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The number of new species described of the genus Terebellides Sars, 1835 (Annelida, Trichobranchidae) in the eastern Atlantic Ocean has greatly increased in the last years. Eleven of these species, all originally described in NE Atlantic Ocean, from the Barents Sea to the Gulf of Guinea, have been studied using micro-computed tomography (micro-CT) thus revealing interspecific differences in several elements of the internal anatomy such as the proportion between stomach regions and size of nephridia, and in the number of lamellae in the digestive gland. Two stomach morphotypes have been distinguished regarding differences in relative length between regions, as well as two morphotypes of nephridia according to their size and wall thickness, and four types of the digestive gland regarding their number of lamellae. Differences in nephridia sizes is the only character apparently related to the geographic distribution of species (i.e. NE Atlantic vs. Gulf of Guinea) but examination of more taxa is needed. A third distinct region was distinguished in the stomach, named here as mid stomach, that differs from the fore and hind stomach in epithelia thickness and by lacking connective muscular sheath. The potential of the micro-CT technique in the search for internal anatomical characters with taxonomic value is discussed.

Subterranean fauna is an important contributor to the global fauna, but it is still understudied and a large part of its taxonomy is not yet resolved. One species complex with unresolved taxonomy is the groundwater amphipod Niphargus ruffoi, endemic to the Alpine chain. Here, we used new samples from across the Alpine arc to review the taxonomic status of the entire clade, including the species N. ruffoi and Niphargus arolaensis. We sequenced four genetic markers from the collected specimens, assessed the phylogenetic position of N. ruffoi within the genus, and studied the structure of this species complex using four molecular species delimitation methods. We tested for recombination using the alignments of the concatenated nuclear rDNA genes. The phylogenetic analyses revealed high support for the monophyly of the studied species complex, defining two lineages (i.e., N. arolaensis and N. ruffoi) within the clade. Molecular species delimitation methods suggested that N. arolaensis is a single species, while N. ruffoi should be considered as a species complex of three (using ITS) to eight (using COI) putative species. Moreover, we found a discrepancy between the different nuclear ribosomal DNA markers, indicating a possible recombination with fragments of 28S DNA of N. ruffoi s. lat. present in the genome of N. arolaensis. For the above-mentioned reasons, the internal phylogenetic structure of N. ruffoi s. lat. could not be fully resolved. Moreover, no clear morphological evidence supported the molecular species delimitation. Consequently, no taxonomic changes were proposed. We postulate that this complex scenario was influenced by Pleistocene climate oscillations with subsequent fragmentation events and secondary contacts, making this an interesting study system to investigate the evolution and biogeography of Alpine clades.

We describe two new species of leptocheliid tanaidaceans, Chondrochelia sublitoralis sp. nov. and Neoleptochelia japonica sp. nov., from Japan. Chondrochelia individuals were collected from 113 to 185 m depth in the Kumano Sea. Chondrochelia sublitoralis sp. nov. resembles Chondrochelia africana, Chondrochelia corsica, Chondrochelia taitungensis, and Chondrochelia tanykeraia in having females with slender chelipeds but differs from them in the length ratio of antennular articles and the setal pattern on maxillipeds, cheliped, pereopods 4–6, and pleopods. Males differ from Chondrochelia durbanensis, for which information on females is lacking, in having pereopod-1 propodus lacking ventrodistal spiniform setae and a uniarticulate uropodal exopod. Chondrochelia sublitoralis sp. nov. varies intraspecifically in the number of female antennular articles, five in larger and four in smaller females. Neoleptochelia japonica sp. nov., collected from the coast of Okinawa Island, differ from Neoleptochelia javaensis (previously the sole species in Neoleptochelia) in the setal pattern on antennae, maxillipeds, cheliped, and pleopods in females; and that on the cheliped in males. Male pereopods 1–3 show a unique subchelate condition that we speculate may function for clasping during copulation. Several females in both species had the second thoracomere demarcated on the carapace, whereas others did not. Cytochrome c oxidase subunit I (COI) gene sequences determined for C. sublitoralis sp. nov. and N. japonica sp. nov. showed intraspecific K2P distances of 0–0.4% and 0–0.5%, respectively. We inferred the phylogenetic positions of the two species in Leptocheliidae based on COI data.

The article describes a new subspecies Eurytemora caspica tethysiana subsp. nova that, according to its genetic and morphological features, is closely related to the recently described species Eurytemora caspica caspica from the Caspian Sea. According to our hypothesis, both of these taxa are relics of the fauna of the Tethys Sea in the last phase of existence (Paratethys).

The described form occupies an intermediate position between Eurytemora caspica caspica and Eurytemora carolleeae by its morphological characteristics. The time of divergence of the described subspecies and the original forms according to molecular clocks is in good agreement with the geological events associated with the evolution of the Tethys Sea (8–20 MYA), which indicates a very slow rate of evolution among representatives of Eurytemora. The morphological differences of our subspecies from the nominative Caspian subspecies are: the shapes of the genital double-somite and P5 distal segment in females. In males sexually dimorphic differences are in the shapes of left P5 exopod and distal segment of the right P5, in ratio L abdomen/L caudal rami.

At the same time, both forms belong to the affinis group of species, which includes also Eurytemora carolleeae and Eurytemora affinis. The new taxon is described and the problem of the Eurytemora species’ evolution in the affinis group is discussed in the present work.

Xenogaster Wasmann is a Neotropical genus of termitophilous rove beetles with 11 known species. During recent surveys in Southeastern Brazil, we collected a new species of this genus, Xenogaster lugens Pires-Silva and Zilberman sp. nov., herein described. This new species is known only from an intermediate stage of development, which prompted a discussion about the range and underestimation of the phenomenon of post-imaginal growth in Termitogastrina (Corotocini). A redescription of X. pilosula Seevers, and comparisons between its stenogastric and physogastric stages are also presented and used in the final discussion on the taxonomical and evolutionary significance of this phenomenon under the frame of the knowledge of post-imaginal growth in the subtribe and also Corotocini in general.

In the Neotropical region, the genetic diversity and bioclimatic preferences of Ephemeroptera are poorly known mainly due to the lack of studies. We used the 16S rRNA mitochondrial gene to examine the genetic structure of Baetodes huaico, an aquatic insect distributed in the Northwest of Argentina. Also, we performed an ecological niche modeling (ENM) to understand bioclimatic preferences and combine with the genetic data to understand historical dynamic distribution of B. huaico. We found that B. huaico populations are genetically structured into two distinct geographic groups. The ENM showed a distributional shift from south to north through time. Also, we recovered a stable region over time in the Southwest of Tucumán with the highest value of suitability and high genetic diversity; this region was previously proposed as a Pleistocene refuge. Our result suggests that the northern group was stable over time and underwent a recent demographic expansion coincident with a glacial refugium, whereas the southern group could have been affected by climatic fluctuations during. The results emphasize possible climatic influences in genetic population differentiation, and contributes to the knowledge of the genetic diversity of Ephemeroptera from subtropical Argentina laying the groundwork for future work for other freshwater insects in our region.

Parental care behaviours including the defence of oviposited eggs are common strategies to increase the fitness of offspring in animals. Among insects, Hemiptera, the true bugs (Heteroptera) and allies, show a wide range of such strategies. Females of some heteropteran species in the family Plataspidae, in addition to standard maternal care of eggs and early instar nymphs, provide protection of eggs by forming an ootheca, a complex structure coating the egg batch. Although not homologous across the insect taxa in which oothecae occur, structures referred to as oothecae are relatively common in insects, but the literature has so far not been summarized comprehensively. The goals of the present study are twofold. First, we provide a detailed description of the egg and ootheca of the tropical plataspid species Libyaspis flavosparsa (Montandon). The oothecal material of Plataspidae originates from a modified epithelium of the midgut thus represents a unique situation within all insects. Second, the known occurrences of oothecae in Insecta are summarized and discussed. This study provides a basis for future investigations both into the ootheca in Heteroptera and in other insects.

Lepidurus couesii is a large freshwater branchiopod that is distributed broadly around the world. In this study, we used molecular and morphological methods to identify and record Lepidurus cf. couesii for the first time in Iran. The Almalou Gul specimens presented the characteristic number of rings, mediodorsal spines on the supra-anal plate, and the sulcus spines of the species L. couesii. A complete morphological characterization of the species and a comparison with previous records of Lepidurus apus in Iran is included in this work. Phylogenetic analysis based on the COI gene recovered the Iranian specimens as an independent lineage within the L. couesii species complex. The GMYC and the ASAP species delimitation models calculated at least four independent lineages within the L. couesii species-complex, some of them with probably restricted distributions. This study stresses –once again– the presence of several species-complexes within this group of crustaceans and the necessity to include molecular phylogenetic research to recognize the specific occurrence of different lineages within the genus Lepidurus.

The epyrine genus Laelius Ashmead, consists of a total of 63 valid species recorded from all zoogeographic regions. Two of them, namely L. firmipennis (Cameron) and L. glossinae (Turner & Waterston), have been recorded from the Afrotropical region. In the present study, we revise all species of Laelius from the Afrotropical region by newly collected specimens, based on an integrative taxonomy approach, combining morphological characters and molecular phylogenetic analyses. We recognize seven species, one previously described, Laelius firmipennis, and six as new species, which are described and illustrated: Laelius pumbaai sp. nov., Laelius sarabiae sp. nov., Laelius scari sp. nov., Laelius simbai sp. nov., Laelius timoni sp. nov. and Laelius zirae sp. nov. Additionally, we propose Laelius glossinae as a junior synonym of Laelius firmipennis based on the morphological characters. Male–female associations of L. firmipennis and L. pumbaai are supported by molecular data, while L. scari by morphological data. We also provide a synopsis of how male–female associations were established in the other species of Laelius. Finally, we present a taxonomic key for all Afrotropical species of Laelius.

The class Polyplacophora (chitons) represents a dorsoventrally flattened mollusk group that has an oval-shaped body covered with eight overlapping sclerites providing bilateral symmetry. Chitons show abnormalities (teratologies) that are characterized by symmetry deviations between the right and left sides of their bodies. As these deviations do not result in damage that affects vital functions, chitons are able to reach adult stages. In this study, we quantify the asymmetric condition of the species Chiton articulatus using a landmark-based geometric morphometric approach to assess variation in shape and bilateral symmetry. A geometric configuration of 22 landmarks and 50 semi-landmarks was created to evaluate shape variation in abnormal and deformed specimens compared to normal Chiton articulatus specimens. Vectors of change in the body shape configurations of chitons indicate that the greatest change occurs in the anterior part of the body, with less change in the middle and posterior parts. This gives chitons a widened appearance and provides anatomic compensation to restore the bilateral symmetry of the body scleritome. The diverse abnormalities and deformities had little impact on shape variations and confirmed that the coalescence condition is an intermediate step between a normal condition and the abnormal conditions of hypomerism or hypermerism. The low levels of fluctuating asymmetry expressed in C. articulatus indicate that despite living in areas of high stress, such as the rocky intertidal coast, this species maintains stability in its development and shape. Our results can serve as a model for studying bilateral symmetry deviation in polyplacophorans.