A story of vicariance? how the geology of oceanic archipelagos influenced the evolutionary history of endemic damselflies.

South Pacific islands provide an ideal study system to explore patterns of speciation, specifically examining the role of dispersal versus vicariance. Dispersal is often the suggested mechanism of diversification in the South Pacific, specifically among remote island chains. Here, we provide a phylogeny of several related genera of Coenagrionidae (Odonata: Zygoptera) from the South Pacific, based on five molecular loci, in order to examine patterns of speciation in the region. We used the endemic damselfly genera Nesobasis, Nikoulabasis, and Vanuatubasis found across both Fiji and Vanuatu. Knowledge of the geologic history of the region was used to inform our understanding of the evolution of these genera. Both archipelagos used to be part of the Vitiaz arc which spanned from the Solomon Islands to Tonga and began to break apart 10-12 Ma. Results of our divergence-time estimations and biogeographic reconstructions support that the breakup of this arc acted as a significant vicariance event in the evolution of these taxa. Specifically, it led to the extant generic diversity seen in these damselflies. We find that within the archipelago of Vanuatu, that Espiritu Santo served as an important source for dispersal to other islands with Malekula acting as a stepping stone to Efate.

Beetle bioluminescence outshines extant aerial predators.

We understand very little about the timing and origins of bioluminescence, particularly as a predator avoidance strategy. Understanding the timing of its origins, however, can help elucidate the evolution of this ecologically important signal. Using fireflies, a prevalent bioluminescent group where bioluminescence primarily functions as aposematic and sexual signals, we explore the origins of this signal in the context of their potential predators. Divergence time estimations were performed using genomic-scale datasets providing a robust estimate for the origin of firefly bioluminescence as both a terrestrial and as an aerial signal. Our results recover the origin of terrestrial beetle bioluminescence at 141.17 (122.63-161.17) Ma and firefly aerial bioluminescence at 133.18 (117.86-152.47) Ma using a large dataset focused on Lampyridae; and terrestrial bioluminescence at 148.03 (130.12-166.80) Ma, with the age of aerial bioluminescence at 104.97 (99.00-120.90) Ma using a complementary Elateroidea dataset. These ages pre-date the origins of all known extant aerial predators (i.e. bats and birds) and support much older terrestrial predators (assassin bugs, frogs, ground beetles, lizards, snakes, hunting spiders and harvestmen) as the drivers of terrestrial bioluminescence in beetles. These ages also support the hypothesis that sexual signalling was probably the original function of this signal in aerial fireflies.

Revision of Vanuatubasis Ober & Staniczek, 2009 (Odonata, Coenagrionidae), with description of seven new species.

Vanuatubasis Ober & Staniczek, 2009 is an endemic genus of damselfly found on the island archipelago of Vanuatu. Previously only three species were assigned to the genus. Here, all known species of Vanuatubasis are formally described and treated, including the association of females for known species. The following new congeners are also described: V.discontinua sp. nov., V.evelynae sp. nov., V.insularivorum sp. nov., V.kapularum sp. nov., V.nunggoli sp. nov., V.rhomboides sp. nov., and V.xanthochroa sp. nov. from material collected across six different islands. An illustrated key to both males and females of all species within Vanuatubasis is provided as well as distributions for all known species.

Oficanthon Paulian, 1985, a junior synonym of Lepanus Balthasar, 1966 (Coleoptera: Scarabaeidae: Scarabaeinae), with redescription of Lepanus mirabilis (Paulian, 1985).

The monotypic genus Oficanthon Paulian, 1985 (Coleoptera: Scarabaeidae: Scarabaeinae) is treated as a junior synonym of the genus Lepanus Balthasar, 1966, and L. mirabilis (Paulian, 1985), new combination is proposed for Oficanthon mirabilis Paulian, 1985. Both morphological and molecular evidence support this synonymy. Morphological evidence further supports its placement within the Lepanus ustulatus species group. Lepanus mirabilis is redescribed.

Factors Influencing the Distribution of Endemic Damselflies in Vanuatu.

Vanuatubasis Ober and Staniczek is a genus of damselfly endemic to Vanuatu. Little is known about the distribution and general natural history of the genus. We present the results of 14 weeks of fieldwork in Vanuatu to provide a better understanding of the biology of this genus. Specifically, we tested ecological niche models to predict the presence of Vanuatubasis throughout the region and explored how water pH may play a role in their distribution and ecology. The results of this fieldwork refined our model and further predicted the presence of this genus on additional islands. We also found stream pH as a strong predictor for the presence of Vanuatubasis, with their presence in alkaline streams significantly higher (p < 0.001). The mean pH for those streams where the genus was collected was 8.44 (n = 53).

Species boundaries in the messy middle-A genome-scale validation of species delimitation in a recently diverged lineage of coastal fog desert lichen fungi.

Species delimitation among closely related species is challenging because traditional phenotype-based approaches, for example, using morphology, ecological, or chemical characteristics, may not coincide with natural groupings. With the advent of high-throughput sequencing, it has become increasingly cost-effective to acquire genome-scale data which can resolve previously ambiguous species boundaries. As the availability of genome-scale data has increased, numerous species delimitation analyses, such as BPP and SNAPP+Bayes factor delimitation (BFD*), have been developed to delimit species boundaries. However, even empirical molecular species delimitation approaches can be biased by confounding evolutionary factors, for example, hybridization/introgression and incomplete lineage sorting, and computational limitations. Here, we investigate species boundaries and the potential for micro-endemism in a lineage of lichen-forming fungi, Niebla Rundel & Bowler, in the family Ramalinaceae by analyzing single-locus and genome-scale data consisting of (a) single-locus species delimitation analysis using ASAP, (b) maximum likelihood-based phylogenetic tree inference, (c) genome-scale species delimitation models, e.g., BPP and SNAPP+BFD, and (d) species validation using the genealogical divergence index (gdi). We specifically use these methods to cross-validate results between genome-scale and single-locus datasets, differently sampled subsets of genomic data and to control for population-level genetic divergence. Our species delimitation models tend to support more speciose groupings that were inconsistent with traditional taxonomy, supporting a hypothesis of micro-endemism, which may include morphologically cryptic species. However, the models did not converge on robust, consistent species delimitations. While the results of our analysis are somewhat ambiguous in terms of species boundaries, they provide a valuable perspective on how to use these empirical species delimitation methods in a nonmodel system. This study thus highlights the challenges inherent in delimiting species, particularly in groups such as Niebla, with complex, relatively recent phylogeographic histories.

Prevalence of leg regeneration in damselflies reevaluated: A case study in Coenagrionidae.

The leg regeneration capabilities of damselflies are understudied. Here we present the first data of regenerated limbs across a genus of damselfly based on adult specimens collected in the field to illustrate the prevalence of limb loss among nymphs. We show that this phenomenon is much more prevalent than previously thought, as 42 percent of individuals were found with regenerated limbs. Furthermore, we test for patterns within these data to begin to unravel the potential causes of limb loss in nymphal damselflies, showing that intrinsic factors such as sex and species cannot explain the patterns of limb loss pointing to environmental factors as the probable cause. We argue that Odonata limb regeneration provides a potentially unique perspective into the nymphal stage of these organisms.

Two new species of coastal Atyphella Olliff (Lampyridae: Luciolinae).

Additional work on the islands of Vanuatu has improved our understanding of the actual diversity of South Pacific coastal fireflies. Prior to recent fieldwork in Vanuatu, the only known lampyrid from Vanuatu was Atyphella aphrogeneia (Ballantyne), a coastal species also found in Papua New Guinea. After further examination, we determined that specimens from Vanuatu formerly classified as Atyphella aphrogeneia actually belong to an undescribed species. New species, Atyphella maritimus Saxton and Powell and Atyphella marigenous Saxton and Bybee, are described from specimens collected in Vanuatu. An updated key for coastal Atyphella in the South Pacific is provided.