We will not discuss here the ways of testing dating hypotheses, which is a rich and generally well-understood subject.
The second statement refers to a less commonly broached topic which needs to be clearly formulated in order to be subjected to a more rigorous hypothesis testing.
This means that there are few old groups in the region, contrary to the expectations of the Gondwanan refuge hypothesis.
Taking the dataset as a whole, the probabilities of the NC crown group and the inclusive Pacific group being older than 37 Ma are highly correlated (rs = 0.931022, p Estimated crown age of the New Caledonian and Pacific island clades from the 40 selected studies.
The results of this meta-analysis provide strong evidence for refuting the hypothesis of a Gondwanan refuge with a biota that originated by vicariance.
The NBER does not define a recession in terms of two consecutive quarters of decline in real GDP.
These studies cover diverse groups of arthropods (21 studies), plants (16), vertebrates (2), and molluscs (1) (Table 1).
In 30 of these studies, the age of the NC crown group and the inclusive Pacific island group was the same because they are the same group (i.e. Taking confidence intervals into account, in 33 phylogenies (82.5%) clades (crown age) were estimated to be strictly younger than the emergence of NC, in six studies (15%) the crown age predated 37 ± 3 Ma, and two studies presented a clade that overlapped this period (Fig. The probability values for most of these groups were either negative or around zero (mean = −2.82; median = −2.93; SE = 0.44, n = 40).
In spite of this, some authors still insist on the idea of a local permanence of a Gondwanan biota, justifying this assumption through a complex scenario of survival by hopping to and from nearby and now-vanished islands.
Based on a comprehensive review of the literature, we found 40 studies dating regional clades of diverse organisms and we used them to test the hypothesis that New Caledonian and inclusive Pacific island clades are older than 37 Ma.