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Arthropods include a high diversity of lineages adapted for silk production. Several species of microscopic phytophagous mites of the hyperdiverse superfamily Eriophyoidea spin web; however, the origin of their silk is unknown. We described a new web-spinning mite, Aberoptus schotiae n. sp., collected from leaves of Schotia brachypetala (Fabaceae) in South Africa and showed that it has a complex life cycle, including two morphotypes of adults and nymphs. Molecular phylogenetic analyses and 28S sequence comparison showed conspecificity of heteromorphic females and rejected synonymy of Aberoptus and Aceria proposed by previous authors. For the first time, we provided SEM images of the web nests and, using a set of different microscopic techniques, described the silk-producing anal secretory apparatus (ASA) of Aberoptus. It comprises two pairs of anal glands (hypertrophied in web-spinning females), three cuticular sacs and a rectal tube leading to the anal opening. This is a unique case (analogy) of anal silk secretion in Chelicerata previously reported only in Serianus (Pseudoscorpiones). Recent findings of rudimentary ASA in distant eriophyoid lineages and the results of this study transform the current paradigm of exoticism of web-spinning eriophyoid taxa into the concept of synapomorphic specialization of the hindgut for excreting the anal gland secretions in Eriophyoidea. [ABSTRACT FROM AUTHOR]

Fungi encompass, in addition to classically well‐studied lineages, an ever‐expanding diversity of poorly known lineages that include, among others, zoosporic chytrid‐like parasites. According to recent phylogenetic analysis based on 18S + 28S rRNA concatenated genes two unusual chytrid‐like fungi Amoeboradix gromovi and Sanchytrium tribonematis form a monophyletic group, the family Sanchytriaceae, which represents a new divergent taxon that remains incertae sedis within Fungi. Zoospores of Amoeboradix gromovi contain one of the longest kinetosomes known in eukaryotic cells, which are composed of microtubular singlets or doublets. However, the ultrastructure of S. tribonematis, the type species of the genus had not been yet studied. Here, we provide the results of TEM investigations of zoospores and sporangia from two strains of S. tribonematis. The two strains are endowed with unusual features. Like in A. gromovi, amoeboid zoospores of S. tribonematis contain a long kinetosome composed of microtubular singlets, and the two orthogonal centrioles in their sporangia have nine microtubular singlets with an internal ring. The morphological and ultrastructural features of S. tribonematis are now included in the improved taxonomic diagnosis for this species. [ABSTRACT FROM AUTHOR]

The aphelids (phylum Aphelida) are phagotrophic parasitoids of algae and represent the most basal branch in superphylum Opisthosporidia, which contains the Microsporidia, Rozellosporidia and Aphelida. Being the closest group to traditional fungi, the aphelids should have ancestral features of both phyla. As in chytrids and other zoosporic fungi, the structure of zoospores is the most informative and important morphological feature for the phylogeny and taxonomy of aphelids. Though a general zoospore description exists for some aphelid species, their flagellar apparatus (kinetid) structure, which contains pivotal taxonomic and phylogenetic characters, has not been studied. Here we represent the kinetid structure in two genera, Aphelidium and Paraphelidium, and demonstrate independent reduction in the kinetid in each genus. The kinetid‐mitochondrion connection found in Aphelidium and Paraphelidium is rare for opisthokonts in general, but present in the most basal branches of Fungi and Opisthosporidia. We suggest, therefore, that this connection represents an ancestral character for both these phyla. [ABSTRACT FROM AUTHOR]

A new vagrant phyllocoptine species, Phyllocoptes bilobospinosusn. sp. (Eriophyidae, Phyllocoptinae), found on tamarisks (Tamarix tetrandra Pallas, T. smyrnensis Bunge, T. ramossisima Ledeb) in Donbass (Ukraine), Crimea, and USA is described based on conventional light microscopy and confocal laser scanning microscopy. Apart from two distinct areas of ventral cuticle bearing large, spike-like microtubercles, the new species possesses a thin translucent supracapitular plate (situated below the frontal lobe of the prodorsal shield), a short longitudinal ventral ridge anterior to the anal lobes, and unusual internal tube-like structures associated with the rectum. Careful examination of purposefully made slide mounts of partially cleared specimens revealed that adults of P. bilobospinosus possess a complex of structures associated with the rectum, including a hypertrophied, four-lobed putative anal gland and four thin tubes connected with a rectal sac. Similar tubular structures previously described in aberoptine mites of the genus Aberoptus from Brazilian Cesalpiniaceae are discussed. The synonymy of genera Aberoptus Keifer and Aceria Keifer is rejected and a new combination, Aberoptus inusitatus (Britto & Navia (in Britto et al. 2008)) n. comb., is proposed. A brief review of the anal glands of Eriophyoidea is given, including a discussion on homology and the variety of forms of the anal secretory apparatus among eriophyoid genera. Further research is needed on the anatomy of anal glands in Eriophyoidea, including transmission electron microscopy based histological analyses and additional studies of eriophyoids with well-developed secretory structures associated with the rectum. These methods will lead to a much better understanding of the evolution and homology of the anal secretory apparatus, which may render it useful for future phylogenetic studies. [ABSTRACT FROM AUTHOR]

A new mackielline mite, Mackiella reclinata n. sp., from a South African indigenous palm-tree, Phoenix reclinata, is described in detail using different microscopy techniques. A CSLM study of M. reclinata n. sp. internal genitalia shows that mites of this genus possess teardrop shaped spermathecae, sausage-like spermathecal tubes directed anteriad and a subtrapezoidal anterior genital apodeme with a peculiar apical plate, orthogonal to the anterior-posterior body axis. Pairwise angles between the spermatheca, spermathecal tube and the longitudinal bridge of M. reclinata n. sp. females were measured. The angle between the spermathecal tube and longitudinal bridge is a quite stable morphometric character and thus is considered to be appropriate for comparison of different eriophyoid taxa. LTSEM and CLSM study shows that M. reclinata n. sp. possesses a unique, broadened frontal lobe of the prodorsal shield comprised of apical and basal parts entirely covering the dorsal palpcoxae. The incompletely described mite species Mackiella borasis Mohanasundaram, 1981 does not conform to the diagnosis of Mackiella and herein is transferred to the subfamily Phytoptinae incertae sedis.