Zoogeography and relationships of Australasian skates (Chondrichthyes: Rajidae)

Aim To investigate distributional patterns and derivation of skates in the Australasian realm. Location Australasia. Methods Genus‐group skate taxa were defined for this region for the first time and new systematic information, as well as bathymetric and geographical data, used to identify distribution patterns. Results The extant skate fauna of Australasia (Australia, New Zealand, New Caledonia and adjacent subAntarctic dependencies) is highly diverse and endemic with sixty‐two species from twelve currently recognized, nominal genus‐group taxa. These include the hardnose skate (rajin) groups Anacanthobatis, Amblyraja, Dipturus, Okamejei, Rajella and Leucoraja, and softnose skate (arhynchobatin) genera Arhynchobatis, Bathyraja, Insentiraja, Irolita, Pavoraja and Notoraja. Additional new and currently unrecognized nominal taxa of both specific and supraspecific ranks also occur in the region. The subfamily Arhynchobatinae is particularly speciose in Australasia, and the New Zealand/New Caledonian fauna is dominated by undescribed supraspecific taxa and species. The Australian fauna, although well represented by arhynchobatins, is dominated by Dipturus‐like skates and shows little overlap in species composition with the fauna of New Zealand and New Caledonia. Similarly, these faunas exhibit no overlap with the polar faunas of the Australian subAntarctic dependencies (Heard and Macdonald Islands) to the south. Skates appear to be absent from the Macquarie Ridge at the southern margin of the New Zealand Plateau. Their absence off New Guinea probably reflects inadequate sampling and the subsequent poor knowledge of that region's deepwater fish fauna. Main conclusions Skates appear to have existed in the eastern, Australasian sector of Gondwana before fragmentation in the late Cretaceous. The extant fauna appears to be derived from elements of Gondwanan origin, dispersal from the eastern and western Tethys Sea, and intraregional vicariance speciation.     

Older than New Caledonia emergence? A molecular phylogenetic study of the eneopterine crickets (Orthoptera: Grylloidea)

Aim A New Caledonian insect group was studied in a world‐wide phylogenetic context to test: (1) whether local or regional island clades are older than 37 Ma, the postulated re‐emergence time of New Caledonia; (2) whether these clades show evidence for local radiations or multiple colonizations; and (3) whether there is evidence for relict taxa with long branches in phylogenetic trees that relate New Caledonian species to geographically distant taxa. Location New Caledonia, south‐west Pacific. Methods We sampled 43 cricket species representing all tribes of the subfamily Eneopterinae and 15 of the 17 described genera, focusing on taxa distributed in the South Pacific and around New Caledonia. One nuclear and three mitochondrial genes were analysed using Bayesian and parsimony methods. Phylogenetic divergence times were estimated using a relaxed clock method and several calibration criteria. Results The analyses indicate that, under the most conservative dating scenario, New Caledonian eneopterines are 5–16 million years old. The largest group in the Pacific region dates to 18–29 Ma. New Caledonia has been colonized in two phases: the first around 10.6 Ma, with the subsequent diversification of the endemic genus Agnotecous, and the second with more recent events around 1–4 Ma. The distribution of the sister group of Agnotecous and the lack of phylogenetic long branches in the genus refute an assumption of major extinction events in this clade and the hypothesis of local relicts. Main conclusions Our phylogenetic studies invalidate a simple scenario of local persistence of this group in New Caledonia since 80 Ma, either by survival on the New Caledonian island since its rift from Australia, or, if one accepts the submergence of New Caledonia, by local island‐hopping among other subaerial islands, now drowned, in the region during periods of New Caledonian submergence.     

New records of marine benthic algae from the Lagon Sud-Ouest of New Caledonia, South Pacific

As part of an ongoing project to substantially increase knowledge of the marine algal flora of the French Pacific territory of New Caledonia, a survey of the Nouméa region was conducted that has resulted in the discovery of 41 previously unrecorded species of macroalgae, including 1 Chlorophyta, 1 Phaeophyceae (Heterokontophyta) and 39 Rhodophyta. Among the biogeographically interesting new records are the green macroalga Rhipilia penicilloides N’Yeurt et Keats (previously endemic to the islands of Fiji some 1000 km east of new Caledonia) and the brown alga Cutleria mollis Allender et Kraft (originally described from Lord Howe Island some 1000 km to the south). The red alga Gloiophloea articulata Weber‐van Bosse, known only from its initial discovery in 1928 from the Mascarene Islands in the western Indian Ocean, is now recorded in the deep‐water channels of the Nouméa region of New Caledonia. The widely distributed Indian Ocean species Corynomorpha prismatica (J. Agardh) J. Agardh has its easternmost distribution record from this area, and Dotyella hawaiiensis (Doty et Wainwright) Womersley et Shepley is recorded for the first time outside its central‐Pacific distribution. These new discoveries represent a 12% increase in the total number of species (377) that are reliably known from New Caledonia.     

Determinants of dietary specialization: a comparison of two sympatric species of sea snakes

Why do some predator species specialize on only a single type of prey whereas others take a broad range? One critical determinant may be the ontogenetic range of body sizes of the predator compared to that of its prey. If any single prey taxon spans only part of the range of prey sizes ingestible by the predator, then the predator will be more likely to take multiple prey taxa. We exploit a model system that provides a robust opportunity to test this hypothesis. We studied two sympatric species of predatory sea snakes, similar in size and general ecology that feed on anguilliform fishes from different habitats in the Great Lagoon of New Caledonia. Eel species from soft‐bottom habitats must construct their own burrows, and thus tend to be more slender‐bodied and less variable in body size than eel species that inhabit variable‐sized crevices among hard coral. As a result, a laticaudine sea snake species (Laticauda saintgironsi) that feeds on hard‐coral‐dwelling eels relies primarily on a single prey species: juveniles take young eels whereas adults consume adult eels of the same species. In contrast, a laticaudine species (L. laticaudata) that forages on soft‐bottom eels switches its prey ontogenetically: juveniles take small eel species whereas adults consume large eel species. Thus, habitat‐imposed constraints on the range of body sizes within each prey taxon generate a striking difference in the degree of dietary specialization of two closely related, sympatric predator species.     

TAXONOMIC REVISION OF SARGASSUM SPECIES (FUCALES,PHAEOPHYCEAE) FROM NEW CALEDONIA BASED ON MORPHOLOGICAL AND MOLECULAR ANALYSES1

Sargassum C. Agardh (1820) is a taxonomically difficult genus distributed worldwide and reported as the most species‐rich genus of the Fucales. It is especially abundant in the Pacific where decreasing species richness is reported to occur from west to east. New Caledonia has been recognized as one of the hotspots of Sargassum diversity; however, species lists available for this region are old and incomplete and have not yet been updated with regard to the latest taxonomic revisions published. This study aimed at revising Sargassum diversity in New Caledonia and to assess its geographic affinities with neighboring Pacific regions. We used combined morphological and DNA analyses on new collections and examined numerous type specimens. Although 45 taxa have been listed in the literature, most of them have been either transferred to synonymy since or misidentified, and in this study, only 12 taxa were recognized as occurring in New Caledonia. They belong to the subgenus Sargassum sect. Binderianae (Grunow) Mattio et Payri (2), sect. Ilicifoliae (J. Agardh) Mattio et Payri (2), sect. Polycystae Mattio et Payri. (1), sect. Sargassum (4), sect. Zygocarpicae (J. Agardh) Setch. (2), and subgenus Phyllotrichia (Aresh.) J. Agardh (1). New Caledonian Sargassum flora appeared as the second richest in the region after the Pacific coast of Australia, with which it has shown high similarity, and shared species with all neighboring regions. One species, S. turbinarioides Grunow, is considered as endemic to New Caledonia. The low genetic diversity detected among several polymorphic species belonging to sect. Sargassum is also discussed.     

Systematic review of a new orb‐weaving spider genus (Araneae: Araneidae), with special reference to the Australasian‐Pacific and South‐East Asian fauna

The Australasian‐Pacific and South‐East Asian species of the new orb‐weaving spider genus Plebs with Plebs eburnus (Keyserling, 1886) as type species are revised. Following this study, Plebs includes a total of 22 species of which seven are here described new. Seven species are found in Australia, two in the Pacific region (New Caledonia, Vanuatu), and two in South‐East Asia (Papua New Guinea, The Philippines). Eleven Asian species are transferred to the new genus. Plebs represent comparatively small orb‐weaving spiders of c. 1.2–15.0 mm body length with a slightly elongated abdomen and humeral (shoulder) humps. Males of most species have two to three stout setae on the ventral side of their fourth coxae. Male pedipalps are characterized by the presence of a single macroseta on the patella, the presence of a paramedian apophysis as basal extension of the conductor, and an apical tegular protrusion. The female epigyne has a scape that is generally much longer than wide. It does not have a terminal pocket and is frequently broken off in a number of species. A phylogenetic analysis of 15 species of Plebs (those for which both sexes are known), 13 Australian/Pacific orb‐weaving spider species representing the most commonly collected clades with paramedian apophysis, three species of Nearctic Eriophora Simon, 1864, and Araneus diadematus Clerck, 1758, as outgroup, identified a single synapomorphy of Plebs based on 35 morphological and three behavioural characters: a distinct, inverted U‐shaped light pattern on the ventral side of the abdomen with two additional white spots anterolateral to the spinnerets. This analysis recovered a monophyletic clade of all Asian Plebs, suggesting a single colonization event of the genus that putatively originated in Australia. Most Plebs species appear to be active during the day. They build a regular orb‐web with vertical stabilimentum in grass and low shrubs. © 2012 The Linnean Society of London, Zoological Journal of the Linnean Society, 2012, 166 , 279–341.     

Diversity of Halimeda (Bryopsidales,Chlorophyta) in New Caledonia: a Combined Morphological and Molecular Study

Halimeda is a genus of calcified and segmented green macroalgae in the order Bryopsidales. In New Caledonia, the genus is abundant and represents an important part of the reef flora. Previous studies recorded 19 species that were identified using morphological criteria. The aim of this work was to reassess the diversity of the genus in New Caledonia using morpho‐anatomical examinations and molecular analyses of the plastid tufA and rbcL genes. Our results suggest the occurrence of 22 species. Three of these are reported for the first time from New Caledonia: Halimeda kanaloana, H. xishaensis, and an entity resembling H. stuposa. DNA analyses revealed that the species H. fragilis exhibits cryptic or pseudocryptic diversity in New Caledonia. We also show less conclusive evidence for cryptic species within H. taenicola     

Panbiogeography of Nothofagus (Nothofagaceae): analysis of the main species massings

Aim The aim of this paper is to analyse the biogeography of Nothofagus and its subgenera in the light of molecular phylogenies and revisions of fossil taxa. Location Cooler parts of the South Pacific: Australia, Tasmania, New Zealand, montane New Guinea and New Caledonia, and southern South America. Methods Panbiogeographical analysis is used. This involves comparative study of the geographic distributions of the Nothofagus taxa and other organisms in the region, and correlation of the main patterns with historical geology. Results The four subgenera of Nothofagus have their main massings of extant species in the same localities as the main massings of all (fossil plus extant) species. These main massings are vicariant, with subgen. Lophozonia most diverse in southern South America (north of Chiloé I.), subgen. Fuscospora in New Zealand, subgen. Nothofagus in southern South America (south of Valdivia), and subgen. Brassospora in New Guinea and New Caledonia. The main massings of subgen. Brassospora and of the clade subgen. Brassospora/subgen. Nothofagus (New Guinea–New Caledonia–southern South America) conform to standard biogeographical patterns. Main conclusions The vicariant main massings of the four subgenera are compatible with largely allopatric differentiation and no substantial dispersal since at least the Upper Cretaceous (Upper Campanian), by which time the fossil record shows that the four subgenera had evolved. The New Guinea–New Caledonia distribution of subgenus Brassospora is equivalent to its total main massing through geological time and is explained by different respective relationships of different component terranes of the two countries. Global vicariance at family level suggests that Nothofagaceae/Nothofagus evolved largely as the South Pacific/Antarctic vicariant in the breakup of a world‐wide Fagales ancestor.     

Australian biogeographical connections and the phylogeny of large genera in the plant family Myrtaceae

Aim To compare the phylogeny of the eucalypt and melaleuca groups with geological events and ages of fossils to discover the time frame of clade divergences. Location Australia, New Caledonia, New Guinea, Indonesian Archipelago. Methods We compare published molecular phylogenies of the eucalypt and melaleuca groups of the plant family Myrtaceae with geological history and known fossil records from the Cretaceous and Cenozoic. Results The Australasian eucalypt group includes seven genera, of which some are relictual rain forest taxa of restricted distribution and others are species‐rich and widespread in drier environments. Based on molecular and morphological data, phylogenetic analyses of the eucalypt group have identified two major clades. The monotypic Arillastrum endemic to New Caledonia is related in one clade to the more species‐rich Angophora, Corymbia and Eucalyptus that dominate the sclerophyll vegetation of Australia. Based on the time of rifting of New Caledonia from eastern Gondwana and the age of fossil eucalypt pollen, we argue that this clade extends back to the Late Cretaceous. The second clade includes three relictual rain forest taxa, with Allosyncarpia from Arnhem Land the sister taxon to Eucalyptopsis of New Guinea and the eastern Indonesian archipelago, and Stockwellia from the Atherton Tableland in north‐east Queensland. As monsoonal, drier conditions evolved in northern Australia, Arnhem Land was isolated from the wet tropics to the east and north during the Oligocene, segregating ancestral rain forest biota. It is argued also that the distribution of species in Eucalyptopsis and Eucalyptus subgenus Symphyomyrtus endemic in areas north of the stable edge of the Australian continent, as far as Sulawesi and the southern Philippines, is related to the geological history of south‐east Asia‐Australasia. Colonization (dispersal) may have been aided by rafting on micro‐continental fragments, by accretion of arc terranes onto New Guinea and by land brought into closer proximity during periods of low sea‐level, from the Late Miocene and Pliocene. The phylogenetic position of the few northern, non‐Australian species of Eucalyptus subgenus Symphyomyrtus suggests rapid radiation in the large Australian sister group(s) during this time frame. A similar pattern, connecting Australia and New Caledonia, is emerging from phylogenetic analysis of the Melaleuca group (Beaufortia suballiance) within Myrtaceae, with Melaleuca being polyphyletic. Main conclusion The eucalypt group is an old lineage extending back to the Late Cretaceous. Differentiation of clades is related to major geological and climatic events, including rifting of New Caledonia from eastern Gondwana, development of monsoonal and drier climates, collision of the northern edge of the Australian craton with island arcs and periods of low sea level. Vicariance events involve dispersal of biota.     

Shift in precipitation regime promotes interspecific hybridization of introduced Coffea species

The frequency of plant species introductions has increased in a highly connected world, modifying species distribution patterns to include areas outside their natural ranges. These introductions provide the opportunity to gain new insight into the importance of flowering phenology as a component of adaptation to a new environment. Three Coffea species, C. arabica, C. canephora (Robusta), and C. liberica, native to intertropical Africa have been introduced to New Caledonia. On this archipelago, a secondary contact zone has been characterized where these species coexist, persist, and hybridize spontaneously. We investigated the impact of environmental changes undergone by each species following its introduction in New Caledonia on flowering phenology and overcoming reproductive barriers between sister species. We developed species distribution models and compared both environmental envelopes and climatic niches between native and introduced hybrid zones. Flowering phenology was monitored in a population in the hybrid zone along with temperature and precipitation sequences recorded at a nearby weather station. The extent and nature of hybridization events were characterized using chloroplast and nuclear microsatellite markers. The three Coffea species encountered weak environmental suitability compared to their native ranges when introduced to New Caledonia, especially C. arabica and C. canephora. The niche of the New Caledonia hybrid zone was significantly different from all three species' native niches based on identity tests (I Similarity and D Schoener's Similarity Indexes). This area appeared to exhibit intermediate conditions between the native conditions of the three species for temperature‐related variables and divergent conditions for precipitation‐related ones. Flowering pattern in these Coffea species was shown to have a strong genetic component that determined the time between the triggering rain and anthesis (flower opening), specific to each species. However, a precipitation regime different from those in Africa was directly involved in generating partial flowering overlap between species and thus in allowing hybridization and interspecific gene flow. Interspecific hybrids accounted for 4% of the mature individuals in the sympatric population and occurred between each pair of species with various level of introgression. Adaptation to new environmental conditions following introduction of Coffea species to New Caledonia has resulted in a secondary contact between three related species, which would not have happened in their native ranges, leading to hybridization and gene flow.     

Panbiogeography of New Caledonia,south‐west Pacific: basal angiosperms on basement terranes,ultramafic endemics inherited from volcanic island arcs and old taxa endemic to young islands

Aim To investigate areas of endemism in New Caledonia and their relationship with tectonic history. Location New Caledonia, south‐west Pacific. Methods Panbiogeographical analysis. Results Biogeographical patterns within New Caledonia are described and illustrated with reference to eight terranes and ten centres of endemism. The basement terranes make up a centre of endemism for taxa including Amborella, the basal angiosperm. Three of the terranes that accreted to the basement in the Eocene (high‐pressure metamorphic terrane, ultramafic nappe and Loyalty Ridge) have their own endemics. Main conclusions New Caledonia is not simply a fragment of Gondwana but, like New Zealand and New Guinea, is a complex mosaic of allochthonous terranes. The four New Caledonian basement terranes were all formed from island arc‐derived and arc‐associated material (including ophiolites) which accumulated in the pre‐Pacific Ocean, not in Gondwana. They amalgamated and were accreted to Gondwana (eastern Australia) in the Late Jurassic/Early Cretaceous, but in the Late Cretaceous they separated from Australia with the opening of the Tasman Sea and break‐up of Gondwana. An Eocene collision of the basement terranes with an island arc to the north‐east – possibly the Loyalty Ridge – is of special biogeographical interest in connection with New Caledonia–central Pacific affinities. The Loyalty–Three Kings Ridge has had a separate history from that of the Norfolk Ridge/New Caledonia, although both now run in parallel between Vanuatu and New Zealand. The South Loyalty Basin opened between Grande Terre and the Loyalty Ridge in the Cretaceous and attained a width of 750 km. However, it was almost completely destroyed by subduction in the Eocene which brought the Loyalty Ridge and Grande Terre together again, after 30 Myr of separation. The tectonic history is reflected in the strong biogeographical differences between Grande Terre and the Loyalty Islands. Many Loyalty Islands taxa are widespread in the Pacific but do not occur on Grande Terre, and many Grande Terre/Australian groups are not on the Loyalty Islands. The Loyalty Islands are young (2 Myr old) but they are merely the currently emergent parts of the Loyalty Ridge whose ancestor arcs have a history of volcanism dating back to the Cretaceous. Old taxa endemic to the young Loyalty Ridge islands persist over geological time as a dynamic metapopulation surviving in situ on the individually ephemeral islands and atolls found around subduction zones. The current Loyalty Islands, like the Grande Terre terranes, have inherited their biota from previous islands. On Grande Terre, the ultramafic terrane was emplaced on Grande Terre in the Eocene (about the same time as the collision with the island arc). The very diverse endemic flora on the ultramafics may have been inherited by the obducting nappe from prior base‐rich habitat in the region, including the mafic Poya terrane and the limestones typical of arc and intraplate volcanic islands.     

Phylogenetic analysis of the endemic New Caledonian cockroach Lauraesilpha. Testing competing hypotheses of diversification

New Caledonia is a tropical hotspot of biodiversity with high rates of regional and local endemism. Despite offering an ideal setting to study the evolution of endemism, New Caledonia has received little attention compared with the other nearby hotspots, particularly New Zealand. Most studies of the Neocaledonian endemism have been carried out at the regional level, comparing the various groups and species present in New Caledonia but absent in neighboring territories. In addition, remarkably high short‐range endemism has been documented among plants, lizard and invertebrates, although these have usually been done, lacking a phylogenetic perspective. Most studies of Neocaledonian endemism have referred to the geological Gondwanan antiquity of the island and its metalliferous soils derived from ultramafic rocks. Very old clades are thought to have been maintained in refugia and diversified on the metalliferous soils. The present study documents the pattern of diversification and establishment of short‐range endemism in a phylogenetic context using the Neocaledonian cockroach genus Lauraesilpha. Mitochondrial and nuclear genes were sequenced to reconstruct phylogenetic relationships among the species of this genus. These relationships, in the light of the species distribution, do not support the hypothesis that species diversified via an adaptive radiation on metalliferous soils and are not consistent with areas of highest rainfall. Species of Lauraesilpha have similar altitudinal ranges and ecological habits and are short‐range endemics on mountains. What our analysis did reveal was that closely related species are found on nearby or contiguous mountains, and thus these formations probably played the key role establishing short‐range endemism (in association with recent climatic changes). © The Willi Hennig Society 2008.     

Island hopping across the central Pacific: mitochondrial DNA detects sequential colonization of the Austral Islands by crab spiders (Araneae: Thomisidae)

Aim Phylogenetic studies concerning island biogeography have been concentrated in a fraction of the numerous hot‐spot archipelagos contained within the Pacific Ocean. In this study we investigate relationships among island populations of the thomisid spider Misumenops rapaensis Berland, 1934 across the Austral Islands, a remote and rarely examined southern Pacific hot‐spot archipelago. We also assess the phylogenetic position of M. rapaensis in relation to thomisids distributed across multiple Polynesian archipelagos in order to evaluate the proposed hypothesis that thomisid spiders colonized Polynesia from multiple and opposing directions. The data allow an examination of genetic divergence and species accumulation in closely related lineages distributed across four Polynesian archipelagos. Location The study focused on four Polynesian hot‐spot archipelagos: the Austral, Hawaiian, Marquesan and Society islands. Methods Mitochondrial DNA sequences comprising c. 1400 bp (portions of cytochrome oxidase subunit I, ribosomal 16S and NADH dehydrogenase subunit I) were obtained from thomisid spiders (64 specimens, representing 33 species) collected in the Australs, the Hawaiian Islands, the Society Islands, the Marquesas, Tonga, Fiji, New Zealand, New Caledonia and North and South America. Phylogenetic analyses using parsimony, maximum‐likelihood and Bayesian approaches were employed to resolve relationships of M. rapaensis to other Polynesian Misumenops and across the Austral Islands. Results Rather than grouping with other Misumenops spp. from the archipelagos of the Society Islands, Marquesas and Hawaiian Islands, M. rapaensis appears more closely related to Diaea spp. from Tonga, Fiji, New Zealand and New Caledonia. Phylogenetic analyses strongly support M. rapaensis as monophyletic across the Austral Islands. Misumenops rapaensis sampled from the two older islands (Rurutu and Tubuai) form reciprocally monophyletic groups, while individuals from the younger islands (Raivavae and Rapa) are paraphyletic. Across the Austral Islands, M. rapaensis exhibits a surprising level of genetic divergence (maximally 11.3%), an amount nearly equivalent to that found across the 16 examined Hawaiian species (14.0%). Main conclusions Although described as a single morphologically recognized species, our results suggest that M. rapaensis comprises multiple genetically distinct lineages restricted to different Austral Islands. Phylogenetic relationships among the island populations are consistent with sequential colonization of this lineage down the Austral archipelago toward younger islands. Analyses support the hypothesis that thomisid spiders colonized the central Pacific multiple times and suggest that M. rapaensis arrived in the Austral Islands from a westward direction, while Misumenops found in neighbouring archipelagos appear to be more closely related to New World congeners to the east. Finally, our data detect asymmetrical rates of morphological evolution and species diversification following colonization of four different Polynesian archipelagos.     

Contrasting responses to water deficits of Nothofagus species from tropical New Guinea and high‐latitude temperate forests: can rainfall regimes constrain latitudinal range?

Aim Comparative responses of Nothofagus species to water deficits were studied to determine whether rainfall regimes could limit the latitudinal ranges of tropical and temperate forest species. Location The study species are native to New Guinea, New Caledonia, Australia, New Zealand, Chile and Argentina. Methods Seedlings of Nothofagus species from a broad latitudinal range were grown in a common environment. Changes in conductance, relative water content and water potential were measured in detached shoots, and together with measurements of tissue injury and biomass allocation, were compared between tropical and temperate species. Results Differences in responses to water deficits between tropical and temperate species appear to reflect differences in climate regimes. In particular, species native to ever‐wet rainfall regimes in New Guinea, where water deficits are generally likely to be short‐lived, were effective at conserving water by reduced stomatal conductance. In contrast, high‐latitude evergreen species on average showed greater development of traits that should enhance water uptake. This was particularly evident in Nothofagus cunninghamii from southern Australia, which developed low water potentials at moderate levels of tissue water deficit and higher root:leaf biomass than tropical species, potentially allowing carbon assimilation to be maximized during warmer, but drier, summer months. However, water relations varied among high‐latitude species. In particular, deciduous species on average showed higher rates of conductance, even during moderate levels of tissue water deficit, than evergreen species. Main conclusions The tropical species appear to conserve water during periods of water deficit (relative to temperate species), which is unlikely to have substantial opportunity costs for growth in ever‐wet climates. However, spread of tropical species to higher latitudes may be limited by water conservation strategies that limit carbon gain in climates in which temperature seasonality is often paired with drier summers. Evergreen species from high latitudes, such as N. cunninghamii, commonly showed traits that should increase water uptake. However, this strategy, while probably maximizing growth in temperate climates with cool winters and drier summers, must limit competitiveness at lower latitudes in summer‐wet climates. We conclude that responses to water regimes may make a significant contribution to the latitudinal limits of some evergreen rain forest species.     

Comparative phylogeography of the centipedes <Emphasis Type="Italic">Cryptops pictus</Emphasis> and <Emphasis Type="Italic">C. niuensis</Emphasis> (Chilopoda) in New Caledonia,Fiji and Vanuatu

The South Pacific is a biodiverse region of extreme evolutionary importance because it harbors ancient lineages and recent radiations. However, few population-level studies of genetic variation have been conducted in the land masses of this region. Likewise, the number of population-level studies using myriapods as models is extremely small. In this article, we compare the genetic structure of two species of centipedes in the genus Cryptops endemic to the South Pacific, one from a continental island, the other from oceanic islands. The level of genetic diversity and structure in C. pictus, a species endemic to New Caledonia, is much higher than in C. niuensis in Fiji and Vanuatu, despite the fact that C. niuensis is spread across two different archipelagos and several islands. The most likely explanation is the relatively young age of the remnants of the Vitiaz Arc (Fiji and Vanuatu) compared to New Caledonia. Using the emergence of Fiji-Vanuatu as a calibration point, C. pictus is estimated to have diverged by 23.4 Mya (upper 95% confidence interval) with a mean estimate of 11.7 Mya versus the 9.7 Mya of C. niuensis. Considering the absence of shared sequences between specimens from different sampling sites and the high genetic structuring within populations, C. pictus appears to be an ideal candidate to assess historical processes at a micro-evolutionary scale in New Caledonia.     

<Emphasis Type="Italic">Pseudorhabdosynochus quadratus</Emphasis> n. sp. (Monogenea: Diplectanidae) from the white-streaked grouper <Emphasis Type="Italic">Epinephelus ongus</Emphasis> (Bloch) (Perciformes: Serranidae) off New Caledonia

Gill diplectanid monogeneans from the camouflage grouper Epinephelus polyphekadion (Bleeker) collected in the coral reef lagoon of New Caledonia, South Pacific, comprise four species. Very few monogeneans were found in most fish examined. Pseudorhabdosynochus dionysos n. sp. has a sclerotised vagina with a robust trumpet, a robust primary canal and two chambers of similar size; it is close to P. bacchus Sigura, Chauvet & Justine, 2007. P. viscosus n. sp. has a sclerotised vagina with a robust trumpet, long primary canal with an extremely thin wall and two small chambers, and a male quadriloculate organ with a characteristic thickening at the extremity of its cone. P. crassus n. sp., the most abundant species, has a sclerotised vagina with a thin-walled trumpet, thin-walled primary canal which is always coiled anteriorly and two small chambers. P. huitoe Justine, 2007, P. manifestus Justine & Sigura, 2007 and P. crassus have very similar sclerotised vaginae; however, species of this ‘huitoe complex’ can be distinguished by measurements of the haptoral hard parts. A few diplectanid specimens found in a single specimen of E. polyphekadion were attributed to P. huitoe, a species originally described from E. maculatus (Bloch) and also rarely found in E. cyanopodus Richardson in New Caledonia; specimens from these three fish species are morphologically indistinguishable.     

908. PTEROSTYLIS REPANDA

Pterostylis repanda, a recently‐named species from New Caledonia, is illustrated. Its distinctions from related species are discussed, and suggestions for its cultivation are given.     

Deciphering patterns of transoceanic dispersal: the evolutionary origin and biogeography of coastal lizards (Cryptoblepharus) in the Western Indian Ocean region

Aim Cryptoblepharus is a genus of small arboreal or rock‐dwelling scincid lizards, widespread through the Indo‐Pacific and Australian regions, with a disjunct outlier in the Malagasy region. The taxonomy within this genus is controversial, with different authors ranking the different forms (now some 36) at various levels, from different species to subspecies of a single species, Cryptoblepharus boutonii. We investigated the biogeography and genetic differentiation of the Cryptoblepharus from the Western Indian Ocean region, in order to understand their origin and history. Location Western Indian Ocean region. Methods We analysed sequences of mitochondrial DNA (partial 12s and 16s rRNA genes, 766 bp) from 48 specimens collected in Madagascar, Mauritius, the four Comoros islands and East Africa, and also in New Caledonia, representing the Australo‐Pacific unit of the distribution. Results Pairwise sequence divergences of c. 3.1% were found between the New Caledonian forms and the ones from the Western Indian Ocean. Two clades were identified in Madagascar, probably corresponding to the recognized forms cognatus and voeltzkowi, and two clades were identified in the Comoro islands, where each island population formed a distinct haplotype clade. The East African samples form a monophyletic unit, with some variation existing between Pemba, Zanzibar and continental Tanzania populations. Individuals from Mauritius form a divergent group, more related to populations from Moheli and Grand Comore (Comoros islands) than to the others. Main conclusions The level of divergence between the populations from the Western Indian Ocean and Australian regions and the geographic coherence of the variation within the Western Indian Ocean group are concordant with the hypothesis of a colonization of this region by a natural transoceanic dispersal (from Australia or Indonesia). The group then may have diversified in Madagascar, from where it separately colonized the East African coast, the Comoros islands (twice), and Mauritius. The genetic divergence found is congruent with the known morphological variation, but its degree is much lower than typically seen between distinct species of reptiles.     

Four species of Pseudorhabdosynochus (Monogenea: Diplectanidae) from the camouflage grouper Epinephelus polyphekadion (Perciformes: Serranidae) off New Caledonia

Gill diplectanid monogeneans from the camouflage grouper Epinephelus polyphekadion (Bleeker) collected in the coral reef lagoon of New Caledonia, South Pacific, comprise four species. Very few monogeneans were found in most fish examined. Pseudorhabdosynochus dionysos n. sp. has a sclerotised vagina with a robust trumpet, a robust primary canal and two chambers of similar size; it is close to P. bacchus Sigura, Chauvet & Justine, 2007. P. viscosus n. sp. has a sclerotised vagina with a robust trumpet, long primary canal with an extremely thin wall and two small chambers, and a male quadriloculate organ with a characteristic thickening at the extremity of its cone. P. crassus n. sp., the most abundant species, has a sclerotised vagina with a thin-walled trumpet, thin-walled primary canal which is always coiled anteriorly and two small chambers. P. huitoe Justine, 2007, P. manifestus Justine & Sigura, 2007 and P. crassus have very similar sclerotised vaginae; however, species of this 'huitoe complex' can be distinguished by measurements of the haptoral hard parts. A few diplectanid specimens found in a single specimen of E. polyphekadion were attributed to P. huitoe, a species originally described from E. maculatus (Bloch) and also rarely found in E. cyanopodus Richardson in New Caledonia; specimens from these three fish species are morphologically indistinguishable.     

Time and tempo of diversification in the flora of New Caledonia

New Caledonia is well known for its rich and unique flora. Many studies have focused on the biogeographical origins of New Caledonian plants but rates of diversification on the island have scarcely been investigated. Here, dated phylogenetic trees from selected published studies were used to evaluate the time and tempo of diversification in New Caledonia. The 12 plant lineages investigated all appear to have colonized the island < 37 Mya, when New Caledonia re‐emerged after a period of inundation, and the timing of these arrivals is spread across the second half of the Cenozoic. Diversification rates are not particularly high and are negatively correlated with lineage age. The palms have the fastest diversification rates and also the most recent arrival times. The lineage ages of rainforest plants suggest that this ecosystem has been present for at least 6.9 Myr. The New Caledonian flora is apparently a relatively old community that may have reached a dynamic equilibrium. Colonization by new immigrants has been possible until relatively recently and diversity‐dependent processes may still be affecting the diversification rates of the earlier colonizers. Further studies on the diversification of large plant clades with exhaustive sampling should help to clarify this. © 2012 The Linnean Society of London, Botanical Journal of the Linnean Society, 2012, 170 , 288–298.