Sexual reproductive cells and processes are highly conserved in a wide range of organisms. A specialized, expandable zygote called the auxospore is a cell known only in diatoms. Auxospores perform two critical functions in the life cycle of most diatoms: (1) as in other sexual organisms, they confer the benefits of genetic recombination to diatom progeny, and (2) restore larger cell size and allow

Astome ciliates are a diverse group of obligate endosymbionts, living in the alimentary tract of invertebrates and vertebrates. In the digestive tube of two endogeic lumbricid earthworms, we discovered Metaradiophrya speculorum sp. n. and re-discovered Maupasella mucronata after almost half a century. Their systematic positions were determined using the 18S rRNA gene, ITS1-5.8S-ITS2 region, and the

Lophodoris G. O. Sars, 1878 is a small genus of goniodoridid nudibranchs that includes only two species: the type species, Lophodoris danielsseni (Friele & Hansen, 1876), and Lophodoris scala Er. Marcus & Ev. Marcus, 1970. Sars (1878) erected Lophodoris in a footnote, without comment. Forty-four years later, Odhner (1922) finally described the type species and defined the diagnostic characteristics

Size-latitude trends in the meiobenthic phylum Kinorhyncha, commonly known as mud dragons, have been explored in oceans worldwide. Generalized least squares regression was used to assess relationships between size and latitude, as well as between size, latitude, and two selected environmental variables that exhibit latitudinal gradation: the sea surface temperature and the net primary productivity

Chemical cues play an important role in short-range communication of butterflies, remarkably in sexual attraction and mate choice. Differentiated scale patches on the wings of male butterflies, the androconia, are involved in the emission of pheromones. Here, we describe the androconial morphology of six sympatric species of Neotropical sulphur butterflies belonging to two genera of the Colias-clade

The spiders of the genus Dysdera are renowned for including woodlouse specialists. In the Canary Islands, Dysdera underwent remarkable local diversification, and 48 endemic species have been reported to date. We aim to disentangle the evolutionary history underpinning this diversity, with particular emphasis on the evolution of the trophic ecology. We collected specimens belonging to 17 Dysdera species

A matrix of 117 morphological characters scored for 77 terminal taxa was subjected to parsimony analysis under equal and implied weighting schemes and to Bayesian inference in order to test the relationships in and between Stephanopis and Sidymella species, as well as its implications for the systematics of the subfamily Stephanopinae. A sensitivity test was performed to evaluate nodal stability. Our

Accurate species delimitation is of primary importance in biodiversity assessments and in reconstructing patterns and processes in the diversification of life. However, the discovery of cryptic species in virtually all taxonomic groups unveiled significant gaps in our knowledge of biodiversity. Mimicry complexes are good candidates to source for cryptic species. Indeed, members of mimicry complexes

Graylings (Thymallus) are among the less well-studied groups of salmonid fishes, especially across their Asian distribution range. Here we perform a comprehensive global review of their phylogeography, systematic diversity and range distributions, including biogeographic reconstruction and assessment of both conservation and taxonomic status of each species. Based on a mitogenomic phylogenetic analysis

The taxonomy of the syrphid genus Chrysotoxum Meigen, 1803 (Diptera: Syrphidae), is complex and currently under scrutiny. Two new species allied with Chrysotoxum vernale, one from the Western Mediterranean, Chrysotoxum hispanicum sp. n. and the other from the Eastern Mediterranean, Chysotoxum anatolicum sp. n., are described and illustrated. Chrysotoxum hispanicum sp. n. is distinguished from the similar

We describe four species of Ochthebius subgenus Cobalius (Coleoptera, Hydraenidae) from coastal rockpools of the western Palaearctic Region: O. anzar sp. nov. (south Morocco, plus a possible specimen from Lanzarote, Canary Islands), O. cortomaltese sp. nov. (Malta), O. evae sp. nov. (Atlantic coast of Morocco and Mediterranean coast of south Spain), and O. gorgadensis sp. nov. (Ilha de Santiago, Cabo

The Aegean archipelago is among the largest on Earth with astonishing biodiversity within Europe. Its territory underwent a massive geotectonic transformation in Neogene that resulted in multitude of changes in land-sea configuration and disintegrated the formerly united Aegean land to a complicated mainland-archipelago system. Therefore, it represents an excellent laboratory for studying evolution

Direct development implies transformations with respect to the anuran biphasic life cycle, including changes in embryonic anatomy. In the clade Brachycephaloidea, skeletal ontogeny is known in Eleutherodactylus coqui of the basal family Eleutherodactylidae. In this work, we study it in four species representing the two other families in the group. We worked with developmental series of Oreobates barituensis

Faustina faustina is a conchologically highly diverse forest gastropod with several morphological forms. It is a Carpathian species, but it also occurs in northern isolated localities, where it was probably introduced. We performed the first phylogeographic analysis of 22 populations, based on three molecular markers: COI, ITS-2, and 28S rRNA. Genetic data were complemented by paleo-distribution models

The genus Oxybelis currently is composed of four taxa despite numerous studies suggesting and describing multiple taxa within the O. aeneus complex. Here, we utilize a multilocus molecular dataset (i.e., cyt b, ND4, 12S, 16S, cmos, PRLR, 3663 bp) to conduct phylogenetic analyses to assess the evolutionary history of Oxybelis. Our molecular analyses find three major lineages of Oxybelis (i.e., O. aeneus

The Niphargus tatrensis species complex, entirely subterranean, has a wide distribution range extending from Southern Poland to Austria and Slovenia. Because of its large and confusing morphological variability, it was subdivided into several ‘forms’, four of which described from Austrian caves. To shed light on this chaotic situation, we sampled the type localities of all described species and forms

The stalked jellyfish (Staurozoa) is an extraordinary clade within medusozoan cnidarians in which the medusa is attached to the substrate unlike the pelagic jellyfishes which compose the rest of the medusozoans. Along with this remarkable feature, staurozoans are characterized by an extremely low number of cells (< 100) in the embryos and larvae. The aim of the present study is to explore early development

The kinetid (flagellar/ciliary apparatus) of eukaryotic cells is an important source of phylogenetic information. It was found to be a prospective morphological phylogenetic marker in sponges, since its arrangement in choanocytes is congruent with the topology of the phylogenetic trees. However, investigation of the kinetid of sponge larval cells remains fragmentary. Here, we report the results of

Evolutionary transitions from benthic to pelagic habitats are major adaptive shifts. Investigations into such shifts are critical for understanding the complex interaction between co-opting existing traits for new functions and novel traits that originate during or post-transition. Gastropod mollusks are of particular interest in regard to benthic-pelagic evolutionary transitions, as shifts from benthic

Hybridization in bryophytes involves a fusion of gametes produced by haploid parental gametophytes of different species. The primary hybrid is thus the short-lived diploid sporophyte, which soon undergoes meiosis prior to the formation of large amounts of haploid spores. We compared morphology of gametophytes (branch leaves) and sporophytes (capsule inclination) from sympatric populations and allopatric

The Andes is recognized as one of the most biodiverse places on Earth, promoting in its uplift process a series of recent rapid diversification events in different biotic groups like birds, mammals, insects and vascular plants. The uplift of the Andes during the Cenozoic acted as a barrier for many biotic groups, as a scenario for radiation processes due to occupancy of different niches and as a corridor

Acoustic communication is an essential part of the mate-finding system of many insects, e.g., ensiferan Orthoptera. In this group, the signals consist typically of relatively simple repetitive sound patterns produced for long times and used by the females for a phonotactic approach to the singing males. However, the situation can be different in duetting species where the females respond acoustically

Raphidioptera (snakeflies) are the least diverse order among extant Holometabola, representing relicts of their rich Mesozoic paleofauna. Baissopteridae are one of the two major lineages from the Mesozoic, but with a poorly known evolutionary history. Here, we report the first fossil record of Baissopteridae from the mid-Cretaceous of Myanmar, represented by a diverse assemblage including 10 new species

The evolutionary history of prey specialisation differs among spider species, particularly among active wandering species which have evolved a variety of prey-capture tactics. Here, we conducted a comparative analysis of prey specialisation and prey capture behaviour in Gnaphosidae. We used nine species each representing a different genus and investigated their acceptance of spiders and ants as prey

Floral innovations are key for pollinator specialization and play a significant role in plant diversification. Orchidaceae present many examples of floral innovations that allow its high degrees of pollinator specialization and promoted speciation. The rich neotropical genus Telipogon evolved an uncinate (=hook-like) viscidium on the pollinarium and setae-bearing flowers, which are uncommon in Orchidaceae;

The publisher regrets that the presentation of Fig. 8 in the original version of this article contained an error where all serotonergic somata , represented as blue circles in Fig. 8c, with associated labels ‘vms’ and ‘vncs5’ were omitted during the publication process

The hawkmoth genus Rhodafra comprises two African species with unclear relationships, as their wing patterns are markedly different, with one species closely resembling species of a related genus, Hyles. The present paper aims to investigate the monophyly and phylogenetic position of Rhodafra in relation to Hyles and other genera of the subtribe Choerocampina (Sphingidae: Macroglossinae: Macroglossini)

In several groups of insects, body structures related to feeding and oviposition are known to have a hardened cuticle by incorporation of transition metals. However, a functional link between metal enrichment and ecological pressures (i.e., adaptation) has been only rarely shown, opening the possibility that in some lineages, the evolutionary history may account for most of the observed variation (i

A typographical error was found in the Table 1 and Figures 5 and 9 legends. The specie name "Lepas anatifera" should have been "Lepas pectinata"

Multiple lines of evidence provided support for the monophyly of the subfamily Neanurinae. Nevertheless, relationships among and within its tribes are largely unknown. The tribe Neanurini, being the second largest within Neanurinae, comprises over 170 species belonging to 29 genera, distributed in the northern hemisphere only, except two species that have been distributed worldwide presumably by human

Comprehensive morphological investigations covering the diversity of metazoan lineages are needed to obtain a complete picture of organ system evolution. Despite the increased amount of studies on lesser-known phyla during the last decades, the gap in knowledge for these lineages is still remarkable. This is the case for kinorhynchs, or mud dragons, where only a few genera, mainly belonging to the

The Eucraniini are a small dung beetle tribe endemic to Argentina (4 genera with 14 species), adapted to live in extremely arid environments, usually feeding on dry, small mammal dung pellets. These beetles grasp the dried pellets lifting them by the foretibiae and run forward on the middle and hindlegs. Here, the eucraniine mouthparts (epipharynx, labium, mandibles and maxillae) and ventral part of

Cladistic biogeography is an evolutionary biogeographic approach that infers area relationships by comparing area cladograms derived from different phylogenetic hypotheses. The South American freshwater ichthyofauna is enriched by an extraordinary number of marine-derived lineages, presenting its own phylogenetic and biogeographic patterns. Here, we performed a Brooks Parsimony Analysis (BPA) with

The epiphytic community on the endemic seagrass Posidonia oceanica from the Mediterranean Sea is well studied, but still harbors some little investigated epiphytic bryozoans. Numerous, yet always small colonies of Pherusella sp. were recently encountered in the Northern Adriatic Sea. The aim of this study was to generate data on the life history, colonial development, and reproduction of the Mediterranean

How larvae of whale and dolphin epibionts settle on their fast-swimming and migrating hosts is a puzzling question in zoology. We successfully reared the larvae of the whale and dolphin barnacle Xenobalanus globicipitis to the cyprid stage. We studied the larval developmental ecology and antennular morphology in an attempt to assess whether an epibiotic lifestyle on this extreme substratum entails

The paper continues the exploration of the morphological and functional diversity of male genitalia in Archaeognatha by the study of an undescribed Charimachilis species. Exoskeletal details are documented by drawings and SEM micrographs. The lack of tubular setae on gonapophyses and penis suggests sperm transfer by direct male-female contact (not via sperm deposited on a thread), while genitalic morphology

Islands are fascinating study systems for biogeography, allowing researchers to investigate patterns across organisms on a comparable geographical scale. They are also often important for conservation. Here, we present the first bio-inventory of the ant fauna of the Aeolian Islands, a Sicilian volcanic archipelago formed within the last million years. We documented a total of 40 species, including

The phylogenetic structure of 23 populations of Crangonyx hobbsi, a stygobitic amphipod species endemic to the Floridan aquifer, is detailed. Molecular genetic analyses (based on three genes the nuclear 18S rDNA, 28S rDNA, and mitochondrial 16S rDNA) point to the presence of at least two phylogenetic clades within the aquifer. These clades align into two major zoogeographic regions, the Northern Suwannee

Dugesia hepta Pala, Casu & Vacca, 1981 and Dugesia benazzii Lepori, 1951 are two freshwater planarian species from the islands of Corsica and Sardinia. Dugesia hepta is endemic of Sardinia and distributed in four northern hydrographic basins where it co-occurs with D. benazzii, which has a wider Tyrrhenian distribution. Although these species have been broadly studied—especially D. benazzii—as regards

The stick-insect genus Pijnackeria includes four diploid bisexual and two polyploid (3n, 4n) parthenogenetic species. Earlier analyses of the tetraploid parthenogen P. hispanica using mitochondrial markers allowed tracing its maternal ancestry to Pijnackeria originis, while no maternal nuclear contribution was found, thus suggesting an androgenetic and hybrid origin. The recently described Pijnackeria

Climatic changes associated with Pleistocene glacial cycles had profound effects on the genetic diversification and distribution of many taxa, especially from environmentally sensitive habitats such as mountain regions. The DNA sequence data (mtCOI and 28S RNA genes) derived from the Merodon rufus group (Diptera: Syrphidae) in central, eastern, and southern Europe was analyzed. Environmental niche

The patterns of genetic and phenotypic diversity in marine life are the result of different geological and ecological processes. We analyzed the pattern of genetic and morphometric variation of the razor clam Ensis macha along its entire geographic distribution. This species is one of the most important shellfish resources of South America. To uncover the genetic variation across this species, we used

The genus Eumerus Meigen 1822 (Diptera: Syrphidae) is widely distributed in the Old World, though recently introduced into America, and their larvae feed on decaying vegetal material and/or inside underground storage organs of many plants, sometimes generating economic losses as pests. However, little is known about Eumerus larval cycles and their interactions with host plants. Here, immatures of three

The publisher regrets that the Table 3 of the original published version of this article is incorrect thus the table is now presented correctly. The original article has been corrected.

Although there is an abundance of species delimitation methods on the market, most approaches depend on predefined assignment of specimens to species or populations. Assignment-free methods, which can simultaneously infer boundaries and relationships among species, are of high importance in cases, when correct pre-assignment is difficult or not at all possible. In this study, we use assignment-free

Arion vulgaris Moquin-Tandon, 1855 is regarded as one of the 100 most invasive species in Europe. The native distribution range of this species is uncertain, but for many years, the Iberian Peninsula has been considered as the area of origin. However, recent studies indicate that A. vulgaris probably originated from France. We have investigated the genetic structure of 33 European populations (Poland

The recognition of Holarctic species, those shared between Nearctic and Palaearctic regions, often implies continuous or recent events of gene flow across the 85-km-wide Bering Strait between Alaska and Russia. During the Pleistocene (2.8–0.012 Mya), the Bering land bridge has provided frequent episodes of continuous, tundra habitat across this barrier, while the taiga forests of the northern hemisphere

Cubozoa jellyfish species exhibit either internal or external fertilization, and reproductive behavior involving spermcasting or complex copulatory sexual behavior, but male gonad morphology has not been investigated broadly in cubozoans. In this study, a histological comparison was conducted of the testes of four cubozoan species in two orders: Carybdea marsupialis (Carybdeidae), Morbakka virulenta

The plausibility of sympatric speciation is still debated despite increasing evidence, such as host races in insects. This speciation process may be occurring in the case of the two phenological forms of the obligatorily myrmecophilous Phengaris arion. The main goal of our research was to study the nature and causes of difference between these forms focusing primarily on the incipient speciation via

Members of family Cymatiidae have an unusually long planktonic larval life stage (veligers) which allows them to be carried within ocean currents and become distributed worldwide. However, little is known about these planktonic veligers and identification of the larval state of many Cymatiidae is challenging at best. Here, we describe the first high-quality scanning electron microscopy images of the

Despite their ecological importance and wide distribution, Cordiaceae have not been subject to detailed anatomical study yet. We examined flower and fruit anatomies of Cordia nodosa and Varronia bonplandii (using paraffin sectioning and light microscopy) in comparison with other woody members of Boraginales. The internal architecture of the superior bicarpellate ovary resulted from the development

The internal female genitalia of 22 species of Aulacigaster are studied, covering all species groups as defined by Rung and Mathis (Smithson. Contrib. Zool., 633, 1–132, 2011). The method of embedding freshly dissected material in polyvinyl lactophenol with an admixture of chlorazol black E is far superior to results achieved by maceration in potassium hydroxide and allows the detection of delicate

Braula coeca has been reported repeatedly, but incorrectly, to have only a single spermatheca—an extremely rare condition in the higher flies. This error is based on the misinterpretation of the ventral receptacle as a single spermatheca combined with the failure to detect the two present but largely reduced dorsal spermathecae. This misconception is of importance, e. g., for correct character coding

The ability to rapidly generate and share molecular, visual, and acoustic data, and to compare them with existing information, and thereby to detect and name biological entities is fundamentally changing our understanding of evolutionary relationships among organisms and is also impacting taxonomy. Harnessing taxonomic data for rapid, automated species identification by machine learning tools or DNA

Rhinocricus Karsch, 1881 has 207 species occurring mainly in the Americas, and more than 60 of them were described from Brazil. The genus was proposed based on the presence of dorsal scobinae on the prozonites. The present study evaluates the monophyly of three species groups previously proposed in Rhinocricus. We evaluated 39 morphological characters and included 30 species as terminal taxa, 9 of

Brush-tailed mice, family Calomyscidae, are endemic to southwestern Asia and are represented by eight described species and three additional lineages. Although this family includes only a single genus, Calomyscus, in which several molecular phylogenies were recovered as a monophyletic clade, no updated evolutionary survey has been undertaken until now. We present a time-calibrated molecular phylogenetic

Prionospio Malmgren 1867 and Aurospio Maciolek 1981 (Annelida: Spionidae) are polychaete genera commonly found in the deep sea. Both genera belong to the Prionospio complex, whose members are known to have limited distinguishing characters. Morphological identification of specimens from the deep sea is challenging, as fragmentation and other damages are common during sampling. These issues impede investigations

With few exceptions, animal mitochondrial genomes are impressively conserved with regard to gene arrangement (synteny). For certain taxonomic groups, specific genomic “hotspot” regions present high levels of gene rearrangements. This is the case for the region between the mitochondrial genes cox2 and atp8 across Annelida, particularly in members of the blood-feeding leeches of the genus Placobdella

This paper explores shape disparity in the sulcus acusticus of saccular otolith using geometric morphometric methods in selected Gerreidae species. First, multivariate linear regressions between size (CS-log-transformed) and shape were implemented to uncover allometry in the variation of the sulcus acusticus at three levels: intraspecific, intrageneric, and interspecific. Second, we assessed species