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The Pacificellinae are a group of small, high-spired land snails distributed on islands across the Pacific. Some species are endemic to particular island groups, but others have wide geographic distributions, several of which have been attributed to anthropogenic transport between islands before western contact. We used DNA sequence data (COI, 16S, ITS2, 28S) from recently collected and historical specimens to estimate a phylogeny of the Pacificellinae, with a focus on Hawaiian species. Phylogenetic analyses support recognizing Lamellidea and Pacificella as distinct genera and indicate that the genus group Tornatellinops should be regarded as a synonym of Lamellidea. The number of taxa defined by species delimitation analyses (ASAP, bPTP, mPTP) varies widely, with between 6 and 42 species estimated in the Hawaiian Islands. These candidate species hypotheses were evaluated in an integrative framework, including shell morphology, geography, and a multilocus phylogeny, to revise the taxonomy of Hawaiian pacificellines. Four Lamellidea species and two Pacificella species are recognized from the Hawaiian Islands, including two widespread species introduced to Hawaiʻi from the South Pacific. Lamellidea peponum in Hawaiʻi shows little genetic divergence from Polynesian specimens previously referred to L. oblonga, and the name L. oblonga is now regarded as a junior synonym. Lamellidea polygnampta is recognized here from across the Hawaiian Islands, L. cylindrica from the island of O‘ahu, and the lowland species, L. extincta, from the main Hawaiian Islands and the Northwestern Islands. The only Pacificella specimens found in Hawai‘i in modern surveys are more closely related to specimens of P. variabilis from Polynesia than to historical specimens of P. baldwini, indicating that the only Pacificella species now found in the main Hawaiian Islands appears to be introduced. Pacificellines have declined in abundance in Hawai‘i over the last century and the two species L. extincta and P. baldwini, formerly present across the Hawaiian Islands, are now either critically endangered or extinct. 

Freshwater systems are among the most threatened habitats in the world and the biodiversity inhabiting them is disappearing quickly. The Hawaiian Archipelago has a small but highly endemic and threatened group of freshwater snails, with eight species in three families (Neritidae, Lymnaeidae, and Cochliopidae). Anthropogenically mediated habitat modifications (i.e., changes in land and water use) and invasive species (e.g., Euglandina spp., non-native sciomyzids) are among the biggest threats to freshwater snails in Hawaii. Currently, only three species are protected either federally (U.S. Endangered Species Act; Erinna newcombi) or by Hawaii State legislation (Neritona granosa, and Neripteron vespertinum). Here, we review the taxonomic and conservation status of Hawaii’s freshwater snails and describe historical and contemporary impacts to their habitats. We conclude by recommending some basic actions that are needed immediately to conserve these species. Without a full understanding of these species’ identities, distributions, habitat requirements, and threats, many will not survive the next decade, and we will have irretrievably lost more of the unique books from the evolutionary library of life on Earth. 

Classic biological control of pest non-marine molluscs has a long history of disastrous outcomes, and despite claims to the contrary, few advances have been made to ensure that contemporary biocontrol efforts targeting molluscs are safe and effective. For more than half a century, malacologists have warned of the dangers in applying practices developed in the field of insect biological control, where biocontrol agents are often highly host-specific, to the use of generalist predators and parasites against non-marine mollusc pests. Unfortunately, many of the lessons that should have been learned from these failed biocontrol programs have not been rigorously applied to contemporary efforts. Here, we briefly review the failures of past non-marine mollusc biocontrol efforts in the Pacific islands and their adverse environmental impacts that continue to reverberate across ecosystems. We highlight the fact that none of these past programs has ever been demonstrated to be effective against targeted species, and at least two (the snails Euglandina spp. and the flatworm Platydemus manokwari) are implicated in the extinction of hundreds of snail species endemic to Pacific islands. We also highlight other recent efforts, including the proposed use of sarcophagid flies and nematodes in the genus Phasmarhabditis, that clearly illustrate the false claims that past bad practices are not being repeated. We are not making the claim that biocontrol programs can never be safe and effective. Instead, we hope that in highlighting the need for robust controls, clear and measurable definitions of success, and a broader understanding of ecosystem level interactions within a rigorous scientific framework are all necessary before claims of success can be made by biocontrol advocates. Without such amendments to contemporary biocontrol programs, it will be impossible to avoid repeating the failures of non-marine mollusc biocontrol programs to date. 

Recent surveys of Oahu’s Waianae Mountains uncovered a small, previously undescribed species of Auriculella that is conchologically similar to the three members of the A. perpusilla group all of which are endemic to the Koolau Mountain Range. However, sequence data demonstrate that the perpusilla group is not monophyletic. Moreover, the new species is not closely related to A. perpusilla or A. perversa , the only extant members of the group, but instead is sister to A. tenella , a species from the high spired A. castanea group. A neotype is designated for A. auricula , the type species of Auriculella ; all members of the conchologically similar perpusilla group are anatomically redescribed; and lectotypes designated for A. minuta , A. perversa , and A. tenella . The new species is described and compared to the type of the genus, members of the perpusilla group, and the genetically similar species A. tenella . 

Abstract The Hawaiian archipelago was formerly home to one of the most species-rich land snail faunas (> 752 species), with levels of endemism > 99%. Many native Hawaiian land snail species are now extinct, and the remaining fauna is vulnerable. Unfortunately, lack of information on critical habitat requirements for Hawaiian land snails limits the development of effective conservation strategies. The purpose of this study was to examine the plant host preferences of native arboreal land snails in Puʻu Kukui Watershed, West Maui, Hawaiʻi, and compare these patterns to those from similar studies on the islands of Oʻahu and Hawaiʻi. Concordant with studies on other islands, we found that four species from three diverse families of snails in Puʻu Kukui Watershed had preferences for a few species of understorey plants. These were not the most abundant canopy or mid canopy species, indicating that forests without key understorey plants may not support the few remaining lineages of native snails. Preference for Broussaisia arguta among various island endemic snails across all studies indicates that this species is important for restoration to improve snail habitat. As studies examining host plant preferences are often incongruent with studies examining snail feeding, we suggest that we are in the infancy of defining what constitutes critical habitat for most Hawaiian arboreal snails. However, our results indicate that preserving diverse native plant assemblages, particularly understorey plant species, which facilitate key interactions, is critical to the goal of conserving the remaining threatened snail fauna. 

Abstract Angiostrongylus cantonensis (rat lungworm), a parasitic nematode, is expanding its distribution. Human infection, known as angiostrongyliasis, may manifest as eosinophilic meningitis, an emerging infectious disease. The range and incidence of this disease are expanding throughout the tropics and subtropics. Recently, the Hawaiian Islands have experienced an increase in reported cases. This study addresses factors affecting the parasite's distribution and projects its potential future distribution, using Hawaii as a model for its global expansion. Specimens of 37 snail species from the Hawaiian Islands were screened for the parasite using PCR. It was present on five of the six largest islands. The data were used to generate habitat suitability models for A. cantonensis , based on temperature and precipitation, to predict its potential further spread within the archipelago. The best current climate model predicted suitable habitat on all islands, with greater suitability in regions with higher precipitation and temperatures. Projections under climate change (to 2100) indicated increased suitability in regions with estimated increased precipitation and temperatures, suitable habitat occurring increasingly at higher elevations. Analogously, climate change could facilitate the spread of A. cantonensis from its current tropical/subtropical range into more temperate regions of the world, as is beginning to be seen in the continental USA.