Huon Peninsula Research Articles

Hidden diversity in semi-fossorial Melanesian forest snakes: A revision of the Toxicocalamus loriae complex (Squamata, Elapidae) from New Guinea

With its conservative set of scalation characters, Toxicocalamus loriae is a morphologically confusing species to which a wide array of phenotypes has been assigned. Careful analysis of 224 museum specimens reveals that multiple distinct species remain hidden under the name T. loriae and that diagnostic, species-level differences are more nuanced in this group of snakes than among other members of the genus. Our taxonomic reassessment leads us to resurrect the species T. lamingtonicomb. nov., T. loennbergiicomb. nov., and T. nymanicomb. nov. from synonymy with T. loriae, retain only T. pratti as a synonym, and describe three new species. As a consequence, T. loriae is no longer recognized as ranging throughout the entire island of New Guinea but is instead restricted to the southern versant of the Papuan Peninsula, and T. lamingtoni and T. spilorhynchussp. nov. are species restricted to that same peninsula’s northern versant. Toxicocalamus loennbergii is known only from the type series taken on the Onin Peninsula in West Papua, Indonesia, Toxicocalamus atratussp. nov. is a high-elevation (800–2200 m) Central Highlands endemic, and T. vertebralissp. nov. ranges from the Central Highlands of Papua New Guinea eastward into the Wau area of Morobe Province. Toxicocalamus nymani inhabits a geologically more heterogenous region, occurring from the Central Highlands eastward to the Huon Peninsula, including Karkar Island, and adjacent areas of Madang Province as well as the northernmost reaches of the Papuan Peninsula. We expect that denser geographic sampling across New Guinea and focussed specimen collection of a few known populations will result in the recognition of additional species in this complex.

High interstadial sea levels over the past 420ka from the Huon Peninsula, Papua New Guinea

The history of sea level across the Quaternary is essential for assessing past and future climate. Global sea-level reconstructions are typically derived from oxygen isotope curves, but require calibration with geological constraints that are scarce prior to the last glacial cycle (>130 thousand years ago). Here we show that the coral reef terrace sequence at the Huon Peninsula (Papua New Guinea) provides such constraints up to ∼420 thousand years ago, through a geometric analysis of high-resolution topographic data. We derive a northward tectonic tilt as regional deformation pattern, and estimate relative sea level for 31 Quaternary periods, including several periods for which no relative sea level data exists elsewhere. Supported by numerical reef models, these estimates suggest that oxygen isotope-based global mean sea-level curves systematically underestimate interstadial sea-level elevations, by up to ∼20 m. Compared to those curves, our results imply a stronger degree of non-linearity between ice-sheet volumes and global temperatures within Quaternary glacial cycles.

Late Quaternary neotectonics in the Bird’s Head Peninsula (West Papua), Indonesia: Implications for plate motions in northwestern New Guinea, western Pacific

New Guinea is a mountainous island in a tectonically active setting with regions experiencing rapid uplift rates as shown by the celebrated emergent coral reef terraces of the Huon Peninsula. In the northern Bird’s Head Peninsula of northwestern New Guinea, rapid uplift has been a feature of the tectonic history over the past 2.7 Ma with the development of the mountainous and highly dissected Kemum High (up to 2200 m) associated with the formation of the Central Bird’s Head Monocline, implying a long-term uplift rate approaching 0.8 m/ka. In this work, Late Quaternary uplift rates of up to 1.28 m/ka were determined for emergent coral reefs in the Manokwari region (northeast of the much larger Kemum High). The rapid uplift rates are based on 230Th-U ages (2.7 ± 0.3 to 246.3 ± 8.0 ka with most ages in the range 69–128 ka) on corals and coralline algae, sampled from calcarenites at elevations of 2.45–77.5 m above present sea level. The rapid uplift indicates neotectonic activity reflecting crustal thickening in the Quaternary and neptunian dykes probably related to gravitational instability. The present-day tectonic setting of the Bird’s Head Peninsula is cryptic, but the combination of uplift and tectonic activity shown by the earthquakes are consistent with ongoing oblique convergence between the Bird’s Head and the adjacent Pacific-Caroline plate. Over the past 2 Ma, plate motion between the Bird’s Head Peninsula and the Pacific-Caroline Plate has been accommodated by incipient south-dipping subduction along the Manokwari Trough to the north (with longer-lived subduction along the New Guinea Trench) and sinistral strike-slip movement along the Yapen fault whereas the Sorong Fault has been largely inactive.

Diversity in Pacific Slender-Toed Geckos, Nactus pelagicus Complex (Reptilia: Squamata), of New Guinea and Adjacent Islands

The diversity within the genus Nactus is slight in comparison to the other Australasian genus of narrow-toed geckos (Cyrtodactylus). The latter now has more than 290 species, with over half of these species newly described in the twenty-first century. In contrast, prior to this study, 12 Nactus species were recognized formally in the recent herpetological literature: three species in the Mascarene Islands, two in the Pacific Islands, three in Australia, and six in New Guinea and associated island groups. Three of these New Guinea species are miniature (snout–vent length ≤ 40 mm) species, and three are in the pelagicus complex; with the exception of the recently described N. kunan, all other New Guinean populations were labeled N. pelagicus even though they were known to be bisexual species and differed from the unisexual N. pelagicus of Oceania. Considering only bisexual New Guinean “pelagicus,” my morphological analyses recognize 24 distinct populations for which I provide new names or resurrected species names from synonymies. Of these 24, two species are extralimital (Morotai and Kei Islands). The sampling of Nactus in Indonesia Papua is very poor, with only one specimen from the base of the Vogelkop, two from south coast drainages, and more than a dozen from islands from the east coast of Cenderawasih Bay; the remainder derive from Papua New Guinea (PNG). The Indonesia Papua populations represent four species, two of which are shared with PNG. Papua New Guinea thus has a total of 20 species, varying from widespread species (e.g., north coast of main Papua to the Sepik-Ramu area) to a single locality in Madang or single islands in the Louisiade Archipelago. Most distributions of the PNG species match at least one other PNG anuran or reptile species. The greatest diversity of PNG species occurs in Madang Province to Huon Peninsula and the Milne Bay mainland with sympatry in both areas. The “pelagicus complex” of species is herein confirmed to be polyphyletic. In spite of its use in this study, its subsequent use should be restricted to the unisexual species and their parental species, of which only one (N. multicarinatus) is known. The preceding represents a subgroup within the larger clade of Australian and New Guinean bisexual species. For the present, I do not recommend a name for this group because a molecular phylogenetic analysis will be required to identify the cladogenesis of the Nactus species.

Seismotectonic model and probabilistic seismic hazard assessment for Papua New Guinea

Papua New Guinea (PNG) lies in a belt of intense tectonic activity that experiences high levels of seismicity. Although this seismicity poses significant risks to society, the Building Code of PNG and its underpinning seismic loading requirements have not been revised since 1982. This study aims to partially address this gap by updating the seismic zoning map on which the earthquake loading component of the building code is based. We performed a new probabilistic seismic hazard assessment for PNG using the OpenQuake software developed by the Global Earthquake Model Foundation (Pagani et al. in Seism Res Lett 85(3):692–702, 2014). Among other enhancements, for the first time together with background sources, individual fault sources are implemented to represent active major and microplate boundaries in the region to better constrain the earthquake-rate and seismic-source models. The seismic-source model also models intraslab, Wadati–Benioff zone seismicity in a more realistic way using a continuous slab volume to constrain the finite ruptures of such events. The results suggest a high level of hazard in the coastal areas of the Huon Peninsula and the New Britain–Bougainville region, and a relatively low level of hazard in the southwestern part of mainland PNG. In comparison with the seismic zonation map in the current design standard, it can be noted that the spatial distribution of seismic hazard used for building design does not match the bedrock hazard distribution of this study. In particular, the high seismic hazard of the Huon Peninsula in the revised assessment is not captured in the current building code of PNG.

Composition of browses consumed by Matschie's tree kangaroo (Dendrolagus matschiei) sampled from home ranges in Papua New Guinea.

Twenty-six samples (n = 24 spp.) of foods eaten, including ferns, shrubs, vines, orchids, herbaceous plants, and tree leaves, were collected from the Yopno, Uruwa, and Som Conservation Area at approximately 1,800 m altitude on the Huon Peninsula, Papua New Guinea (PNG). Samples were weighed fresh in the field and transported to the Lae National Herbarium in PNG for drying and confirmed identification, before transporting to the US for analysis of primary nutrient composition and minerals. Water content averaged 76 ± 10% (mean ± standard deviation); on a dry matter (DM) basis, foods averaged moderate protein (11 ± 5%), and soluble carbohydrate (27 ± 8%) content, along with exceptionally low starch (1 ± 1%) and crude fat (3 ± 2%) values, and moderate to high values in fiber fractions (neutral detergent fiber 52 ± 13%, acid detergent fiber 39 ± 10%, lignin 15 ± 6%). Calculated metabolizable energy content of native forages averaged 1.9 ± 0.3 Mcal/kg DM (ruminant model). Macromineral concentrations (DM basis) were not exceptional (calcium 1.1 ± 1.0%, phosphorus 0.2 ± 0.1%, magnesium 0.3 ± 0.2%, potassium 1.8 ± 0.9%, sodium 0.02 ± 0.02%), and select trace minerals were within anticipated ranges for herbivores (copper 12 ± 13 mg/kg, iron 48 ± 26 mg/kg, zinc 34 ± 18 mg/kg) with the exception of manganese (268 ± 225 mg/kg), which could be considered on the high end of dietary adequacy for most herbivores. These data provide useful information that can be used to adjust nutrient targets for dietary development and feeding management of captive populations of tree kangaroos.

Introduction The 41–43 species of birds-of-paradise (Paradisaeidae) (Beehler & Pratt 2016; Gill & Donsker 2019) are renowned for their exquisite beauty and plumage, and their diversity of extraordinary courtship displays (Gilliard 1969; Cooper & Forshaw 1977; Coates 1990; Frith & Frith 2009; Laman & Scholes 2012; Ligon et al. 2018). Males of the majority of birds-of-paradise (35–37 species) are presumed

Introduction The 41–43 species of birds-of-paradise (Paradisaeidae) (Beehler & Pratt 2016; Gill & Donsker 2019) are renowned for their exquisite beauty and plumage, and their diversity of extraordinary courtship displays (Gilliard 1969; Cooper & Forshaw 1977; Coates 1990; Frith & Frith 2009; Laman & Scholes 2012; Ligon et al. 2018). Males of the majority of birds-of-paradise (35–37 species) are presumed

Standing Together: New Guinean Villagers and the Pacific War in the Huon Peninsula

ABSTRACT This article analyses the struggle of civilians at the home front during the Pacific War (1941–45). The home front under analysis is the Huon Peninsula, a strategically important stretch of coastline on the New Guinea mainland. From late 1941 the Huon was a ‘borderland’ of overlapping colonial rule, partly occupied by Japanese forces, still patrolled by Australian coastwatchers, and serviced by (three) remaining German missionaries. From 1943 onward, large stretches were heavily bombed by Allied forces. Histories abound on battles and army units that moved through the region, memoirs of coastwatchers tell of survival and clandestine operations behind enemy lines, and mission histories focus on the missionaries’ sacrifice. In contrast, this article places New Guinea villagers as the central focus of the story by using rare documents written by village elders during and shortly after the war as the central documentation.

Nest, egg, incubation behaviour and vocalisations of the New Guinea endemic Black Pitohui Melanorectes nigrescens

The Black Pitohui Melanorectes nigrescens (Pachycephalidae) is endemic to mid-mountain forests in mainland New Guinea. Spectrograms of three different songs recorded in the Yopno Urawa Som Conservation Area (YUS CA), Huon Peninsula, Papua New Guinea, are presented. We describe the elevation and nest-site, height above the ground, structure and materials of a nest with an egg, discovered in the YUS CA. The colour and dimensions of the egg are documented. We present photographs of the nest-site, nest, and egg, and compare these with previously described eggs and a nest. We observed only the female Black Pitohui incubating the single-egg clutch. We compare the meagre information on pitohui breeding biology with that of Australian whistlers and shrike-thrushes.

Nest, egg, incubation behaviour and parental care in the Huon Bowerbird Amblyornis germana

The Huon Bowerbird Amblyornis germana , recently elevated to species status, is endemic to montane forests on the Huon Peninsula, Papua New Guinea. The polygynous males in the Yopno Urawa Som Conservation Area build distinctive maypole bowers. We document for the first time the nest, egg, incubation behaviour, and parental care of this species. Three of the five nests found were built in tree-fern crowns. Nest structure and the single-egg clutch were similar to those of MacGregor’s Bowerbird A. macgregoriae . Only the female Huon Bowerbird incubated. Mean length of incubation sessions was 30.9 minutes and the number of sessions daily was 18. Diurnal incubation constancy over a 12-hour day was 74%, compared with a mean of ~70% in six other members of the bowerbird family. The downy nestling resembled that of MacGregor’s Bowerbird. Vocalisations of a female Huon Bowerbird at a nest with a nestling are described and illustrated.

Nest, egg and parental care of a nestling in the New Guinean Lesser Ground-robin Amalocichla incerta

The Lesser Ground-robin Amalocichla incerta (Petroicidae) is endemic to mid-mountain forests in mainland New Guinea. Spectrograms of four songs are depicted. We describe the elevation and nest-site, height above the ground, structure and materials of three nests discovered in the Yopno Urawa Som Conservation Area, Huon Peninsula, Papua New Guinea, and compare these observations with two previously described nests. All three of the nests in the present study were 1.0–2.1 m above ground. The colour and dimensions of two eggs are described. At one nest with a feathered nestling estimated to be 13–16 days of age, a pair of adults disposed of faecal sacs and provisioned the nestling at a rate of 7.5 feeds per hour. The nestling period of 22 days was similar to that of two other montane New Guinean robins, but longer than that of most temperate and tropical Australian robins.

Critical Christianity: Translation and denominational conflict in Papua New Guinea by Courtney Handman

Reviewed by: Critical Christianity: Translation and denominational conflict in Papua New Guinea by Courtney Handman Joel Bradshaw Courtney Handman. 2015. Critical Christianity: Translation and denominational conflict in Papua New Guinea. Anthropology of Christianity, 16. Oakland: University of California Press. ISBN 9780520283763. $26.95. xiv + 307 pp. Softcover. It all started in 1956, when SIL's Ernie and Marjorie Richert arrived at the Kipu Lutheran station in the Waria River valley in southern Morobe Province, Papua New Guinea (PNG), and began to translate the New Testament and promote literacy in a newly unified language based on the central Kipu dialect that came to be called Guhu-Samane (GS). The translation was finished in 1974, and they returned to the United States in 1976, having planted the seeds for a revival in 1977 that culminated in two breakaway denominations, the New Life Bible Church and the Reformed Gospel Church, which destroyed the longtime Lutheran monopoly in the area. It was a tiny, distant echo of the role of vernacular languages in the Protestant Reformation. Language plays a major role in this story. During her 16 months of fieldwork between 2005 and 2007, Courtney Handman (H) apparently learned the language well enough to delve into such issues as the ethnogenesis of the language-defined community, the usage and mixing of languages in religious settings, and some of the grammatical inadequacies in the Guhu-Samane [End Page 147] translation of the New Testament. This book contains a lot more linguistic analysis than its title might suggest, although it is scattered throughout the discussion and not very easy to extract. Part One (3 chapters) focuses on the role of the missions, Part Two (2 chapters) on Christian village life, and Part Three (3 chapters) on denominational conflict. Chapter 1, "Sacred Speakers or Sacred Groups" (41–63), describes the approach of the colonial Lutheran mission in New Guinea. The Waria River valley was pacified before 1914, mostly to protect gold prospectors (93), and therefore was evangelized early as well. The Lutherans focused their efforts on groups, not individuals, and built large-scale church organizations using regional lingua francas. In Papuan-speaking areas of Morobe Province, the Lutherans adopted Kâte, a Trans–New Guinea family language originally spoken on the Huon Peninsula just inland of Jabêm, an Oceanic language adopted for Austronesian-speaking areas (47). Chapter 2, "Linguistic Locality and the Anti-Institutionalism of Evangelical Christianity" (64–89), presents the SIL policy "that a tribe be evangelized in its own language" (46; emphasis in original), in the belief that ideas presented in one's "heart language" more effectively reach one's innermost self (45). I remain very skeptical of that belief, because it seems to assume that every innermost self is essentially monolingual, and that every human can be assigned to one language-defined tribe. My impression is that in traditional New Guinea—as in many other thoroughly multilingual regions—language, culture, and community boundaries rarely coincide. Nowadays, however, "people speaking mutually intelligible varieties of speech constitute a single market for vernacular literacy and Bible-translation efforts" (Bradshaw 2001:299). H makes a similar point (170–171): While it is impossible to get a sense of precolonial language ideologies, it is unlikely that something approaching German Romantic linguistic identity was a particularly important component of social life in the past. … Guhu-Samane communities were more likely multiethnic and multilingual, with fluid boundaries and overlapping cultural traditions. Chapter 3, "Translating Locality" (90–119), chronicles how Ernie Richert managed to create a newly language-defined community under a new language name, Guhu-Samane, meaning 'many men's houses', the men's house being the center of traditional initiation rituals, called poro. The German Lutheran missionaries attempted to suppress all such heathen rituals, which they called Balumskulten (from the Jabêm word balôm 'ghost, spirit, bullroarer', equivalent to poro) and considered their main spiritual rivals (149). Richert created his new ethnolinguistic entity by recruiting men who represented each of the dialects (which differ mostly in lexicon and the articulation of a few phonemes), by conducting literacy seminars just among speakers of GS dialects, by publishing a vernacular language newspaper, and by collecting poro guhu artifacts that had...

Age and setting of Permian Slide Mountain terrane ophiolitic ultramafic-mafic complexes in the Yukon: Implications for late Paleozoic-early Mesozoic tectonic models in the northern Canadian Cordillera

The Yukon Tanana (YTT) and Slide Mountain terranes (SMT) of the Cordillera in Canada and Alaska were interpreted in terms of opening and closing of a Late Devonian-Permian Japan Sea-style backarc basin behind a continental arc built upon YTT, which rifted from Laurentia during the Famennian-early Mississippian. Formation of Famennian transitional oceanic lithosphere supports rifting, but a combination of existing and new data on the setting and age of SMT ophiolites do not support the Japan Sea model.The studied Clinton Creek and Midnight Dome complexes represent suprasubduction zone ophiolites formed at ca. 265 Ma, consistent with analyses of other SMT ophiolites. Ultramafic rocks dominate most ophiolites. They lack sheeted dikes and contain relatively minor volumes of mafic plutonic and volcanic rocks, suggesting they formed in oceanic core complexes characterised by slow spreading and low magma productivity. The Permian ophiolites formed during or immediately after eclogite formation in YTT, coeval with or immediately preceding emplacement of orogenic peridotites into YTT due to hyperextension. Several tectonic scenarios are discussed. We propose that YTT is a composite terrane comprising a continental block and an oceanic arc-backarc complex with the latter obducted onto the former during the middle Permian-early Triassic Klondike orogeny. Obduction may have come from the west or east, but east-directed obduction is most consistent with geological constraints. Obduction was followed by initiation of west-dipping subduction east of the composite YTT; slab roll back causing extension in the composite upper plate, leading to exhumation of orogenic peridotites. Tectonic relationships show many analogies to the collision between Australia and the New Britain arc, in which collision in the Huon Peninsula of New Guinea is contemporaneous with extension in Australian crust in the adjacent Woodlark basin. Syn-orogenic Permian Klondike calc-alkaline magmatism is attributed to extension in a Woodlark basin-like setting rather than a representing a continental arc.

Limited support for the “abundant centre” hypothesis in birds along a tropical elevational gradient: implications for the fate of lowland tropical species in a warmer future

AbstractAimSince Darwin, ecologists have assumed that species tend to be abundant in the centre of their geographic distributions and rare at their range edges. We test two predictions of this abundant centre hypothesis: (a) that species are common in the centre of their range and rare at the edges and (b) that empirical distributions along environmental gradients are well described by symmetric bell‐shaped curves.LocationA reef‐to‐ridgetop elevational gradient in the Yopno–Urawa–Som Conservation Area (YUS CA) on the Huon Peninsula in Papua New Guinea.TaxonBirds.MethodsWe use mist net capture rates to quantify species’ abundances as a function of range position, then fit a series of models with different shapes, including symmetric curves, to species’ empirical abundance distributions.ResultsSpecies peak abundances were located near species’ low elevation range edges, high elevation range edges and everywhere in between. Real abundance distributions were fit well by symmetric curves in fewer than half of the species we analysed. Most lowland species have high abundances at their low elevation margin near sea level.Main conclusionsWe find only limited support for the abundant centre hypothesis. Most lowland species appear to currently occupy a “truncated” realized niche, suggesting that they will be able to persist at low elevations even as temperatures increase and that lowland biotic attrition is unlikely. In addition to analyses, we present (a) a full species list for the 256 species recorded thus far within the YUS CA, with elevational limits for all forest species and (b) the raw data from our extensive mist net surveys. This information provides valuable baseline data that can be used by future biodiversity scientists to evaluate the changes in the YUS avifauna and will be generally useful to biodiversity scientists studying tropical elevational gradients.

Uranium uptake history, open-system behaviour and uranium-series ages of fossil Tridacna gigas from Huon Peninsula, Papua New Guinea

Molluscs incorporate negligible uranium into their skeleton while they are living, with any uranium uptake occurring post-mortem. As such, closed-system U-series dating of molluscs is unlikely to provide reliable age constraints for marine deposits. Even the application of open-system U-series modelling is challenging, because uranium uptake and loss histories can affect time-integrated uranium distributions and are difficult to constrain. We investigate the chemical and isotopic distribution of uranium in fossil Tridacna gigas (giant clams) from Marine Isotope Stage (MIS) 5e (128–116ka) and MIS 11 (424–374ka) reefs at Huon Peninsula in Papua New Guinea. The large size of the clams enables detailed chemical and isotopic mapping of uranium using LA-ICPMS and LA-MC-ICPMS techniques. Within each fossil Tridacna specimen, marked differences in uranium concentrations are observed across the three Tridacna growth zones (outer, inner, hinge), with the outer and hinge zones being relatively enriched. In MIS 5e and MIS 11 Tridacna, the outer and hinge zones contain approximately 1ppm and 5ppm uranium respectively. In addition to uptake of uranium, loss of uranium appears prevalent, especially in the MIS 11 specimens. The effect of uranium loss is to elevate measured [230Th/238U] values with little effect on [234U/238U] values. Closed-system age estimates are on average 50% too young for the MIS 5e Tridacna, and 25% too young for the MIS 11 Tridacna. A complex, multi-stage uptake and loss history is interpreted for the fossil Tridacna and we demonstrate that they cannot provide independent, reliable geochronological controls on the timing of past reef growth at Huon Peninsula.

A biomineralization study of the Indo-Pacific giant clam Tridacna gigas

The giant clam, Tridacna gigas, is an important faunal component of reef ecosystems of the Indo-Pacific region. In addition to its ecological role, shells of this bivalve species are useful bioarchives for past climate and environmental reconstructions. However, the biomineralization processes involved in shell aragonite deposition are insufficiently understood. Here, we present a study of the shell microstructure of modern specimens from Palm Island, Great Barrier Reef (GBR), Australia, and Huon Peninsula, Papua New Guinea (PNG), using a combination of petrography, scanning electron microscopy, electron backscatter diffraction, Raman spectroscopy and stable carbon isotope ratios. Daily growth increments were recognizable in all specimens through ontogeny, and counting these growth lines provides a robust specimen age estimate. For the internal layers, paired increments of organized aragonitic needles and compact, oblong crystals were recognized in a specimen from PNG, whereas specimens from GBR were composed of shield-like crystals that were not definable at the microscale. The combination of nutrient availability, rainfall and solar irradiance are likely to be the most significant factors controlling shell growth and may explain the observed differences in microstructure. The external layer, identical in all specimens, was composed of dendritic microstructure that is significantly enriched in 13C compared to the internal layer, suggesting different metabolic controls on layer deposition. We propose that the mineralization of the internal and external layers is independent from each other and associated with the activity of specific mantles. Future studies using T. gigas shells as bioarchives should consider the microstructure as it reflects the environment in which the individual lived and the differences in mineralization pathways of internal and external layers.

Probabilistic seismic hazard map of Papua New Guinea

We developed a probabilistic seismic hazard map of Papua New Guinea expressed in terms of peak ground acceleration with return period of 475 years. The calculations were performed for bedrock site conditions (Vs30 = 760 m/s). A logic-tree framework was applied to include epistemic uncertainty in the seismic source as well as ground motion modelling processes. Two seismic source models were developed using area source zones and smoothed seismicity, respectively. Based on available geological and seismological data, defined seismic sources were classified into four different tectonic environments. For each of the tectonic regimes three ground motion prediction equations were selected and used to estimate the ground motions at a grid of sites with spacing of 0.1° in latitude and longitude. Results show a high level of hazard in the coastal areas of Huon Peninsula and New Britain–Bougainville regions and a relatively low level of hazard in the southwestern part of Papua New Guinea. Seismic hazard disaggregation results show that in the Huon Peninsula region high seismic hazard is caused by modelled frequent moderate to large earthquakes occurring on the Ramu-Markham Fault Zone. In the New Britain–Bougainville region the distance to the subduction zone associated with the New Britain Trench mainly controls the calculated level of hazard. It is also shown that the estimated level of peak ground acceleration is very sensitive to the selection of ground motion prediction equations. Overall our results differ significantly from those of previous studies, and we surmise that these differences are due to our use of modern ground motion prediction equations and earthquake source information.

ENSO variability during MIS 11 (424–374 ka) from Tridacna gigas at Huon Peninsula, Papua New Guinea

Marine Isotope Stage 11 (MIS 11) from ∼424,000 to 374,000 yrs ago included one of the longest and warmest interglacials of the last 800,000 yrs, and is a potential analogue for the Holocene due to the similarity of Earth's orbital configuration at this time. The question of how the El Niño–Southern Oscillation (ENSO) responds to warmer background climates remains unanswered and is critical to understand how the ENSO system will evolve under the influence of anthropogenic warming. In this study, we present a 35 yr-long, high-resolution record of MIS 11 climate variability in the Western Pacific Warm Pool (WPWP) based on coupled measurements of skeletal Mg/Ca and δ18O in giant Tridacna gigas clams from Huon Peninsula, Papua New Guinea. The δ18O of modern T. gigas from Huon Peninsula faithfully records sea surface temperature, salinity/rainfall and regional ENSO variability. The geochemical integrity of the MIS 11 T. gigas for recording paleo-ENSO events was established through trace element screening, detailed petrography and SEM analysis. The fossil T. gigas δ18O record indicates that ENSO was operating during a 35-yr window in MIS 11, but with fewer events of shorter duration compared to those experienced during the last 100 yrs. The suppressed ENSO variability in the MIS 11 T. gigas record corresponds with a reduction in the amplitude of the average annual cycle in δ18O values. Distinctive changes in local insolation seasonality, and T. gigas δ18O, brought about by changes in Earth's orbit, provide an additional geochronological constraint on the timing of reef growth at Huon Peninsula to around 402 ka during the MIS 11.3 sub-stage (∼424–395 ka).

Comparative mtDNA analyses of three sympatric macropodids from a conservation area on the Huon Peninsula, Papua New Guinea

Matschie’s tree kangaroo (Dendrolagus matschiei), New Guinea pademelon (Thylogale browni), and small dorcopsis (Dorcopsulus vanheurni) are sympatric macropodid taxa, of conservation concern, that inhabit the Yopno–Urawa–Som (YUS) Conservation Area on the Huon Peninsula, Papua New Guinea. We sequenced three partial mitochondrial DNA (mtDNA) genes from the three taxa to (i) investigate network structure; and (ii) identify conservation units within the YUS Conservation Area. All three taxa displayed a similar pattern in the spatial distribution of their mtDNA haplotypes and the Urawa and Som rivers on the Huon may have acted as a barrier to maternal gene flow. Matschie’s tree kangaroo and New Guinea pademelon within the YUS Conservation Area should be managed as single conservation units because mtDNA nucleotides were not fixed for a given geographic area. However, two distinct conservation units were identified for small dorcopsis from the two different mountain ranges within the YUS Conservation Area.

ENSO reconstructions over the past 60 ka using giant clams (Tridacna sp.) from Papua New Guinea

AbstractWe present 12 seasonally resolved δ18O profiles of giant clams (Tridacna sp.) from the Huon Peninsula, Papua New Guinea, spanning discrete periods of time (9–38 years) over the past 60 ka. The interannual anomaly time series of these shells are used to reconstruct interannual variability which can predominantly be attributed in the modern climate to the El Niño–Southern Oscillation (ENSO) in this region. We have found a significant reduction in interannual δ18O variance during the early Holocene, whereas during Marine Isotope Stage 3 there were at least some periods with variance not significantly different to the twentieth century. We show that ENSO variability seen during the late twentieth century is rare but not unprecedented within glacial climates.