Invertebrate Systematics最新文献

The evolution of animal genitalia has been an intriguing topic of research since Darwin proposed that sexual selection is acting upon these traits. Pseudoscorpions (Arachnida) are an interesting model to test this hypothesis since they exhibit a wide array of sexual traits and sexual strategies, including the development of elaborate spermatophores. In this context, we (1) explored the phylogenetic relationships within Withiidae using somatic, sexual characters, and molecular data; (2) estimated times of diversification of the lineages within the family; and (3) explored rates of change of male genitalia characters. We found strong support for the monophyly of Withidae and for both the Neotropical and the non-Neotropical clades; as for the sister group of Withiidae, there is no conclusive evidence since molecular data suggest Atemnidae, supporting previous molecular studies, but the combined morphological and molecular data pointed to Cheliferidae instead, with high support in both cases. The dating analysis suggests that Withiidae originated in the Cretaceous and its main diversification occurred during the Eocene. We also found that sensory traits such as the position of the trichobothria isb and ist , and not genital traits such as length of the ejaculatory canal, change faster, challenging the prediction of higher change rates in the former. In conclusion, for pseudoscorpions, factors other than sexual selection may contribute to stronger selective pressures over their morphology.

Accurate identification of species and distributions is essential for developing effective conservation and recovery strategies for threatened taxa. Owing to the extreme shell variation and evolutionary convergence, defining and classifying species based solely on morphology can be a challenging and ambiguous process. The freshwater mussel genus Schistodesmus (Bivalvia, Unionidae), which is endemic to China, has traditionally been considered to comprise only two species: Schistodesmus lampreyanus and Schistodesmus spinosus . In this study, an extensive collection of samples from China was conducted and an integrative taxonomic approach, including shell morphology, soft-body anatomy, molecular systematics and biogeography, was employed to investigate the genus Schistodesmus . The results reveal three cryptic species: Schistodesmus luqiaoensis sp. nov. , Schistodesmus tongpenensis sp. nov. and Schistodesmus xinyuensis sp. nov. , and well-supported phylogenetic relationships are reconstructed based on mitochondrial genomic data. This discovery increases the number of species in the genus to five, thereby substantially improving our understanding of its diversity and systematic relationships. The molecular clock analysis and biogeographical reconstruction based on fossil-calibrated dating indicate that the ancestor of the genus originated in the paleo-Yangtze River Basin during the Eocene (c . 50.74Ma), with species diversification beginning c .18.68Ma in the Early Neogene. The uplift of the Qinghai-Tibet Plateau, along with associated paleoclimate changes and local river capture events, significantly facilitated the diversification process of this group. This study not only reconstructs the species diversity framework of Schistodesmus but also highlights the significance of integrated molecular technologies in addressing morphological convergences and promoting effective species conservation. ZooBank: urn:lsid:zoobank.org:pub:C997B546-CB1D-4050-AC64-2F132739C22C.

The taxonomy of the genus Macrobrachium , a group of mostly amphidromous shrimps inhabiting unstable streams on Indo-Pacific tropical islands, is based on several characters repeatedly associated with specific environments and stream velocities. This allows the identification of morphological traits that improve an organism's stability in given flow conditions and an assessment of their monophyly. This study investigates whether the altitude-dependent distribution of certain Macrobrachium species - characterised by specific morphological traits - is phylogenetically constrained or a result of phenotypic plasticity. We first use an integrative taxonomy approach to assess species hypotheses based on ~200 individuals collected across the Indo-Pacific. We then construct multi-gene phylogenetic trees (65 individuals; 3-5 concatenated genes; 2711bp) to explore the evolutionary origins of morphological similarities among closely related species. Our results support the species status of 30 Macrobrachium species, with 16 species exhibiting distinct morphologies and 14 species forming 5 species complexes. Phylogenetic and distribution patterns of closely related species suggest habitat-driven speciation, with species differentiating in similar environments across vast distances. This indicates that diversification can occur over large distances, yet still in sympatry within a given environment. Lastly, our findings suggest that the Macrobrachium body shape is derived from evolutionarily conserved adaptations to flow velocity.

The dragon millipedes are a unique and diverse group of diplopods, endemic to limestone habitats in South-east Asia, and yet several new genera and species are still to be discovered. Among these, a recent field survey uncovered several striking specimens featuring alternately long and short legs on each diplosegment, a morphological trait previously unseen in the family Paradoxosomatidae or any other diplopods, except for the genus Pandirodesmus Silvestri, 1932 (family Chelodesmidae). Using mitochondrial (COI , 16S ) and nuclear (28S ) genetic data, alongside detailed morphological analysis in order to confirm their status, we reconstructed phylogenetic trees of dragon millipedes through maximum likelihood and Bayesian inference. The phylogenetic trees strongly support the monophyly of all dragon millipedes, as well as of each nominal dragon millipede genus. The results also revealed the new specimens forming a distinctly separate clade that is closely related to Spinaxytes . Based on these findings, we establish a new monotypic genus of dragon millipedes to accommodate a new species, Alternaxytes bipectinata gen. nov., sp. nov., within the tribe Orthomorphini of the family Paradoxosomatidae. Morphologically, Alternaxytes gen. nov. is characterised by unique gonopodal features and heteropodous legs, suggesting a case example of convergent evolution within Diplopoda. ZooBank: urn:lsid:zoobank.org:pub:E8C1488C-AF69-4F52-9F65-7645C7498D60.

Violin spiders are an old, diverse genus of spiders, which includes medically significant species. Among its members, the Neotropical laeta group is particularly notable, as it includes the largest spiders of the genus, such as Loxosceles laeta (Nicolet). In this paper, I describe a new species belonging to this group, Loxosceles galianoa , sp. nov., from male and female specimens collected in the dry Argentinean north-west. The new species is the southernmost native member of the laeta group, and its phylogenetic placement is confirmed by a novel phylogenetic analysis based on molecular data and a taxon sampling including members of all Loxosceles species groups. The morphology of the endogyne of the new species prompted me to survey and characterise the morphological diversity of the female genitalia in Loxosceles . I review the homologies of the parts of the female genitalia in this genus. I argue that an enlarged uterus externus with a narrowed opening is synapomorphic for the laeta species group, whereas in the lineage containing the rufescens and gaucho groups the uterus externus may be sclerotised and bear numerous deep transversal ridges. I here hypothesise that Loxosceles is an example of a clade where female genital morphology is more diverse and has accumulated more morphological novelties than that of males. The geographic origin of the medically significant Loxosceles laeta is briefly discussed. Although this species is commonly referred as the 'Chilean recluse spider', I here argue that this species most likely originated in Peru and has been introduced to other South American countries by human action. The type material of Loxosceles accepta Chamberlin, 1920 is examined and illustrated. Loxosceles gaucho Gertsch, 1967 is newly recorded from Argentina and Paraguay. ZooBank: urn:lsid:zoobank.org:pub:5EA253F0-4742-4031-9F34-095076B00073.

Freshwater meiofauna in the Neotropics remain vastly understudied, and many species are yet to be discovered due to sampling biases and methodological constraints. In this study, we describe Carianotus dives gen. nov., sp. nov., a new genus and species within Chaetonotidae (Chaetonotida: Paucitubulatina) from Brazil. This species, found in several regions spanning over 3000-km linear distance, features a unique set of morphological features, importantly a distinctive crest of five lanceolate-leaf-shaped spines deriving from small basal scales on the anterior dorsal head. The integrative description is based on light and scanning electron microscopy and molecular phylogenetic analyses of concatenated 18S and 28S rDNA sequences. Our analyses suggest the phylogenetic placement of Carianotus gen. nov. within a paraphyletic branch of Chaetonotus , with spined Chaetonotus lineages and spineless species of Lepidodermella . This research highlights the importance of integrative taxonomy in uncovering hidden biodiversity within the Neotropical region, and demonstrates the still underexplored status of the freshwater meiofauna of Brazil, with many species yet to be discovered. ZooBank: urn:lsid:zoobank.org:pub:D37B6DAB-6E0C-4D8B-B956-D29C066AA284.

Leeches of the genus Limnatis are known ectoparasites of vertebrates, including humans and domestic animals, with some species causing significant health complications. In this study, we describe Limnatis anouarensis sp. nov., a new nasal leech species from Tunisia and compare it with Limnatis nilotica sensu stricto from Tunisia and Morocco. Morphological analyses were conducted using light and scanning electron microscopy, focusing on external and internal structures. Additionally, mitochondrial (cytochrome c oxidase subunit I, COI; 12S rRNA, 12S) and nuclear (28S rRNA, 28S) gene fragments were sequenced for molecular characterisation. The new species is distinguished by its larger size, distinct reproductive system morphology and unique dorsal colouration, characterised by a median orange band and marginal orange stripes, in contrast to the black-striped pattern of L. nilotica (Moore, 1938). Molecular analyses confirmed that mitochondrial markers provide reliable species identification, whereas the analysed fragment of 28S gene was fully conserved and unsuitable for differentiation. These findings confirm the presence of at least two distinct Limnatis species in North Africa, emphasising the need for further taxonomic and ecological studies to clarify their distribution, host specificity and potential medical significance. ZooBank: urn:lsid:zoobank.org:pub:7CA59D0E-1D42-4A02-B886-D198DD88E698.

The infratribe Neosatyriti is a section of the entirely Neotropical subtribe Pronophilina, accounting for 57 species distributed from southern Patagonia to the Andes of northern Peru, and along the Atlantic coast, with the highest diversity in central Chile. They are found in two main types of habitats, i.e. puna, pampas and subantarctic grasslands, and Valdivian forests and Chilean matorral, from sea level to nearly 5000m above sea level. We propose a phylogenetic hypothesis of the infratribe based on molecular data obtained by target enrichment (TE) of 621 nuclear loci, totalling 248,373 base pairs, from 53 species of this infratribe and 12 outgroups. Our analysis confirms that Neosatyriti is monophyletic with full support. Based on these results, we propose eight new combinations and two status reinstatements. Molecular data are congruent with morphological characters except for Homoeonympha which appears to be paraphyletic, thus almost all the genera described originally by L. Herrera, K. Hayward and W. Heimlich in the Twentieth century based only on morphological characters are confirmed as valid, except for Haywardella that is synonymised with Pampasatyrus . Neosatyriti diverged from other Pronophilina some 23Ma and split into two major lineages some 20Ma. Our reconstructions do not indicate a single area of origin, rather a multisource origin, but they suggest the Neosatyriti originated in the lowlands, and that their ancestral plants were non-bambusoid grasses. Major divergence of the infratribe started some 12-11Ma when it split into the 'Neomaenas clade' (9 genera), the 'Pampasatyrus clade' (4 genera) and the 'Neosatyrus clade' (5 genera). The next main radiation took place some 7-5Ma with the switch to bamboo host plants and the colonisation of Valdivian forests. The final dispersal of the tribe was associated with the colonisation of Mata Atlantica some 6-5Ma, and high Andean puna in Peru in the Early Pleistocene. ZooBank: urn:lsid:zoobank.org:pub:29A961D1-99EF-465C-87E7-FB5B3570E3AE.

The family Unionidae is a diverse and ecologically significant group of freshwater invertebrates, playing a keystone role in the energy flow and nutrient cycling in aquatic ecosystems. A recent taxonomic revision of the East Asian endemic subtribe Cristariina within Unionidae has revealed its division into seven genera. As an important part of East Asia, China harbours an exceptionally diverse and highly unique fauna of freshwater mussels. However, a comprehensive understanding of species diversity and phylogenetic relationships of Cristariina remains elusive due to inadequate sampling in previous studies, particularly in China. Here, we conducted comprehensive taxonomic and mitogenomic phylogenetic analyses of Cristariina based on extensive sampling across 17 provinces in China. The COI sequences of Cristariina in GenBank were thoroughly examined, and combined with the sequences obtained from this study, a total of 33 monophyletic groups were identified. By integrating molecular data and morphological characteristics, we describe a new genus and species: Acudonta baitiaoensis gen. nov., sp. nov. , as well as a newly recorded species for China (Cristaria truncata ). Additionally, we confirm that the nominal species Anemina euscaphys syn. nov. , Anemina fluminea syn. nov. and Anemina globosula syn. nov. are junior synonyms of Anemina arcaeformis through integrative taxonomy. Mitogenomic phylogeny establishes the following robust phylogenetic framework at the generic level within Cristariina: ((((Sinanodonta + Acudonta gen. nov. ) + (Beringiana + Pletholophus )) + ((Anemina + Buldowskia ) + Amuranodonta )) + Cristaria ). Besides Sinanodonta and Cristaria , the distribution of other genera of Cristariina in China exhibits distinct faunal regions of endemism. ZooBank: urn:lsid:zoobank.org:pub:30E44DEB-3CCD-47F7-A2B2-3FA851BE434E.