New Hebrides

2020 ◽  
Author(s):  
Keyword(s):  
2017 ◽  
Vol 4 (9) ◽  
pp. 170862 ◽  
Author(s):  
H. Ritchie ◽  
A. J. Jamieson ◽  
S. B. Piertney

Genome size varies considerably across taxa, and extensive research effort has gone into understanding whether variation can be explained by differences in key ecological and life-history traits among species. The extreme environmental conditions that characterize the deep sea have been hypothesized to promote large genome sizes in eukaryotes. Here we test this supposition by examining genome sizes among 13 species of deep-sea amphipods from the Mariana, Kermadec and New Hebrides trenches. Genome sizes were estimated using flow cytometry and found to vary nine-fold, ranging from 4.06 pg (4.04 Gb) in Paralicella caperesca to 34.79 pg (34.02 Gb) in Alicella gigantea . Phylogenetic independent contrast analysis identified a relationship between genome size and maximum body size, though this was largely driven by those species that display size gigantism. There was a distinct shift in the genome size trait diversification rate in the supergiant amphipod A. gigantea relative to the rest of the group. The variation in genome size observed is striking and argues against genome size being driven by a common evolutionary history, ecological niche and life-history strategy in deep-sea amphipods.


Island Arc ◽  
2001 ◽  
Vol 10 (1) ◽  
pp. 33-50 ◽  
Author(s):  
Sebastien Meffre ◽  
Anthony J Crawford

The Southern region of the New Hebrides consists of five islands of very different size, clearly separated from and with a cooler climate than the remainder of the archipelago. Only the three largest islands have been studied botanically. These islands are Aneityum and Erromanga, now sparsely populated, where there is still extensive climax vegetation on the deep, infertile soils, and Tanna, with a dense human population, where, except in mountainous regions, there is scarcely anything but secondary vegetation, on generally fertile soils that are periodically rejuvenated by ash showers from a continuously active volcano. The principal vegetation types recognized are: dense Agathis (kauri) - Calophyllum forest; cloud forest, with mosses and ferns, on ridges above 500 m altitude; low forests or thickets with Euphorbiaceae, Hibiscus or Leucaena ; open Acacia spirorbis forest; thickets of Myrtaceae and Vaccinium ; various associations more or less dominated by grasses. The flora, though relatively rich in the New Hebridean context, appears poor in comparison with that of Fiji, to which it is nevertheless fairly closely related, and even poorer in comparison with that of New Caledonia. Its wider affinities are Malaysian.


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