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. 2013 Apr 23;8(4):e62086. doi: 10.1371/journal.pone.0062086

Table 3. Comparisons of vertebrates arriving during the Cenozoic.

Question, Null Hypothesis, and Interpretation Pearson’s Chi squareValue, df, P Fisher’s ExactTest P
Is there a difference in vertebrate class representation of tetrapod arrivals from Africa vs. Asia (the Indian subcontinent and Southeast Asia)?
H0: There is no difference in tetrapod class representation between those arriving from Africavs. Asia during the Cenozoic. Reject. Conclusion: Mammals and reptiles are far more likely thanbirds to have arrived from Africa than from Asia. 19.293, df = 3, P<0.001 <0.001
Is this source difference dependent on the direction of ocean currents?
H01: There is no difference in tetrapod class representation of African vs. Asian arrivals beforethe mid-Miocene. Reject. Conclusion: Before the shift in ocean currents, mammals andreptiles are more likely than birds to have arrived from Africa. 8.603, df = 3, P = 0.035  = 0.017
H02: There is no difference in tetrapod class representation of African vs. Asian arrivals afterthe mid-Miocene. Reject. Conclusion: After the shift in ocean currents, mammals andreptiles are more likely than birds to have arrived from Africa. 13.03, df = 3, P = 0.005  = 0.005
H03: There is no change in overall tetrapod class representation among arrivals before andafter the mid-Miocene. Fail to reject. Conclusion: Both before and after the mid-Miocene,birds and mammals dominate arrivals. 2.653, df = 3, P = 0.448  = 0.482
H04: There is no change in geographic source among arrivals before and after the mid-Miocene.Fail to reject. Conclusion: Both before and after the mid-Miocene, most colonizersarrive from Africa. 3.097, df = 3, P = 0.377  = 0.348
What, then, was the effect of the shift in ocean currents?
H01: There is no change in dispersal advantage of vertebrate arrivals from before to afterthe mid-Miocene. Reject. Conclusion: After the mid-Miocene, the percentage ofdispersal-disadvantaged taxa colonizing Madagascar decreases. 17.392, df = 1, P<0.001 <0.001
H02: There is no change in locomotor type of vertebrate arrivals from before to after themid-Miocene. Reject. Conclusion: After the mid-Miocene, the percentage of volantcolonizers increases markedly. 15.335, df = 2, P<0.001 <0.001