The marine gastropod genus Laevilitorina is exclusive to the Southern Hemisphere, with 21 species from southern South America, Antarctica, Australia, New Zealand, and sub-Antarctic Islands. We present a comprehensive revision of Laevilitorina, using molecular and morphological analyses, to address formally the interspecific divergences within the nominal taxon Laevilitorina caliginosa s.l. We confirm

Tardigrade taxonomy is most often hindered by prevalent outdated species descriptions, lack of integrative redescriptions, scarce genetic information, and fragmentary sampling. Here, we diagnose the problems obscuring phylogenetic inference and the taxonomy of the cosmopolitan family Ramazzottiidae. We carried out the most extensive phylogenetic analysis of this family to date, with a considerable

Four new species of the scaleless black dragonfish genus Eustomias are described based on specimens collected during the ABRACOS (Acoustics along the BRAzilian COaSt) expeditions along the Fernando de Noronha Ridge, off northeastern Brazil, western tropical Atlantic. Eustomias (Haploclonus) antea sp. nov. differs from its congeners by having a long chin barbel without appendages, ending in a very small

Dugesia hepta and D. benazzii are two species found in Sardinia and Corsica. Previous studies have been unable to resolve their evolutionary relationships and there was doubt about the monophyly of D. benazzii. This study used molecular and morphological data to develop a rigorous species-delimitation procedure within an integrative framework. Three different species discovery methods (ABGD, GMYC,

The World Health Organization declared COVID-19 a pandemic on 11 March 2020. The ‘anthropause’ almost emptied our streets of vehicles. In urban areas, automobile traffic is a major environmental factor, and tardigrades can serve as bioindicators of environmental change. During the winter of 2019–2020, samples were taken both before and during the COVID-19 lockdown. In both cases, traffic variables

Although neobatrachians represent about 95% of anuran diversity, their fossil record, especially during the Mesozoic, remains scarce and often limited to a few damaged specimens with uncertain affinities. In South America, fossil neobatrachians have been identified from the Cretaceous deposits in Chile, Argentina, and Brazil. Here, we describe a new species of fossil neobatrachian from the Late Cretaceous

Armophorid ciliates of family Clevelandellidae represent ecologically interesting symbionts of ecologically interesting hosts: wood-eating cockroaches of subfamily Panesthiinae unrelated to the termite/Cryptocercus lineage. Moreover, these protists exhibit a peculiar morphology, with the posteriorization of oral structures being the most striking of their unique characters. Despite that, the family

Hypsibiidae are the most species-rich group within the Hypsibioidea, and three (Diphasconinae, Itaquasconinae, and Pilatobiinae) of its four subfamilies are characterized by a division of the foregut into a rigid buccal and a flexible pharyngeal tube. The aim of this work is to provide a comprehensive background for sound taxonomic studies on several hypsibiid lineages. We redescribe the type species

Bath sponges, included in the Spongiidae (Demospongiae: Dictyoceratida), are distributed across the oceans of the world, with a greater abundance in temperate, subtropical, and tropical zones. Their harvest started during ancient times in the Mediterranean Sea, which shed light on the whole family. Most of the Mediterranean Spongiidae have been reported repeatedly from the Northeast Atlantic, notably

Research on Pleistocene Amazonian refugia has predominantly targeted forest-dwelling taxa, although evidence suggests that endemic species have also evolved in peripheral Amazonian enclaves of open–dry habitats. In Rondônia, Brazil, Tropidurus lizards are restricted to savannah relicts that were once connected to the core Cerrado biome. These populations are currently allocated under Tropidurus oreadicus

Mesothelae, or primitively segmented trapdoor spiders, form the most basal clade among living spiders. In Southeast Asia, Liphistius is the only genus recognized in the extant family Liphistiidae. Liphistius taxonomy and species identification are based largely on characters of the genitalia; however, the female genitalia show high intraspecific variation, males are rarely collected, and the phylogenetic

The Opalinida comprise ciliated protists that live as intestinal endoparasites in poikilothermic vertebrates. They are classified as one group of colourless Stramenopiles, the Opalinata, along with Proteromonadida (Proteromonas and Karotomorpha). The validity of certain opalinid genera is questionable, and their genetic relationships remain unclear. In this study, we conducted complete ribosomal DNA

The analyses of Plio-Pleistocene speciation processes in the Horn of Africa are relevant for understanding the evolution of biodiversity patterns of this understudied part of the world. Here we analyse comprehensive genomic and morphological data of the recently delimited murid genus Ochromyscus, one of the few with Afro-Arabian distribution. Using an integrative taxonomic approach, we delimit three

Recently it was purported that autofluorescence (AF) in Paramacrobiotus n. sp. provided protection from UV radiation. If true, this would be the first documentation of an adaptive function for AF in any microscopic animal. We review what is currently known about AF in tardigrades, and we provide the first true colour images of tardigrade fluorescence. To assess the hypothesis of AF as UV protection

Using a phylogenetic analysis as a baseline, we conducted a taxonomic revision of the genus Loncovilius Germain, 1903 which now includes 10 valid species. Of them, six species, all restricted to the southern Andean region, are described as new for science: Loncovilius barclayi sp. nov., L. cantharoides sp. nov., L. carlsbergi sp. nov., L. hammondi sp. nov., L. impunctus sp. nov., and Loncovilius variabilis

Morphological species identification is the traditional way to identify species. More recently, biodiversity studies have depended on DNA barcoding for species identification. Mismatches between morphological and genetic species identification caused by voucher specimen misidentifications lead to ambiguous species identification. We used barnacles of the genera Amphibalanus and Balanus to investigate

Establishment of extant terrestrial vertebrate faunas in North America was influenced by a set of factors associated with temporal changes in climate and ecology that operated at different geographic scales. While the biogeography of extant taxa can be inferred from phylogenies, these omit lineages that have gone regionally extinct and for which the only direct evidence is the fossil record. A comprehensive

In this study, we present the first integrative revision of the Boreal and Arctic calcareous sponges of the genus Leucosolenia with a specific focus on its biodiversity in the White Sea. The material for this work included a combination of newly collected specimens from different regions of the North-East Atlantic and the White Sea and historical museum collections. An integrative analysis was implemented

Cytogenetics can be used as a tool to study the evolution of polyploidy and taxonomy. Here we focus on aquatic African pipids, dwarf clawed frogs (Hymenochirus). Our study reveals that dwarf clawed frogs, present for decades in captivity, are best referred to as Hymenochirus sp. instead of the commonly used name ‘H. boettgeri’ or sometimes ‘H. curtipes’. We present the first karyotype from a morphologically

Lepidonotopodinae is a subfamily of Polynoidae endemic to deep-sea chemosynthetic ecosystems around the world. Nevertheless, their species composition and phylogeny have only been systematically studied in hydrothermal vents of the Eastern and Western Pacific. Here, we morphologically and genetically examined worms in Lepidonotopodinae from vents across three Indian Ocean ridges, revealing two new

Ginglymodians (e.g. gars) are a group of holostean fishes with a rich fossil history in the Mesozoic. The resolution of interrelationships among extinct ginglymodians is central to the problem of understanding the origin of this clade. Here, a new fossil ginglymodian, Diandongichthys ocellatus gen. et sp. nov., is described based on 13 well-preserved specimens from the Early-Middle Triassic (Anisian)

Ray-finned fishes, which compose nearly half of living vertebrate diversity, provide an excellent system for studying the evolution of novel body forms. Lampriformes is a species-poor lineage of acanthomorph ray-finned fishes that has evolved two very different and highly specialized body plans suited to life in pelagic oceanic habitats: the deep, round-bodied bathysomes and the ribbon-like taeniosomes

Green, brown and black pigments are uncommon in the otherwise typically yellow to orange Echiniscidae. Viridiscus, a genus currently represented by a handful of species, in which cuticular coloration varies from a light green through dark green to almost black, has been an exception. Here, we uncover a new echiniscid lineage from the primeval subtropical and tropical rainforests of India and Tanzania

In caridean shrimps, sexual systems vary from gonochorism to various forms of hermaphroditism. The shrimp Salmoneus carvachoi has been reported to exhibit both male (appendix masculina) and female (brooding embryos) anatomical characteristics simultaneously. Our aim was to examine the sexual system of S. carvachoi and to test the hypothesis of protandric simultaneous hermaphroditism (PSH) in this species

Integrative studies have revealed cryptic radiations in several Caribbean lineages of heterobranch sea slugs, raising questions about the evolutionary mechanisms that promote speciation within the tropical Western Atlantic. Cyerce Bergh, 1871 is a genus comprising 12 named species in the family Caliphyllidae that lack the photosynthetic ability of other sacoglossans but are noted for vibrant colours

Hiatella is among the most poorly understood bivalve genera. Most of the species remain known only from shell morphology, which has proved to be extremely variable in the group. Few studies have addressed their anatomy and biology, and no studies have combined morphological, anatomical and biological characters with molecular characters. This has led to the hiatellids all around the world being regarded

Dead coral rocks are prevalent hard substrates in shallow warm waters, providing habitat for various infaunal and boring invertebrates. Despite this, the nature of species interactions, especially symbiotic relationships, among them remains poorly understood. Bonellia (Annelida: Thalassematidae: Bonelliinae) is a group of greenish echiuran worms commonly inhabiting cavities inside dead coral rocks

The genera Xerobiotus and Pseudohexapodibius are xerophilic and characterized by reduced appendages and claws as adaptations to move between small interstices. To increase the knowledge of their biodiversity, biogeography and phylogeny, several specimens from European countries and Australia were analysed using an integrative approach, i.e. morphological, karyological and molecular studies (18S, 28S

Diplura are an ancient group of basal (apterygote) hexapods that thrive in various cryptic terrestrial habitats. Despite an ancient origin that extends at least to the Devonian period, the dipluran fossil record is exceedingly sparse. Here, we document five very rare fossil specimens of the family Campodeidae in amber from the Miocene of the Dominican Republic and the Eocene of the Baltic region. Microscopic

The thermal tolerance of ectotherms is a critical factor that influences their distribution, physiology, behaviour, and, ultimately, survival. Understanding the factors that shape thermal tolerance in these organisms is, therefore, of great importance for predicting their responses to forecasted climate warming. Here, we investigated the voluntary thermal maximum (VTmax) of nine grassland viper taxa

Three new eyeless species of Nereis from organic falls (whale bones and wood parcels) in the Southwestern Atlantic from depths between 550 and 3285 m are described, and the eyeless species Neanthes shinkai is transferred to Nereis. All new species and Nereis shinkai comb. nov. can be distinguished from the majority of Nereis species by the absence of eyes and by the presence of small and delicate paragnaths

The hyperparasitism of tetracotyle metacercariae (Cotylurus sp.; Strigeidae) in trematode asexually multiplicating larval stages (sporocysts and/or rediae) within snail intermediate hosts have been perceived for years as a highly evolved mode of life strategy within trematodes, enhancing their development and transmission success. Here, we verified these data and the potential implications for the

The bushbuck (Tragelaphus scriptus) is an antelope widely distributed throughout sub-Saharan Africa that varies greatly in body size, horn length and coat patterning. Recent taxonomic work has suggested reclassification as two or more species. Molecular studies have shown a deep mitochondrial divergence between north-western (scriptus) and south-eastern (sylvaticus) bushbuck populations, and morphological

Lygodactylus is the most speciose gekkonid group in Africa, with several additional, candidate species already identified from previous studies. However, in mainland Africa, several groups remain only partially resolved, and there are several taxonomic inconsistencies. Lygodactylus gutturalis was described from Guinea-Bissau in the 1870s and since then, the species has been recorded from West to East

Hypersaline lakes in arid and semi-arid areas are unique ecosystems that harbour unique extremophile organisms such as Artemia, the paradigmatic example of adaptation to harsh living conditions. We assessed the mitogenomic biodiversity of Artemia species from the Tibetan Plateau, China, a remote and yet minimally disturbed ecosystem with a variety of hypersaline lakes. Analysis of ten Tibetan salt

Examination of a fossil from a Miocene Konservat-Lagerstätte (c. 11–16 Mya) from Australia shows it to be an astioid jumping spider that is here described as Simaetha sp. indet. Fossilization in the iron oxide–hydroxide mineral goethite led to a high-fidelity preservation of not only the exterior, but of the pharyngeal plate and a neuropile in the cephalothorax. The discovery of the fossil supports

The Anteosauridae (Dinocephalia) were the largest predators of Guadalupian (Middle Permian) land communities. The, thus far, only known South American anteosaurid is the medium-sized syodontine Pampaphoneus biccai. This taxon was, until now, known only by its holotype, recovered from an outcrop of the Rio do Rasto Formation, Southern Brazil. Here we describe in detail an almost complete Pampaphoneus

Species displaced outside their native range may face new pressures resulting from both environmental gradients and important differences in ecosystem structure. We investigated how this may impact the morphological variation of a globally introduced carnivoran, the small Indian mongoose. Previous research showed size variations in several introduced populations, suggesting that these differences resulted

Heterolepidoderma is a widely distributed gastrotrich genus encompassing 22 freshwater and 15 marine species. In the present study, two new Heterolepidoderma and four new Heterolepidoderma-like species were discovered in the inland waters of Central Europe. Although Heterolepidoderma-like species exhibited all the morphological features typical of Heterolepidoderma, both nuclear and mitochondrial genes

During courtship, prezygotic barriers are thought to maintain the diversity of species since differences in phenotypic traits and reproductive behaviours are likely to be involved in maintaining species boundaries. However, introgressive hybridization has been reported in many different taxa and the resulting hybrids usually possess phenotypic features, including behaviours, that are intermediate between

Tingid classification has been problematic since the recognition of the family. The exaggerated ornamentation of many tingids has caused confusion in morphology-based phylogenies due to convergence. Also, some genera, like Ulonemia, lack exaggerated structures and their diagnoses rely on reduced morphology, making identification difficult. The relationship between these genera is of great interest

Using two molecular markers (COI and 12S) collected from seven genera and 20 species of coral associated and fire coral-associated barnacles, we examined whether genetic differentiation occurs between the Indian (total 261 sequences) and Pacific populations (195 sequences). Molecular phylogenetic analysis revealed pyrgomatinid barnacles formed two major sister-clades: the Cantellius clade and the major

Despite the recent advent of molecular data to assess the phylogeny of many invertebrate groups, the systematics of the pseudoscorpion family Chernetidae is unresolved, even though it comprises a quarter of the world’s generic pseudoscorpion diversity. We derive a preliminary molecular phylogeny of chernetids to assess subfamilial and generic monophyly using mitochondrial (COI) and nuclear (28S rRNA

Strigamia centipedes are widespread in European forest soils. However, a complex and inconsistent taxonomy has developed over time. Based on a modern species concept, we evaluated multiple lines of evidence for speciation among inland populations of Strigamia from the Italian region to the Baltic region, across central Europe. Hypotheses of species delimitation were drawn independently from: (1) morphological

Many vertebrates, both homeo- and poikilothermic, show a significant relationship between body size and environmental temperature. Whether such an association may exist in microscopic invertebrates has been less explored. Therefore, we decided to analyse terrestrial Tardigrada from various habitats worldwide to examine whether these animals reveal any relationship pattern between body size and environmental

Tank bromeliads provide a vast amount of stagnant water high up in the Neotropical forest canopy. However, the aquatic macroinvertebrate diversity in this specialized habitat remains poorly explored. Here, we study obligatorily bromeliadicolous species of the diving beetle genus Copelatus Erichson, 1832. We review the known species Copelatus bromeliarum Scott, 1912 (Trinidad and Venezuela) and Copelatus

The Ethiopian Highlands represent one of the most important centres of endemism on Earth. Six endemic species of laminate-toothed rats have been reported from Ethiopia in a previous study based mostly on morphological analyses. Largely missing genetic data for some of the species, insufficient sampling across Ethiopia, and presence of a pseudogene on cytochrome b created knowledge gaps in basic taxonomy

Two new species of ctenodactylid rodents, Prodistylomys taatsinius sp. nov. and Prodistylomys mongoliensis sp. nov., are described from the Valley of Lakes, Central Mongolia. They represent the first record of this genus in Mongolia. Prodistylomys is characterized by a simple dental pattern and high hypsodonty, reflecting an adaptation for tough vegetation in a dry environment, which is congruent with

We present a new classification of the catfish family Ariidae based on a total-evidence hypothesis, which incorporates data from the examination of 249 morphological and 5603 molecular characters from 131 species. The named taxa in the proposed classification represent groups of species found in the Maximum Parsimony, Maximum Likelihood, and Bayesian Inference analyses or, in some cases, two of the

The false blister beetle tribe Stenostomatini includes only the genus Stenostoma, with four species showing an intriguing distribution: Stenostoma lowei (Madeira), Stenostoma cossyrense (Pantelleria), Stenostoma melitense (Malta and southern Sicily) and Stenostoma rostratum, widely distributed along the Mediterranean and North Atlantic coasts. The evolutionary history leading to this distribution has

The Palaeogene is a very important time period for mammalian evolution because it documents the first occurrence of many groups. One such group is the enigmatic Ptolemaiida, best known from the Early Oligocene of the Fayum Depression in Egypt, where it is represented by three genera, Ptolemaia, Qarunavus, and Cleopatrodon, including five species. Among these, Qarunavus meyeri is especially rare, as

Although the neochoristodere Champsosaurus is well documented in Campanian deposits of western North America, species-diagnostic remains from these strata are restricted to the Dinosaur Park Formation of Alberta, Canada. Here, we describe an exceptionally well-preserved specimen of Champsosaurus lindoei from the Two Medicine Formation of Montana, USA—one of the few occurrences of the genus within the

The crabs in the subfamily Polydectinae (family Xanthidae) have adapted a defence behaviour in which living invertebrates are used as protection from predators. The polydectine crabs carry a living invertebrate, a sea anemone or nudibranch, in each claw, which is positioned in front of the body and waved to scare off attackers. In an attempt to trace the origin of this behaviour, we sequenced the complete

Pantepui s.l. is a remote, biodiverse region of ~400 000 km2 containing at least five endemic reptile genera and a number of ancient vertebrate lineages. Here, we describe an additional endemic snake genus and species, Paikwaophis kruki gen. nov., sp. nov. (Dipsadidae: Xenodontinae), recently collected in the Pantepui cloud forest that sits at the base of the steep cliffs of Roraima-tepui and Wei-Assipu-tepui

Tetraodontidae is the most speciose family of Tetraodontiformes and is represented by fish popularly known as pufferfishes. They are characterized by modified jaws with four dental plates and the ability to inflate their bodies. Tetraodontids are distributed throughout the world and have a wide range of habitat use. One of its genera, Sphoeroides, shows a biogeographical pattern, with 19 of its 21

Hymenodora represents the most scantily studied branch of the pelagic shrimp belonging to the superfamily Oplophoroidea. We present a phylogenetic revision based on 80 morphological characters and six genes. Molecular and morphological phylogenetic analyses, along with molecular distances calculated with the use of six genes, suggest a family-level status of the clade Hymenodoridae including Hymenodora

The southern three-banded armadillo, Tolypeutes matacus, is one of the most representative species of the South American Chaco region. The susceptibility of this species to climatic changes and its good number of paleontological records has led to the study of their range dynamics for untangling the effects of Quaternary oscillations. These studies yielded contradictory results, suggesting expansion

Tardigrades are rarely included in large biodiversity surveys, mainly because of the impracticalities that follow larger sampling and identification of these microscopic animals. Consequently, there is a lack of data on their biogeographical distribution. Here, we analyse environmental DNA sequences of eutardigrades obtained with a metabarcoding protocol on Danish soil samples collected during a national

Palaeozoic fossils of whip scorpions (Arachnida: Uropygi: Thelyphonida) are extremely rare, with only seven species of this age previously described. A new species of fossil whip scorpion, as well as the first ichnospecies assignable to this group, are described here from the Carboniferous Narragansett Basin of Massachusetts, USA. A body fossil from the Rhode Island Formation (Moscovian) is referred

The inner ear labyrinth is an organ able to perceive balance and spatial orientation, but the drivers of its morphological variation across and within vertebrate lineages are unclear. We assess two competing hypotheses whether this organ, and specifically the semicircular canals, modifies its shape as a functional adaptation to ecology and locomotion, or according to the constraints of skull morphology