. pumilio

36

48

F = M

Live

F < M

F < M

ns

ns

[26]

     

(0.93)

(0.7)

(0.05)

(0.2)

 

 Leiopelmatidae

  Leiopelma pakeka

  

F > M

Live

ns

ns

[24]

 Leptodactylidae

  Engystomops pustulosus

107

52

F > M

 

M < F

M < F

ns

ns

[27]

  Leptodactylus podicipinusb

128

191

F > M

Preserved

F < M

F < M

[5]

  Leptodactylus fuscusc

24

25

F = M

Live

ns

ns

[5]

 Ranidae

  Pelophylax ridibundusc

30

20

F > M

Live

M < F

ns

[29]

Caudata

 Salamandridae

  Salamandra salamandra

35

31

F > M

Preserved

ns

ns

ns

ns

[28]

  Triturus cristatus

25

20

F = M

Preserved

ns

ns

ns

ns

[17]

     

(−0.18)

(−0.3)

(−0.2)

(−0.18)

 

  Ichthyosaura (Mesotriton) alpestris

42

39

F > M

Preserved

M < F

M < F

M < F

M < F

[17]

     

(−0.34)

(−0.37)

(− 0.48)

(− 0.33)

 

  Lissotriton montandoni

42

33

F > M

Preserved

ns

ns

M < F

M < F

[17]

     

(−0.01)

(− 0.03)

(− 0.26)

(−0.32)

 

  Lissotriton vulgaris

42

41

F > M

Preserved

ns

ns

M < F

M < F

[17]

     

(−0.13)

(−0.03)

(− 0.4)

(− 0.29)

 
  1. Abbreviations: M Male, F Female; SVL Snout-vent length; FL Left forelimbs, FR Right forelimbs, BL Left hindlimbs, BR Right hindlimbs, ns No significant differences. Number of study populations: a – three populations, b–6 populations; c – two populations. # - variant II, according to numbering protocol for forelimb fingers reflecting the hypothesis that the first digit was reduced during phylogenesis in Anura. In other cases, the digit ratio was calculated for variant I (reflecting that the fifth digit was reduced) [24,25,26,27, 29]. For more details see Fig. 1