Abstract:The biogeographical paradigm of New Caledonia has recently changed. Although this island is now considered by many as oceanic, its study is still often impeded by some old misconceptions concerning either regional geology or phylogenetic analysis of evolution and biogeography. I discuss ten points that I feel are especially detrimental, to help focus on the real debate and the real questions: (1) its geological history cannot be understood from the basement only; (2) the island submergence was not due simply t… Show more
“…Some authors portray New Caledonia as an ancient continental island carrying relictual Gondwanan flora and fauna to its present location and, therefore, identify diversification after vicariance as the main driver of local diversity [6–9]. The wider use of phylogenetic methods initiated a paradigm [10,11] substantiating the idea that New Caledonia is better described as an old Darwinian island and its biotic origin very well explained by transoceanic dispersal [4,12–16]. Figure 1.Map of New Caledonia and sampling localities.…”
The origin of the astonishing New Caledonian biota continues to fuel a heated debate among advocates of a Gondwanan relict scenario and defenders of late oceanic dispersal. Here, we study the origin of New Caledonian Trigonopterus flightless weevils using a multimarker molecular phylogeny. We infer two independent clades of species found in the archipelago. Our dating estimates suggest a Late Miocene origin of both clades long after the re-emergence of New Caledonia about 37 Ma. The estimation of ancestral ranges supports an ancestral origin of the genus in a combined region encompassing Australia and New Guinea with subsequent colonizations of New Caledonia out of New Guinea in the mid-Miocene. The two New Caledonian lineages have had very different evolutionary trajectories. Colonizers belonging to a clade of foliage dwellers greatly diversified, whereas species inhabiting leaf-litter have been less successful.
“…Some authors portray New Caledonia as an ancient continental island carrying relictual Gondwanan flora and fauna to its present location and, therefore, identify diversification after vicariance as the main driver of local diversity [6–9]. The wider use of phylogenetic methods initiated a paradigm [10,11] substantiating the idea that New Caledonia is better described as an old Darwinian island and its biotic origin very well explained by transoceanic dispersal [4,12–16]. Figure 1.Map of New Caledonia and sampling localities.…”
The origin of the astonishing New Caledonian biota continues to fuel a heated debate among advocates of a Gondwanan relict scenario and defenders of late oceanic dispersal. Here, we study the origin of New Caledonian Trigonopterus flightless weevils using a multimarker molecular phylogeny. We infer two independent clades of species found in the archipelago. Our dating estimates suggest a Late Miocene origin of both clades long after the re-emergence of New Caledonia about 37 Ma. The estimation of ancestral ranges supports an ancestral origin of the genus in a combined region encompassing Australia and New Guinea with subsequent colonizations of New Caledonia out of New Guinea in the mid-Miocene. The two New Caledonian lineages have had very different evolutionary trajectories. Colonizers belonging to a clade of foliage dwellers greatly diversified, whereas species inhabiting leaf-litter have been less successful.
“…New Caledonia is the oldest oceanic island [17,18]. It is considered a biodiversity hotspot due to its magnificent flora and fauna, which is characterized by a high number of locally endemic species that are under threat due to nickel mining, repeated fires, and invasive species [10, 19–23].…”
New Caledonia is a biodiversity hotspot, with an extremely high number of endemic species with narrow distribution ranges that are at high risk of extinction due to open-cast nickel mining, invasive species and seasonal man-induced fires. Mentions of micro-endemism permeate the literature on the biota of this archipelago. However, so far there has been no research comparing distribution range in different animal groups. The aim of this study is to examine the implication of different sampling effort variables in order to distinguish micro-endemicity from data deficiency, and evaluate the distribution range, frequency, and extent to which micro-endemism is common to several groups of organisms. We compiled a dataset derived from publications in Zoologia Neocaledonica, comprising 1,149 species, of which 86% are endemic to New Caledonia. We found that the sampling effort variables that were best correlated with distribution range were the number of sampling dates and the number of collectors per species. The median value of sampling dates was used to establish a cut-off point for defining adequately sampled species. We showed that, although only 52% of species were sampled adequately enough to determine their distribution range, the number of species with a very narrow distribution range was still high. Among endemics from New Caledonia, 12% (116 species) have ranges ≤5.2km2 and 3.9% (38 species) have ranges between 23 and 100 km2. Surprisingly, a similar trend was observed in non-endemic species: 22% occurred in areas ≤ 5.2 km2, and 8% in areas 23–100 km2, suggesting that environmental dissimilarity may play an important role in the distribution of these species. Micro-endemic species were predominant in 18 out of 20 orders. These results will contribute to a re-assessment of the IUCN red list of species in this archipelago, indicating that at least 116 species are probably critically endangered.
“…25 species (all endemic) that show morphological connections to Australia and New Guinea, except one apparently endemic undescribed genus. The diversity and endemism of New Caledonia's amblyopinine fauna will act as a useful model group for addressing questions about the biogeographic history of the island when respective taxa become available for molecular study (Grandcolas, ). New Guinea hosts c .…”
Section: Discussionmentioning
confidence: 99%
“…The Amblyopinini fauna of New Caledonia remains undescribed; however, we are aware of c. 25 species (all endemic) that show morphological connections to Australia and New Guinea, except one apparently endemic undescribed genus. The diversity and endemism of New Caledonia's amblyopinine fauna will act as a useful model group for addressing questions about the biogeographic history of the island when respective taxa become available for molecular study (Grandcolas, 2017). New Guinea hosts c. 40 species of endemic Amblyopinini, all with morphological connections to Australia and New Caledonia, also to be tested molecularly when respective material becomes available.…”
Section: Austral Biogeography and Disjunct Faunasmentioning
The rove beetle tribe Amblyopinini (Coleoptera: Staphylinidae: Staphylininae) is a recently discovered monophyletic lineage comprising an estimated 1000 or more species of mainly leaf‐ and log litter‐dwelling predatory insects found throughout the southern hemisphere. Of these, a single genus Heterothops Stephens somehow conquered all continents in the northern hemisphere as well. A few lineages of amblyopinines independently evolved into highly derived predators of mammal ectoparasites from free‐living ancestors. In return, they are tolerated in the mammal fur and nests, which is a unique example of cleaning symbiosis between insects and vertebrates. For over a century the great majority of free‐living southern amblyopinines were incorrectly placed in the northern hemisphere‐restricted, and superficially similar, rove beetle genera from the subtribe Quediina. Only their mammal‐associated derived forms were understood as amblyopinines, a nonmonophyletic taxon of volatile status and enigmatic sister‐group relationships of its various members. Here we present the first comprehensive phylogeny of Amblyopinini inferred with Bayesian analysis of a six‐gene molecular dataset (4672 bp) across a broad sample of taxa (90 species). This phylogeny provides a framework for the badly needed taxonomic inventory of this group and, in particular, reveals at least two independent origins of mammal association within the tribe. It frames the upcoming in‐depth interdisciplinary exploration of a variety of phenomena such as evolution of the austral biota in response to continental drift and climate change, biotic exchange between southern and northern continents, origin and evolution of beetle–mammal symbiosis, and pathways and constraints of the evolutionary parallelisms.
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