Complex within a Complex: Integrative Taxonomy Reveals Hidden Diversity in Cicadetta brevipennis (Hemiptera: Cicadidae) and Unexpected Relationships with a Song Divergent Relative

Look closely and listen carefully: unexpected cicada diversity in northern Sardinia, with the description of a new species (Cicadidae: Tibicina)

Integrative taxonomy combines different data sources as a way to detect separately evolving metapopulation lineages or species. This method is applied to cicada populations found in northern Sardinia, based on acoustic, morphological and ecological data. Thereby, the genus Tibicina turned out to be more diverse than previously expected. Besides the anticipated Tibicina corsica corsica and T. nigronervosa, both scientifically described from the neighbouring island of Corsica, two poorly or previously unknown species have been discovered. Tibicina longisyllaba sp. nov. is here described as new. Tibicina corsica s.l. forms a small species complex where syllable periods of the song – the movement cycle of the acoustic organs – are specific without overlaps. Some coloration and hair cover characters, as well as the shape of the song apparatus, are not diagnostic on their own, but highly significant between species. Species occur sympatrically, parapatrically or allopatrically and prefer specific habitats from grassland to closed forests. All four Tibicina taxa are endemic to parts of Sardinia or to the Corso-Sardinian archipelago. The new findings are important for biodiversity conservation and public awareness. The loud, strident calling songs dominate the summer sounds of the islands. The group could form a showcase with respect to biogeography, phylogeny, speciation and sound production.

Relicts from Glacial Times: The Ground Beetle Pterostichus adstrictus Eschscholtz, 1823 (Coleoptera: Carabidae) in the Austrian Alps

Simple Summary

The extant distribution of many plants and animals is the result of the dynamics of the last ice ages with their recurrent advances and retreats of the northern ice sheet and the glaciers in the mountains. The arctic-alpine distribution is a special case where a species occurs in the subarctic/arctic regions and locally restricted in the alpine mountain regions of central or southeastern Europe. Among the ground beetles, several species display this type of distribution, one of which is Pterostichus adstrictus. In Europe, this ground beetle has been thought to have its southernmost occurrences in Wales and southern Scandinavia. In this study, we provide the first reliable record of P. adstrictus from the Austrian Alps based on morphological determination and comparison to other closely related species as well as molecular genetic data. Furthermore, the seasonal occurrence as well as empirical habitat preferences of P. adstrictus in the Austrian Alps are described.

Abstract

The last ice age considerably influenced distribution patterns of extant species of plants and animals, with some of them now inhabiting disjunct areas in the subarctic/arctic and alpine regions. This arctic-alpine distribution is characteristic for many cold-adapted species with a limited dispersal ability and can be found in many invertebrate taxa, including ground beetles. The ground beetle Pterostichus adstrictus Eschscholtz, 1823 of the subgenus Bothriopterus was previously known to have a holarctic-circumpolar distribution, in Europe reaching its southern borders in Wales and southern Scandinavia. Here, we report the first findings of this species from the Austrian Ötztal Alps, representing also the southernmost edge of its currently known distribution, confirmed by the comparison of morphological characters to other Bothriopterus species and DNA barcoding data. Molecular data revealed a separation of the Austrian and Finish specimens with limited to no gene flow at all. Furthermore, we present the first data on habitat preference and seasonality of P. adstrictus in the Austrian Alps.

Checklist and provisional atlas of singing cicadas (Hemiptera: Cicadidae) of Bulgaria, based on bioacoustics

Background

The singing cicadas (Hemiptera: Cicadidae) of Bulgaria were poorly known. There are published records for 14 species: Cicadaorni, Lyristesplebejus, Cicadatraatra, Cicadatrahyalina, Cicadatrapersica, Cicadettamontana, Cicadettamediterranea, Dimissalnadimissa, Oligoglenatibialis, Tympanistalnagastrica, Pagiphoraannulata, Saticulacoriaria, Tibicinahaematodes and Tibicinasteveni.

New information

Two species from this list were doubtful in the beginning of our study, since Tympanistalnagastrica is distributed in central and southern Portugal and Saticulacoriaria is a north African species.

We checked three major institutional collections housed in Sofia, Bulgaria: the National Museum of Natural History (SOFM), the Institute of Zoology (ZISB) and the Biology Faculty of Sofia University "St. Kliment Ohridski" (BFUS). We confirmed 11 of the species mentioned in literature, except Cicadettamediterranea and found two additional species: Cicadatraplatyptera and Cicadettamacedonica (the specimens in BFUS were bioacoustically confirmed).

Based on this knowledge, we further investigated the singing cicadas of Bulgaria with the use of morphological and bioacoustic methods in the years 2008, 2009, 2010, 2012, 2016, 2018 and 2019. We were not able to confirm the presence of Cicadatrapersica and Cicadettamediterranea, but found three additional species: Cicadettabrevipennis s. lat., Cicadettacantilatrix and Tettigettulapygmea. Using the bioacoustic methods, we also detected unknown singing patterns, which could belong to three or four additional taxa, which need to be described.

The Bulgarian fauna of singing cicadas at the moment consists of 16 confirmed and 3-4 potential species.

Off-target capture data, endosymbiont genes and morphology reveal a relict lineage that is sister to all other singing cicadas

Phylogenetic asymmetry is common throughout the tree of life and results from contrasting patterns of speciation and extinction in the paired descendant lineages of ancestral nodes. On the depauperate side of a node, we find extant ‘relict’ taxa that sit atop long, unbranched lineages. Here, we show that a tiny, pale green, inconspicuous and poorly known cicada in the genus Derotettix, endemic to degraded salt-plain habitats in arid regions of central Argentina, is a relict lineage that is sister to all other modern cicadas. Nuclear and mitochondrial phylogenies of cicadas inferred from probe-based genomic hybrid capture data of both target and non-target loci and a morphological cladogram support this hypothesis. We strengthen this conclusion with genomic data from one of the cicada nutritional bacterial endosymbionts, Sulcia, an ancient and obligate endosymbiont of the larger plant-sucking bugs (Auchenorrhyncha) and an important source of maternally inherited phylogenetic data. We establish Derotettiginae subfam. nov. as a new, monogeneric, fifth cicada subfamily, and compile existing and new data on the distribution, ecology and diet of Derotettix. Our consideration of the palaeoenvironmental literature and host-plant phylogenetics allows us to predict what might have led to the relict status of Derotettix over 100 Myr of habitat change in South America.