Samoan Islands Research Articles

Conceptualizing a Mentoring Framework for Samoan and Pacific Island Teachers

As teachers continue to leave the teaching profession Ministries of Education continue to find ways to address this problem. Research indicated mentoring as an effective approach to support novice teachers (Stock & Duncan, 2010) resulting in many countries developing mentoring programs. Research found that teacher mentoring programs positively impact teacher retention (Ingersoll & Strong, 2011), however Tomlinson (2019) argued that there is lack of structure to guide mentors within many mentoring programs. Knight et al. (2014) showed some concerns regarding the practice of those individuals who are involved in mentoring of novice teachers and went on to emphasize the importance of identifying and defining mentoring strategies. Moreover, Will (2017 cited by Tomlinson 2019) stressed the value of quality mentoring and the need for mentors to establish a defined set of mentoring strategies for effective facilitation of professional development of new teachers. In a similar vein, Schwan, Wold, Moon, Neville, and Outka (2020) citing Breaux and Wong, (2003); Callahan (2016); Darling-Hammond (2012; White & Mason, 2003) also stressed the importance of developing organized and meaningful mentoring programs to address the issue of teacher attrition. While numerous studies have been conducted on mentoring programs elsewhere however there is dearth research on a structured and meaningful mentoring program within the Pacific including Samoa. There is a great need to develop a mentoring program within the Samoan context as this can develop mentors’ knowledge and understanding in supporting teachers and to address the teacher attrition problem.

How Samoan Workers under Colonial Regimes Enlarged their World

The Samoan Islands have never really fallen off the world’s radar since it became the site of an ‘almost war’ between the Great Powers of the United States, Britain, and Germany in 1889. That war was averted by the intervention of a hurricane that sent to the bottom three U.S. and three German warships and cost many lives. A decade later, the Samoan Islands were carved up between Germany and the United States, with Britain withdrawing to tend to other imperial interests in the Pacific and Africa. In 1914, World War I saw Germany evicted from the western Samoan islands in favor of New Zealand and a League of Nations mandate, while the United States continued to enjoy the protective naval harbor in American Samoa to the east. Things went relatively quiet between the wars, though both parts of the Samoas were experiencing independence movements. And Margaret Mead was sowing the seeds of her most famous work of social science, Coming of Age in Samoa, researched in the American Samoa islands. Western Samoa burst back into prominence in 1962 as the Pacific’s first independent island nation, enjoying thereafter a reputation as one of the Pacific’s most stable and relatively prosperous states. Wrapped in the embrace of the U.S. Navy, American Samoa sailed serenely on.

A complete COI library of Samoan butterflies reveals layers of endemic diversity on oceanic islands

AbstractWe investigated the entire butterfly fauna of the Samoan Archipelago (Pacific Ocean) by combining COI barcode sequences for specimens from these islands with those available in repositories at larger biogeographic scale. Haplotype networks and a generalized mixed Yule‐coalescent (GMYC) model were applied to identify evolutionary significant units (ESUs). The ESUs from Samoan islands were compared with ESUs of the same or sister taxa regionally and worldwide to explore the level of endemicity and of congruence between established taxonomy and COI barcodes. The level of ESUs endemicity was similar to that shown by species and subspecies. Australia was the most frequent origin for Samoan lineages, followed by Orient‐Asia. When comparing the agreement and mismatch between established taxonomy and ESUs between the Australia‐Oceania region and Europe and North America, the COI molecular marker revealed a similar performance in taxonomic identification. Despite this overall convergent pattern, the degree of mtDNA divergence and the analysis of functional traits suggested that the mechanisms producing patterns of genetic differentiation in temperate butterflies over ancient continental lands differ to those occurring across a vast ocean into geologically young islands. Mechanisms on Samoan islands include relatively recent and exceptional oceanic dispersal, possibly followed by repeated extinction events. In the Australia‐Oceania region we found a similar fraction of species showing introgression with the maintenance of phenotypic differences as it occurs on the mainland, but the phenomenon was limited to sectors of each species distribution area. Regular gene flow among the Samoan islands seems to prevent allopatric speciation within the archipelago.

Salmonella enterica Serovar Typhi on an Island: No H58, No Multidrug Resistance, but for How Long?

Little genomic data is available for typhoid fever from island nations, though the disease has a moderately high burden there. Sikorski et al. (M. J. Sikorski, T. H. Hazen, S. N. Desai, S. Nimarota-Brown, et al., mBio 13:e01920-22, 2022, https://doi.org/10.1128/mbio.01920-22) studied 306 Salmonella enterica serovar Typhi genomes from the Samoan Islands collected during 1983 to 2020 and reported dominance of a rare genotype, 2.5.4, and no H58 (genotype 4.3.1). They found pansusceptibility of all isolates to three first lines of antimicrobial agents (ampicillin, chloramphenicol, and cotrimoxazole). This commentary evaluates the importance of these findings for the Samoan Islands and how they can help the global typhoid community. The microbial community in the environment and human gut could have played a role in the lack of antimicrobial resistance (AMR). However, drug-resistant strains may arrive soon at the island, as their international spread is common. Further investigation would help the global typhoid community to better understand the evolution of an isolated pathogen community and the effect of vaccination there.

Development of a Risk-Factor Questionnaire for the Infant Ear and Hearing Program in Samoa.

Congenital hearing loss is the most common sensory disorder present at birth. While universal newborn hearing screening is the standard for most high-income countries, alternative models are under consideration for most low and middle-income countries. The Pacific Islands have among the highest rates of paediatric ear disease and deafness in the world, and an interim Infant Ear and Hearing Program is currently being developed for the Polynesian nation of Samoa. The inclusion of a routine risk-factor questionnaire for childhood deafness in the Infant Ear and Hearing Program package is a feasible alternative for well-baby clinics in Samoa. The World Health Organisation advocates that all member states should implement newborn and infant hearing screening. This includes a risk-factor questionnaire developed from the joint committee on infant hearing risk-factors, as well as additional risk-factors unique to low and middle income countries. The present paper examines all known risk-factors for childhood deafness to develop an appropriate and evidence-based questionnaire for inclusion in the Samoan Child Health Book and Infant Ear and Hearing Program package. From a starting point of 19 risk-factors, 11 risk-factors were included with no changes; 5 risk-factors were modified to align with current health service availability in Samoa; 2 risk-factors were excluded due to cultural inappropriateness and irrelevance for Samoa; and 1 risk-factor was added for our Samoan and Pacific Island context. There are 17 items on the final risk-factor questionnaire for childhood deafness developed for Samoa. The Infant Ear and Hearing Program package will also include ear examinations and monitoring of hearing developmental milestones. The risk-factor questionnaire will be reviewed again in 5years' time for the next edition of the Samoan Child Health Book.

The impact of primary processes and secondary alteration on the stable isotope composition of ocean island basalts

Molybdenum and uranium are redox sensitive elements that experience isotope fractionation in the Earth-surface environment. Recent studies have explored the transfer of these fractionated signals in subduction zones to arc magmas, but less is known about the full variation of these isotopic tracers in the mantle, particularly domains of the mantle that may feed hot spots. Here, we present Mo and U isotope data for lava samples from Pitcairn, the Samoan Islands, and St. Helena, representing classic localities for the EM-1 (enriched mantle 1), EM-2 (enriched mantle 2) and HIMU (high μ, where μ is 238U/204Pb) endmembers.Mo and U isotope compositions are highly variable for each location, and the range of variation largely overlaps between the three localities. However, some of this variation may be attributable to chemical weathering and low-temperature alteration effects, as revealed by 234U/238U disequilibrium, also reported here; many samples, especially from Pitcairn, have a 234U deficit, while a few others have a 234U excess. Samples with the greatest 234U deficit tend to have the highest Ce/Mo for a given locality and samples with the lowest δ98Mo typically show considerable 234U/238U disequilibrium, suggesting that Mo was leached during weathering with preferential loss of heavy isotopes.Of the samples with 234U and 238U activity in equilibrium from the three localities, most have δ98Mo values lower than the published average for MORB, but they have δ238U values within uncertainty of MORB. In contrast, two Samoan samples have δ98Mo values similar to MORB but have isotopically light δ238U. While the low δ98Mo seen in many samples could be attributable to the incorporation of subducted sediments into the plume sources, such sediment would have needed to be deposited under oxic oceanographic conditions that were not prevalent until the Neoproterozoic; in contrast, radiogenic isotope compositions tend to point towards a much greater age of recycled components in the plume sources. Instead, we consider the most likely cause of the light Mo isotope compositions to be incorporation into the source region of ancient subducted ocean crust that experienced Mo isotope fractionation during devolatilization, which favored loss of the heavy isotopes, as has been proposed in several recent studies. This is in line with models for the origin of the EM-1 and HIMU source, along with a portion of the Samoan source. The two Samoan samples with isotopically light U, but MORB-like δ98Mo, may reflect influence of a distinct pool of mid-Proterozoic recycled ocean crust.

Extreme isotopic heterogeneity in Samoan clinopyroxenes constrains sediment recycling

Lavas erupted at hotspot volcanoes provide evidence of mantle heterogeneity. Samoan Island lavas with high 87Sr/86Sr (>0.706) typify a mantle source incorporating ancient subducted sediments. To further characterize this source, we target a single high 87Sr/86Sr lava from Savai’i Island, Samoa for detailed analyses of 87Sr/86Sr and 143Nd/144Nd isotopes and major and trace elements on individual magmatic clinopyroxenes. We show the clinopyroxenes exhibit a remarkable range of 87Sr/86Sr—including the highest observed in an oceanic hotspot lava—encompassing ~30% of the oceanic mantle’s total variability. These new isotopic data, data from other Samoan lavas, and magma mixing calculations are consistent with clinopyroxene 87Sr/86Sr variability resulting from magma mixing between a high silica, high 87Sr/86Sr (up to 0.7316) magma, and a low silica, low 87Sr/86Sr magma. Results provide insight into the composition of magmas derived from a sediment-infiltrated mantle source and document the fate of sediment recycled into Earth’s mantle.

PENGARUH SUBTITUSI TEPUNG TERIGU DENGAN TEPUNG SUKUN (Artocarpus altilis) TERHADAP MUTU KIMIA KUE SEMPRONG

Breadfruit (Artocarpus altilis) is one of the main fruit producing plants of the Moraceae family. This plant has long been cultivated by the people of Indonesia and even in several countries in the Pacific region such as Fiji, Tahiti, the Samoan Islands, and Hawaii, breadfruit has been used as a traditional staple food. The consumption of breadfruit is generally still limited as a snack and a vegetable and as an alternative food source, breadfruit is proven to have a high nutritional content. The purpose of this study was to determine the effect of substitution of wheat flour with breadfruit (Artocarpus altilis) on the chemical quality of semprong cake or egg roll. The treatment design in this research on the substitution of wheat flour with breadfruit flour (Artocarpus altilis) on the chemical quality of semprong cakes, namely: P0 (100 grams of wheat flour), P1 (75 grams of wheat flour + 25 grams of breadfruit flour), P2 (50 grams of wheat flour + 50 grams of breadfruit flour), P3 (75 grams of wheat flour + 25 grams of breadfruit flour), and P4 (100 grams of breadfruit flour). The experimental design used was a randomized randomized design (CRD) with 5 treatments and 4 replications. The results of the proximate analysis test included moisture, ash, fat, protein and carbohydrate content, with an average value of 3.50% water content, 1.07% ash content, 26.97% fat content, 4.21% protein content, and 63.88% carbohydrate content.

Xylocopa sonorina Smith, 1874 from Vancouver, British Columbia, Canada (Hymenoptera: Apidae, Xylocopinae) with comments on its taxonomy.

BackgroundOnly one species of large carpenter bee, Xylocopa virginica (Linnaeus, 1771), has been recorded from Canada, albeit restricted to southern Ontario and Quebec. However, a single female specimen identified by Hurd in 1954 as X. varipuncta Patton, 1879 from British Columbia is in the C.A. Triplehorn Insect Collection at The Ohio State University (OSUC), suggesting that this species was accidentally introduced into coastal western Canada. As wood-nesters, many large carpenter bees are likely capable of expanding their range great distances by natural and unnatural transport methods while nesting inside suitable substrates, the presumed mode of transport into western Canada, and likely elsewhere. The ease at which the nests are transported has likely contributed to the nomenclatural and distributional ambiguity surrounding this species due to morphological similarities of specimens from North America, Hawaii, and several South Pacific islands.New informationBy comparing DNA barcodes of specimens from the western United States to specimens from Hawaii, we confirm the early opinion of P.H. Timberlake (Timberlake 1922) that specimens long established on the Hawaiian Islands are the same X. varipuncta from continental North America. Furthermore, these DNA barcode sequences also match those of specimens identified as X. sonorina Smith, 1874 from the French Polynesian and Samoan Islands, thus fully supporting the opinion of Groom et al. (2017) that all are likely conspecific. As X. sonorina, a species described from and likely introduced to Hawaii is the oldest name available, X. varipuncta is here placed into synonymy. Additional research will be needed to trace the timing and pathway of introduction and establishment of X. sonorina; it is presumed that the species is native to the southwestern United States but has been established in Hawaii since the mid-1800s. It is also established in French Polynesia, the Samoan Islands, and likely other south Pacific islands, with additional records of occurrence from Java, New Zealand, and now Canada.

Evolutionary history of modern Samoans

Archaeological studies estimate the initial settlement of Samoa at 2,750 to 2,880 y ago and identify only limited settlement and human modification to the landscape until about 1,000 to 1,500 y ago. At this point, a complex history of migration is thought to have begun with the arrival of people sharing ancestry with Near Oceanic groups (i.e., Austronesian-speaking and Papuan-speaking groups), and was then followed by the arrival of non-Oceanic groups during European colonialism. However, the specifics of this peopling are not entirely clear from the archaeological and anthropological records, and is therefore a focus of continued debate. To shed additional light on the Samoan population history that this peopling reflects, we employ a population genetic approach to analyze 1,197 Samoan high-coverage whole genomes. We identify population splits between the major Samoan islands and detect asymmetrical gene flow to the capital city. We also find an extreme bottleneck until about 1,000 y ago, which is followed by distinct expansions across the islands and subsequent bottlenecks consistent with European colonization. These results provide for an increased understanding of Samoan population history and the dynamics that inform it, and also demonstrate how rapid demographic processes can shape modern genomes.

Twenty-six new species of Hoploscopa (Lepidoptera, Crambidae) from South-East Asia revealed by morphology and DNA barcoding.

Hoploscopa Meyrick (Lepidoptera: Crambidae) is a fern-feeding genus found in montane areas of South-East Asia and Melanesia, eastwards up to the Samoan Islands. It includes sixteen described species, with at least 70 further undescribed species known from scientific collections. An iterative approach including morphological and molecular characters was used in order to explore the diversity of Hoploscopa. The hitherto described species are revised, and descriptions authored by T. Léger and M. Nuss are provided for an additional 26 new species: H. agtuuganonensissp. nov., H. albipunctasp. nov., H. albomaculatasp. nov., H. anacanthasp. nov., H. boletasp. nov., H. cynodontasp. nov., H. danaoensissp. nov., H. gombongisp. nov., H. gracilissp. nov., H. ignitamaculaesp. nov., H. isarogensissp. nov., H. jubatasp. nov., H. kelamasp. nov., H. kinabaluensissp. nov., H. mallyisp. nov., H. marijoweissaesp. nov., H. matheaesp. nov., H. niveofasciasp. nov., H. pangrangoensissp. nov., H. parvimaculasp. nov., H. pseudometacrossasp. nov., H. sepanggisp. nov., H. sumatrensissp. nov., H. titikasp. nov., H. tonsepisp. nov., H. ypsilonsp. nov. Using a protocol specific for the amplification of DNA from old museum specimens, we recovered 101 COI barcodes for all but one of the newly described species, with 76 being barcode compliant (>487 bp). Species delimitation analyses suggest cryptic diversity, with six cases reflecting allopatric divergence, and two further cases found in sympatry.

Sulfur isotope characterization of primordial and recycled sources feeding the Samoan mantle plume

Understanding present-day mantle heterogeneity is key to understanding the geochemical evolution of our planet. The Samoan islands are the type locality for the Enriched Mantle (II) reservoir that is thought to be produced from the subduction and recycling of marine sediment from upper continental crust. In addition to hosting extreme radiogenic isotope compositions from the EM II reservoir, Samoa also exhibits contributions from other mantle reservoirs in a dilute form including the EM (I) (recycled continental material), HIMU (recycled oceanic crust), and DMM (depleted upper mantle) mantle reservoirs. The plume system feeding the Samoan islands sits above a seismically imaged Large Low Shear Velocity Province (LLSVP) and an Ultra-Low Velocity Zone (ULVZ) that is thought to contribute, in addition to recycled components, the recently discovered early-formed (primordial) components with negative μ182W and high 3He/4He. Recent work measuring sulfur isotopes in ocean island basalts has established that recycled oceanic and continental crust host unique S-isotope compositions that can be identified at various hotspot localities. Here we document previously unknown relationships between Δ33S and radiogenic tungsten, helium and lead isotopes from 7 Samoan basalts (from the islands of Ofu, Vailulu'u and Malumalu) that suggest mixing between several endmembers. One, a HIMU influence that has slight positive Δ33S and positive δ34S; another, related to EM II that has near zero Δ33S and positive δ34S; a third, which is primordial with negative μ182W, high 3He/4He, that has Δ33S=0 and negative δ34S. From this, we conclude that the indistinguishable Δ33S of the primordial endmember from that of the convective mantle indicates that sulfur isotopes were homogenized early in Earth's history. The Vailulu'u sample with HIMU characteristics, carries a small but resolvable Δ33S that allows, but does not require mass-independent Archean Δ33S to shift the Δ33S. The observed correlations involving Δ33S support arguments linking Pb, He, and W geochemistry to a deep mantle process and places constraints on questions related to the sources of mantle geochemical heterogeneity.

Understanding the preferences of rural communities for adaptation to 21st-century sea-level rise: A case study from the Samoan islands

This paper explores the perceived adaptation preference of rural island communities in addressing future climate change risks, particularly those concerning sea-level rise. The research explores the role of culture and local politics, and differences among various age and gender groups within the community regarding preferred adaptation pathways for coping with the impacts of future sea-level rise. A participatory action approach, in the form of a community workshop, was employed, which separated participants into community identified groupings. Differences in community groups' adaptation preferences emerged, though the range of adaptation measures considered were limited, probably due to the participants’ limited exposure to adaptation mechanisms in their immediate surroundings. Overall, the communities surveyed tended to be conservative, especially in their attitudes towards western adaptation solutions developed in non-island contexts.

Pacific Lithosphere Evolution Inferred from Aitutaki Mantle Xenoliths

Abstract Highly siderophile element (HSE: Os, Ir, Ru, Pt, Pd, Re), major and trace element abundances, and 187Re–187Os systematics are reported for xenoliths and lavas from Aitutaki (Cook Islands), to investigate the composition of Pacific lithosphere. The xenolith suite comprises spinel-bearing lherzolites, dunite, and harzburgite, along with olivine websterite and pyroxenite. The xenoliths are hosted within nephelinite and alkali basalt volcanic rocks (187Os/188Os ∼0·1363 ± 13; 2SD; ΣHSE = 3–4 ppb). The volcanic host rocks are low-degree (2–5%) partial melts from the garnet stability field and an enriched mantle (EM) source. Pyroxenites have similar HSE abundances and Os isotope compositions (Al2O3 = 5·7–8·3 wt %; ΣHSE = 2–4 ppb; 187Os/187Os = 0·1263–0·1469) to the lavas. The pyroxenite and olivine websterite xenoliths directly formed from—or experienced extensive melt–rock interaction with—melts similar in composition to the volcanic rocks that host the xenoliths. Conversely, the Aitutaki lherzolites, harzburgites and dunites are similar in composition to abyssal peridotites with respect to their 187Os/188Os ratios (0·1264 ± 82), total HSE abundances (ΣHSE = 8–28 ppb) and major element abundances, forsterite contents (Fo89·9±1·2), and estimated extents of melt depletion (<10 to >15%). These peridotites are interpreted to sample relatively shallow Pacific mantle lithosphere that experienced limited melt–rock reaction and melting during ridge processes at ∼90 Ma. A survey of maximum time of rhenium depletion ages of Pacific mantle lithosphere from the Cook (Aitutaki ∼1·5 Ga), Austral (Tubuai’i ∼1·8 Ga), Samoan (Savai’i ∼1·5 Ga) and Hawaiian (Oa’hu ∼2 Ga) island groups shows that Mesoproterozoic to Neoproterozoic depletion ages are preserved in the xenolith suites. The variable timing and extent of mantle depletion preserved by the peridotites is, in some instances, superimposed by extensive and recent melt depletion as well as melt refertilization. Collectively, Pacific Ocean island mantle xenolith suites have similar distributions and variations of 187Os/188Os and HSE abundances to global abyssal peridotites. These observations indicate that Pacific mantle lithosphere is typical of oceanic lithosphere in general, and that this lithosphere is composed of peridotites that have experienced both recent melt depletion at ridges and prior and sometimes extensive melt depletion across several Wilson cycles spanning periods in excess of two billion years.

Tropical Cyclone Amos (2016) Forecasting Challenges: A Model’s Perspective

ABSTRACT The tropical cyclone (TC) named Amos (2016) that impacted the Samoan Islands on 23 April 2016 was a particularly difficult storm to forecast. Both the intensity changes and the track of Amos represent a significant challenge for forecasters and this is briefly summarized in this report. Model forecasts initially indicated that the cyclone would track south of the Samoan Islands. However, the forecasts generally changed to a direct hit over Samoa as a Category 4 storm at approximately 0000 UTC 24 April based on model cycles initialized at 0000 UTC 23 April. TC Amos’ central pressure dropped from 983 hPa to 957 hPa between 0000 UTC 21 April and 0000 UTC 23 April. The models did not pick up on this rapid intensification until the intensification had already begun around 0000 UTC 21 April. The models also struggled to capture the rapid weakening of TC Amos due to vertical wind shear that began 0000 UTC 24 April as the cyclone continued to move north of the islands. Because of the initially ominous track forecasts for TC Amos to hit land, preparations for a Category 3 or Category 4 cyclone were underway in the Samoan islands and the population prepared for the worst. After the center of the storm moved north of the islands as a weaker storm than anticipated, the residents of the Samoan Islands were both surprised and relieved that the cyclone only gave a “glancing blow” to the islands and that the impacts were not as bad as originally feared. An in-depth evaluation of this particular tropical cyclone helps to shed some light on model deficiencies and can be used to help determine future model changes.

Sea Level Rise in the Samoan Islands Escalated by Viscoelastic Relaxation After the 2009 Samoa‐Tonga Earthquake

AbstractThe Samoan islands are an archipelago hosting a quarter million people mostly residing in three major islands, Savai'i and Upolu (Samoa), and Tutuila (American Samoa). The islands have experienced sea level rise by 2–3 mm/year during the last half century. The rate, however, has dramatically increased following the Mw 8.1 Samoa‐Tonga earthquake doublet (megathrust + normal faulting) in September 2009. Since the earthquake, we found large‐scale gravity increase (0.5 μGal/year) around the islands and ongoing subsidence (8–16 mm/year) of the islands from our analysis of Gravity Recovery And Climate Experiment gravity and GPS displacement data. The postseismic horizontal displacement is faster in Samoa, while the postseismic subsidence rate is considerably larger in American Samoa. The analysis of local tide gauge records and satellite altimeter data also identified that the relative sea level rise becomes faster by 7–9 mm/year in American Samoa than Samoa. A simple viscoelastic model with a Maxwell viscosity of 2–3×1018 Pa s for the asthenosphere explained postseismic deformation at nearby GPS sites as well as Gravity Recovery And Climate Experiment gravity change. It is found that the constructive interference of viscoelastic relaxation from both megathrust and normal faulting has intensified the postseismic subsidence at American Samoa, causing ~5 times faster sea level rise than the global average. Our model indicates that this trend is likely to continue for decades and result in sea level rise of 30–40 cm, which is independent of and in addition to anticipated climate‐related sea level rise. It will worsen coastal flooding on the islands leading to regular nuisance flooding.

Evolutionary Genomics of Samoans

Archaeological studies estimate the initial settlement of Samoa at 2,750-2,880 years ago, and identified only limited human modification to the landscape and settlement until about 1,000-1,500 years ago. A complex history of migration follows Samoa’s initial peopling; first with populations sharing ancestry with Papuan-speaking groups and more recently with Europeans, Africans, and East Asians due to European colonialism. Using 1,197 Samoan high coverage whole genomes, we identify population splits between the major Samoan islands, and detect asymmetrical gene flow to the capital city. Approximately, 25% of Samoan genomes come from Papuan related ancestry, which we find as the likely source of the archaic Denisovan haplotypes in Samoans. We also find that Samoans had an extreme bottleneck until about 1,000 years ago, followed by distinct expansions between the islands, and subsequent bottlenecks consistent with European colonization. These results give insights to an ongoing archaeological debate about the peopling of Samoa.

<p class="Body">To the knowledge of oribatid mites (Acari, Oribatida) of Samoa

A new species of oribatid mites of the family Galumnidae (Acari, Oribatida) is described from Samoa; Pergalumna enricoi sp. nov. differs from Pergalumna foveolata Hammer, 1973 by the elongate oval, transversely oriented notogastral porose areas Aa and heavily tuberculate prodorsum. An identification key to the known species of the genus Pergalumna from the Australian region is presented. A list of oribatid mite taxa of the Samoan Islands, including 77 species/subspecies from 56 genera and 29 families, is provided.

Tracing mantle sources in the northern Lau back-arc basin by independent component analysis of basalt isotopic compositions

ABSTRACT The northern Lau back-arc basin (NLB) lavas display a diverse geochemical nature caused by complex geological processes in this region. Independent component (IC) analysis was applied to investigate the nature of mantle sources in the NLB, based on a compiled geochemical data set from the NLB, central-southern Lau Basin (C-SLB), Pacific and Indian Ocean ridges, and Samoan islands. We identified three ICs in the five-dimensional space of Sr-Nd-Pb isotopic ratios, which can account for 96.5% of the isotopic variance. The correlations between the ICs and the incompatible trace elements ratios were further used to examine the origin of these ICs. The first IC (IC1) separates Samoan islands (IC1 < −1) from the other groups, and shows negative correlation with (La/Sm)N ratios. The second IC (IC2) discriminates mid-ocean ridge basalts (MORBs) from Pacific (IC2 > 0) and Indian (IC2 < 0) Ocean ridges as well as the C-SLB (IC2 > 0) and NLB (IC2 < 0) lavas. IC2 correlates positively with Ba/Th ratios. The third IC (IC3) distinguishes MORBs (IC3 > 0) and back-arc basin lavas (IC3 < 0), and displays a negative correlation with Th/Nb values. On a regional scale in the NLB, there is a broad increase in IC1, IC2, and IC3 from the north to the south. Only IC3 presents obvious decrease from the west to the east, i.e. with decreasing distance from the arc. The geochemical nature and the statistical properties of these ICs suggest that IC1 is related to an enriched mantle component most likely from the nearby Samoan plume, and the IC2 corresponds to a fluid-rich component from the subducting Pacific slab. The IC3 may represent partial melt of recycled subducted sediment or recycled continental crustal materials. The geographic distribution of three ICs supports that the relatively recent mixing of Samoan plume materials with the subduction-metasomatized back-arc mantle may be responsible for the observed geochemical diversity in NLB lavas.

Beyond the Last Glacial Maximum: Island endemism is best explained by long‐lasting archipelago configurations

AbstractAimTo quantify the influence of past archipelago configuration on present‐day insular biodiversity patterns, and to compare the role of long‐lasting archipelago configurations over the Pleistocene to configurations of short duration such as at the Last Glacial Maximum (LGM) and the present‐day.Location53 volcanic oceanic islands from 12 archipelagos worldwide—Azores, Canary Islands, Cook Islands, Galápagos, Gulf of Guinea, Hawaii, Madeira, Mascarenes, Pitcairn, Revillagigedo, Samoan Islands and Tristan da Cunha.Time periodThe last 800 kyr, representing the nine most recent glacial–interglacial cycles.Major taxa studiedLand snails and angiosperms.MethodsSpecies richness data for land snails and angiosperms were compiled from existing literature and species checklists. We reconstructed archipelago configurations at the following sea levels: the present‐day high interglacial sea level, the intermediate sea levels that are representative of the Pleistocene and the low sea levels of the LGM. We fitted two alternative linear mixed models for each archipelago configuration using the number of single‐island endemic, multiple‐island endemic and (non‐endemic) native species as a response. Model performance was assessed based on the goodness‐of‐fit of the full model, the variance explained by archipelago configuration and model parsimony.ResultsSingle‐island endemic richness in both taxonomic groups was best explained by intermediate palaeo‐configuration (positively by area change, and negatively by palaeo‐connectedness), whereas non‐endemic native species richness was poorly explained by palaeo‐configuration. Single‐island endemic richness was better explained by intermediate archipelago configurations than by the archipelago configurations of the LGM or present‐day.Main conclusionsArchipelago configurations at intermediate sea levels—which are representative of the Pleistocene—have left a stronger imprint on single‐island endemic richness patterns on volcanic oceanic islands than extreme archipelago configurations that persisted for only a few thousand years (such as the LGM). In understanding ecological and evolutionary dynamics of insular biota it is essential to consider longer‐lasting environmental conditions, rather than extreme situations alone.