Marine mussels in Mytiloidea Rafinesque, 1815, are ecologically and commercially significant, but their phylogenetic relationships and taxonomic classification remain controversial. In this study, we aimed to clarify the phylogenetic relationships within Mytiloidea and provide new molecular evidence for the taxonomy of problematic taxa. Complete mitochondrial genomes and five gene fragments, including cox1, 16S rRNA, 18S rRNA, 28S rRNA, and the histone H3 gene, were newly obtained for nine species representing four subfamilies: Mytilinae, Brachidontinae, Septiferinae, and Mytiliseptinae. All mitogenomes are double-stranded circular molecules characterized by a high A + T content and significantly variable gene arrangements. Phylogenetic analysis recovered Mytiloidea as two major clades. The monophyly of Mytilinae and Crenellinae were well supported, based on nuclear and mitochondrial gene fragments, and further analysis is required to determine the monophyly of Brachidontinae. Our results support the placement of Perna within the Crenellinae and provide molecular evidence for revising the taxonomic status of Trichomya hirsuta and Dentimodiolus species. The estimation of divergence time suggested that Mytiloidea originated during the Silurian, with major subfamily divergences occurring during the Mesozoic. Overall, this study provides new molecular evidence and advances the understanding of the complex phylogenetic relationships within Mytiloidea.
This study evaluated the potential global distribution of the invasive planthopper Ricania speculum under current and future climate change scenarios. To ensure robust predictions, a multialgorithmic approach was taken, integrating XGBoost, which is an advanced machine learning technique rarely used in species distribution modeling (SDM), with MaxEnt and Random Forest. The performance evaluation revealed that all models exhibited high predictive accuracy that exceeded 0.85 true skill statistics for all three algorithms. Under current climate conditions, the three algorithms predicted high habitat suitability across 8.9%–11.1% of the global terrestrial area (excluding Antarctica), with 7.6% of the total world area identified as suitable by a weighted ensemble approach. The key areas of suitability were concentrated in Eastern and Southern Asia, northern South America, the Mediterranean coast, and coastal regions of Central Africa. Under the SSP585 climate change scenario, a consistent northward shift and range expansion was projected, with the ensemble suitable area increasing to 18% of the total world area by 2090. This represents a 2.4-fold increase relative to the current conditions. These findings emphasize the growing invasion risk posed by R. speculum under accelerating climate change. Moreover, these results provide a valuable scientific basis for the development of proactive pest management and biosecurity strategies. Furthermore, this study highlights the applicability of XGBoost, an algorithm with previously limited application in SDM, as a viable methodological option, thereby suggesting its potential for extensive adoption in future studies.
Recent phylogenomic studies have clarified many higher-level relationships within Octocorallia, but the generic boundaries of many acanthogorgiid-like taxa within Malacalcyonacea remain poorly defined. During shallow-water surveys along the coast of China, we collected three gorgonian colonies that could not be assigned confidently to any described genus on the basis of comparative morphology. Using an integrative approach combining colony, polyp, and sclerite morphology with ultraconserved element (UCE) phylogenomics, we recovered these specimens as a distinct lineage within Malacalcyonacea M8 Clade C, sister to the sampled Anthogorgia lineage comprising A. divaricata and A. ochracea with maximal support (SH-aLRT/UFBoot = 100/100). The new lineage is distinguished from its phylogenomic relatives by the following combination of characters: colony arborescent; polyps fully retractile in low conical calyces on all sides of the branches; anthocodial armature consisting of a collaret and points; calicular sclerites arranged in eight loose longitudinal bands; coenenchyme and calyces with warty or occasionally branched spindles, some blunt-ended. It differs morphologically from the most similar genus, Calicogorgia, in having calyces distributed on all sides of the branches (vs. laterally arranged) and calicular sclerites in eight loose longitudinal bands (vs. eight bands each composed of two distinct rows). We therefore establish Curvagorgia gen. nov. and describe Curvagorgia caerulea gen. et sp. nov. as the type species by monotypy.
The Sea of Japan is a semi-enclosed marginal sea in the northwestern Pacific whose bathyal communities exhibit a depauperate species diversity due to anoxic events during the last glacial maximum. Cold seeps associated with chemosynthetic ecosystems were discovered in this region over three decades ago, yet their fauna have not been characterised. Here, we surveyed three bathyal seeps in the northeastern Sea of Japan off Okushiri Island, Hokkaido, to reveal their faunal composition and environmental conditions. We documented only eight macrofaunal species across all sites, of which six are well-known ambient fauna, with just two gastropod species in the genera Provanna and Hyalogyrina being seep endemics. Dissolved oxygen (DO) concentrations were consistently reduced on the seep bacterial mats, while the temperature remained similar to the ambient seawater. The Provanna species was new to science and is named P. cocytus sp. nov., characterised by a smooth shell with very convex whorls and a nearly holostomous aperture and a radula with a truncated central tooth cusp and the lateral teeth lacking a buttress. Phylogenetic reconstruction using the mitochondrial cytochrome c subunit I (COI) gene recovered P. cocytus sp. nov. as sister to all other congeners, indicating this genus did not recolonise the Sea of Japan after the last glacial maximum from seep or vent sources. The low species richness at seeps likely represents a combined effect of shallow connections limiting dispersal and impacts of the very cold Japan Sea Proper Water to larval settlement. Our results contribute to the understanding of the biodiversity in the Sea of Japan and close a major knowledge gap in the biogeography of chemosynthesis-based ecosystems across the western Pacific.
The taxonomy of Chilean Myotis has long been contentious, particularly regarding the status of M. arescens relative to M. atacamensis and M. chiloensis. Here, we use an integrative framework combining genome-wide single nucleotide polymorphisms (SNPs), morphometrics, and bioacoustics to reassess lineage boundaries and evolutionary relationships in Chilean Myotis. We analyzed 19,707 high-quality SNPs from 80 specimens spanning the full latitudinal distribution of the group, 10 external and craniodental measurements from 123 specimens, and 825 echolocation pulses from free-flying bats. Population genomic analyses revealed three genetic clusters, but only M. atacamensis formed a deeply divergent and well-supported lineage, with no detectable recent gene flow to southern taxa. In contrast, M. arescens and M. chiloensis showed shallow genetic differentiation, strong asymmetric gene flow, and a latitudinal gradient of shared ancestry. Phylogenetic reconstruction based on SNPs failed to recover reciprocal monophyly between M. arescens and M. chiloensis, and process-based species delimitation strongly supported a two-lineage model comprising M. atacamensis and a single southern lineage (M. chiloensis + M. arescens). Morphometric and bioacoustics analyses mirrored these patterns: M. atacamensis was clearly differentiated in skull size and echolocation calls, whereas M. arescens and M. chiloensis formed overlapping morpho-acoustic continua. Together, our results indicate that M. atacamensis is an independently evolving desert-adapted lineage, while M. arescens represents a northern population within a geographically structured M. chiloensis. We therefore recommend recognizing only two Myotis species in Chile and interpreting M. arescens as a population-level unit within M. chiloensis, with important implications for taxonomy, biogeography, and conservation assessments.
The ground beetle subgenera Abea Morita and Micronialoe Park, Kwon & Lafer are a small group within the genus Pterostichus, endemic to Japan and Korea. In this study, we apply an integrative approach combining molecular and morphological evidence to resolve their taxonomic problems at subgeneric and specific levels. Phylogenetic reconstruction of Pterostichus and related genera using 28S rRNA supported Micronialoe as a junior synonym of Abea. Examination of more than 250 specimens of Korean Abea revealed eight distinct morphotypes defined by male genitalia, despite high external morphological similarity. Phylogenetic analysis using a concatenated dataset of 28S rRNA and COI recovered seven major clades within Korean Abea, supporting four new species: Pterostichus subterraneus sp. nov., P. bifoveolatoides sp. nov., P. mixtus sp. nov., and P. multispinulosus sp. nov. Genetic divergence analyses under the Kimura 2-parameter model revealed a barcoding gap in 28S rRNA (0.9%-1.0%) but overlap in COI (1.0%-1.5%). Traditional morphometric analyses of 190 specimens, based on two raw measurements and 13 ratios, did not clearly resolve species boundaries for most species. These results underscore the importance of integrating molecular evidence and male genital morphology for species delimitation within Abea. Our phylogenetic framework further provided insights into subterranean adaptation and genital evolution. Additionally, time-calibrated analyses and ancestral area reconstruction suggested dispersal of Abea and related subgenera from China to Korea and Japan. Together, these findings provide insight into the systematics and biogeography of Pterostichus ground beetles.
The complete mitochondrial genome of Clarias nieuhofii collected from Phatthalung, Thailand (16,502 bp) was assembled and annotated. The study aimed to understand the mitochondrial genome composition, examine genetic divergence, and explore the phylogenetic relationships within and between populations of C. nieuhofii. The goal was also to contribute to the understanding of Sundaland biogeography and inform future conservation strategies. The circular mitogenome, which contained 13 protein-coding genes (PCGs), two rRNAs, 22 tRNAs, and a control region (CR), had 28 genes encoded on the heavy strand, whereas NADH dehydrogenase subunit 6 (ND6) and eight tRNAs were encoded on the light strand. The genome was AT-biased (57.85%-57.87%), which is consistent with other Clarias species. DNA barcoding (cytochrome c oxidase subunit I [COI] and cytochrome b [Cytb]) and species delimitation analyses were conducted to assess intra- and interspecific divergence. A positive COI barcoding gap (1.91%) but a negative Cytb gap (-6.94%) were observed. Delimitation tests variably split the three C. nieuhofii groups, with Cytb separating all groups and COI distinguishing Thai sequences (Group 3: Sumatra, Thailand) from those from Kalimantan (Group 1: Sumatra, Kalimantan). Phylogenetic and molecular analyses recovered three well-supported, geographically structured clades (divergence similar to 18 million years ago [MYA]), in which Thai and Sumatran samples clustered together, and Kalimantan samples formed distinct clades. These results suggest cryptic diversity within C. nieuhofii, underscoring the biogeography of Sundaland and the need for broader sampling and region-specific conservation.
Reliable identification of non-indigenous species (NIS) is essential for preventing and managing biological invasions. In marine environments, this process is often hampered by limited research on small-sized taxa and a decline in taxonomic expertise. Misidentifications have been reported for decades and continue to occur in certain invertebrate groups. This study highlights this issue within an amphipod genus currently invading the Mediterranean Sea. The Atlantic benthic amphipod Serejohyale spinidactyloides (Schellenberg, 1939) was sampled between 2016 and 2017 at two Sicilian intertidal sites: Stagnone di Marsala Lagoon and Altavilla Milicia (southern Italy, central Mediterranean). Both sites were characterised by mytilid beds of the Lessepsian mussel Brachidontes pharaonis (P. Fischer, 1870). The finding represents the first record of both the genus and the species in Italian waters, and the second record of the genus in the Mediterranean since 2019 (Bizerte Lagoon, Tunisia). We provided a redescription of S. spinidactyloides based on the Sicilian specimens and the holotype from the Museum f & uuml;r Naturkunde, Berlin. Diagnostic characters of congeneric Serejohyale species were reassessed to improve future monitoring of NIS. Based on growth-related morphological changes, we suggest a synonymy between Serejohyale ramalhoi (Reid, 1939) and Serejohyale spinidactylus (Chevreux, 1926), and propose an updated Atlanto-Mediterranean distribution for the genus.
The morphology of larval and pupal stages of longhorn beetles is of critical importance in both evolutionary and applied contexts, often providing diagnostic characters that are inaccessible in adults. Nevertheless, the systematic utility of immature-stage morphology has been limited by challenges in accurate species-level identification, largely due to insufficient comparative material and the lack of standardized identification frameworks. In this study, we analyzed a total of 1057 cytochrome oxidase I (COI) sequences, including 520 newly generated sequences (161 larvae, 109 pupae, and 250 adults) and 537 publicly available sequences retrieved from GenBank. Of the 270 preliminarily identified immature specimens, 143 (53.0%) were confirmed, 64 (23.7%) were newly identified to the species level, and 18 (6.7%) were reidentified after misidentification. The remaining 45 specimens (16.7%) remained unidentified at the species level. Based on these results, we discuss the microstructural characteristics of immature stages, present preliminary cases of morphological misidentification, and demonstrate how molecularly validated immature morphology can clarify the systematic placement of problematic taxa. The barcode data generated in this study provide a robust foundation for an integrated DNA barcode library and highlight the essential role of accurately identified immature stages in longhorn beetle systematics.
The diversity of birds is well documented globally. However, the same attention has generally not been given to their parasites, which comprise many times their diversity. Here, we present data from a large-scale survey of chewing lice found infesting birds in the Indo-Burma biodiversity hotspot of western Yunnan, China. A combination of morphological and phylogenies based on COI barcodes was used to assess the amount of cryptic speciation, host generalists, and variation in host associations. We examined 908 birds, representing 111 species. Overall louse prevalence was 26.3%, and 67 louse species were identified, representing 24 genera, of which 17 species have been previously described. Additionally, 41 new louse/host associations were recorded. Interestingly, Guimaraesiella impiger a well-known host generalist found throughout Southeast Asia was only present on three host individuals despite many of its hosts being examined. Also, Resartor elugeus previously reported from Alcippe fratercula yunnanensis in Yunnan was absent in our sampling despites examining 126 A. f. yunnanensis. However, R. elugeus was found infesting multiple Stachyris nigriceps in our survey. This shift in host association may be due to our sampling sites being at different elevations, but more data needs to be collected before this conclusion can be made. However, we can conclude that this is only a drop in the bucket when it comes the louse diversity of Yunnan. Additionally, the unique mountainous landscape of Yunnan coupled with the bird diversity present has created an environment for the potential of many host switching opportunities.
Alentiana, a genus within the subfamily Lepidastheniinae of Polynoidae, is an obligately commensal deep-sea group exclusively associated with sea anemones. Currently, only two valid species are recognized, with the genus's species diversity and phylogenetic relationships remaining poorly understood. In this study, we systematically investigated polynoid specimens collected from four seamounts in the tropical western Pacific. Integrating morphological observations (including SEM observations of chaetal ultrastructure) and genome skimming data, we describe two new species: Alentiana barnichae sp. nov. and A. fiegei sp. nov., clarifying their morphological diagnostic characters and body size-related intraspecific variations. Phylogenetic analyses based on 13 mitochondrial protein-coding genes and four ribosomal genes revealed that Alentiana forms a well-supported monophyletic clade, which is sister to the deep-sea subfamily Macellicephalinae but not closely related to other genera traditionally assigned to Lepidastheniinae. Lepidastheniinae was clearly recovered as polyphyletic, and notably, it shares terminally inserted lateral antennae with Lepidonotinae without exhibiting a close phylogenetic relationship, thus challenging the reliability of traditional taxonomic characters. Ancestral state reconstruction indicated that terminally or subterminally inserted lateral antennae represent a plesiomorphy of Polynoidae, while deeply incised neuropodia are a product of convergent evolution presumably driven by ecological pressures and cannot serve as an exclusive diagnostic character for Lepidastheniinae. This study enriches the species diversity and geographical distribution records of Alentiana, clarifies its phylogenetic position, and provides insights for revising the taxonomic system of Polynoidae and understanding the evolution of key morphological traits.
The family Coralliidae (Octocorallia) includes ecologically and economically important octocorals that build rigid, three-dimensional skeletal frameworks from shallow reefs to the deep sea. Despite extensive morphological study, species boundaries remain difficult to delimit because of morphological convergence, phenotypic plasticity, and the limited resolution of commonly used molecular markers. During benthic surveys in the Xisha Islands, South China Sea, we discovered a new coralliid species, Paraminabea xishaensis sp. nov. The new species resembles P. aldersladei in overall colony form but can be distinguished by a consistent suite of diagnostic sclerite characters, most notably stalk sclerites with a continuous transverse groove and the presence of six- to eight-radiate forms approaching double stars; autozooid and siphonozooid pores were not apparent. Phylogenomic analyses based on 2903 ultraconserved element (UCE) loci recover P. xishaensis sp. nov. as sister to P. aldersladei with strong support within a family-wide UCE phylogeny framework of Coralliidae, consistent with its recognition as a distinct species. The phylogeny further recovers five deeply divergent and internally coherent lineages within Coralliidae: Sphaerasclera, Paraminabea, a clade comprising Sibogagorgia, Paragorgia, Hemicorallium, Corallium, and Pleurocorallium, Minabea, and Anthomastinae. This phylogenomic framework provides a comparative baseline for future studies that incorporate expanded sampling and genome-derived single-copy orthologs to investigate adaptive evolution, mitonuclear discordance, and ecological diversification across Coralliidae.
Discordance between mitochondrial DNA (mtDNA) trees and species history is not uncommon and caused by several well-known processes. Differences in phylogenetic signal between loci within the mtDNA genome have received less attention. Large amounts of nuclear genomic data provide the opportunity to resolve uncertain phylogenetic inference in cases of discordance. We examined relationships among three putative divergent lineages of Chinese webbed-toed gecko: Gekko subpalmatus, G. cib (formerly G. subpalmatus) and G. melli. MtDNA sequences (ND2/COXI) were analyzed and an mtDNA tree that supported ((G. melli and G. subpalmatus) and G. cib) was obtained. This differed from a recent well-supported mtDNA-based phylogeny. To resolve this, we estimated species trees using genomic SNPs (from genotyping-by-sequencing), which supported our ND2/COXI tree. We investigated how the mtDNA loci used in these studies might provide discordant phylogenetic signals by comparison of 16 trees obtained from individual mtDNA loci. Well-supported trees, but with two distinct topologies, were obtained for six of the loci, while the remaining 10 loci provided weakly-supported topologies. Only three mtDNA loci provided a well-supported tree that was concordant with the genomic SNPs tree. This suggests that differences in phylogenetic signal across the mitochondrial genome misled previous phylogenetic inference. Divergence time dating revealed quite similar internal node ages, which likely exacerbated this effect. Finally, we analyzed generalized divergence in body dimensions: the two nonsister taxa G. subpalmatus and G. cib were the least divergent lineage pair, potentially explaining previous incorrect conclusions. We conclude that different well-supported phylogenetic histories can be supported by different mtDNA loci while large numbers of genomic SNPs provide more reliable topologies.
The widespread Indo-West Pacific ghost crab, Ocypode ceratophthalmus (Pallas, 1772) is found to be a species-complex containing three distinct species. An Indian Ocean form, O. celadon sp. nov. occurs along the shores of East Africa, thence becoming an insular species spreading eastwards as far as Christmas Island. A central Indo-West Pacific species, O. ceratophthalmus is found from about Pakistan eastwards to Fiji, north to the southern part of the main islands of Japan and south down the coasts of Australia, and is the dominant species along the continental beaches throughout the region. O. urvillii Gu & eacute;rin, 1829, is newly raised from synonymy for an insular Pacific Ocean form that extends from Hawai'i and Clipperton Island in the central East Pacific, westwards into the northeastern Indian Ocean as far the Cocos (Keeling) Islands. A mitochondrial genetic study from cytochrome c oxidase subunit 1 (COI) supports the recognition of these three species. Each species can be relatively easily separated by claw characters, including the stridulatory crests on the major chela, the form of the male first gonopods (G1), the live colours and patterns, and other characters related to granulation and spination.
In this article, we carry out a study of the genus Abax (Carabidae, Pterostichini) based on mitochondrial and nuclear markers to test hypotheses about its evolutionary history in an integrative taxonomical framework. The subgenera Pterostichoabax (four species) and Abacopercus (monotypic) are likely natural taxa supported by all data. Pterostichoabax was nested within the species of the nominal subgenus Abax, which is rendered polyphyletic. The subgenus Abax is subdivided into a few clades that include two or more taxa and correspond to monophyletic lineages. The subdivisions within Abax parallelepipedus and Abax pyrenaeus are related to the geographical origin and may correspond to current subspecies. The results support hypotheses about a close relationship within the species of the POBE group (A. pilleri, A. oblongus, A. baeninngeri, and A. exaratus); between A. carinatus, A. pyrenaeus, and A. parallelus; the basal position of A. schueppeli; and the monophyly of Pterostichoabax. In contrast, hypotheses about a close relationship between the species pairs schueppeli-carinatus, parallelepipedus-fiorii, and ovalis-parallelus were not supported by molecular results. The evolutionary history of Abax has been traced back to the Middle Tortonian (10.3 MYA). Successive lineage splits during the second half of the Miocene gave rise to the main lineages, with rapid intraspecific radiation during the Pleistocene. Lineage diversification included moderate ecological, behavioral, and molecular changes accompanied by morphological conservatism and diversified geographical patterns. Our results constitute a framework for future studies on the evolutionary radiation of the genus Abax and other carabids during the Miocene in the western Palearctic and contribute to developing a natural classification of the genus.
African Vine Snakes of the genus Thelotornis are highly specialised arboreal colubrids distributed across sub-Saharan Africa. Despite pronounced morphological conservatism, the genus occupies diverse forest, woodland and savanna-associated habitats. The genus has long been characterised by unresolved species boundaries and taxonomic uncertainty, particularly regarding the placement of the monotypic Xyelodontophis uluguruensis. We investigated phylogenetic relationships and species boundaries within Thelotornis using an integrative framework with broad geographic and ecological sampling. Phylogenetic inference was based on two mitochondrial (cyt b and ND4) and two nuclear (c-mos and NT3) markers analysed under maximum-likelihood (IQ-TREE2) and multispecies coalescent (Species Tree And Classification Estimation, Yarely [STACEY]) frameworks. Species boundaries were further assessed using haplotype networks, mitochondrial divergence, single-locus barcoding (Assemble Species by Automatic Partitioning [ASAP]) and unsupervised machine learning (UML) clustering (super self-organising map [SuperSOM]) integrating genetic, morphological, ecological and spatial data. Seven independently evolving lineages are supported, with Thelotornis monophyletic only when Xyelodontophis uluguruensis is included. Thelotornis capensis subspecies are recognised as distinct species, and an undescribed lineage from Vamizi Island, Mozambique, has been identified. Emergence of the genus trace to the Mid-Miocene (ca. 16.6 Mya), with Late-Miocene diversification giving rise to a West-East African forest lineage (T. kirtlandii and T. uluguruensis comb. nov.) and an East-Southern African lineage comprising habitat generalists (T. usambaricus, T. sp., T. mossambicanus and T. capensis) alongside the savanna specialist T. oatesi stat. nov. Morphological, ecological and genetic evidence support the distinctiveness of all seven lineages, informing a revised diagnosis of Thelotornis. These results indicate a recent ecological radiation shaped by historical habitat dynamics, facilitating forest niche conservatism while ecological opportunity enabled savanna diversification, resolving taxonomic ambiguity and revealing hidden diversity.
The debate over the correct scientific name of golden pompano in Chinese aquaculture, centered on the controversy between Trachinotus anak and T. ovatus, has persisted for several decades. In this study, 328 specimens of golden pompano were collected from 10 sampling sites in southern China, encompassing stocks from mariculture enterprises, local cage-culture farms, and the wild populations. The samples were identified based on morphological keys and cytochrome c oxidase subunit I (COI) reference sequences of important taxonomic works for Trachinotus. Of these, 326 individuals were morphologically identified as T. anak, characterized by a blade-like supraoccipital and inverted-L shape supraneurals. Only two individuals were identified as T. blochii, diagnosed by a tear-drop-shaped first supraneural. In phylogenetic analyses, all the analyzed Trachinotus sequences were clustered into 16 clades, corresponding to 16 valid species in genus Trachinotus. COI sequences of the 326 T. anak specimens were summarized into five haplotypes (Farm1-5), which form a well-supported clade with the T. anak reference sequences. Farm6, identified in two specimens, was resolved in the T. blochii clade. Additionally, we analyzed 58 COI sequences of Trachinotus species uploaded by Chinese researchers, whose haplotypes (Online1-9) were identified as T. baillonii, T. blochii, and T. anak. None of the Chinese Trachinotus sequences was included in the T. ovatus clade, suggesting that T. ovatus, the most commonly used name, is incorrect and should no longer be used for golden pompano in China. The holotype of T. ovatus was designated in 1896, which enforced the name to delegate a spotted Atlantic species. Taken together, our findings unequivocally support that the correct scientific name for golden pompano in China is T. anak.
The tribe Apantelini sensu Mason is the largest tribe within the subfamily Microgastrinae (Hymenoptera: Braconidae). It consists of parasitoids that attack a wide range of families of Lepidoptera and have potential significance for biological control. However, genera (and species-groups) included in this tribe often overlap, and due to the large number of species, they have never been tested extensively at a large scale, such as across the whole mitogenome. This study examined the mitogenomes of 25 species, including 21 newly sequenced species, representing four genera (Apanteles Foerster, Dolichogenidea Viereck, Parapanteles Ashmead, and Pholetesor Mason) traditionally regarded as Apantelini in China. Phylogenetic relationships among these species were inferred using MrBayes and IQ-TREE based on four data matrices (PCG123, PCG123 + RNA, PCG12, and AA). The average A + T content of the sequenced mitochondrial genomes was relatively high (86.5%), and gene rearrangements were evident, especially in the ater and taeniaticornis groups of the genus Apanteles. The phylogenetic analysis among these Chinese species revealed key relationships among major species-groups and genera. The genera Apanteles and Dolichogenidea were clearly separated, but A. mycetophilus was identified as a transitional group and very likely represents a different genus. Major species-groups, such as A. ater and D. ultor, were confirmed to be monophyletic. However, the A. taeniaticornis group is no longer supported as a distinct species-group based on the results of the current study, and their members actually belong to the ater-group. And we propose a new combination, Dolichogenidea hyposidrae comb. nov. (Wilkinson, 1928), based on the molecular data from this study, which cluster the species within the ultor-group. Additionally, the relationships between Dolichogenidea, Parapanteles, and Pholetesor are discussed.
The Mediterranean Sea is one of the major reservoirs of marine biodiversity and harbors an exceptionally high number of endemic species. Nevertheless, the taxonomic status of many of these endemics still requires confirmation through integrative, modern approaches. We hereby first investigated the identity and status of a rare and endemic box crab, known either as Calappa rosea or Calappa rissoana, through a multidisciplinary approach that capitalized on the use of nomenclatural rules, museology, integrative taxonomic approaches (morphology, complete mitochondrial genomes, nuclear markers, and phylogenetic analyses), and passive citizen science. Almost all morphological characters failed to differentiate it from the related species Calappa granulata, whereas differences in coloration were mostly confirmed here. However, all molecular approaches supported the conspecificity of these two taxa. The combined use of passive citizen science and statistical analyses revealed that the formerly endemic species is an unrecognized ontogenetic stage of C. granulata, and, in particular, a rare transitional phase that connects early juveniles to fully developed adults. This renders the investigated taxon a new junior synonym of C. granulata and solves nomenclatural and taxonomic ambiguities related to native Mediterranean box crabs, which have remained unsettled for over 200 years. The present study, therefore, provides the first comprehensive reconstruction of the ontogenetic changes occurring in the common Mediterranean box crab throughout its various life stages and raises questions on whether these transitions occur worldwide across box crabs or are restricted to a few species. Finally, it presents new, conspicuous, and detailed morphological and molecular data on the type species of the genus Calappa, facilitating future phylogenetic reconstructions and taxonomic assignments within the entire family Calappidae, and discusses the putative occurrence of the other box crabs in the area, suggesting a critical re-evaluation of all historical data and records.
