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Abstract New Guinea is the largest tropical island in the world and hosts immense endemic biodiversity. However, our understanding of how the gradual emergence of the terrestrial ecosystems of the island over the last 40 Myr has generated this biological richness is hampered by poorly documented species diversity and distributions. Here, we address both these issues through an integrative taxonomy and biogeographical approach using Hylophorbus, a New Guinea-endemic genus of frogs with 12 recognized species. We delimited candidate species by integrating mitochondrial DNA, nuclear DNA, and bioacoustics, then investigated their evolutionary history. Our results suggest that the current taxonomy of the genus misses true species diversity by ≥3.5-fold. Nevertheless, most candidate species (27) remain unconfirmed because of missing data, whereas five were identified unambiguously as undescribed (we describe three of these formally). Time-calibrated phylogenetic analyses suggest that Hylophorbus diversification began ~9 Mya in the northern or eastern portion of New Guinea. It would appear that lineages dispersed to new terrestrial habitats in the west, notably uplifted by the central range orogeny, until eventually reaching the Bird’s Head during the Mio-Pliocene (7–5 Mya). Conversely, a past barrier appears to have prevented north–south dispersal. These data suggest that new habitat availability has primarily driven the diversification of Hylophorbus. 

Abstract Cryptic ecologies, the Wallacean Shortfall of undocumented species’ geographical ranges and the Linnaean Shortfall of undescribed diversity, are all major barriers to conservation assessment. When these factors overlap with drivers of extinction risk, such as insular distributions, the number of threatened species in a region or clade may be underestimated, a situation we term ‘cryptic extinction risk’. The genusLepidodactylusis a diverse radiation of insular and arboreal geckos that occurs across the western Pacific. Previous work onLepidodactylusshowed evidence of evolutionary displacement around continental fringes, suggesting an inherent vulnerability to extinction from factors such as competition and predation. We sought to (1) comprehensively review status and threats, (2) estimate the number of undescribed species, and (3) estimate extinction risk in data deficient and candidate species, inLepidodactylus. From our updated IUCN Red List assessment, 60% of the 58 recognized species are threatened (n = 15) or Data Deficient (n = 21), which is higher than reported for most other lizard groups. Species from the smaller and isolated Pacific islands are of greatest conservation concern, with most either threatened or Data Deficient, and all particularly vulnerable to invasive species. We estimated 32 undescribed candidate species and linear modelling predicted that an additional 18 species, among these and the data deficient species, are threatened with extinction. Focusing efforts to resolve the taxonomy and conservation status of key taxa, especially on small islands in the Pacific, is a high priority for conserving this remarkably diverse, yet poorly understood, lizard fauna. Our data highlight how cryptic ecologies and cryptic diversity combine and lead to significant underestimation of extinction risk. 

Systematic investigations of vertebrate faunas from the islands of Melanesia are revealing high levels of endemism, dynamic biogeographic histories, and in some cases surprisingly long evolutionary histories of insularity. The bent-toed geckos in the Cyrtodactylus sermowaiensis Group mainly occur in northern New Guinea and nearby islands, however a further isolated population occurs on Manus Island in the Admiralty Archipelago approximately 300 km to the north of New Guinea. Here we first present a review of the genetic diversity, morphological variation and distribution of Cyrtodactylus sermowaiensis from northern New Guinea. Genetic structure and distributional records within Cyrtodactylus sermowaiensis broadly overlap with underlying Terranes in northern New Guinea, suggesting divergence on former islands that have been obscured by the infill and uplift of sedimentary basins since the late Pleistocene. Based on a combination of genetic and morphological differentiation we then describe the population from Manus Island as a new species, Cyrtodactylus crustulus sp. nov. This new species emphasises the high biological endemism and conservation significance of the Admiralty Islands, and especially Manus Island.  

Abstract In₂O₃, an n‐type semiconducting transparent transition metal oxide, possesses a surface electron accumulation layer (SEAL) resulting from downward surface band bending due to the presence of ubiquitous oxygen vacancies. Upon annealing In₂O₃in ultrahigh vacuum or in the presence of oxygen, the SEAL can be enhanced or depleted, as governed by the resulting density of oxygen vacancies at the surface. In this work, an alternative route to tune the SEAL by adsorption of strong molecular electron donors (specifically here ruthenium pentamethylcyclopentadienyl mesitylene dimer, [RuCp*mes]₂) and acceptors (here 2,2′‐(1,3,4,5,7,8‐hexafluoro‐2,6‐naphthalene‐diylidene)bis‐propanedinitrile, F₆TCNNQ) is demonstrated. Starting from an electron‐depleted In₂O₃surface after annealing in oxygen, the deposition of [RuCp*mes]₂restores the accumulation layer as a result of electron transfer from the donor molecules to In₂O₃, as evidenced by the observation of (partially) filled conduction sub‐bands near the Fermi level via angle‐resolved photoemission spectroscopy, indicating the formation of a 2D electron gas due to the SEAL. In contrast, when F₆TCNNQ is deposited on a surface annealed without oxygen, the electron accumulation layer vanishes and an upward band bending is generated at the In₂O₃surface due to electron depletion by the acceptor molecules. Hence, further opportunities to expand the application of In₂O₃in electronic devices are revealed. 

Abstract New Guinea has been considered both as a refuge for mesic rainforest-associated lineages that contracted in response to the late Cenozoic aridification of Australia and as a centre of biotic diversification and radiation since the mid-Miocene or earlier. Here, we estimate the diversity and a phylogeny for the Australo-Papuan forest dragons (Sauria: Agamidae; ~20 species) in order to examine the following: (1) whether New Guinea and/or proto-Papuan Islands may have been a biogeographical refuge or a source for diversity in Australia; (2) whether mesic rainforest environments are ancestral to the entire radiation, as may be predicted by the New Guinea refuge hypothesis; and (3) more broadly, how agamid ecological diversity varies across the contrasting environments of Australia and New Guinea. Patterns of lineage distribution and diversity suggest that extinction in Australia, and colonization and radiation on proto-Papuan islands, have both shaped the extant diversity and distribution of forest dragons since the mid-Miocene. The ancestral biome for all Australo-Papuan agamids is ambiguous. Both rainforest and arid-adapted radiations probably started in the early Miocene. However, despite deep-lineage diversity in New Guinea rainforest habitats, overall species and ecological diversity is low when compared with more arid areas, with terrestrial taxa being strikingly absent.