|Origin of the Hawaiian marine fauna: dispersal and vicariance as indicated by barnacles and other organisms|
Newman, W.A. (1986). Origin of the Hawaiian marine fauna: dispersal and vicariance as indicated by barnacles and other organisms, in: Gore, R.H. et al. Crustacean biogeography. Crustacean Issues, 4: pp. 21-49
In: Gore, R.H.; Heck, K.L. (1986). Crustacean biogeography. Crustacean Issues, 4. A.A. Balkema: Rotterdam, The Netherlands [etc.]. ISBN 90-6191-593-7. 292 pp., more
In: Schram, F.R. (Ed.) Crustacean Issues. Balkema/CRC Press/Taylor & Francis: Rotterdam. ISSN 0168-6356, more
The Hawaiian Archipelago is situated in relative isolation, especially from other high islands, in the subtropical fringe of the North Pacific between 20 and 29°N. The isolation from high islands as well as low islands is emphasized because there are some notable differences between the biotas of the two types. Most of the biota inhabiting the Hawaiian Islands represents a depauperate extension or attenuation of the Indo- West Pacific biota and most marine forms are wide ranging eurytopic species. There are also some cosmopolitan species as well as a variety of endemics. The Hawaiian shallow water fauna is relatively young (Tertiary), at least as far as the balanomorph barnacles and hermatypic corals are concerned, and within the latter there has been a marked turnover at the generic level since the Miocene. Therefore, I agree with most previous authors that long range dispersal accounts for the general nature of the biota. A number of authors have noted a marked similarity, including shared species, between some elements of the Hawaiian biota with that of the high island reaches of the eastern South Pacific. This observation is inconsistent with the general Indo-West Pacific attenuation pattern. Representatives should be found in between, and to explain their absence 'extinction' and 'island integration' hypotheses have been proposed. So far, island integration has not been corroborated on geological grounds, and it is biologically unsound because of the time frame involved. However, there is historical evidence favoring the extinction hypothesis. The distributional anomaly is primarily an amphitropical pattern, comparable to that observed in the zooplankton. The latter has been explained on oceanographic grounds, by invoking Pleistocene events in the Eastern Pacific, with dispersal between the two regions from south to north, the same direction as for the insular biotas. This explanation becomes especially attractive for the insular biotas when Pleistocene eustatic sea level changes, as well as concomitant cooler sea surface temperatures across the tropics, are considered. During low stands of the sea, low islands such as the Line Islands, which range across the equator towards Hawaii from the south, became high islands, whereby the notable isolation of the Hawaiian Archipelago from high islands of the South Pacific became dramatically reduced. It also appears that the isolated islands of the Eastern Pacific were involved as stepping stones for insular forms between these two regions.