The cavernicolous species Prionoglaris kapralovi sp. nov. is described from Armenia. A key to the three species of Prionoglaris known from adults is given and the variability of some characters is discussed. All published locality records of the genus, including those of nymphs, are summarized, along with previously unpublished records based on the collection of the Geneva Natural History Museum.

Hydromedusae were photographed and collected during 75 night-time dives in the Gulfstream off Florida. Most of the collected material was used to obtain DNA extracts and subsequently to determine part of the mitochondrial 16S rRNA gene, a barcode marker preferentially used for hydrozoans. The morphological data and the 16S barcodes permitted us to identify 46 species and 6 additional species nameable only to the genus level. Photos and descriptions are provided for all of them and the taxonomy and species status discussed. Six new species are described: Pandeopsis prolifera n. spec., Zanclea mayeri n. spec., Corymorpha floridana n. spec., Staurodiscus luteus n. spec., Octophialucium irregularis n. spec., Solmaris flavofinis n. spec. The new family Wuvulidae is proposed for the genus Wuvula Bouillon, Seghers & Boero, 1988. The new name Aequorea neocyanea is introduced for Zygodactyla cyanea L. to avoid a secondary homonymy with Aequorea cyanea . Zygodactyla cyanea was considered to be a synonym of Aequorea forskalea for most of the 20th century, but we present arguments that it should be kept distinct from the latter and it must be transferred to the genus Aequorea. The genus Otoporpa is regarded here as congeneric with Pegantha and its type species Otoporpa polystriata is therefore changed to Pegantha polystriata () new comb. Dipleurosoma brooksii is recognized as a new synonym of Staurodiscus kellneri (); Staurodiscus heterosceles as a new synonym of Staurodiscus tetrastaurus ; Orchistoma agariciforme and Tetracannota collapsum both as new synonyms of Orchistoma pileus (). The following Indo-Pacific species are newly recorded for the Atlantic Ocean: Pandeopsis ikarii (Uchida, 1927), Aequorea taiwanensis ; Zygocanna apapillatus Xu, Huang & Guo, 2014; Gastroblasta timida ; Cunina becki ; and Pegantha polystriata (). The 16S sequences also permitted us to discover several new links with polyp stages, this for Cirrhitiara superba (), Euphysilla pyramidata Kramp, 1955, Zancleopsis dichotoma, and Melicertissa mayeri Kramp, 1959. Detailed, high resolution photos of living medusae were found to be very useful for taxonomic purposes and are mostly preferable to preserved, damaged specimens obtained with plankton nets. Photos of living animals also permit us to better document material used to determine 16S barcodes and make the latter useable for taxonomic revisions.

The species group formerly included in the genus Syleter from the Oriental region is redefined resulting in the split of three genera, the original genus Syleter and two new genera, Parasyleter gen. nov. and Clypeuspinus gen. nov. Genus descriptions of the three genera and an identification key to the three genera is provided. Type species for the three genera are either re-established or designated and illustrations are provided for all of them. The genus Syleter is revised. The species Syleter acutipalpis (Putzeys) is resurrected to species status from synonymy with S. paradoxus (Putzeys). For S. acutipalpis a lectotype has been designated in order to maintain nomenclatural stability. The following new taxa are described: S. sinepunctatus sinepunctatus sp. nov., S. sinepunctatus kluangensis ssp. nov., and S. gradus sp. nov. A key to the Syleter species is provided. The genus Clypeuspinus gen. nov. is represented by one species, C. validus (Andrewes) comb. nov., which is redescribed.

The Peruvian high-altitude spider species Erigone palustris , a member of the psychrophilaspecies group, is redescribed and illustrated. This species is very similar to the northern European hypoarcto-boreal E. svenssoni , different only in a few minor details of the male palp. A list of the psychrophila-species group is presented and its biogeography is discussed.

Syrphidae are pollinators, pest predators and decomposers in European ecosystems. Camprodon (Girona province, Spain) is a valley with rich vegetation and high habitat diversity in the eastern Pyrenees. However, hoverfly biodiversity in this valley was poorly known. To explore the high potential of this area for Syrphidae, a survey with hand-net was undertaken in July/August 2020 in the valley. The list of Syrphidae species from the valley increases to 88, whilst that of the Girona province now extends to 119 species. Chrysotoxum lessonae is reported for the first time from the Iberian Peninsula. The specimens of Xylota tarda and Cheilosia hypena () represent the first documented records of these species for the Iberian Peninsula and Spain, respectively; i.e. these two species were known to occur in the Iberian Peninsula and Spain but without further locality details. A total of 19 species were new to the region of Catalonia and 23 to the Girona province. Cheilosia was the genus with the highest number of species recorded, as expected from the combination of mountains, diversity of forest vegetation, and presence of rivers/streams of the Camprodon valley. Faunistic results from this fieldwork are relevant to knowledge of Diptera from Catalonia, a region of Spain where this insect family is understudied.

Dissomphalus is a cosmopolitan genus with 424 described species. Here, all 287 Pan-American species of Dissomphalus are analyzed in order to be allocated to species groups under an alpha taxonomic approach. Thirty-four species groups composed of species with known males were initially considered. The following six species-groups are newly proposed: chiapanus, confusus, cornutus, fungosus, lamellatus and napo. The following eleven species groups are fused into four: dissomphaloides with amplus, altivolans with apertus, xanthopus with microstictus, kansanus with secretus, basidentatus and stellatus with vallensis, and strabus with tuberculatus. Forty-seven incertae sedis species are grouped and 29 are newly grouped. A total of 35 species groups are now recognized and all of the 11 species known exclusively by females remain unallocated to groups. A pictorial key to the species groups is first proposed.

A new species of minute cave-dwelling centipedes, Lithobius radjai sp. nov., is described and illustrated based on specimens collected from a cave in Croatia (Balkan Peninsula). A detailed account of the morphology of specimens of both sexes is provided. Furthermore, a brief comparison with other morphologically similar species is presented, and the type locality of the new species is mapped.

Intra- and interspecific variability of Pergamasus scorilai Juvara-Balş, 1973 and P. decebali Juvara-Balş, 1973 from Romania is investigated through morphological comparison and morphometric analyses. An analysis of morphological differences is used to show intraspecific variability and to establish the taxonomic limits of each species. We studied the proximal apophysis of tibia II in males and the endogynium of females. Using multivariate analyses based on 10 and 9 measurements for males and females, respectively, we demonstrate that the two species can be distinguished unambiguously. Relying on a variable selection approach, we also determine the most useful characters for the identification of these two very similar species. In this case only two tibial measurements allowed to correctly identify all male individuals, while at least six different measurements are needed for the discrimination of female specimens. Finally, we provide an exhaustive overview of male characteristics for the entire species-group, and we place P. instipatus in the synonymy of P. caninatellus .

Six new species of the genus Ctenoneura are presented: C. complicata sp. nov., C. virgata sp. nov., C. asymmetrica sp. nov., C. emarginata sp. nov., C. orlovi sp. nov. and C. gorochovi sp. nov. Morphology-based descriptions of the new species are given. Some questions concerning morphology and the taxonomic position of the genus Ctenoneura are briefly discussed. Changes in the method of working with small and weakly sclerotized cockroaches are proposed.

Two new dilepidid cestodes parasitic in common landbirds of Ivory Coast are described. Spiniglans thomassankara sp. nov. was found in Ploceus nigerrimus castaneofuscus (Ploceidae) and other Ploceus species along the lagoon system of the South East of the country. It shows characters similar to those of members of both Spiniglans and Dictymetra but lacks a clearly visible ductus masculinus. It is characterized by 24-26 comparatively long hooks and a massive ovary. Monopylidium comoensis sp. nov. was found in Gymnoris dentata (Passeridae) in the Sudanian savanna from the North Eastern corner of the country. It shows 20-22 hooks 13.5-16.5 long, 14-25 testes and a distally enlarged vagina. The unknown parasites richness of very common hosts is underscored.

Two new genera of Afrotropical Crambinae are described and illustrated: Afrocharltona gen. n. including A. katanga sp. n. from the Democratic Republic of the Congo and A. oblongissima sp. n. from Botswana, Namibia and Zambia, and Afroromieuxia gen. n. including A. aarviki sp. n. from Tanzania, A. bernardlandryi sp. n. from the Democratic Republic of the Congo, and A. ustjuzhanini sp. n. from Zambia.