Many taxa in the Acrididae have controversial phylogenetic positions. A typical example of such controversies is the phylogenetic positions of the genera Caryandoides, Paratoacris, Fer and Longchuanacris, as well as some other related taxa, which were placed in Oxyinae by some authors, but were considered members of the subfamily Catantopinae by others. In this study, the complete mitogenomes of nine species were sequenced using next-generation sequencing, the characteristics of the newly sequenced mitogenomes are presented briefly, and the phylogeny of the Oxyinae and Catantopinae are reconstructed using a selected dataset of mitogenome sequences under maximum likelihood and Bayesian inference frameworks. The results show that the four controversial genera were consistently assigned to the subfamily Oxyinae rather than Catantopinae in all phylogenetic trees deduced from different datasets under different frameworks, and this finding is entirely consistent with their morphological characters. Therefore, it is more appropriate to place them in Oxyinae rather than Catantopinae. In addition, the results from our analysis also confirm the membership of the genus Apalacris in Coptacrinae rather than Catantopinae, and indicate the uncertainty in the phylogenetic position of the genus Traulia, and a more in-depth study is necessary to resolve the relationship of Traulia with other catantopine groups or Coptacrinae.

The genus Taczanowskia Keyserling, 1879 is one of the rarest groups of spiders in the orb-weaving family Araneidae, with only five species described and 17 specimens cited in publications. Our study provides new insights into the evolutionary relationships and diversity of Taczanowskia. Using morphological data, we tested the evolutionary relationships of the genus within the family Araneidae and propose the first phylogenetic hypothesis depicting the relationships among species of Taczanowskia. Our results place Taczanowskia as sister to Mastophora Holmberg, 1876, and confirm the monophyly of Taczanowskia. We describe the first species of Taczanowskia from Ecuador, collected at a Waorani community on the River Curaray basin, Amazonian lowlands of Ecuador. The new species can be easily diagnosed from all other species of Taczanowskia by having two tubercles in the opisthosoma; a distinct patchy dark–light colouration pattern with dark spots concentrated towards the anterior margin and on the lateral tips; small bundles of white setae forming a reticulum across the dorsal part of the opisthosoma, and the first two femora thick but lacking teeth on the margin.

Phyllodistomum is one of the most species-rich genera of parasitic platyhelminths, with 120 species described worldwide; they infect the urinary bladder of marine and freshwater fishes. As the number of new species within the genus has increased, morphological conservatism, and the lack of reliable diagnostic traits make the separation of species a challenging task. The increase of genetic data for Phyllodistomum species has permitted the use of an integrative taxonomy approach as a framework for species discovery and delimitation. DNA sequences (28S rRNA and COI mtDNA) were obtained from individuals of Phyllodistomum sampled in 29 locations across Middle America, and used in combination with morphology, host association and geographic distribution to uncover five new congeneric species. Morphologically, the new species are relatively similar; there are no unique morphological traits to readily distinguish them. We first investigated species boundaries through phylogenetic analyses of the independent and concatenated datasets; analyses recognised five candidate species showing reciprocal monophyly and strong clade support, particularly for COI data. The interspecific 28S rRNA and COI sequence divergence among the new species from 0.4 to 18.4% and from 5.1 to 27% respectively. These results were further validated by a Bayesian species delimitation approach. The five new species are well supported by molecular data used in combination with other sources of information such as host association and geographical distribution and are described herein as Phyllodistomum romualdae sp. nov., P. virmantasi sp. nov., P. isabelae sp. nov., P. scotti sp. nov., and P. simonae sp. nov.

Benthesicymidae is a monophyletic group of Decapoda adapted to a life on the sea-floor, in the near-bottom layer, in the bathy- and in the mesopelagic, within an impressive depth range from a few hundred metres (Gennadas) to several thousand metres (Benthesicymus). Higher taxa are known to conquer all main oceanic biotopes such as the benthic, benthopelagic, and pelagic and a wide depth range but few family-level groups have clades evolved within all these oceanic realms. Therefore, the global fauna of Benthesicymidae provides a rare opportunity for an insight into phylogenetic processes favouring colonisation of all principal oceanic biotopes. The first comprehensive phylogenetic study of Benthesicymidae (all 37 valid species) is based on six molecular markers and 105 morphological characters (including 72 female and male copulatory characters). Analyses resulted in trees with similar topology and the same set of robust clades. Molecular methods based on 167 sequences (84 new) provided better resolution of deeper nodes and generally higher support of the clades, while morphological methods allowed analyses of all valid species of the global fauna. Phylogenetic analyses support the monophyly and robustness of all currently known genera except Gennadas, which was split into Gennadas Bate, 1881, Amalopenaeus Smith, 1882, and Notogennema gen. nov. We also retrieved two major clades for which we erected two new subfamilies: Benthesicyminae subfam. nov. (presumably benthic, genera Altelatipes, Bathicaris, Benthesicymus, and Benthonectes) and Gennadinae subfam. nov. (presumably pelagic, genera Amalopenaeus, Bentheogennema, Benthoecetes, Boreogennema, Gennadas, Maorrancaris, and Notogennema gen. nov.). We revealed two groups of morphological characters, that are interlinked evolutionarily: (1) petasma and thelycum; (2) body, mouthparts, and pereopods. Morphological traits within benthic and pelagic clades are different, a model explaining the differences is proposed. Along with previous studies, our results confirm the idea that the elaboration of the copulatory structures is a key to successful colonisation of the pelagic realm. These results extend our knowledge about evolution in the largest habitual biotope of our planet and phylogenetic processes favouring colonisation of all principal oceanic biotopes.

Numerous faunistic and ecological studies have been conducted throughout the Indo-Pacific Ocean to assess its biodiversity. Despite the abundance of research, studies on the species that inhabit the Indo-Pacific are still necessary due to its extent and high species richness. The major species richness of the genus Okenia Menke, 1830 (Nudibranchia, Goniodorididae) is found in the Indo-Pacific Ocean, including 38 of 60 valid species. Nevertheless, this number does not represent the real biodiversity, since at least 20 more species are already reported in field-guides as undescribed species belonging to this genus. The systematics of the genus Okenia are still unclear since it has been the subject of only a few and incomplete studies. In the present paper, we describe five new Okenia species from the coastlines of Japan, Mozambique and Australia: Okenia aurorapapillata sp. nov., Okenia elisae sp. nov., Okenia nakanoae sp. nov., Okenia siderata sp. nov. and Okenia tenuifibrata sp. nov. Moreover, anatomical details not previously described of Okenia atkinsonorum, Okenia barnardi, Okenia cf. echinata, Okenia hallucigenia, Okenia hiroi, Okenia japonica, Okenia pellucida, Okenia pilosa and Okenia rhinorma are provided. New partial sequences of standard markers (COI, 16S rRNA and H3) were obtained and a phylogenetic analysis that included all species with available data was performed.