Invertebrate Systematics最新文献

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.

The conoidean family Raphitomidae is arguably one of the most diverse groups of deep-sea gastropods. A previous molecular phylogenetic study, based on material from bathyal and abyssal waters of temperate south-eastern Australia and aiming to define the taxonomic boundaries of several genera, distinguished a total of 54 primary species hypotheses (PSHs) in the region. Although many of these have been fully taxonomically investigated, several others await taxonomic characterisation. Focussing on samples of those remaining putative taxa, this study subjected a comprehensive mitochondrial DNA dataset of representative deep-sea raphitomids to the species delimitation method ABGD, which recognised 14 PSHs from Australian waters. Following additional evaluation of shell and radular features, as well as examination of geographic and bathymetric ranges, 13 of these were converted to secondary species hypotheses (SSHs). Three SSHs were described as new and tentatively assigned to the genera Eubela Dall, 1889, Pleurotomella Verril, 1872 and Xanthodaphne Powell, 1942. The remaining 10 were assigned to named species, for which additional anatomical and radular data were also provided. Although some of the species studied appear to be comparatively rare and no inference is made about their geographic and bathymetric distributions, others exhibit transoceanic ranges or occupy remarkably wide depth intervals. ZooBank: urn:lsid:zoobank.org:pub:531B6770-279D-488C-9D81-A06E07D12C79.

Delectopecten is a small genus of the family Pectinidae (Bivalvia: Pectinida) that remains poorly studied in terms of both morphology and phylogeny. Here, we describe the first member of this genus from deep-sea hydrothermal vent ecosystems, D. thermus sp. nov., based on morphological investigations and molecular analyses of a specimen collected from the Higashi-Ensei vent field (962-m depth) in the northern Okinawa Trough. Morphologically, this new species resembles D. vancouverensis and D. gelatinosus in shell size, shape, auricle size and sculpture. However, D. thermus sp. nov. can be distinguished from its congeneric species (including 9 extant and 12 fossil species) by its unequal auricles (the anterior one being larger than the posterior), inwardly recurved anterior auricle of the left valve and a large byssal notch angle of ~90°. Comparisons of genetic sequences from three mitochondrial and three nuclear gene fragments supported the placement of the new species in the genus Delectopecten . Further phylogenetic analyses using these gene markers support that Delectopecten is monophyletic and positioned as an early diverging clade of the family Pectinidae. Additionally, the mitogenome of D. thermus sp. nov. was assembled and annotated, a first for its genus - revealing significant divergences in gene order compared to other pectinids. The 16S rRNA amplicon analysis of the gill tissue indicated that this vent-dwelling scallop does not exhibit symbiosis with chemosynthetic bacteria. A key to all known species of Delectopecten is provided to aid the identification of species in this understudied genus. ZooBank: urn:lsid:zoobank.org:pub:D3D5D4AD-EE39-49F0-9782-12A5D6752A67.