Expanding Earth /
The Significance of Biogeographical
Evidence:
The Significance of Biogeographical
Evidence:
| 3. Trans-Pacific Biotic Disjunctions The precise regions that unite along the matching outlines (e.g. Tasmania and South-central Chile) share hundreds of poor-dispersing sister taxa found nowhere else in the world. The following are just a few of the biogeographical problems that this presents to plate tectonics: |
| 3a. These taxa cannot cross oceans. Countless narrow-range, sister taxa that are rejoined in expanding Earth paleomaps are separated by vast oceans in plate tectonics. These taxa include purely freshwater fish; terrestrial vertebrates; shallow, bottom dwelling marine taxa that cannot survive in the deep ocean; weakly-flying birds; even lumbering dinosaurs. Not only would all of these taxa have to manage a jump-dispersal event across the full-breadth of a superocean -- a feat otherwise unknown in these types of organisms -- they then would have had to never end-up anywhere else. For some reason, the taxa would have had to prefer jaunts between regions that were juxtaposed on expanding Earth paleomaps. To mention one of hundreds of examples: the closest relatives of the Fijan banded (right) occur in California and Mexico. No other iguanas inhabit any other island in the Central or West Pacific. |
| 3b. The Oceanic Island /Wide-Ranging Problem Taxa that are able to cross large marine gaps are wide-ranging and appear on other oceanic islands. For example, all species of plants on Pitcairn are from wide-ranging ancestors, distributed throughout the Pacific. Pitcairn, unlike New Zealand, does not exclusively share any plant with South America -- even though Pitcairn is roughly half as far away from S. America as New Zealand. Quite simply, taxa that can reach remote oceanic islands can reach nearer ones too. This empirically challenges hypotheses of cross-ocean dispersal currently used to explain narrow-range, trans-Pacific biotic disjunctions. In other words, if the poor-dispersing taxa shared by South America and New Zealand, New Caledonia, and Fiji really are capable of cross-ocean dispersal, they should appear on at least a few of the 25,000 other islands in the Pacific, and they do not. |
Adamstown on Pitcairn
| 3c. The Ancient Island Problem Of more than 25,000 islands in the Pacific, only three are old enough to have once been in proximity with South America according to expanding Earth paleomaps: New Zealand, New Caledonia, Fiji. All problematic disjunctions of narrow-range taxa occur on those three islands -- or the more ancient continental regions of Australia, New Guinea and Indonesia. None of the other islands in the Pacific boast problematic disjunctions of poor-dispersing taxa with the Western Americas. (Hawaii, which is merely 3900 km from the nearest continent, has no native, non-volant terrestrial vertebrates at all -- let alone all from one particular narrow region 7000 km away.) |
| Coming soon: The Mozambique Channel and the Torres Strait provide a more significant barrier to dispersal than Panthalassa; all arguments used by Wegener are also valid for the Pacific; Index of similarity analyses from the Upper-Triassic. |
