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Species identification is an essential and vital basis for biological research. Since several fish species have similar appearances and shapes at different developmental stages and researchers lack experience identifying these fish species, molecular techniques are needed. In Thailand, fish species of the family Notopteridae consist of two genera and four species, including Notopterus notopterus, Chitala ornata, Chitala blanci, and Chitala lopis. The combination of the cytochrome c oxidase I (COI) gene sequences with a nonsequencing approach, high-resolution melting (HRM), was developed to discriminate four target species in a rapid, reliable and cost-effective manner. One of three designed primer pair sets, Notop-HRMF1/Notop-HRMR1, was the most appropriate and provided four distinct melting curves. In addition, ten fish species of other families were used for the specificity test, and only the four target species of Notopteridae were specific for this primer pair set. The results of this study indicated that COI-HRM analysis is an efficient approach for identifying species of Notopteridae in Thailand. Applications of this technique may be used to investigate species of this family in processed fish products or larval fish species in several spawning grounds for sustainable fishery resource management.

The larval morphology of Perlidae is relatively understudied compared to that of their adult counterparts, making it challenging to identify species using traditional morphological methods. In this study, we describe and illustrate the larvae of two stonefly species, Kamimuria petasus Chen, 2019 and Neoperla tuberculata Wu, 1937, based on specimens collected from China. Despite sharing a close resemblance in external morphology, the larvae of K. petasus and N. tuberculata can be distinguished based on their color pattern, chaetotaxy, and details of mouthparts. In addition, we generated and compared two DNA barcoding sequences for these two larvae. The analysis revealed that while the two species share some similar sequences, they exhibit high sequence divergence, which can be used to aid in the identification of the two different species based on immature material. The larval morphology and DNA barcodes provided in this study will supplement the classification of Perlidae larvae, enabling their more accurate and reliable identification in both full-evidence phylogenetic studies and bio-monitoring practices in the field.

The present study documents novel egg parasitoid-host associations between two genera of baeine wasps and a myrmecomorph spider, Myrmaplata plataleoides (O. Pickard-Cambridge) from West Bengal, India. Until now, no egg parasitoids have been reported from any myrmecomorph spiders. Of the two species, Idris bharati Debnath and Rajmohana sp. nov. is described as new, while Odontacolus markadicus Veenakumari is reported for the first time from the eggs of M. plataleoides. The mt COI DNA barcode sequences for these two species are the only sequences of baeine wasp species from India. Additionally, a preliminary phylogenetic tree has been provided for the members of Idris. Some interesting observations on the nesting behaviour and maternal care of M. plataleoides are also provided.

Tardigrades are aquatic microinvertebrates, that can be found from the poles to the tropical regions. However, knowledge about their diversity and distribution is still limited, especially regarding the Neotropical region. In addition, many species described in the past were considered cosmopolitan but new morphological, morphometric and especially molecular studies have demonstrated the existence of species complexes. The species Milnesium tardigradum Doyère, 1840 is an example that highlights this issue. Many M. tardigradum records made in South America date from the time when this species was considered cosmopolitan and exhibiting large intraspecific variability. However, current revisions of the genus using modern techniques indicate that the M. tardigradum sensu stricto is most likely restricted to the Palaearctic region. In this contribution, we describe a new species, Milnesium iniquum sp. nov. from south-eastern Brazil, with additional records from Argentina and French Guiana, utilising integrative taxonomy framework. The new species is characterised by having smooth cuticle, presence of dorsal pseudoplates, adult claw configuration [3-3]-[3-3] and [2-2]-[2-2] in hatchlings (early positive CC change), with internal and anterior spurs larger than external and posterior spurs and by presence of short cuticular bars on legs IV.

The ultrastructural differences are shown between the cytoarchitecture of the excretory bladder and excretory inclusions in four digenean species, two azygiids, the marine Otodistomum cestoides and the freshwater Azygia lucii, the marine derogenid Derogenes varicus and the freshwater allocreadiid Acrolichanus auriculatus. The unusual cytoarchitecture of the bladder epithelium of the azygiid digeneans, consisting along its entire length of two alternating, morphologically different zones, tegumental and cellular excretory epithelial zones, connected by septate junctions, has recorded for the first time for the Digenea and, in general, for the Neodermata. It, possible, suggests the participation of the tegumental distal cytoplasmic layer in the formation of their excretory bladder epithelium. Like most digeneans, the excretory bladder of A. auriculatus and D. varicus has a syncytial epithelial lining. Based on available literature and our own results, we can confirm the presence of the excretory corpuscles in adult marine digeneans and their absence from freshwater species, regardless of the digenean localization in their host. The present study shown that in marine digeneans, the excretory corpuscles are associated with specialized excretory cells or excretory syncytial epithelium. Ultrastructural data were obtained on the possible growth of the excretory bladder epithelium due to the migration of undifferentiated cells into the epithelial lining in studied marine species. We may assume that the bladder epithelium of marine adult digeneans specializes, in addition to the excretory function, in osmoregulatory function.

Xiphocentron species are often distinguished only by subtle differences in genital structures, and species are usually described with small type series not allowing the distinction of intra and interspecific variation. Herein we evaluated for the first time the use of the forewing geometric morphometrics to verify Xiphocentron species distinctiveness at a population level. Most of the known specimens from Atlantic rainforest and Brazilian savanna were analyzed, including six new species (Xiphocentron guarani sp. n., Xiphocentron karaja sp. n., Xiphocentron schmidi sp. n., Xiphocentron tapuia sp. n., Xiphocentron tupi sp. n., Xiphocentron xokleng sp. n.). Species were analyzed in two comparative datasets of species with similar genitalia. Forewing shape among species differed statistically. Canonical variate analysis showed partial overlapping of wing shape in most species except to X. karaja sp. n. and X. xokleng sp. n. Cross-validation test was able to discriminate species with an overall correctness of 64.65 % and 73.15 % in each dataset. So, forewing morphometrics showed moderate to high effectiveness depending on the Xiphocentron species, but had a lower informativeness compared to the >80 % correctness shown in studies with another Trichoptera genus, Smicridea. The lower forewing distinction in Xiphocentron might be associated with a stronger functional selection of wing traits related to miniaturization. Additionally, two very similar species described from the same locality Xiphocentron steffeni and Xiphocentron ilionea were re-described, clarifying their distinctiveness.

Agrotis Ochsenheimer (Lepidoptera: Noctuidae) is a widespread, cosmopolitan genus, with 20 species occurring in South America. Two of those species are considered major pests of different crops, Agrotis ipsilon (Hufnagel) and Agrotis robusta (Blanchard). The latter is often confused with Agrotis malefida Guenée in the literature and, despite its economic importance, its immature stages have been only superficially described. Agrotis canities (Grote), although never regarded as a pest, is known to use some crops as hosts and is commonly captured in light traps. However, its immature stages are unknown, making the evaluation of its true economic importance difficult. In this study, we examine in detail the external morphology and ultrastructure of the egg, larva and pupa of A. robusta and A. canities using light and scanning electron microscopy. Furthermore, we provide an identification key for those four species including all immature stages and up-to-date maps of their distribution in South America. Finally, we discussed the application of immature stages morphology of Agrotis species in systematic and phylogenetic studies. Particularly, we examine the morphology of the trichobothria, or “tonosensillum”, through larval development and the progressive and differential development of abdominal legs in each species.

To better understand the antennal morphology and sensilla distribution of Spilococcus alhagi (Hall) in different instars, the antennae are examined using light microscopy and scanning electron microscopy. The results show that the antennae of S. alhagi could be differentiated in different instars based on their stucture, number of flagellomere, and sensillar distribution. Functional antennae of S. alhagi appear in first instar nymphs, adult females, and adult males as many scale insects. The antennae of first-instar nymphs comprise six segments, and each antenna has 62–71 sensilla of eight types, including sensilla basiconica (SB), one type of sensilla trichoidea (ST1), two types of sensilla companiform (SCa, sSCa), two types of sensilla coeloconica (SCo1, SCo2) and two types of sensilla chaetica (SCh1, SCh2). The antennae of adult females have eight segments, but each antenna has 164–188 sensilla of the same eight types as the first instar nymphs. The antennae of adult males are more developed, and each antenna contains ten segments and 670–725 sensilla of eleven types, including knobbed seta sensilla (Ks), intersegmental sensilla (Ins), two types of sensilla trichoidea (ST1, ST2), two types of sensilla companiform (SCa, sSCa), two types of sensilla coeloconica (SCo1, SCo2) and three types of sensilla chaetica (SCh1, SCh2, bSCh). Of these, four types of sensilla, viz., Ks, ST2, Ins, bSCh are only observed on the antennae of adult males. The prepupa-like and pupa-like male nymphs both possess simplified antennae, and exhibit four types of sensilla (ST1, SCa, SCh1, SCh2). Based on these results, the morphogenic changes and potential functions of antennae of S. alhagi in different instars are discussed.

Myopinella Michelsen (Diptera: Anthomyiidae) is a very small group of flies endemic to South America. The genus includes only two species, Myopinella angustifrons (Malloch) and Myopinella appendiculata (Stein). The species had been previously recorded from Argentina, Bolivia, and Peru. Here, we redescribe M. angustifrons and M. appendiculata based on female and male specimens, with detailed illustrations, photographs and scanning electronic microscopy images. We also present and describe in detail the outstanding modified male sternites for the family Anthomyiidae. Also, we analyze intraspecific and interspecific divergences with COI sequences of both Myopinella species and other Anthomyiidae, and present several new records. Finally, the generic name Myopinella Michelsen, 2010 is revalidated.

Plesiopelma longisternale is a widespread tarantula in Argentina and its limit is difficult to determine due to their morphological variation among populations. Males are distinguishable by the following character combination: a field of spines on the apical half of the palpal tibia, a very long embolus and a field of spines on the reotrolateral face of cymbium; females are characterized by long spiraled ducts distant from each other. Here, we used mitochondrial DNA (cox1) to reconstruct the first phylogeny of P. longisternale, in combination with morphological data and molecular species delimitation, to assess the taxonomic limits of this species. Our phylogenetic results confirm a close relationship among the populations from central Argentina and a new evolutionary independent lineage identified as a new species, Plesiopelma absconditus, which is here diagnose, described and illustrated. We further analyzed the diagnostic characters of P. longisternale through the examination of the types and specimens from many populations and found that their morphological intraspecific variations largely overlap. Altogether, our results demonstrate that some of the variability of P. longisternale in central Argentina represent polymorphisms of a single species supported by molecular data. In addition, we discovered a new species from this genus distinguishable by molecular and morphological data and highlight the need for multiple lines of evidence to solve the taxonomic problems in species of tarantulas.