Loyalty Islands Research Articles

Chapter 6 The Loyalty Islands and Ridge, New Caledonia

Abstract The Loyalty Ridge lies to the east and NE of the Norfolk Ridge. The three main Loyalty Islands (Maré, Lifou and Ouvéa) emerge from the ridge at the same latitude as Grande Terre. The islands are uniformly composed of carbonate deposits, except for Maré, where Middle Miocene intra-plate basalts and associated volcaniclastic rocks form restricted outcrops. Miocene rhodolith limestones constitute the bulk of the carbonate cover of the three islands. On Maré, these platform accumulations are locally topped by a dolomitic hardground, which, in turn, is covered by Pliocene–Pleistocene coral-bearing formations. These coral reef constructions are preserved as elevated rims over all three islands and define an atoll stage in their development. The Pleistocene–Holocene palaeoshoreline indicators include fringing bioconstructions and marine notches and record both eustatic sea-level changes and tectonic deformation. The ridge has been in the forebulge region in front of the active Vanuatu subduction zone since the Pliocene and each of the three islands has been uplifted and tilted to varying degrees. Offshore, the Loyalty Ridge continues northwards to the d'Entrecasteaux Zone and southwards to the Three Kings Ridge. Although typically volcanic, the nature of the deep Loyalty Ridge remains unknown.

About this title - New Caledonia: Geology, Geodynamic Evolution and Mineral Resources

This memoir summarizes current knowledge on the geology of New Caledonia, its geodynamic evolution and mineral resources, based on published and unpublished information. It comprises ten research papers, each addressing a particular geological assemblage or topic. After an introductory chapter and a review of the published geodynamic models of evolution of the SW Pacific, Chapters 3-5 focus on the main geological assemblages of Grande Terre: the pre-Late Cretaceous basement terranes, the Late Cretaceous to Eocene cover, and the Eocene Subduction-Obduction Complex, one of the largest and best-preserved in the world. Chapter 6 is devoted to the Loyalty Islands and Ridge. Chapter 7 deals with the mostly terrestrial post-obduction units, including regolith. Chapter 8 deals with palaeobiogeography and discusses plausible scenarios of biotic evolution. Chapters 9 and 10 provide a comprehensive review of New Caledonia's mineral resources. The volume will be of interest to stratigraphers, sedimentologists, marine geologists, palaeontologists, palaeogeographers, igneous and metamorphic petrologists, geochemists, geochronologists, and specialists in tectonics, geodynamic evolution, regoliths, ophiolites and economic geology.

A new record of the Dwarf Sea Krait (Laticauda frontalis) from the Loyalty Islands, New Caledonia

ABSTRACT Common in Vanuatu, the Dwarf Sea Krait Laticauda frontalis also is known from five old records (in the 1880s and 1890s) from the Loyalty Islands, between Vanuatu and the main island of New Caledonia. Those records have been interpreted by some authorities as errors, or as reflecting occasional waifs rather than breeding populations. We now report an additional specimen of L. frontalis from the Loyalty Islands island of Maré, and we review distributional data for this species and for the closely allied L. saintgironsi. Sympatry on the western coast of Maré confirms that these two taxa warrant separate species status despite their minimal genetic divergence.

A new coastal species of Pseuderanthemum (Acanthaceae) from Loyalty Islands (New Caledonia) and Vanuatu with notes on P. carruthersii

When dealing with the taxonomy of Pacific coastal species within the region of New Caledonia and Vanuatu, one should examine all names published in Australasia and other Pacific islands. When the putative new species is also closely related to a highly praised ornamental species with many cultigens and with many old horticultural names, the task becomes more arduous. This is the case for the new species we describe as Pseuderanthemum melanesicum Gâteblé, Ramon & Butaud, which is closely related to the now pantropical cultivated species P. carruthersii (Seem.) Guillaumin s.l. Compared to P. carruthersii, P. melanesicum has carnose and shiny leaves, pedicels and sepals covered with glandular hairs, a short and enlarged corolla tube and can produce fertile capsules. The new species is a coastal taxon occurring naturally in the Melanesian archipelagos of New Caledonia and Vanuatu. This species seems uncommon in the Loyalty Islands but more common in the archipelago of Vanuatu and we propose it as Critically Endangered in New Caledonia, Vulnerable in Vanuatu and Least Concern when the IUCN evaluation is done globally.

Metapopulation Vicariance, Age of Island Taxa and Dispersal: A Case Study Using the Pacific Plant Genus Planchonella (Sapotaceae).

Oceanic islands originate from volcanism or tectonic activity without connections to continental landmasses, are colonized by organisms, and eventually vanish due to erosion and subsidence. Colonization of oceanic islands occurs through long-distance dispersals (LDDs) or metapopulation vicariance, the latter resulting in lineages being older than the islands they inhabit. If metapopulation vicariance is valid, island ages cannot be reliably used to provide maximum age constraints for molecular dating. We explore the relationships between the ages of members of a widespread plant genus (Planchonella, Sapotaceae) and their host islands across the Pacific to test various assumptions of dispersal and metapopulation vicariance. We sampled three nuclear DNA markers from 156 accessions representing some 100 Sapotaceae taxa, and analyzed these in BEAST with a relaxed clock to estimate divergence times and with a phylogeographic diffusion model to estimate range expansions over time. The phylogeny was calibrated with a secondary point (the root) and fossils from New Zealand. The dated phylogeny reveals that the ages of Planchonella species are, in most cases, consistent with the ages of the islands they inhabit. Planchonella is inferred to have originated in the Sahul Shelf region, to which it back-dispersed multiple times. Fiji has been an important source for range expansion in the Pacific for the past 23 myr. Our analyses reject metapopulation vicariance in all cases tested, including between oceanic islands, evolution of an endemic Fiji–Vanuatu flora, and westward rollback vicariance between Vanuatu and the Loyalty Islands. Repeated dispersal is the only mechanism able to explain the empirical data. The longest (8900 km) identified dispersal is between Palau in the Pacific and the Seychelles in the Indian Ocean, estimated at 2.2 Ma (0.4–4.8 Ma). The first split in a Hawaiian lineage (P. sandwicensis) matches the age of Necker Island (11.0 Ma), when its ancestor diverged into two species that are distinguished by purple and yellow fruits. Subsequent establishment across the Hawaiian archipelago supports, in part, progression rule colonization. In summary, we found no explanatory power in metapopulation vicariance and conclude that Planchonella has expanded its range across the Pacific by LDD. We contend that this will be seen in many other groups when analyzed in detail.

Recent advances in New Caledonian biogeography.

The biota of New Caledonia is one of the most unusual in the world. It displays high diversity and endemism, many peculiar absences, and far-flung biogeographic affinities. For example, New Caledonia is the only place on Earth with both main clades of flowering plants - the endemic Amborella and 'all the rest', and it also has the highest concentration of diversity in conifers. The discovery of Amborella's phylogenetic position led to a surge of interest in New Caledonian biogeography, and new studies are appearing at a rapid rate. This paper reviews work on the topic (mainly molecular studies) published since 2013. One current debate is focused on whether any biota survived the marine transgressions of the Paleocene and Eocene. Total submersion would imply that the entire fauna was derived by long-distance dispersal from continental areas since the Eocene, but only if no other islands (now submerged) were emergent. A review of the literature suggests there is little actual evidence in geology for complete submersion. An alternative explanation for New Caledonia's diversity is that the archipelago acted as a refugium, and that the biota avoided the extinctions that occurred in Australia. However, this is contradicted by the many groups that are anomalously absent or depauperate in New Caledonia, although represented there by a sister group. The anomalous absences, together with the unusual levels of endemism, can both be explained by vicariance at breaks in and around New Caledonia. New Caledonia has always been situated at or near a plate boundary, and its complex geological history includes the addition of new terranes (by accretion), orogeny, and rifting. New Caledonia comprises 'basement' terranes that were part of Gondwana, as well as island arc and forearc terranes that accreted to the basement after it separated from Gondwana. The regional tectonic history helps explain the regional biogeography, as well as distribution patterns within New Caledonia. These include endemics on the basement terranes (for example, the basal angiosperm, Amborella), disjunctions at the West Caledonian fault zone, and great biotic differences between Grande Terre and the Loyalty Islands.

The enigmatic palaeoecology and palaeobiogeography of the giant, horned, fossil turtles of Australasia: a review and reanalysis of the data

The distribution pattern of the bizarre Australasian giant, horned, fossil turtles of the clade Meiolaniidae has puzzled biogeographers since their discovery late in the nineteenth century. While their distribution suggests a Gondwanan origin, the lack of fossil evidence from key times and places has inhibited a better understanding of their dispersal pathways to Australia and the south-west Pacific islands in which their fossils have been found. Much palaeoecological speculation related to their dispersal capabilities, ranging from purely terrestrial to freshwater, estuarine, and saltwater lifestyles, has been proposed to explain their enigmatic presence across a wide swath of Oceania. Various lines of fossil, anatomical and ecological evidence now strongly suggest a highly terrestrial lifestyle, and we believe these traits, reinforced by an abundance of marine predators and ever-widening saltwater gaps between land areas during the Late Mesozoic and Tertiary, minimise the importance of saltwater dispersal as an explanation for the observed meiolaniid distribution pattern. Here we propose that the fragmentation of Gondwana provided the main dispersal vehicle for the meiolaniids and that land connections were also used to access suitable habitats and expand their range. The recently recognised continent of Zealandia, along with Australia, South America, and probably Antarctica, transported all known meiolaniid turtles to their present locations. However, ice cover on Antarctica, and the nearly total submergence of Zealandia in essence preclude the current likelihood of fossil discovery in these critical locations. The islands of New Caledonia, Tiga (in the Loyalty Islands), Walpole, and Lord Howe served as refugia for Zealandia meiolaniids as the continent submerged.

Cancer Incidence Among Children in New Caledonia, 1994 to 2012.

New Caledonia (NC) is a small French territory in the Pacific Ocean with a relatively young (32% under 20) and multiethnic population. It is divided into 3 districts: Loyalty Island, the North, and the South, each with specific population characteristics. The aim of this study was to describe childhood cancer age-standardized incidence rate (ASR) in NC, compare it with the estimated one in France , and to determine whether residence and ethnicity may have an influence on intrapopulation ASR. All incident cancer cases diagnosed between 1994 and 2012 in children (0 to 14 y) resident in NC for more than 6 months were included. With 162 registered cases, the ASR for all cancers combined was 142.2 (range, 104.9 to 193.3) cases per million children per year and was not different from what was estimated in France (156.6). However, incidence varies according to the place of residence, with a higher ASR in the Loyalty Island district for several types of neoplasms, but not according to the ethnicity. The small migratory flux between this district and the rest of the territory may have led to these results, but, because of the small number of cases, no conclusion can be drawn.

Dietary inflammatory potential and differentiated thyroid carcinoma: A population-based case-control study in New Caledonia

Introduction The incidence of differentiated thyroid carcinoma (DTC) varies considerably across the world, with particularly high incidence rates in Melanesians of New Caledonia. Despite research efforts, current knowledge on the etiology of thyroid carcinoma remains limited. Exposure to ionizing radiations during childhood is a well-established environmental risk factor. Tall height and large body size have consistently been associated with DTC. The increased risk of thyroid cancer in patients with autoimmune thyroid diseases also suggests a role of chronic inflammation in disease occurrence. To explore the role of dietary components with pro- or anti-inflammatory effects, we examined the association between DTC and the Dietary Inflammatory Index (DII) - a novel diet-based score estimating diet-induced inflammation. Methods We conducted a countrywide population-based case-control study in the multiethnic population of New Caledonia during 1993–1999. The study included 324 cases with histologically confirmed papillary or follicular carcinoma and 402 population controls. Based on a food frequency questionnaire that included 117 items, we calculated a DII score for each individual. The DII score was analyzed both as a continuous and as a categorical variable (quartiles) based on the sex-specific DII distribution among controls. Odds ratios (OR) and corresponding 95% CIs were calculated using unconditional logistic regression models adjusted for age, sex, ethnic community (Melanesian, European, other), province of residence (South, North, Loyalty Islands) and body mass index. Results An increased OR of thyroid cancer was observed in subjects in the highest quartile of DII score (pro-inflammatory diet) vs. the lowest quartile (anti-inflammatory diet) (OR: 2.20; 95% CI: 1.33, 3.63; P-trend = 0.002). Higher ORs were observed among residents of the Southern province (OR: 2.67; 95% CI: 1.40, 5.08; P-trend = 0.003), among ever smokers (OR: 2.99; 95% CI: 1.34, 6.69; P-trend = 0.0005), and among obese participants (OR: 3.34; 95% CI: 1.28, 8.68; P-trend = 0.006). These findings suggest that a pro-inflammatory diet is associated with increased risk of differentiated thyroid carcinoma.

A taxonomic revision of the genus Capparis (Capparaceae) in New Caledonia

ABSTRACTA revision of the genus Capparis has been carried out in New Caledonia, a global biodiversity hotspot with a high rate of endemism in its vascular flora. The taxonomic treatment of Capparis in this area required study because of some incompletely known taxa and deviating forms. Based on morphological and distributional investigations carried out on historical and recent herbarium collections, four species are recognised in New Caledonia: C. spinosa, belonging to sect. Capparis; C. quiniflora, belonging to sect. Monostychocalix; and C. parvifolia and C. artensis, both belonging to sect. Busbeckea. Capparis spinosa is represented by subsp. cordifolia, a taxon widespread in several Pacific islands, for which only scanty collections from the Loyalty Islands have been examined. Capparis quiniflora, widely distributed from the Malesian Region to Australia, is present along the coast and lowlands of New Caledonia on various substrata up to c. 250 m elevation. Capparis parvifolia is endemic to Mont Kaala, North Province of New Caledonia, where it is reported on ultramafic substrata from c. 100 to 800 m. Capparis artensis, known from New Caledonia and Vanuatu, is widespread prevalently on ultramafic substrata from sea level to c. 700 m. A nomenclatural novelty, C. artensis var. dielsiana comb. et stat. nov., is here proposed and seven lectotypes are designated. A key to species is provided, along with descriptions, distributions and autecological data. Capparis loranthifolia var. bancroftii, formerly recorded from a single mountain range of New Caledonia, is excluded from the flora of the island.

Investigating the March 28th 1875 and the September 20th 1920 earthquakes/tsunamis of the Southern Vanuatu arc, offshore Loyalty Islands, New Caledonia

New Caledonia's Loyalty Islands are located in the southwest region of the Pacific ocean in the highly seismogenic southern Vanuatu subduction zone and therefore may be subject to devastating local tsunamis. Over the past 150years, two large tsunamis were triggered by major earthquakes on March 28th 1875 and September 20th 1920. In this study, we use historical observations of these tsunamis (mostly in the form of testimonials), earthquake scenarios, and tsunami modeling to derive the magnitudes of these earthquakes, as well as tsunami runup and inundation maps. Assuming that these earthquakes were located on the interplate megathrust zone, the 1875 earthquake's magnitude was Mw8.1–8.2 and the 1920 event's magnitude was Mw7.5–7.8. The tsunami damage inflicted on the Lifou and Maré islands was approximately proportional to these magnitudes, with Maré being less impacted due to favorable wave directivity. Damage at Ouvéa island may have varied irregularly with the magnitude due to the effects of resonance. This study demonstrates that the quantitative characteristics of historical tsunamigenic earthquakes may be derived from qualitative estimates of tsunami runup.

Not all spotted cats are leopards: evidence for a Hemilienardia ocellata species complex (Gastropoda: Conoidea: Raphitomidae)

The small conoidean Hemilienardia ocellata is one of the easily recognizable Indo-Pacific “turrids”, primarily because of its remarkable eyespot colour pattern. Morphological and molecular phylogenetic analyses revealed four species that share this “characteristic” colour pattern but demonstrate consistent differences in size and shell proportions. Three new species – Hemilienardia acinonyx sp. nov. from the Philippines, H. lynx sp. nov. from Papua New Guinea and H. pardus sp. nov. from the Society and Loyalty Islands – are described based on the results of phylogenetic analyses. Although the H. ocellata species complex clade falls in a monophyletic Hemilienardia, H. ocellata and H. acinonyx sp. nov. possess a radula with semi-enrolled or notably flattened triangular marginal teeth, a condition that diverges substantially from the standard radular morphology of Hemilienardia and other raphitomids.

Trepanation and enlarged parietal foramen on skulls from the Loyalty Islands (Melanesia).

The goal of this study is a comprehensive examination of openings discovered on two skulls in the collection of skeletal remains from the Loyalty Islands (Melanesia). The skull No. 1524 displayed an evidence of successful trepanation, and the skull No. 7985 revealed openings that were reminiscent of a trepanation, however, we are inclined to believe that in the latter case we are dealing with a rare genetic anomaly - enlarged parietal foramen.

Nouméa at the Crossroads of New Caledonian Multilingualism

This paper aims at questioning two diasporic communities settled in Noumea, New Caledonia's capital city. The first consists of those with internal (domestic) mobility (from Lifou and Ouvea, Loyalty Islands), while the second are those from Vanuatu, the product of external (inter-regional) migration. From these case studies, we examine how unevenly they are managed bytthe weight of linguistic norms on everyday language practices of diasporic urban speakers of Drehu, Iaai and Bislama languages. This contribution also investigates the strategies used by diasporic speakers as well as language institutions, like the Kanak Languages Academy, to maintain their languages and preserve their heritage.

Recent spread of the Sida Leafbeetle, Calligrapha pantherina Stål, 1859 (Coleoptera: Chrysomelidae: Chrysomelinae) in New Caledonia

We report the recent arrival and subsequent spread of the Sida Leafbeetle, Calligrapha pantherina Stål, 1859, in the archipelago of New Caledonia. The species seems to have a rapid spread as it is now recorded all along the west coast and also have spread to the Loyalty Islands. The first specimen was caught in November 2012. This is a biocontrol agent which was introduced in the Pacific Region against invasive Malvaceae (Sida spp.). This accidental arrival would help to control the alien weed, Sida acuta Burm. f., in New Caledonia. But this establishment raises some questions about potential threats on the two endemic New Caledonian Sida species. We also discuss this arrival and subsequent installation in the context of global change and biosecurity issues, particularly in such a biodiversity hotspot.

Anomalous Variation in GPS TEC, Land and Ocean Parameters Prior to 3 Earthquakes

The present study reports the analysis of GPS TEC prior to 3 earthquakes (M > 6.0). The earthquakes are: (1) Loyalty Island (22°36′S, 170°54′E) on 19 January 2009 (M = 6.6), (2) Samoa Island (15°29′S, 172°5′W) on 30 August 2009 (M = 6.6), and (3) Tohoku (38°19′N, 142°22′E) on 11 March 2011 (M = 9.0). In an effort to search for a precursory signature we analysed the land and ocean parameters prior to the earthquakes, namely SLHF (Land) and SST (Ocean). The GPS TEC data indicate an anomalous behaviour from 1–13 days prior to earthquakes. The main purpose of this study was to explore and demonstrate the possibility of any changes in TEC, SST, and SLHF before, during and after the earthquakes which occurred near or beneath an ocean. This study may lead to better understanding of response of land, ocean, and ionosphere parameters prior to seismic activities.

Reinstatement of the Loyalty Islands Sandalwood, Santalum austrocaledonicum var. glabrum (Santalaceae), in New Caledonia.

Sandalwoods encompass 19 species restricted to southeast Asia and the Pacific. The species Santalum austrocaledonicum Vieill. (Santalaceae) is endemic to New Caledonia (Grande-Terre, Isle of Pines, Loyalty Islands) and Vanuatu, where several varieties are recognized. The Loyalty Islands sandalwood variety is here reinstated as Santalum austrocaledonicum var. glabrum Hürl. emend. Butaud & P.Firmenich, mut. char. It was previously considered a synonym of the type variety; however, new morphological and genetic studies confirmed its distinctiveness. The key for New Caledonian varieties of Santalum austrocaledonicum has been updated and a short description of its essential oil composition and organoleptic quality is given.

Reptile Remains from Tiga (Tokanod), Loyalty Islands, New Caledonia

Archaeological excavations on Tiga provide the first vouchered herpetological records for this small island between Lifou and Mare in the Loyalty Islands. Eighty-three skeletal elements from four sites yielded material assignable to skinks (Emoia loyaltiensis, Lioscincus nigrofasciolatus), geckos (Bavayia crass i-collis, B. sp., Gehyra georgpotthasti, Nactus pelagicus), and a boid snake (Candoia bihroni) all known from elsewhere in the Loyalties, as well as undetermined material consistent with these and other Loyalties lizards. Diagnostic features of geckos versus skinks for elements commonly recovered from archaeological sites and from owl pellets are discussed. Gehyra georgpotthasti has a limited distribution in the Loyalties and its occurrence on Tiga clarifies its range. The boid snake is the only reptile likely to have been harvested by human inhabitants of Tiga. The presence of gekkonid geckos in pre-European times is confirmed and contrasts with the situation of Grande Terre fossil sites, where only diplodactylid geckos have been recovered. Although it is anticipated that all species recovered from archaeological sites are still present on the island, a modern herpetofaunal survey is needed.

Stigmaphyllonpatricianum-firmenichianum (Malpighiaceae), a new species from Loyalty Islands, New Caledonia.

A new species of Stigmaphyllon (Malpighiaceae) is described: Stigmaphyllon patricianum-firmenichianum Butaud. It is restricted to the coral islands of Ouvéa, Lifou and Maré in the Loyalty Islands Province (New Caledonia) and is most similar to Stigmaphyllon discolor (Gand.) C.E.Anderson, known from New Caledonia and Solomon Islands. Previously, plants now known as Stigmaphyllon patricianum-firmenichianum were included in Stigmaphyllon taomense (Baker f.) C.E.Anderson, endemic to the northern part of Grande-Terre and Belep Islands (New Caledonia). A new circumscription of Stigmaphyllon taomense is proposed. The regional key for New Caledonian species of Stigmaphyllon is updated.

The land crabs of the Discoplax longipes A. Milne-Edwards, 1867 species group, with description of a new species from Guam (Crustacea: Decapoda: Brachyura: Gecarcinidae).

Specimens of the gecarcinid land crab Discoplax longipes A. Milne-Edwards, 1867, from the western Pacific, can be separated into two distinct groups on the basis of DNA (mitochondrial 16S rDNA and cytochrome oxidase subunit I) and structure of the male first gonopod. On the basis of this data, the material that occurs from the Loyalty Islands to French Polynesia is shown to be D. longipes s. str., whereas specimens from Guam are here referred to a new pseudocryptic species, D. michalis n. sp. The two species are described and figured; and a revised key to the long-legged Discoplax species is provided.