Insights into the molecular phylogeny of Rhaphidophoridae, an ancient, worldwide lineage of Orthoptera

Phylogeny and biogeography of the wingless orthopteran family Rhaphidophoridae

Cave crickets (Rhaphidophoridae) are insects of an ancient and wingless lineage within Orthoptera that are distributed worldwide except in Antarctica, and each subfamily has a high level of endemicity. Here, we show the comprehensive phylogeny of cave crickets using multi-gene datasets from mitochondrial and nuclear loci, including all extant subfamilies for the first time. We reveal phylogenetic relationships between subfamilies, including the sister relationship between Anoplophilinae and Gammarotettiginae, based on which we suggest new synapomorphies. Through biogeographic analyses based on divergence time estimations and ancestral range reconstruction, we propose novel hypotheses regarding the biogeographic history of cave crickets. We suggest that Gammarotettiginae in California originated from the Asian lineage when Asia and the Americas were connected by the Bering land bridge, and the opening of the western interior seaway affected the division of Ceuthophilinae from Tropidischiinae in North America. We estimate that Rhaphidophoridae originated at 138 Mya throughout Pangea. We further hypothesize that the loss of wings in Rhaphidophoridae could be the result of their adaptation to low temperatures in the Mesozoic era.

Fossil-calibrated phylogenies of Southern cave wētā show dispersal and extinction confound biogeographic signal

The biota of continents and islands are commonly considered to have a source-sink relationship, but small islands can harbour distinctive taxa. The distribution of four monotypic genera of Orthoptera on young subantarctic islands indicates a role for long-distance dispersal and extinction. Phylogenetic relationships were inferred from whole mtDNA genomes and nuclear sequences (45S cassette; four histones). We used a fossil and one palaeogeographic event to calibrate molecular clock analysis. We confirm that neither the Australian nor Aotearoa-New Zealand Rhaphidophoridae faunas are monophyletic. The radiation of Macropathinae may have begun in the late Jurassic, but trans-oceanic dispersal is required to explain the current distribution of some lineages within this subfamily. Dating the most recent common ancestor of seven island endemic species with their nearest mainland relative suggests that each existed long before their island home was available. Time estimates from our fossil-calibrated molecular clock analysis suggest several lineages have not been detected on mainland New Zealand, Australia, or elsewhere most probably due to their extinction, providing evidence that patterns of extinction, which are not consistently linked to range size or lineage age, confound biogeographic signal.

Two new species of the genus Diestramima from China (Orthoptera: Rhaphidophoridae: Aemodogryllinae)

The genus Diestramima comprises 41 species from Asia with 31 species distributed in China. In this study, we reconstruct the phylogeny tree of Diestramima species by maximum likelihood and Bayesian inference based on three mitochondrial genes (COI, 12S and 16S). The result indicates that the phylogenetic results are coherent with that based on five molecular markers (COI, 12S, 16S, 18S and 28S). Moreover, two new species, D. pingmengensis sp. nov. He & Zong and D. gulinjingensis. sp. nov. Zong & He are described. Their validities are also supported by morphological features. Furthermore, D. sichuanensis Zhu & Shi, 2022 is treated as a junior synonym of D. guangxiensis Qin, Wang, Liu & Li, 2016 based on both morphological and molecular features.

Phylogeny and Integrative Taxonomy of the Genera Gymnaetoides and Pseudotachycines (Orthoptera: Rhaphidophoridae)

The genera Gymnaetoides and Pseudotachycines are endemic to China and are morphologically homogeneous. The few available diagnostic characters make species identification particularly challenging. Species cannot be classified according to the given generic diagnosis, and phylogenetic analyses have not been reported. Here, we reconstruct the phylogeny using Bayesian inference and maximum likelihood and employ four approaches to delimit species. The results suggest that both Gymnaetoides and Pseudotachycines are paraphyletic. Therefore, we revise their taxonomy based on the combination of morphological characters and molecular data. A new genus Homotachycines Zhu & Shi gen. nov. is erected, and six new combinations are proposed. Species delimitation identifies 15 new species and one new subspecies: Gymnaetoides huangshanensis, G. petalus, G. yangmingensis, G. lushanensis, Pseudotachycines procerus, P. procerus guizhouensis, P. zhengi, P. nephrus, P. sagittus, P. fengyangshanensis, Homotachycines triangulus, H. quadratus, H. baokangensis, H. fusus, H. concavus, and H. qinlingensis sp. nov. Moreover, we find that the shapes of the dorsal lateral lobes and the dorsal median lobe of the male genitalia are also important characters for identifying these genera and that the shapes of the dorsal and lateral sclerites of the male genitalia are suitable for the classifications of species.

Systematic revision of the trans-Bassian moriomorphine genus Theprisa Moore (Coleoptera, Carabidae)

The Australian genus Theprisa Moore, 1963, is taxonomically revised to comprise five species, two newly described: Theprisadarlingtoni Liebherr & Porch, sp. nov. of Tasmania, and Theprisaotway Liebherr, Porch & Maddison, sp. nov. from the Otway Ranges, Victoria. Two previously described species, T.australis (Castelnau) and T.montana (Castelnau), are distributed in the mountains of Victoria. The third previously described species, T.convexa (Sloane) is found in Tasmania. A lectotype is designated for T.convexa because the various syntypes are ambiguously labelled. Cladistic analysis based on morphological characters establishes monophyly of Theprisa relative to the Australian genera Sitaphe Moore and Spherita Liebherr. This and a second clade of Australian genera (Pterogmus Sloane, Thayerella Baehr, and Neonomius Moore) do not form a natural group, but are cladistically interdigitated among two monophyletic New Zealand lineages (Tarastethus Sharp, and Trichopsida Larochelle and Larivière) suggesting substantial trans-Tasman diversification among these groups. Hypothesized relationships within Theprisa are consistent with two bouts of speciation involving the Bass Strait; an initial event establishing T.convexa as adelphotaxon to the other four species, and a more recent event establishing the sister species T.darlingtoni and T.montana. Geographic restriction of T.otway to the Otway Ranges is paralleled by Otway endemics in several other carabid beetle genera, as well as by endemics in numerous other terrestrial arthropod taxa. Whereas these numerous Otway endemics support the distinctive nature of the Otway Range fauna, their biogeographic relationships are extremely varied, illustrating that the Otways have accrued their distinctive biodiversity via various means.

Phylogenomic analysis sheds light on the evolutionary pathways towards acoustic communication in Orthoptera

Acoustic communication is enabled by the evolution of specialised hearing and sound producing organs. In this study, we performed a large-scale macroevolutionary study to understand how both hearing and sound production evolved and affected diversification in the insect order Orthoptera, which includes many familiar singing insects, such as crickets, katydids, and grasshoppers. Using phylogenomic data, we firmly establish phylogenetic relationships among the major lineages and divergence time estimates within Orthoptera, as well as the lineage-specific and dynamic patterns of evolution for hearing and sound producing organs. In the suborder Ensifera, we infer that forewing-based stridulation and tibial tympanal ears co-evolved, but in the suborder Caelifera, abdominal tympanal ears first evolved in a non-sexual context, and later co-opted for sexual signalling when sound producing organs evolved. However, we find little evidence that the evolution of hearing and sound producing organs increased diversification rates in those lineages with known acoustic communication.