The Tropical Conservativism Hypothesis proposes that processes of speciation, extinction, and dispersal resulted in higher species richness in the tropics and decreased away from the equator, implying that species richness increased in the tropics and fell away from the equator. The Biogeographical Conservativism Hypothesis proposes that the processes in question are not unique to the tropics, but rather rely on historical biogeography to determine species richness distribution. To test the two theories, 77 genuine species belonging to the genus Gnomeskelus were discovered. The number of species and latitudinal degrees distant from the equator had a significant connection (r=-0.7145, r2=0.5105, n=77, p0.00001). Alternatively, an evolutionary predisposition for temperate habitats could have resulted in climatic dispersal restrictions based solely on temperature seasonality gradients.
School of Animal, Plant & Environmental Sciences, University of the Witwatersrand, Johannesburg 2050, South Africa
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