Understanding how the remarkable phenotypic diversity observed in organisms arises through shifts in macroevolutionary patterns and tempos is a fundamental challenge in evolutionary biology. Phenotypes often evolve in a mosaic pattern during adaptive transitions. For organisms that have invaded highly specialized habitats, such as the unique two-phase interface habitats (water surfaces), the macroevolutionary history of their phenotypic diversification remains only superficially understood. Semiaquatic bugs (Insecta: Heteroptera: Gerromorpha), which exhibit extensive habitat diversification and unparalleled phenotypic innovation, represent one of the most successful extant adaptive groups at this interface and provide an excellent system for study. By analyzing their adaptive transitions and phenotypic macroevolutionary history, we demonstrate that Gerromorpha experienced a single major adaptive transition from land to the water surface. Subsequently, semiaquatic bugs successfully colonized a wide range of distinct water-surface habitats. During this process, phenotypic space was explored under strong constraints and along pronounced mosaic trajectories; i.e., different body regions exhibited markedly distinct patterns of phenotypic space occupation and partitioning, as well as markedly different evolutionary rates. Furthermore, we showed that this mosaic pattern of phenotypic space occupation and rates of exploration had complex and critical effects on the invasion and colonization of water-surface habitats. Our study provides a typical case of macroevolutionary dynamics in species adapted to specialized air-water interface habitats, emphasizing the complex and significant roles of environmental context and functional demands in shaping patterns of phenotypic evolution.

A revision is provided for the Rhagoveliaauga subgroup, endemic to the higher mountain areas of New Guinea, and a segregate of the larger Rhagovelia novacaledonica group. This treatment covers 3 previously described species-R. auga D. Polhemus, R. crinita Lansbury, and R. thysanotos Lansbury-and also provides descriptions of 14 new species as follows: R. kaindi from the Owen Stanley Range of Papua New Guinea; R. fordi from the Saruwaged Range of Papua New Guinea; R. maai, R. gressitti, R. sinofi and R. nonduglana from the Eastern Highlands of Papua New Guinea; R. microcephala and R. altamontana from the Western Highlands of Papua New Guinea; R. bosavi from Mt. Bosavi, Papua New Guinea; R. cyclopica from the Cyclops Mountains of Indonesian New Guinea; R. bintang from the Star Mountains of Indonesian New Guinea; R. dani from the Baliem Valley of Indonesian New Guinea; and R. wapoga and R. ziwa from the Sudirman Range of Indonesian New Guinea. Photomicrographs of the dorsal habitus in both sexes, male genitalia, and other key morphogical characters are provided for all of the new species proposed, accompanied by photographs of representative habitats, distribution maps and a key to the species of the subgroup.

The plant bug genus Engytatus (Heteroptera, Miridae) is represented by 29 species globally, with a small insular radiation in Hawaii, many of which show strong host-plant specificity. Recent botanical survey efforts in challenging terrain on the Hawaiian island of Kauai, utilizing a remotely operated aerial drone collection tool, resulted in the discovery of a previously unknown plant species, the recently described Schiedea waiahuluensis (Caryophyllaceae), that also harbors an undescribed Engytatus species, described here as Engytatus pali. Based on characters of the male genitalia, antennae and rostrum, this new taxon appears most closely related to several other Engytatus species endemic to Kauai and Oahu. Photomicrographs are provided of diagnostic characters for the new species and other similar congeners from Kauai and Oahu, along with notes on its association with the host species S. waiahuluensis. This discovery highlights the utility of novel aerial drone collection techniques in documenting the biodiversity of remote, topographically inaccessible habitats, for both plant and insect species.

The new species Rhagovelia sumbana is described from the island of Sumba in the Lesser Sunda Islands. The species possesses character states that place it in the R. sarawakensis group, whose members are otherwise known only from the Sundaland continental platform. The presence of this species on Sumba provides additional supporting evidence for the prevailing tectonic hypothesis that Sumba is a displaced continental fragment rifted from an original position on the southeast margin of Sundaland near Borneo, and the geological evidence for this is briefly reviewed. Photomicrographs of key morphological characters for R. sumbana, a map of its known distribution on Sumba, and a photograph of the type-locality habitat are provided.

Hawai'i's pinapinao (Megalagrion McLachlan) comprises a radiation of 23 endemic damselfly species within Coenagrionidae. Despite being a unique study system for understanding geology's impacts on evolutionary processes among Odonata, the understanding of these damselflies' temporal, geographic and phylogenetic origins remains incomplete. Testing macroevolutionary hypotheses has been hampered by conflicting topologies. To resolve these uncertainties, we performed phylogenetic analyses including divergence time estimation with 90 nuclear loci (>50 kbp) and 2 mitochondrial loci (>1 kbp), sampling representatives from 37 genera within core Coenagrionidae and 90% of Megalagrion species, including multiple island populations. We used ancestral range estimations, diversification analyses, agent-based simulation modelling and ancestral state reconstruction to infer the group's origin and biogeography and assess traits' roles in diversification. Our findings indicate Megalagrion's ancestor diverged from core Coenagrionidae in the early Eocene (similar to 51 MA) and diversified in the early Miocene (similar to 19 MA), suggesting Megalagrion's MRCA predates Kaua'i's emergence by 7-21 MY. Diversification analyses suggest a low rate after Megalagrion diverged from Coenagrionidae followed by a sudden increase around 19 MA, and simulation modelling supports extinction playing a significant role. Extant Megalagrion diversity is largely explained by ecological diversification into at least five clades with distinct breeding habitats that likely evolved on Northwestern Hawaiian Islands that are now-sunken seamounts. Speciation continued as descendants dispersed to current Hawaiian Islands as islands emerged. Species breeding in seeps further diversified within the island of Kaua'i. Our results highlight including geologic changes over time in evolutionary studies and increase understanding of diversification patterns, biogeography and adaptive radiation on islands.

The genus Stridulivelia is exclusive to the Americas, with a Neotropical distribution ranging from Mexico to Argentina. It comprises 16 valid species and is divided into two subgenera: Stridulivelia Hungerford and Aenictovelia J. Polhemus. The subgenus Aenictovelia, found in North America and northern South America, is characterized by the absence of stridulatory structures in its six species. However, photos and detailed descriptions are scarce in the literature for some of them. Here, we provide photos and descriptions of the male genitalia of all species of S. (Aenictovelia): S. chocoana Morales, Molano and Moreira, S. cinctipes (Champion), S. epeixis (Drake and Menke), S. pueblana (Drake), S. secerna J. Polhemus, and S. speciosa J. Polhemus and D. Polhemus, and also present new distribution records for three of these species. A key to species of S. (Aenictovelia), maps with all their geographic records, and a discussion on the morphology of the two subgenera also are presented.

Water crickets of the subfamily Haloveliinae are semi‐aquatic bugs occurring in freshwater and marine habitats throughout the Indo‐Australian region, presently including six genera with more than 80 extant species. Whether lineage diversification in Haloveliinae is associated with the utilization of new ecological niches caused by transition events between freshwater and marine habitats remains poorly understood. We investigate the evolutionary history of Haloveliinae using large‐scale phylogenomic datasets and a set of novel redefined morphological characters based on 24 ingroup taxa representing all recognized genera. Our phylogenetic results based on the novel datasets definitively indicate that the freshwater genus Strongylovelia Esaki as currently defined is paraphyletic and supports the establishment of a new genus: Metavelia gen. nov., including three congeneric species: Metavelia patiooni comb. nov. (type species), Metavelia priori comb. nov. and Metavelia albicolli comb. nov. Reconstruction of ancestral habitats suggests a freshwater origin for the Haloveliinae. Divergence time estimations reveal that the origin of the monophyletic marine clade occurred at around 83 Ma (95% highest posterior density: 71–98 Ma) in the Late Cretaceous, involving a single transition event from freshwater to marine habitats. This time coincides with the period of high global sea levels in the Late Cretaceous. During this period, the marine incursions caused by the massive sea level rise flooded the continental margins, especially in Southeast Asia, where ancestral Haloveliinae were probably distributed. The appearance of new marine habitats after the marine incursions (e.g., intertidal, mangroves and estuarine) probably led to a subsequent establishment and diversification of the marine lineages.

Two new species of Rhagovelia are described from southern New Guinea: R. kiunga from the Fly River basin of Papua New Guinea, and R. timikana from the Iweka River basin of Indonesian New Guinea. These species are placed in a newly defined R. kiunga species group on the basis of shared distinctive morphological character states. Photographic figures of the dorsal habitus in both sexes and other key morphological characters are provided for both species, along with line drawings of the male parameres and a distribution map.

Thirty-four new species of Rhagovelia are described from the East Papua Composite Terrane of far eastern New Guinea. The new taxa described from this area are as follows: R. yela, R. woa, and R. mbo from Rossel Island; R. tagula, R. kolukolu, and R. riu from Tagula Island; R. bwagabwaga from Misima Island; R. suloga from Woodlark Island; R. torrenticola and R. elongata from Goodenough Island; R. awaetowa from Fergusson Island; R. dibuwa from Normanby Island; R. basima from Fergusson and Normanby islands; R. kalawai from Sideia and Basilaki islands; R. guiagoila from Basilaki, Sideia and Sariba islands; R. tufi, R. bowutu, R. obscura, R. upalai, R. antap, R. goilala, R. udabe, R. watuti, R. peninsularis, R. auga, R. aviavi, R. tekadu, R. sapoi, R. mimani, R. dinga, R. ivimkana, R. loriae, R. grisea, and R. cheesmanae from the Owen Stanley Range of eastern New Guinea. Redescriptions are also provided for five previously described species occurring in this portion of New Guinea: R. peggiae Kirkaldy, R. hirsuta Lansbury, R. priori Lansbury, R. caesius Lansbury and R. aureospicata Lansbury. A regional key is provided for these 39 species of Rhagovelia occurring in the Papuan Peninsula and adjacent island groups, accompanied by figures of the male parameres and other diagnostic morphological structures, and distribution maps for all species.

AbstractWater crickets of the subfamily Haloveliinae are semi‐aquatic bugs occurring in freshwater and marine habitats throughout the Indo‐Australian region, presently including six genera with more than 80 extant species. Whether lineage diversification in Haloveliinae is associated with the utilization of new ecological niches caused by transition events between freshwater and marine habitats remains poorly understood. We investigate the evolutionary history of Haloveliinae using large‐scale phylogenomic datasets and a set of novel redefined morphological characters based on 24 ingroup taxa representing all recognized genera. Our phylogenetic results based on the novel datasets definitively indicate that the freshwater genus Strongylovelia Esaki as currently defined is paraphyletic and supports the establishment of a new genus: Metavelia gen. nov., including three congeneric species: Metavelia patiooni comb. nov. (type species), Metavelia priori comb. nov. and Metavelia albicolli comb. nov. Reconstruction of ancestral habitats suggests a freshwater origin for the Haloveliinae. Divergence time estimations reveal that the origin of the monophyletic marine clade occurred at around 83 Ma (95% highest posterior density: 71–98 Ma) in the Late Cretaceous, involving a single transition event from freshwater to marine habitats. This time coincides with the period of high global sea levels in the Late Cretaceous. During this period, the marine incursions caused by the massive sea level rise flooded the continental margins, especially in Southeast Asia, where ancestral Haloveliinae were probably distributed. The appearance of new marine habitats after the marine incursions (e.g., intertidal, mangroves and estuarine) probably led to a subsequent establishment and diversification of the marine lineages.

Water crickets of the subfamily Haloveliinae are semi-aquatic bugs occurring in freshwater and marine habitats throughout the Indo-Australian region, presently including six genera with more than 80 extant species. Whether lineage diversification in Haloveliinae is associated with the utilization of new ecological niches caused by transition events between freshwater and marine habitats remains poorly understood. We investigate the evolutionary history of Haloveliinae using large-scale phylogenomic datasets and a set of novel redefined morphological characters based on 24 ingroup taxa representing all recognized genera. Our phylogenetic results based on the novel datasets definitively indicate that the freshwater genus Strongylovelia Esaki as currently defined is paraphyletic and supports the establishment of a new genus: Metavelia gen. nov., including three congeneric species: Metavelia patiooni comb. nov. (type species), Metavelia priori comb. nov. and Metavelia albicolli comb. nov. Reconstruction of ancestral habitats suggests a freshwater origin for the Haloveliinae. Divergence time estimations reveal that the origin of the monophyletic marine clade occurred at around 83 Ma (95% highest posterior density: 71-98 Ma) in the Late Cretaceous, involving a single transition event from freshwater to marine habitats. This time coincides with the period of high global sea levels in the Late Cretaceous. During this period, the marine incursions caused by the massive sea level rise flooded the continental margins, especially in Southeast Asia, where ancestral Haloveliinae were probably distributed. The appearance of new marine habitats after the marine incursions (e.g., intertidal, mangroves and estuarine) probably led to a subsequent establishment and diversification of the marine lineages.

Two species of the genus Valleriola Distant, 1904 (Heteroptera: Leptopodomorpha: Leptopodidae: Leptopodinae: Leptopodini) are described as new: Valleriola asiatica sp. nov. from Laos and Hainan Island of China, and Valleriola bui sp. nov. from Laos and Thailand. In addition, Leptopus riparius Hsiao, 1964 is newly recorded for Vietnam, Valleriola javanica Drake & Hottes, 1951 is newly recorded for Laos, and additional records are provided for Leptopus riparius, Valleriola javanica and Valleriola buenoi (Usinger, 1942). Photographs of the dorsal habitus, heads, hemelytra, fore femora, male parameres and live specimens are provided, accompanied by a distribution map for the species of Leptopodini occurring in East and Southeast Asia.

The aim of this study was to analyze morphological types and arrangement of the leg sensilla of Corixidae, Ochteridae and Gelastocoridae, in relation to their various habitats. The leg sensilla of four species of Corixidae, six of Gelastocoridae and two of Ochteridae were studied. Eight main types of sensilla with six subtypes of sensilla trichodea and four subtypes of sensilla chaetica were found and described. The greatest variability was observed among mechanoreceptive sensilla. The study showed differences in the shape of the legs between strictly aquatic and terrestrial taxa. It is the first attempt to describe leg sensilla among nepomorphan taxa.

A bstract Studies of the Papuan region have provided fundamental insights into both the evolutionary processes generating its exceptional biodiversity, as well support for alternative hypotheses of geological history. Lying at the junction of five tectonic plates, this region has experienced a turbulent geological history that has not only produced towering mountains allowing elevational specialization, and island archipelagos of varying distance promoting vicariance, but also active margins where land masses have collided and been subsequently rifted apart creating a mosaic of intermixed terranes with vastly different geological histories which may influence the evolutionary history of its biota. Asterophryine frogs are a hyperdiverse clade representing half the world’s microhylid diversity (over 360 species) centered on New Guinea and its satellite islands. We show that vicariance facilitated by geological history, and not elevational specialization best explain this far and wide distribution of a clade that should have poor dispersal abilities. Thus, some of the predictions of island biogeography theory are supported if informed by geological history. We recovered a mainland tectonic unit, the East Papua Composite Terrane (EPCT), as the center of origin for Asterophryinae and no fewer than 71 instances of what appear to be long-distance dispersal events, 29 of which are between mainland regions, with 42 from the mainland to the islands, some presently as far as 200 km away from source populations over open ocean. Furthermore, we find strong support for a “Slow and Steady” hypothesis for the formation of the northern margin of New Guinea by many separate accretion events during the Miocene, over other major geological alternatives, consistent with the 20 M year age of the clade and arrival via the EPCT. In addition, the historical biogeography of our frogs strongly support an affiliation of the Louisiade Archipelago and Woodlark Island with the Owen Stanley Mountain range on the EPCT, and the recent proximity of the large New Britain island. Our results show that Asterophryinae did not have to repeatedly and independently disperse across and large ocean barriers to the offshore islands, but that the current distribution can be explained through vicariance and short-distance oceanic dispersal as historical land connections disappeared and islands slowly became separated from each other. We show that islands have a life history, undergoing changes in area through island-building and erosion, but also change in distance from other land masses, with consequent opportunities for dispersal, isolation, and cladogenesis of their biotas. More broadly, we can begin to see how the geological history of the Papuan region can result in the rapid accumulation and staggering number of extant species.

We examined the morphology, colour patterns and genetic relationships of Nososticta populations allied to N. salomonis (Selys) from across Melanesia. Seven species-level taxa are recognised in the N. salomonis 'complex': N. africana (Schmidt), N. boonei sp. nov., N. chrismulleri Theischinger & Richards, N. hedigeri sp. nov., N. salomonis (Selys), N. stueberi sp. nov., and N. tagula sp. nov. All of these species are black damselflies with blue markings, and they differ from all other Nososticta by having: 1) a prominent spike on the male superior appendage, 2) a prominent angular base of the male inferior appendage, and 3) a complex posterior lobe on the female pronotum bearing two pairs of processes in the rough shape of a chair when viewed laterally. A molecular phylogeny based on the DNA barcode fragment of the COI gene plus two nuclear genes indicates that these seven species are closely related, but more extensive sampling of Nososticta species is required to confirm that they form a monophyletic group.

Studies of the Papuan region have provided fundamental insights into the evolutionary processes generating its exceptional biodiversity, but the influence of geological processes merits further study. Lying at the junction of five tectonic plates, this region has experienced a turbulent geological history that has not only produced towering mountains allowing elevational specialization and island archipelagos with varying degrees of isolation promoting vicariance, but also active margins where land masses have collided and been subsequently rifted apart creating a mosaic of intermixed terranes with vastly different geological histories. Asterophryine frogs are a hyperdiverse clade representing half the world's microhylid diversity (over 360 species) centered on New Guinea and its satellite islands. We show that vicariance facilitated by geological history explains this far and wide distribution of a clade that should have poor dispersal abilities. We recovered a mainland tectonic unit, the East Papua Composite Terrane (EPCT), as the center of origin for Asterophryinae and no fewer than 71 instances of what appear to be long-distance dispersal events, 29 of which are between mainland regions, with 42 from the mainland to the islands, some presently as far as 200 km away from source populations over open ocean. Furthermore, we find strong support for a "Slow and Steady" hypothesis for the formation of the northern margin of New Guinea by many separate accretion events during the Miocene, over other major geological alternatives, consistent with the 20 M year age of the clade and arrival via the EPCT. In addition, the historical biogeography of our frogs strongly supports an affiliation of the Louisiade Archipelago and Woodlark Island with the Owen Stanley Range on the EPCT, and the recent proximity of the large New Britain Island. Our results show that Asterophryinae did not have to repeatedly and independently disperse across large ocean barriers to the offshore islands, against the predictions of island biogeography theory, but that the current distribution can be explained through vicariance and short-distance oceanic dispersal as historical land connections disappeared and islands slowly became separated from each other. We show that islands have a life history, changing in distance from other land masses, with consequent opportunities for dispersal, isolation, and cladogenesis of their biotas. More broadly, we can begin to see how the geological history of the Papuan region can result in the rapid accumulation and staggering number of extant species.