Speciation history and widespread introgression in the European short-call tree frogs (Hyla arborea sensu lato, H. intermedia and H. sarda).

European tree frogs (Hyla) characterized by short temporal parameters of the advertisement call form six genetically differentiated but morphologically cryptic taxa, H. arborea sensu stricto, H. orientalis and H. molleri from across Europe to western Asia (together referred to as H. arborea sensu lato), two putative taxa within H. intermedia (Northern and Southern) from the Italian Peninsula and Sicily, and H. sarda from Sardinia and Corsica. Here, we assess species limits and phylogenetic relationships within these 'short-call tree frogs' based on mitochondrial DNA and nuclear protein-coding markers. The mitochondrial and nuclear genes show partly incongruent phylogeographic patterns, which point to a complex history of gene flow across taxa, particularly in the Balkans. To test the species limits in the short-call tree frogs and to infer the species tree, we used coalescent-based approaches. The monophyly of H. arborea sensu lato is supported by the mtDNA as well as by the all-gene species tree. The Northern and Southern lineages of H. intermedia have been connected by nuclear gene flow (despite their deep mtDNA divergence) and should be treated as conspecific. On the contrary, the parapatric taxa within H. arborea sensu lato should be considered distinct species (H. arborea, H. orientalis, H. molleri) based on the coalescent analysis, although signs of hybridization were detected between them (H. arborea×H. orientalis; H. arborea×H. molleri). A mitochondrial capture upon secondary contact appears to explain the close mtDNA relationship between the geographically remote Iberian H. molleri and H. orientalis from around the Black Sea. Introgressive hybridization occurred also between the Balkan H. arborea and northern Italian H. intermedia, and between the Minor Asiatic H. orientalis and Arabian H. felix arabica (the latter belonging to a different acoustic group/clade). Our results shed light on the species limits in the European short-call tree frogs and show that introgression played an important role in the evolutionary history of the short-call tree frogs and occurred even between taxa supported as distinct species.

Evolutionary history of Ichthyosaura alpestris (Caudata, Salamandridae) inferred from the combined analysis of nuclear and mitochondrial markers.

Widespread species with morphologically and ecologically differentiated populations are key to understand speciation because they allow investigating the different stages of the continuous process of population divergence. The alpine newt, Ichthyosaura alpestris, with a range that covers a large part of Central Europe as well as isolated regions in all three European Mediterranean peninsulas, and with strong ecological and life-history differences among populations, is an excellent system for such studies. We sampled individuals across most of the range of the species, and analyzed mitochondrial (1442 bp) and nuclear (two nuclear genes -1554 bp- and 35 allozyme loci) markers to produce a time-calibrated phylogeny and reconstruct the historical biogeography of the species. Phylogenetic analyses of mtDNA data produced a fully resolved topology, with an endemic, Balkan clade (Vlasina) which is sister to a clade comprising an eastern and a western group. Within the former, one clade (subspecies I. a. veluchiensis) is sister to a clade containing subspecies I. a. montenegrina and I. a. serdara as well as samples from southern Romania, Bosnia-Herzegovina, Serbia and Bulgaria (subspecies I. a. reiseri and part of I. a. alpestris). Within the western group, populations from the Italian peninsula (subspecies I. a. apuana and I. a. inexpectata) are sister to a clade containing samples from the Iberian Peninsula (subspecies I. a. cyreni) and the remainder of the samples from subspecies I. a. alpestris (populations from Hungary, Austria, Poland, France, Germany and the larger part of Romania). Results of (∗)BEAST analyses on a combined mtDNA and nDNA dataset consistently recovered with high statistical support four lineages with unresolved inter-relationships: (1) subspecies I. a. veluchiensis; (2) subspecies I. a. apuana+I. a. inexpectata; (3) subspecies I. a. cyreni+part of subspecies I. a. alpestris (the westernmost populations, plus most Romanian populations); and (4) the remaining populations, including subspecies I. a. serdara, I. a. reiseri and I. a. montenegrina and part of subspecies I. a. alpestris, plus samples from Vlasina. Our time estimates are consistent with ages based on the fossil record and suggest a widespread distribution for the I. alpestris ancestor, with the split of the major eastern and western lineages during the Miocene, in the Tortonian. Our study provides a solid, comprehensive background on the evolutionary history of the species based on the most complete combined (mtDNA+nDNA+allozymes) dataset to date. The combination of the historical perspective provided by coalescent-based analyses of mitochondrial and nuclear DNA variation with individual-based multilocus assignment methods based on multiple nuclear markers (allozymes) also allowed identification of instances of discordance across markers that highlight the complexity and dynamism of past and ongoing evolutionary processes in the species.

Molecular diversity of Pseudoscorpiones in southern High Appalachian leaf litter.

The Pseudoscorpiones fauna of North America is diverse, but in regions like the southern Appalachian Mountains, they are still poorly documented with respect to their species diversity, distributions and ecology. Several families have been reported from these mountains and neighbouring areas. Here we analyse barcoding data of 136 specimens collected in leaf litter, most of them from high-elevation coniferous forest. We used ASAP as a species delimitation method to obtain an estimation of the number of species present in the region. For this and based on interspecific genetic distance values previously reported in Pseudoscorpions, we considered three different genetic Kimura two-parameter distance thresholds (3%/5%/8%), to produce more or less conservative estimates. These distance thresholds resulted in 64/47/27 distinct potential species representing the families Chthoniidae (33/22/12 species) and Neobisiidae (31/25/15) and at least six different genera within them. The diversity pattern seems to be affected by the Asheville Depression, a major biogeographic barrier in this area, with a higher diversity to the west of this geographic feature, particularly within the family Neobisiidae. The absence of representatives from other families amongst our studied samples may be explained by differences in their ecological requirements and occupation of different microhabitats.

Molecular diversity of Diplura in southern High Appalachian leaf litter.

The fauna of Diplura, the two-pronged bristletails (Hexapoda), of the southern Appalachians has received little focused systematic attention. Existing literature suggests the fauna to comprise around a dozen species. Based on a broader DNA barcode-based survey of high elevation litter arthropods in the region, we suggest the fauna to be much richer, with automated species delimitation methods hypothesising as many as 35 species, most highly restricted to single or closely proximate localities. Such a result should not be very surprising for such small, flightless arthropods, although it remains to be seen if other markers or morphology support such high diversity. The region still remains sparsely sampled for these more cryptic elements of the arthropod fauna and much larger numbers of species undoubtedly remain to be discovered.

Bio-inspired design of hard-bodied mobile robots based on arthropod morphologies: a 10-year systematic review and bibliometric analysis.

This research presents a 10-year systematic review based on bibliometric analysis of the bio-inspired design of hard-bodied mobile robot mechatronic systems considering the anatomy of arthropods. These are the most diverse group of animals whose flexible biomechanics and adaptable morphology, thus, it can inspire robot development. Papers were reviewed from two international databases (Scopus and Web of Science) and one platform (Aerospace Research Central), then they were classified according to: year of publication (January 2013 to April 2023), arthropod group, published journal, conference proceedings, editorial publisher, research teams, robot classification according to the name of arthropod, limb's locomotion support, number of legs/arms, number of legs/body segments, limb's degrees of freedom, mechanical actuation type, modular system, and environment adaptation. During the screening, more than 33000 works were analyzed. Finally, a total of 174 studies (90 journal-type, 84 conference-type) were selected for in-depth study: Insecta - hexapod (53,8%), Arachnida - octopods (20.7%), Crustacea - decapods (16,1%), and Myriapoda - centipedes and millipedes (9,2%). The study reveals that the most active editorials are the Institute of Electrical and Electronics Engineers Inc., Springer, MDPI, and Elsevier, while the most influential researchers are located in the USA, China, Singapore, and Japan. Most works pertained to spiders, crabs, caterpillars, cockroaches, and centipedes. We conclude that "arthrobotics" research, which merges arthropods and robotics, is constantly growing and includes a high number of relevant studies with findings that can inspire new methods to design biomechatronic systems.

How complex is the Bufo bufo species group?

Species delineation remains one of the most challenging tasks in the study of biodiversity, mostly owing to the application of different species concepts, which results in contrasting taxonomic arrangements. This has important practical consequences, since species are basic units in fields like ecology and conservation biology. We here review molecular genetic evidence relevant to the systematics of toads in the Bufo bufo species group (Anura, Bufonidae). Two studies recently published in this journal (Recuero et al., MPE 62: 71-86 and García-Porta et al., MPE 63: 113-130) addressed this issue but reached opposing conclusions on the taxonomy of the group (four versus two species). In particular, allozyme data in the latter paper were interpreted as evidence for hybridization across species (between B. bufo-B. spinosus and B. bufo-B. verrucosissimus). We tested claims for hybridization through re-analysis of allozyme data for individuals instead of populations, to be able to distinguish between sympatry with and without admixture, and found no evidence of hybridization across taxa. We propose alternative explanations for the observed patterns that García-Porta et al. (2012) failed to consider. In the absence of unequivocal evidence for hybridization and introgression, we reject the proposal to downgrade Bufo spinosus and Bufo verrucosissimus to the subspecies level.

Molecular diversity of Protura in southern High Appalachian leaf litter.

The higher elevations of the southern Appalachian Mountains, U.S.A., host a rich, but little-studied fauna of Proturan hexapods. Here, we publish 117 Proturan barcode sequences from this region, estimated by automated species delimitation methods to represent 72 distinct species, whereas only nine species have previously been reported from the region. Two families, Eosentomidae and Acerentomidae, co-occur at most sampling sites, with as many as five species occurring in sympatry. Most populations exhibit very low haplotype diversity, but divergences amongst populations and amongst closely-related species are very high, a finding common to other phylogeographic studies of Proturans. Though we were unable to identify any of the barcodes to species, they form a useful, if preliminary, glimpse of southern Appalachian Proturan diversity.

A second species of the pill millipede genus Nearctomeris Wesener, 2012 (Diplopoda, Glomerida) from the Great Smoky Mountains, USA.

We describe a second species of Nearctomeris Wesener, 2012, a genus of pill millipede endemic to the southern Appalachians, based on morphological and molecular evidence. The fauna of Glomerida in America is characterized by its low diversity, and Nearctomerissmokysp. nov. is only the fifth species of the order known from the eastern United States. Our phylogenetic analyses based on COI sequences recover a tentatively monophyletic lineage including both eastern American genera Onomeris Cook, 1896 and Nearctomeris, with a common ancestor in the Late Cretaceous to Mid Eocene and extant diversity within genera dating back to the Miocene. Our results suggest that the observed low diversity of the group in the eastern US is likely caused by extinction events, but it is also possible that new species are yet to be found. We provide new records for Nearctomerisinexpectata Wesener, 2012, Onomerisunderwoodi Cook, 1896 and O.australora Hoffman, 1950; the latter is here reported for the first time from South Carolina. We also present DNA barcoding data for all species of Glomerida present in the US that are not yet publicly available.

A new systematic arrangement for the blister beetle genus Eurymeloe (Meloini, Meloidae, Coleoptera) with the description of a new species from Spain.

The taxonomic status and subgeneric arrangement of the genus Eurymeloe have been debated for decades. In this work, the internal taxonomy of Eurymeloe is redefined by recognising three subgenera: Eurymeloe for the former Eurymeloebrevicollis species group, Coelomeloe for Eurymeloetuccia, and Bolognaia Ruiz, García-París, Sánchez-Vialas & Recuero, subgen. nov., to accommodate the species of the formerly recognised Eurymeloerugosus species group. Additionally, a new species of the newly described subgenus Bolognaia is described from the Iberian Peninsula based on molecular and morphological traits. The new species, Eurymeloe (Bolognaia) orobatessp. nov., can be distinguished from all other species of Eurymeloe by the following combination of morphological traits: dispersed brownish setae over the body that are arranged in small tufts on the abdominal terga; a small, very transverse pronotum that presents a unique macrosculpture; a deeply and densely punctured integument of the head and pronotum; and the very rugose elytra. The characters displayed by E.orobates suggest that the species groups that were previously defined and recognised for Eurymeloe, and that are now integrated within the newly erected subgenus Bolognaia, are non-monophyletic.

Phylogenetic patterns in zopherine beetles are related to ecological niche width and dispersal limitation.

Niche conservatism has been proposed as the mechanism driving speciation in temperate montane clades through range fragmentation during climatic oscillations. Thus, a negative relationship between speciation rates and niche width is expected. Here, we test this prediction using American zopherine beetles. Our phylogenetic analyses recovered two clades in addition to that of the genus Zopherus: the genera Verodes and Phloeodes, which originated most likely in the Eocene, and diversified during the Miocene and the Pliocene. The assessment of clade niche width in relation to clade diversity supported the proposition of narrow niches leading to a higher probability of range fragmentation during climatic oscillations, thus increasing speciation. Additionally, almost all current populations of Phloeodes and Verodes are located within regions that retained favourable climatic conditions across warm and cold Pleistocene periods, suggesting that dispersal limitation is a strong factor controlling clade distribution. In sum, our results suggest that (i) niche width is a major determinant of the probability of speciation in temperate montane clades, by controlling the probability of potential range fragmentation and (ii) dispersal limitation is also a major determinant of the speciation process, by increasing the fragmentation of realized ranges even when potential distributions are cyclically fused during climatic oscillations. When dispersal limitation is extreme, as in zopherine beetles, populations persist just in those areas that have retained suitable conditions during extremes of past climatic oscillations. Paradoxically, this relict condition confers zopherine beetles great resilience for facing future climate change.

Evolutionary history of Lissotriton helveticus: multilocus assessment of ancestral vs. recent colonization of the Iberian Peninsula.

The Pleistocene was characterized by climatic changes that greatly altered the distribution of organisms. Population extinctions, bottlenecks, isolation, range expansions and contractions were often associated with glaciations, leaving signatures in the spatial patterns of genetic diversity across species. Lissotriton helveticus belongs to a Pan-European lineage of newts that were strongly affected by glaciations and represent an excellent model to analyse the effect of generalized climatic changes in phylogeographic patterns. We studied the genetic diversity of the species using data from two mitochondrial and three nuclear genes analyzed in a Bayesian phylogenetic framework to investigate the historical processes shaping spatial patterns of genetic diversity. Mitochondrial haplotypes cluster in four different groups present in the Iberian Peninsula and of Pleistocene origin, probably by allopatric fragmentation. Nuclear genes present no obvious geographic structure patterns, suggesting gene flow and generalized incomplete lineage sorting. Populations north of the Pyrenees are closely related to those from northeastern Iberia, suggesting recent range expansion from this region. Historical demographic analyses indicate a demographic expansion starting about 100,000years ago and more recent population declines. Compared to other Lissotriton species, L. helveticus includes only relatively young genetic lineages, suggesting a Central European pre-Pleistocene distribution followed by complete extirpation of the species during glaciations in that area. Historical demographic trends in the Iberian Peninsula are reversed with respect to the more Mediterranean species Lissotriton boscai, indicating different responses of both species to climate changes. Diversity patterns among Lissotriton species seem to be defined by four main factors: ancestral distributions, colonization capabilities, interactions with other species and effective population sizes. Differences in these factors define two types of species, referred to as "R" (refugia) and "S" (sanctuaries) that explain part of the diversity in patterns of genetic diversity created by glaciations in Western Europe.

A new Mediterranean species of Dolistenus (Diplopoda, Platydesmida, Andrognathidae), with an updated key for the genus and the first contribution for a barcode database of European Platydesmida.

Dolistenus Fanzago, 1874 is a widespread Mediterranean millipede genus of the order Platydesmida, currently including three valid species, each with relict distributions. Here we describe a fourth species of Dolistenus, and characterize it using morphological and molecular (mitochondrial DNA) characters. We provide an updated key to the species of Dolistenus and the first COI barcode sequences for the new species and several other European representatives of the Andrognathidae (Platydesmida).

Limited long-distance dispersal success in a Western European fairy shrimp evidenced by nuclear and mitochondrial lineage structuring.

Anostraca are known by their ability for long-distance dispersal, but the existence in several species of deep, geographically structured mtDNA lineages suggests their populations are subjected to allopatric differentiation, isolation, and prevalence of local scale dispersion. Tanymastix stagnalis is one of the most widespread species of Anostraca and previous studies revealed an unclear geographical pattern of mtDNA genetic diversity. Here, we analyze populations from the Iberian and Italian Peninsulas, Central Europe, and Scandinavia, with the aim to characterize the patterns of genetic diversity in a spatio-temporal framework using mtDNA and nuclear markers to test gene flow among close populations. For these aims we built a time-calibrated phylogeny and carried out Bayesian phylogeographic analyses using a continuous diffusion model. Our results indicated that T. stagnalis presents a deeply structured genetic diversity, including 7 ancient lineages, some of them even predating the Pleistocene. The Iberian Peninsula harbors high diversity of lineages, with strong isolation and recent absence of gene flow between populations. Dispersal at local scale seems to be the prevailing dispersal mode of T. stagnalis, which exhibits a pattern of isolation-by-distance in the Iberian Peninsula. We remark the vulnerability of most of these lineages, given the limited known geographic distribution of some of them, and the high risk of losing important evolutionary potential for the species.

Catalogue, distribution, taxonomic notes, and conservation of the Western Palearctic endemic hunchback beetles (Tenebrionidae, Misolampus).

Hunchback darkling beetles of the Ibero-Maghrebian genus Misolampus Latreille, 1807 (Tenebrionidae, Stenochiinae) encompass six species: M. gibbulus (Herbst, 1799), M. goudotii Guérin-Méneville, 1834, M. lusitanicus Brême, 1842, M. ramburii Brême, 1842, M. scabricollis Graells, 1849, and M. subglaber Rosenhauer, 1856. Previously known distribution ranges of the species were delineated using many old records, the persistence of such populations being questionable under the current situation of global biodiversity loss. Additionally, the status of geographically isolated populations of the genus have been the subject of taxonomic controversy. An exhaustive bibliographical revision and field search was undertaken, and the Misolampus collection of the Museo Nacional de Ciencias Naturales (MNCN-CSIC) was revised. The aims are to (i) provide an updated geographic distribution range for the species of Misolampus; (ii) to determine the taxonomic status of controversial populations; (iii) to provide a catalogue for Misolampus; and (iv) to discuss the conservation status of these saproxylic beetles. As a result, a catalogue including synonymies and type localities, geographical records, diagnoses, and information on natural history for all species of Misolampus is presented. The results reveal that the distribution ranges of the species of Misolampus have not undergone a reduction in the last century, and indicate the presence of the genus in areas where it had never been recorded before. The morphological variability of M. goudotii drove the proposal of different taxa that are here formally synonymised as follows: M. goudotii Guérin-Méneville, 1834 = M. erichsoni Vauloger de Beaupré, 1900, syn. nov. = M. peyerimhoffi Antoine, 1926, syn. nov.

A new distinctive species of Barydesmus (Diplopoda, Polydesmida, Platyrhacidae) from Ecuador, with an annotated bibliographical checklist of the American Platyrhacidae.

Currently with 85 named species, the family Platyrhacidae in America is still poorly studied, particularly regarding Barydesmus Cook, 1896, the most diversified among the American genera. The center of diversification of Barydesmus lies in the northern third of the Andes Mountains, a megadiverse region where surely more species of these large, conspicuous diplopods await description. Here we present a new species, Barydesmus nangaritza sp. nov., easily diagnosable by the shape of the paranota, unique among the American Platyrhacidae. We provide also an updated bibliographical, annotated checklist of the whole family in America, with the aim of encouraging further studies in the group. The checklist includes the following new combinations under the genus Barydesmus: Barydesmus acanthopleurus (Hoffman, 1960) comb. nov., B. acanthosternus (Brölemann, 1900) comb. nov., B. acompus (Chamberlin, 1941) comb. nov., B. aequinoctius (Attems, 1914) comb. nov., B. affinis (Brölemann, 1919) comb. nov., B. andinus (Cook, 1896) comb. nov., B. azulae (Kraus, 1956) comb. nov., B. balsapuertus (Chamberlin, 1941) comb. nov., B. bifasciatus (Silvestri, 1897) comb. nov., B. bombonus (Chamberlin, 1941) comb. nov., B. broelemanni (Attems, 1914) comb. nov., B. brunnior (Chamberlin, 1941) comb. nov., B. celinus (Chamberlin, 1941) comb. nov., B. chuncho (Chamberlin, 1941) comb. nov., B. clathratus (Gervais, 1847) comb. nov., B. comptus Cook, 1896 comb. nov., B. contayus (Chamberlin, 1941) comb. nov., B. dunalii (Gervais, 1847) comb. nov., B. exsul (Cook, 1896) comb. nov., B. festae (Silvestri, 1897) comb. nov., B. fuscatus (Chamberlin, 1941) comb. nov., B. helophorus (Attems, 1899) comb. nov., B. incus (Chamberlin, 1941) comb. nov., B. javarynus (Schubart, 1950) comb. nov., B. leucus (Chamberlin, 1941) comb. nov., B. loretus (Chamberlin, 1941) comb. nov., B. manserichus (Chamberlin, 1941) comb. nov., B. medius (Chamberlin, 1941) comb. nov., B. obscurus (Kraus, 1955) comb. nov., B. orellanus (Chamberlin, 1941) comb. nov., B. pococki (Brölemann, 1911) comb. nov., B. retentus (Chamberlin, 1941) comb. nov., B. riparius (Carl, 1902) comb. nov., B. rufipes (Koch, 1847) comb. nov., B. scaber (Koch, 1847) comb. nov., B. socius (Chamberlin, 1941) comb. nov., B. strenuus (Silvestri, 1897) comb. nov., B. tambonus (Chamberlin, 1952) comb. nov., B. tapichus (Chamberlin, 1941) comb. nov., B. trichotypus (Chamberlin, 1941) comb. nov., B. utoquinius (Chamberlin, 1941) comb. nov. and B. zygethus (Chamberlin, 1941) comb. nov.

Mitochondrial phylogeography of the Iberian endemic frog Rana iberica, with implications for its conservation.

Genetic characterization of species using phylogeographic approaches represents a basic reference to understand their evolutionary history as well as to identify conservation priorities to protect areas of particular interest regarding evolutionary potential. Even in well-studied regions such information is lacking for the majority of species, including many endemic species with reduced distribution ranges. We investigate the phylogeographic pattern of the Iberian frog Rana iberica, an endemic amphibian restricted to Central and North-Western Iberian Peninsula. Using mitochondrial sequences, we reconstruct the phylogeographic history of the species to test the effect of Quaternary climate changes on the evolutionary diversification of lineages, that is, the differentiation of mitochondrial lineages and the formation of genetic diversity melting pots, and integrate phylogeographic evidence for future conservation planning. Our results indicate the existence of 3 main mitochondrial lineages differentiated during the Upper Pleistocene. Both historical demographic analyses and climatic niche modeling show a strong effect of glacial climate changes, suggesting recurrent range contractions and expansions. Under such circumstances, differentiation took place most likely by isolation in allopatric interglacial refugia. Secondary lineage admixture in northern Portugal generated a broad mixed zone with highest nucleotide diversity. Given its particular evolutionary potential, its reduced distribution and eventual threats under current climate change scenario, conservation priorities should focus on the isolated lineage from Sierra de Guadalupe.

Phylogeography of Pseudacris regilla (Anura: Hylidae) in western North America, with a proposal for a new taxonomic rearrangement.

The Baja California populations of Pseudacris regilla, a widespread species in Western North America ranging from British Columbia to southern Baja California, are characterized by extensive geographic fragmentation. We performed phylogeographic and historical demographic analyses on 609 bp of the cytochrome b mitochondrial gene of 110 individuals representing 28 populations to determine the relative influences of current and historical processes in shaping the present distribution of genetic diversity on the Baja California Peninsula. Haplotypes from this area were nested in a clade with three well-differentiated groups. Two of these groups are from Baja California Sur and another is from California and Baja California. The estimated date for the split of these groups, between 0.9-1 Ma, fits with previously proposed hypotheses of vicariance due to different transpeninsular seaways, although successive population fragmentation and expansion due to climatic oscillations during Pleistocene glaciations cannot be discarded. Historical demographic analyses detected signs of past population expansions, especially in the southernmost group. With respect to populations north of this region, two older clades were identified, one with haplotypes mainly distributed in central California, and the other corresponding to the northern half of the species range, in what apparently is a recurrent pattern in the Pacific coast of North America. Based on the concordance between mt-DNA and available allozyme data indicating that these species have a long independent evolutionary history, we propose to consider the three major clades as distinct species: P. regilla, P. pacifica, and P. hypochondriaca.