Morphology, reproductive biology and molecular genetics of ovoviviparous freshwater gastropods (Cerithioidea, Pachychilidae) from the Philippines, with description of a new genus Jagora

The new genus Jagora of the family Pachychilidae Troschel, 1857 is described for the type species Melania asperata Lamarck, 1822 from the Philippines. In addition to J. asperata, a second endemic species of the new genus, J. dactylus (I. Lea & H.C. Lea, 1850), is recognized on the basis of shell morphometry and molecular genetic data (cytochrome C oxidase I and 16S rRNA). The taxonomic history of J. asperata and J. dactylus is revised and the recent distribution documented on basis of available museum material and the authors’ own field collections. J. asperata occurs on Luzon and its satellite islands Leyte and Samar, while J. dactylus is restricted to the Visayan islands Bohol, Cebu, and Guimeras. The morphology of the two species is presented and illustrated in detail, and compared to taxa of the closely related genus Brotia H. Adams, 1866 to which they were previously assigned. Among the South‐east Asian freshwater Cerithioidea of the family Pachychilidae, which were previously subsumed under Brotia for their more or less similar shell morphology and operculum, three distinct lineages can be distinguished, in particular by means of distinct reproductive anatomy: (1) the species of Brotia sensu stricto from mainland South‐east Asia, Sumatra, Borneo and Java, which all exhibit a subhaemocoelic brood pouch; (2) the pachychilid species endemic to Sulawesi, currently assigned to the genera Brotia and Tylomelania, as well as both species of Pseudopotamis endemic to the Torres Strait Islands, which possess a uterine brood pouch; (3) the females of the Philippine Jagora, which carry egg capsules, embryos and advanced juvenile stages within the mantle cavity — a unique reproductive feature. Associated with this mode of ovoviviparity, Jagora is characterized by additional unique properties of the reproductive system including a deeply incised and long sperm gutter in the medial lamina, a very short and posteriorly positioned spermatophore bursa formed by the medial lamina, and a prominent lateral ridge functioning as a seminal receptacle. These characteristics are exclusive to Jagora and are consequently considered to represent autapomorphies of this clade which is endemic only to the Philippines. The zoogeographical implications are discussed in connection with a recently developed palaeogeographical reconstruction.     

A palynological investigation of Holocene vegetation change in Torres Strait, seasonal tropics of northern Australia

The islands of Torres Strait occupy a shallow area of submerged continental shelf narrowly separating Cape York Peninsula, Australia, from New Guinea. The human history of Torres Strait is unique with respect to mainland northern Australia. Island vegetation, however, exhibits a strong affinity with the environments of the western lowlands regions of Cape York Peninsula and with the vegetation of seasonal tropical Australia in general. Cape York Peninsula is both climatically and biologically diverse, yet few pollen studies have been carried out in its seasonally tropical environments. A summary presentation of palynological results, tracing the nature of vegetation change in Torres Strait, offers a possible framework for vegetation changes in similar environments on mainland Australia and also provides an opportunity to explore the relationship between Quaternary change in humid-tropical Australian environments and their seasonal-tropical counterparts.Six pollen records from Torres Strait provide evidence of vegetation change and fire history over approximately the last 8000 years. Near-shore sediments reveal a Holocene succession in vegetation incorporating lower-tidal mangrove, upper-tidal mangrove, saltmarsh and freshwater swamp communities. Extensive stable mangrove communities dominated coastal Torres Strait between approximately 6000 and 3000 radiocarbon years before present (yr BP). Inland, the strongest Myrtaceae-forest and rainforest representation occurs around the mid-Holocene only to be replaced by open sclerophyll woodlands, as tree density and diversity decline in the last 3000 years. The development of continuous island freshwater swamp conditions, at the coast and inland, is similarly restricted to the late Holocene (c. 2600 yr BP) and fire, as a prominent feature in the Torres Strait environment, is also a relatively recent phenomenon. Comparisons with regional mainland Australian palynological records reveal a degree of consistency in results from Torres Strait suggesting a similarity in late Quaternary trends through Australian humid and seasonally tropical environments. A number of differences, however, are also apparent, highlighting a degree of diversity which warrants further attention.     

Novel reproductive modes in freshwater clams: brooding and larval morphology in Southeast Asian taxa of Corbicula (Mollusca, Bivalvia, Corbiculidae)

While the majority of marine bivalves are oviparous, the two freshwater families among the order Veneroida, i.e. Corbiculidae and Sphaeriidae, comprise species with ovoviviparous and viviparous reproduction. Within the Corbiculidae, the genus Corbicula, which is well‐known for its invasive and, thus, ecologically important representatives, is characterized by (i) a wide range of limnic habitats, inhabiting both brackish water and freshwater environments, and (ii) contrasting modes of reproduction, including ‘planktonic’ development via a free‐swimming larva vs. intrabranchial incubation (brooding) of shelled juveniles. The present investigation of five species of Corbicula from the Indonesian islands Sumatra and Sulawesi, which were hitherto not studied anatomically, adds to the diversity in reproductive patterns in this genus. As a unique feature among Corbicula we here report on two newly observed modes of brooding in species endemic to Sulawesi, (i) tetragenous brooding (i.e. in both demibranchs) in Corbicula possoensis Sarasin & Sarasin, 1898 from Lake Poso, and (ii) prolonged incubation in the maternal gills, with juvenile shells reaching up to 1.3 mm in length and with a well‐developed hinge in C. linduensis Bollinger, 1914 from the Lindu River system. In contrast, a third method is seen in the following taxa that incubate their young in their inner demibranchs only until the stage of juveniles with straight‐hinged shells (D‐shaped): C. matannensis Sarasin & Sarasin, 1898 from Lake Matano and Lake Mahalona, C. loehensis Kruimel, 1913 from Lake Masapi (all on Sulawesi) and C. moltkiana Prime, 1878 from Lakes Maninjau and Singkarak (on Sumatra). Details of the anatomical and histological features of ctenidia are described for each type of brooding, and some trends in the evolution of reproductive strategies within the Corbiculidae are discussed, comparing them with those known from other limnic molluscs.     

Past and future epidemic potential of chikungunya virus in Australia

BackgroundAustralia is theoretically at risk of epidemic chikungunya virus (CHIKV) activity as the principal vectors are present on the mainland Aedes aegypti) and some islands of the Torres Strait (Ae. aegypti and Ae. albopictus). Both vectors are highly invasive and adapted to urban environments with a capacity to expand their distributions into south-east Queensland and other states in Australia. We sought to estimate the epidemic potential of CHIKV, which is not currently endemic in Australia, by considering exclusively transmission by the established vector in Australia, Ae. aegypti, due to the historical relevance and anthropophilic nature of the vector.Methodology/Principal findingsWe estimated the historical (1995–2019) epidemic potential of CHIKV in eleven Australian locations, including the Torres Strait, using a basic reproduction number equation. We found that the main urban centres of Northern Australia could sustain an epidemic of CHIKV. We then estimated future trends in epidemic potential for the main centres for the years 2020 to 2029. We also conducted uncertainty and sensitivity analyses on the variables comprising the basic reproduction number and found high sensitivity to mosquito population size, human population size, impact of vector control and human infectious period.Conclusions/SignificanceBy estimating the epidemic potential for CHIKV transmission on mainland Australia and the Torres Strait, we identified key areas of focus for controlling vector populations and reducing human exposure. As the epidemic potential of the virus is estimated to rise towards 2029, a greater focus on control and prevention measures should be implemented in at-risk locations.     

Phytolith and starch analysis of sediment samples from two archaeological sites on Dauar Island,Torres Strait,northeastern Australia

Current archaeological research suggests that first human occupation of the Torres Strait Islands occurred sometime between 2500 and 3000 cal b.p., and evidence indicates that the development of agricultural mound-and-ditch systems occurred there after 1200 cal b.p. Although archaeological remains testify to the existence of a marine based subsistence economy prior to 1200 cal b.p., the potential presence of earlier prehistoric horticultural signatures has yet to be adequately examined. This study investigates such evidence through a preliminary application of fossil phytolith and starch grain analysis using excavated sediments from two archaeological sites on Dauar Island, eastern Torres Strait. The results show the early presence of yam (Dioscorea sp.), and Musa species not endemic to the island. The occurrence of these edible plant types in association with carbonised phytoliths and anthropogenic shell and bone deposits may be indicative of a combined insular horticultural and marine subsistence system on Dauar Island. We suggest that with a larger and appropriate phytolith reference set for the research area, there is a potential to more clearly define human induced changes to vegetation and patterns of subsistence in the Torres Strait Islands.     

Ancient lakes as hotspots of diversity: a morphological review of an endemic species flock of <Emphasis Type="Italic">Tylomelania</Emphasis> (Gastropoda: Cerithioidea: Pachychilidae) in the Malili lake system on Sulawesi,Indonesia

The viviparous freshwater gastropod Tylomelania (Caenogastropoda: Cerithioidea: Pachychilidae) endemic to the Indonesian island Sulawesi has radiated extensively in two ancient lake systems. We here present the first systematic species-level review of taxa in the five lakes of the Malili lake system, which contains the most diverse and best studied freshwater fauna on Sulawesi. Our results indicate a significantly higher diversity of Tylomelania in these lakes than previously perceived based on morphological evidence for delimiting the taxa. We describe nine new species, thus increasing the number of taxa known from the Malili lakes to 25. Tylomelania species are inhabiting all available substrates in the lakes, and the diversity of habitats is reflected in an unparalleled range of radula types in this closely related group. Several species show a high intraspecific variability in some characters, and their closer investigation will probably lead to the discovery of more cryptic species. As it is, this species flock on Sulawesi is among the largest freshwater mollusc radiations known. Since the Malili lake system also contains other large endemic species flocks of e.g. crustaceans and fishes, it is a major hotspot of freshwater biodiversity in Asia to become a conservation priority. Handling editor: K. Martens     

A Novel Approach to Tradition: Torres Strait Islanders and Ion Idriess

This paper considers the significance of the novel Drums of Mer (1941) in contemporary Torres Strait Islanders' lives. Its use as narrative by many Islanders today constitutes one means by which men especially have come to know themselves, white others, and their past. In particular, I explore the ways in which this story appeals to and is appealed to by Yam Island people. Contrary to literary deconstructions of Idriess's representations of Aboriginal and Torres Strait Islander people, my paper argues that in seriously attending to Torres Strait readings of Drums of Mer we can see that for contemporary Islander readers, it is not themselves who are other but rather the white protagonists. I employ Said's (1994) notion of ‘cultural overlap’ and de Certeau's (1988) understandings of reading and writing as ‘everyday practices’ to frame my analysis of the differing impacts of the historical novel, Drums of Mer, and the Reports of the Cambridge Anthropological Expedition to Torres Straits. It is through story telling that Yam Island selves are placed in the past and the present, and in Idriess's memorable story a similar effect is achieved. In his novel approach, the past becomes his-story, a romanticised refraction of the Reports. Unlike the Reports, this novel is a sensual rendering of a Torres Strait past, and at this level it operates as a mnemonic device for Yam Island people, triggering memories and the imagination through the senses. This Torres Strait Islander detour by way of a past via a story, can be understood as a means by which Yam Island people continue to actively produce powerful images of themselves, for both themselves and for others.     

Two new species and a new Australian record of Bactrocera Macquart (Diptera: Tephritidae: Dacinae) from northern Queensland, Torres Strait and Papua New Guinea

Abstract  Bactrocera (Bactrocera) speewahensis Fay & Hancock sp. n. is described from northern Queensland and B. (B.) torresiae Huxham & Hancock sp. n. is described from Boigu, Saibai and Dauan islands in Torres Strait and southern Papua New Guinea. Bactrocera (B.) nigrovittata Drew is newly recorded from Australia. All records are of male flies responding to chemical lures.     

Response of a southern temperate marsupial, the Tasmanian pademelon (Thylogale billardierii), to historical and contemporary forest fragmentation

Despite only limited Pleistocene glacial activity in the southern hemisphere, temperate forest species experienced complex distributional changes resulting from the combined effects of glaciation, sea level change and increased aridity. The effects of these historical processes on population genetic structure are now overlain by the effects of contemporary habitat modification. In this study, 10 microsatellites and 629 bp of the mitochondrial control region were used to assess the effects of historical forest fragmentation and recent anthropogenic habitat change on the broad-scale population genetic structuring of a southern temperate marsupial, the Tasmanian pademelon. A total of 200 individuals were sampled from seven sites across Tasmania and two islands in Bass Strait. High mitochondrial and nuclear genetic diversity indicated the maintenance of large historical population sizes. There was weak phylogeographical structuring of haplotypes, although all King Island haplotypes and three Tasmanian haplotypes formed a divergent clade implying the mid-Pleistocene isolation of a far northwestern population. Both the mitochondrial and nuclear data indicated a division of Tasmanian populations into eastern and western regions. This was consistent with a historical barrier resulting from increased aridity in the lowland 'midlands' region during glacial periods, and with a contemporary barrier resulting from recent habitat modification in that region. In Tasmania, gene flow appears to have been relatively unrestricted during glacial maxima in the west, while in the east there was evidence for historical expansion from at least one large glacial refuge and recolonization of Flinders Island.     

Vicariance and dispersal across an intermittent barrier: population genetic structure of marine animals across the Torres Strait land bridge

Biogeographic barriers, some transitory in duration, are likely to have been important contributing factors to modern marine biodiversity in the Indo-Pacific region. One such barrier was the Torres Strait land bridge between continental Australia and New Guinea that persisted through much of the late Pleistocene and separated Indian and Pacific Ocean taxa. Here, we examine the patterns of mitochondrial DNA diversity for marine animals with present-day distributions spanning the Torres Strait. Specifically, we investigate whether there are concordant signatures across species, consistent with either vicariance or recent colonization from either ocean basin. We survey four species of reef fishes (Apogon doederleini, Pomacentrus coelestis, Dascyllus trimaculatus, and Acanthurus triostegus) for mtDNA cytochrome oxidase 1 and control region variation and contrast these results to previous mtDNA studies in diverse marine animals with similar distributions. We find substantial genetic partitioning (estimated from F-statistics and coalescent approaches) between Indian and Pacific Ocean populations for many species, consistent with regional persistence through the late Pleistocene in both ocean basins. The species-specific estimates of genetic divergence, however, vary greatly and for reef fishes we estimate substantially different divergence times among species. It is likely that Indian and Pacific Ocean populations have been isolated for multiple glacial cycles for some species, whereas for other species genetic connections have been more recent. Regional estimates of genetic diversity and directionality of gene flow also vary among species. Thus, there is no apparent consistency among historical patterns across the Torres Strait for these co-distributed marine animals.     

Records of two sugarcane pests Eumetopina flavipes Muir (Hemiptera: Delphacidae) and Chilo terrenellus Pagenstecher (Lepidoptera: Pyralidae) from Torres Strait and far north Queensland

Abstract  The State of Queensland includes islands within Torres Strait. However, Quarantine legislation separates these islands from mainland Australia, and divides them into two Quarantine zones. Details of the Torres Strait and far north Queensland distribution and damage levels of Eumetopina flavipes Muir (sugarcane leafhopper) and Chilo terrenellus Pagenstecher (sugarcane stem borer) are published here for the first time. The delphacid is a known vector of the sugarcane disease, Ramu stunt, which occurs in northern Papua New Guinea (PNG) and possibly other locations. Eumetopina flavipes has been known to occur on islands within Torres Strait and the communities near the tip of Cape York Peninsula since 1983. The disease is not known to be present in this population of the bugs. The sugarcane stem borer, C. terrenellus , has been detected on a number of occasions in sugarcane on two of the three Torres Strait islands closest to PNG (Saibai and Dauan). Its 'appearance' at these two sites is intermittent and damage levels are never as high as in the nearby communities in the Western Province of PNG. The majority of sugarcane plantings on Torres Strait islands are yellow and purple varieties of chewing cane ( Saccharum officinarum ) which is the host for all records reported here. Recent detection of Chilo crypsimetalla (Turner) on several islands in Torres Strait is reported, although this is not thought to be a pest of sugarcane.     

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.     

Cryptic speciation and phylogeographic relationships in the elephant ear sponge Ianthella basta (Porifera,Ianthellidae) from northern Australia

Morphological delineation of sponge species is hindered by the narrow range of fixed diagnostic characters and our limited knowledge of how much phenotypic plasticity the sponge body plan assumes in response to environmental conditions. Here, we make use of the partial mitochondrial cytochrome c oxidase subunit I (COI) gene and the second internal transcribed spacer (ITS2) region to assess the taxonomic validity of colour morphotypes observed in the elephant ear sponge Ianthella basta (Pallas, 1776) across its distribution range in northern Australia, and explore levels and patterns of genetic diversity among populations of the species collected from both sides of the Torres Strait. Molecular phylogenetic analyses revealed congruent topologies consistent with three evolutionarily significant units (ESUs) that were independent of the morphology of the sponge. ESU I includes previously morphologically and genetically delineated western Pacific specimens of I. basta (Guam), and probably corresponds to the type specimen originally described from Indonesia. ESU I occurs in almost all sampling sites across northern Australia, suggesting considerable levels of connectivity among reefs throughout the Torres Strait. ESUs II and III are each exclusively associated with a geographic region of high sponge species richness separated by Torres Strait, and probably represent the result of historical population fragmentation. © 2012 The Linnean Society of London, Zoological Journal of the Linnean Society, 2012, 166 , 225–235.     

Phylogeography of the olive sea snake, Aipysurus laevis (Hydrophiinae) indicates Pleistocene range expansion around northern Australia but low contemporary gene flow

Pleistocene sea-level fluctuations profoundly changed landmass configurations around northern Australia. The cyclic emergence of the Torres Strait land bridge and concomitant shifts in the distribution of shallow-water marine habitats repeatedly sundered east and west coast populations. These biogeographical perturbations invoke three possible scenarios regarding the directions of interglacial range expansion: west to east, east to west, or bidirectional. We evaluated these scenarios for the olive sea snake, Aipysurus laevis, by exploring its genetic structure around northern Australia based on 354 individuals from 14 locations in three regions (Western Australia, WA; Gulf of Carpentaria, GoC; Great Barrier Reef, GBR). A 726-bp fragment of the mitochondrial DNA ND4 region revealed 41 variable sites and 38 haplotypes, with no shared haplotypes among the three regions. Population genetic structure was strong overall, phiST=0.78, P<0.001, and coalescent analyses revealed no migration between regions. Genetic diversity was low in the GBR and GoC and the genetic signatures of these regions indicated range or population expansions consistent with their recent marine transgressions around 7000 years ago. By contrast, genetic diversity on most WA reefs was higher and there were no signals of recent expansion events on these reefs. Phylogenetic analyses indicated that GBR and GoC haplotypes were derived from WA haplotypes; however, statistical parsimony suggested that recent range expansion in the GBR-GoC probably occurred from east coast populations, possibly in the Coral Sea. Levels of contemporary female-mediated gene flow varied within regions and reflected potential connectivity among populations afforded by the different regional habitat types.     

Typological thinking and the conservation of subspecies: the case of the San Clemente Island loggerhead shrike

Abstract.  Hybridization with closely related taxa poses a significant threat to endangered subspecies (e.g. outbreeding depression, inbreeding) and confounds efforts to manage and conserve these taxa through a loss of taxonomic identity, in part because of the practical necessity of defining subspecies in a typological manner. We examined nine morphological characters in 167 post-juvenile museum specimens to determine if loggerhead shrikes Lanius ludovicianus Linnaeus 1766 on San Clemente Island (off the coast of California) remain diagnosable as L. l. mearnsi Ridgway (1903); an island endemic listed as endangered by the United States Fish and Wildlife Service. Four recent shrike specimens from the island were compared to historical specimens using a bivariate scatter plot and a discriminant function (the latter was used to classify recent specimens post hoc). The few recent specimens were not diagnosable as L. l. mearnsi , but instead appear to be intergrades between L. l. mearnsi and L. l. anthonyi Mearns 1898 (the subspecies endemic to Santa Cruz, Santa Catalina, Santa Rosa and Anacapa islands), and are perhaps closer to pure anthonyi . Our data and the species' natural history and distribution suggest that shrikes currently on San Clemente Island are the result of genetic 'swamping' of mearnsi by anthonyi . Under a necessarily typological definition of a subspecies, it is evident that mearnsi is probably no longer diagnosable. However, we conclude that protection of the entire Channel Islands population of the loggerhead shrike would be the best management strategy, as the species has declined drastically throughout the islands.     

Mitochondrial phylogeography of New Zealand freshwater crayfishes, Paranephrops spp

Tectonic movement at the boundary of the Indo-Australian and Pacific Plates during the Miocene and Pliocene is recognized as a driving force for invertebrate speciation in New Zealand. Two endemic freshwater crayfish (koura) species, Paranephrops planifrons White 1842 and Paranephrops zealandicus White 1842, represent good model taxa to test geological hypotheses because, due to their low dispersal capacity and life history, geographical restriction of populations may be caused by vicariant processes. Analysis of a mitochondrial DNA marker (cytochrome oxidase subunit I) reveals not two, but three major koura lineages. Contrary to expectation, the cryptic West Coast group appears to be more closely related to P. zealandicus than to P. planifrons and has diverged earlier than the final development (Late Pleistocene) of Cook Strait. Our date estimates suggest that koura lineage diversification probably coincided with early to mid-Alpine orogeny in the mid-Pliocene. Estimates of node ages and the phylogenies are inconsistent with both ancient Oligocene and recent postglacial Pleistocene range expansion, but suggest central to north colonization of North Island and west to east movement in South Island during mid- to late Pliocene. Crypsis and paraphyly of the West Coast group suggest that morphological characters presently used to classify koura species could be misleading.     

Collection of wind-borne haematophagous insects in the Torres Strait,Australia

Circumstantial evidence has implicated wind-borne mosquitoes (Diptera: Culicidae) in the introduction of Japanese encephalitis (JE) virus into Australia from the New Guinea mainland. A study was initiated on Saibai Island in the northern Torres Strait, during January and February 2000, to identify the potential source of insects collected in aerial (kytoon) and surface-level traps. Wind speed and direction were recorded to determine wind profiles during insect sampling. Northerly winds capable of carrying insects from New Guinea to Saibai Island were only present on three out of 18 nights sampled. Only three male mosquitoes, comprising two Verrallina funerea (Theobald) and one Ochlerotatus vigilax (Skuse), were collected in aerial samples, and were most likely of local origin. Culicoides midges were also collected in aerial nets and included gravid/parous C. bundyensis Lee and Reye, and one parous C. histrio Johannsen. Highest densities of arthropods (up to 1562/million m3) were on 30 January 2000 when NW winds, sustained for six hours, probably introduced midges from the New Guinea mainland. Adult mosquitoes (including three female Ve. funerea and a single female Ficalbia) and Culicoides (including two gravid C. bundyensis and one parous C. cordiger Macfie) were also collected in 2 m high mast nets during northerly surface winds. Although the results do not provide evidence that wind-blown mosquitoes introduced JE from New Guinea into Australia, they do not preclude that strong N winds associated with low pressure systems SW of the Torres Strait could have done so. However, results suggest that Culicoides were more likely than mosquitoes to reach high altitude and travel long distances during the light N winds experienced during the study.     

The flea genus Sigmactenus (Siphonaptera: Leptopsyllidae): three new taxa from Sulawesi, updated identification key, and distribution map for all known species and subspecies

One new species and two new subspecies of fleas are described. These are S. sulawesiensis n. sp. from North and Central Sulawesi, S. alticola pilosus n. ssp. from Central Sulawesi, and S. alticola crassinavis n. ssp. from North Sulawesi. All three of these new taxa are ectoparasites of native, endemic murine rodents. Two of the new taxa, S. sulawesiensis and S. alticola crassinavis, coexist on the same mountain, Gunung Moajat, in North Sulawesi. The related S. alticola alticola, which becomes the nominate subspecies, parasitises the murine rodent Maxomys alticola in northern Borneo (Sabah) and it is hypothesized that Sigmactenus first colonized Sulawesi as an ectoparasite of ancestral Maxomys, or perhaps Rattus, as these murines dispersed from southeast Asia to Sulawesi; 15 endemic murine rodent species belonging to these two genera are known to currently inhabit Sulawesi. An identification key and distribution map are included for all known species and subspecies of Sigmactenus. In addition to the three new taxa and S. a. alticola, these include: S. celebensis from South Sulawesi, S. timorensis from Timor, S. toxopeusi from New Guinea, and S. werneri from the Philippines (Mindanao and Negros).     

Compulsory Pilotage in the Torres Strait: Overcoming Unacceptable Risks to a Sensitive Marine Environment

This article explores arguments about the international legality of compulsory pilotage in the Torres Strait. Although the measure has been opposed by some user states because the Torres Strait is a strait used for international navigation, Australia and Papua New Guinea believe compulsory pilotage is necessary to overcome the risks posed by unpiloted shipping passing through the hazardous waters. The good health of the marine environment in the Torres Strait is essential, particularly for the well-being of indigenous peoples of the area. The article concludes that compulsory pilotage in Torres Strait reflects the obligations of both the user and border states to preserve and protect the marine environment and has support in international law.     

Oceanic interchange and nonequilibrium population structure in the estuarine dependent Indo-Pacific tasselfish,Polynemus sheridani

We assayed mtDNA haplotype [300 base pairs (bp) control region] geography and genealogy in the Indo-Pacific tasselfish, Polynemus sheridani from its contiguous estuarine distribution across northern Australia (n = 169). Eight estuaries were sampled from three oceanographic regions (Timor Sea, Gulf of Carpentaria and the Coral Sea) to assess the impact of Pleistocene sea level changes on the historical connectivity among P. sheridani populations. Specifically, we investigated the genetic consequences of disruption to Indian-Pacific Ocean connectivity brought about by the closure of the Torres Strait. Overall there was significant population subdivision among estuaries (FST = 0.161, PhiST = 0.187). Despite a linear distribution, P. sheridani did not show isolation by distance over the entire sampled range because of genetic similarity of estuaries greater than 3000 km apart. However, significant isolation by distance was detected between estuaries separated by less than 3000 km of coastline. Unlike many genetic studies of Indo-Pacific marine species, there was no evidence for an historical division between eastern and western populations. Instead, phylogeographical patterns were dominated by a starlike intraspecific phylogeny coupled with evidence for population expansion in both the Gulf of Carpentaria and the Coral Sea but not the Timor Sea. This was interpreted as evidence for recent west to east recolonization across of northern Australia following the last postglacial marine advance. We argue that although sufficient time has elapsed postcolonization for populations to approach gene flow-drift equilibrium over smaller spatial scales (< 3000 km), the signal of historical colonization persists to obscure the expected equilibrium pattern of isolation by distance over large spatial scales (> 3000 km).