Molecular and taxonomic analyses in troglobiotic Alpioniscus (Illyrionethes) species from the Dinaric Karst (Isopoda: Trichoniscidae)

Species richness of terrestrial isopods is high in caves of the Dinaric Karst, which hosts ~10% of the world’s nominal oniscidean troglobionts. The most widespread taxon is the southern European genus Alpioniscus, which consists of two subgenera: Alpioniscus s.s. and Illyrionethes. Before this study, 14 nominal troglobiotic Illyrionethes taxa were recorded from the Dinaric Karst. Our molecular analyses using two mitochnodrial DNA (16S rRNA and COI) fragments and a nuclear gene (H3) fragment on all known Dinaric taxa identified three distinct lineages: strasseri-, heroldi- and magnus-lineage. Our results confirmed the validity of most nominal species. The exceptions are Alpioniscus balthasari, which consists of two different species including Alpioniscus iapodicus, and Alpioniscus heroldi, which is paraphyletic with respect to Alpioniscus bosniensis. The strasseri-lineage was highly supported by all phylogenetic methods used; therefore, we performed a detailed morphological analysis to distinguish and characterize the species of this group. New morphological characters, such as body part ratios, are proposed for future species identification. In addition, we redescribe three known species (Alpioniscus strasseri, Alpioniscus christiani and Alpioniscus balthasari) and describe two new ones (Alpioniscus hirci sp. nov. and Alpioniscus velebiticus sp. nov.). As a result, 15 nominal species of Illyrionethes are currently known from the Dinaric Karst.

Terrestrial isopods in urban environments: an overview

In an increasingly urbanized world scientific research has shifted towards the understanding of cities as unique ecosystems. Urban land use change results in rapid and drastic changes in physical and biological properties, including that of biodiversity and community composition. Soil biodiversity research often lags behind the more charismatic groups such as vertebrates and plants. This paper attempts to fill this gap and provides an overview on urban isopod research. First, a brief overview on urban land use change is given, specifically on the major alterations on surface soils. Historical studies on urban isopods is summarized, followed by the status of current knowledge on diversity, distribution, and function of urban isopod species and communities. A review of more than 100 publications revealed that worldwide 50 cities and towns have some record of terrestrial isopod species, but only a few of those are city-scale explorations of urban fauna. A total of 110 isopod species has been recorded although the majority of them only once. The ten most frequently occurring isopods are widely distributed synanthropic species. Knowledge gaps and future research needs call for a better global dataset, long term monitoring of urban populations, multi-scale analyses of landscape properties as potential drivers of isopod diversity, and molecular studies to detect evolutionary changes.

Isopod distribution and climate change

The unique properties of terrestrial isopods regarding responses to limiting factors such as drought and temperature have led to interesting distributional patterns along climatic and other environmental gradients at both species and community level. This paper will focus on the exploration of isopod distributions in evaluating climate change effects on biodiversity at different scales, geographical regions, and environments, in view of isopods’ tolerances to environmental factors, mostly humidity and temperature.

Isopod distribution is tightly connected to available habitats and habitat features at a fine spatial scale, even though different species may exhibit a variety of responses to environmental heterogeneity, reflecting the large interspecific variation within the group.

Furthermore, isopod distributions show some notable deviations from common global patterns, mainly as a result of their ecological features and evolutionary origins. Responses to human disturbance are not always traceable, but a trend towards community homogenisation is often found under strong global urbanisation processes.

In general, even though it is still not clear how predicted climate change will affect isopod distribution, there is evidence that mixed effects are to be expected, depending on the region under study.

We still lack robust and extensive analyses of isopod distributions at different scales and at different biomes, as well as applications of distribution models that might help evaluate future trends.

Integrative taxonomy reveals a new genus and new species of Philosciidae (Crustacea: Isopoda: Oniscidea) from the Neotropical region

Although new methods and data are conquering space in the field of taxonomy, such as integrative taxonomy, most terrestrial isopod species are still described based only on morphology. Species of the genus Atlantoscia Ferrara and Taiti, 1981 were the first and are the unique terrestrial isopods from the Neotropics for which a molecular phylogeny was already conducted. Previous results indicated that this genus could be paraphyletic, and a more detailed analysis would be required. Our aim was to reconstruct the phylogeny of Atlantoscia using mitochondrial and nuclear markers and test its monophyly by integrating molecular and morphological data. We observed that, indeed, Atlantoscia is paraphyletic. Atlantoscia ituberasensis Campos-Filho, Lisboa and Araujo, 2013 and Atlantoscia rubromarginata Araujo and Leistikow, 1999 were placed in a new genus of terrestrial isopods, Paratlantoscia gen. nov., together with a new species described in the present study, Paratlantoscia robusta sp. nov. The new genus is defined by the presence of specialized respiratory areas in the pleopod exopods and its validity is highly corroborated by molecular analyses and by biogeographic information. This study highlights the importance of multiple and complementary perspectives as a way to improve the quality of species hypothesis and associated descriptions.