Allopatric Research Articles

The Role of Telehealth in Rural Healthcare Access

This study investigates the effect of telehealth in reducing healthcare inequities in rural communities. Rural communities confront considerable challenges, including geographic isolation, provider shortages, and limited access to healthcare facilities, which exacerbate health inequities. Telehealth provides an innovative solution by allowing remote access to healthcare services, eliminating the need for travel, and improving healthcare results. This review looks at current telehealth adoption trends, successful case studies, and future potential to extend telehealth services in remote areas. Finally, telemedicine is a viable way to close the healthcare access gap in remote populations. Keywords: Telehealth, rural healthcare, healthcare disparities, geographic barriers, provider shortages.

DECENTRALIZATION DYNAMICS: ASSESSING LOCAL GOVERNMENT PERFORMANCE IN LINGGA

This study examines the implementation of decentralization in Lingga, Indonesia, focusing on the performance of the local government (Pemda) and its impacts on community engagement and public service delivery. Utilizing a qualitative case study approach, the research reveals both significant successes and ongoing challenges associated with decentralization. While increased local autonomy has fostered greater community participation and responsiveness to local needs, persistent issues such as financial dependency, bureaucratic inefficiencies, and geographic isolation hinder effective governance. The findings highlight disparities in public service access, particularly for marginalized communities in remote areas. The study contributes to the broader discourse on decentralization by emphasizing the need for context-specific policies that address local realities. Based on these insights, several policy recommendations are proposed, including enhanced financial support for local governments, capacity-building initiatives for local officials, and the development of inclusive governance mechanisms. These measures aim to strengthen the implementation of decentralization in Lingga, ensuring that it delivers equitable and effective governance outcomes for all residents.

Accessibility of methadone treatment via public transit for syringe services program participants in Miami-Dade County, Florida.

Methadone is an opioid receptor agonist medication used in the treatment of opioid use disorder (OUD). Geographic distance to opioid treatment programs (OTPs) is a major barrier to treatment, given requirements for direct observation of dosing and periodic drug screens, and 'methadone treatment deserts' are defined as a public transit threshold of 30 minutes. The purpose of this study was to examine public transit access to methadone treatment for participants of a syringe services program (SSP) in Miami-Dade County, Florida. Public transit times were calculated using the R library r5r, which facilitates multi-modal transportation network routing. General Transit Feed Specification data was combined with street network data from OpenStreetMap for Miami-Dade County. Transit times were estimated from the population-weighted centroid of each zip code (n=79) with participants of Miami's only SSP (n=1597) to the nearest OTP (n=4) using 10 departure windows aligned with OTP service hours. The mean one-way transit time from zip codes with SSP participants in Miami-Dade County to the nearest OTP was 80 minutes. 75 of the 79 (95%) zip codes with SSP participants in Miami-Dade County have a mean transit time to the closest OTP greater than 30 minutes. Transit times differ substantially between zip codes with different numbers of SSP participants, but not between departure windows. Nearly all zip codes with SSP participants in Miami-Dade County can be classified as 'methadone treatment deserts'. Geographic isolation of methadone treatment from public transit routes represents a significant barrier to equitable OUD treatment.

Pollinator shifts despite hybridisation in the Cape's hyperdiverse heathers (Erica, Ericaceae).

Interrogating the ecological and geographic factors that influence population divergence dynamics can reveal why some groups of organisms diversify more prolifically than others. One such group is the heathers (Erica, Ericaceae), the largest plant genus in the Cape Floristic Region. We study Erica abietina, a highly variable species complex with four subspecies differing in geographic range, habitat and pollination syndrome. We test for population differentiation, hybridisation, introgression and pollinator-driven divergence using genotyping-by-sequencing on samples across the entire distribution. We find five variably distinct genetic groups, with one subspecies comprising two independent lineages that are geographically isolated and occur on different soil types. Phylogenetic analysis suggests two independent shifts between bird and insect pollination, with accompanying genetic divergence. However, for one pair of populations with different pollinators, we uncover several individuals of hybrid origin at a site of sympatry. These results suggest that floral differentiation driven by divergent selection acts in concert with geographic isolation to maintain reproductive isolation and promote speciation. Our investigations reveal a highly dynamic system whose diversity has been shaped by a variety of interacting forces. We suggest that such a system could be a model for much of the diversification of the Cape flora.

Does a coexisting congener of a mixed mating species affect the genetic structure and selfing rate via reproductive interference?

Reproductive interference is defined as an interspecific interaction that reduces fitness via mating processes. Although its ecological and evolutionary consequences have attracted much attention, how reproductive interference affects the population genetic structures of interacting species is still unclear. In flowering plants, recent studies found that self-pollination can mitigate the negative effects of reproductive interference. Selfing-biased seed production is expected to increase population-level inbreeding and the selfing rate, and limits gene flow via pollinator outcrossing among populations. We examined the population genetics of the mixed-mating annual herb Commelina communis f. ciliata, focusing on reproductive interference by the sympatric competing congener C. communis using microsatellite markers. First, we found that almost all C. c. f. ciliata populations had relatively high inbreeding coefficients. Then, comparing sympatric and allopatric populations, we found evidence that reproductive interference from a competing congener increased the inbreeding coefficient and selfing rate. Allopatric populations exhibit varied selfing rates while almost all sympatric populations exhibit extremely high selfing rates, suggesting that population selfing rates were also influenced by unexamined factors, such as pollinator limitation. Besides, our findings revealed that reproductive interference from a competing congener did not limit gene flow among populations. We present the first report on how reproductive interference affects the genetic aspects of populations. Our results suggested that the high selfing rate of C. c. f. ciliata promotes its sympatric distribution with C. communis, even in the presence of reproductive interference, although it is not clear whether reproductive interference directly causes the high selfing rate.

Genetic variability of 23 autosomal STRs in Austroasiatic-speaking populations from Thailand.

Austroasiatic (AA) speakers constitute around 4% of the population of Thailand, while the majority (89.4%) speak Kra-Dai (KD) languages. Previous forensic and population genetic studies in various Thai populations have employed a limited number of short tandem repeats (STRs). This study aims to expand the investigation of the genetic makeup of AA populations in Thailand and their relationship to KD populations using a larger number of autosomal STRs with the VeriFiler™ Plus PCR Amplification Kit. We generated 593 new genotypes from AA-speaking groups and combined them with previously reported data from AA and KD groups. A total of 1,129 genotypes across 23 STR loci were used to construct the largest allelic frequency profile for Thai and Lao populations. However, several loci deviated from Hardy-Weinberg equilibrium, likely due to the reduced genetic diversity in some highland populations, which should be considered in forensic investigations. Beyond forensic applications, our findings reveal genetic differences between AA-speaking groups in Northern and Northeastern Thailand. The AA groups from Northeastern Thailand exhibit greater genetic homogeneity and diversity, likely due to population interactions. In contrast, reduced diversity and increased heterogeneity in AA groups from Northern Thailand are possibly driven by genetic drift and cultural and geographic isolation. In conclusion, we emphasize the usefulness of increasing the number of autosomal STRs in forensic and anthropological genetic studies. Additional Y-STR and X-STR data from various AA-speaking groups in Thailand would further enhance and strengthen forensic STR databases in the region.

First record of Scotocampa sheljuzhkoi Gyulai & L. Ronkay (Lepidoptera: Noctuidae: Noctuinae) from Kazakhstan

The little-known Noctuidae species Scotocampa sheljuzhkoi Gyulai & L. Ronkay, 2002 is reported from Kazakhstan for the first time. The species was previously considered as endemic to South and Southwest Mongolia and the new distribution data increase its known range by over 750 km to the west. Adults, male genitalia and the habitats of S. sheljuzhkoi and its allopatric sister species Scotocampa indigesta Staudinger, 1888 occurring in the Ili River Valley (SE Kazakhstan) are illustrated. The photograph of the female genitalia of the holotype of Scotocampa crassipuncta (Püngeler, 1905) known from Tarim Basin is illustrated for the first time.

The importance of geographic and sociodemographic aspects in the characterization of mucopolysaccharidoses: a case series from Ceará state (Northeast Brazil).

Geographic and sociodemographic aspects may influence the natural history and epidemiology of mucopolysaccharidoses (MPS). The main objective in this work was to evaluate the clinical, molecular, and geographic profile of MPS in a population from Ceará (Northeast Brazil). For this, we have performed a descriptive cross-sectional study based on clinical evaluation, interviews with patients and/or family members, and review of medical records of 76 MPS patients. MPS II was the most common type, with the most affected individuals presenting missense pathogenic variants. Patients with MPS I proved to be the most severe clinical phenotype, presenting the first symptoms (mean: 7.1 months; SD = 4.5) and being diagnosed earlier (2.2 years; SD = 2.1) in comparison with the other types. In addition, we have shown that 13 individuals with MPS VI were born of consanguineous marriages in small, nearby cities, in a place where geographical isolation, consanguinity, and clusters of genetic diseases were previously reported. Ten of these individuals (at least, seven different families) presented a rare pathogenic variant in the ARSB gene, c.1143-8T > G in homozygosity, previously reported only among Iberian and South American patients. The results presented here provide a comprehensive picture of MPS in an important state of the Brazilian Northeast, a region that concentrates many risk factors for rare genetic diseases, such as endogamy, inbreeding, and reproductive isolation. We discuss the possible evolutionary processes and biosocial dynamics that can help to explain this finding in terms of population medical genetics and public health.

Disease, climate, environment and the fortunes of Buddhism during the Tibetan Empire 618–842 CE

The official adoption of Buddhism by the Tibetan state in the mid-8th Century (761-762 CE) was relatively late compared to its permeation from northern India to elsewhere in south and east Asia, due to the country’s geographical isolation. Whilst reasons for its adoption remain uncertain, it is thought that the religion provided a strong unifying influence permitting both the consolidation and subsequent expansion of the Tibetan Empire. Early historical records suggest that the religion was prohibited in 739-741 CE and again in 841-842 CE, the latter coinciding with the fall of the Tibetan Empire. This research presents a detailed examination of Tibetan and Chinese historical records and also of recent fine-resolution palaeoclimatic reconstructions to demonstrate that the ‘oscillating fate’ of Buddhism during the Tibetan Empire (618-842 CE), was not only linked to the economic fortunes of the Tibetan state as previously envisaged, but also inextricably to disease, the long-term regional climatic deterioration and possibly also to a series of natural disasters, many of which were recorded in the north and north-west of the Tang Empire adjacent to Tibet, as well as in Tibet itself. These ‘disasters’ noted in the historic records, and both catalogued and quantified here, indicate extreme pressures placed on the rural economy of the Tibetan Plateau and adjoining areas by crop failures, the death of many livestock and associated widespread famine and human mortality. The ‘chaos & disorder’ of the latter stages of the reign of Emperor Ralpachen (815-836/838 CE), as well as the Second Prohibition of Buddhism by the last Tibetan Emperor Lang Darma can therefore now not only be related to climatic-environmental deterioration, but also to the likely loss of public faith in both Tibetan Emperors and in Buddhism. It is possible that in the eyes of superstitious Tibetans, neither their rulers nor the state religion could address an accelerating spiral of crises. Devine displeasure could have been further signified by a devastating earthquake in Tibet sometime between 839-842 CE and the subsequent ‘implosion’ of the Tibetan Empire should no longer be considered surprising.

Niche evolution during allopatric and sympatric diversification of Aeonium (Crassulaceae) on the Canary Islands

Abstract Although species radiations on island archipelagos are broadly studied, the geographic and ecological modes of speciation that underlie diversification are often not fully understood. Both allopatry and sympatry play a role during radiations, particularly on islands with profound habitat diversity. Here, we use the most diverse Canary Island plant radiation, Aeonium (Crassulaceae), to phylogenetically test two hypotheses: (1) allopatric speciation, which predicts that closely related taxa are ecologically similar but do not co-occur, and (2) sympatric speciation, whereby closely related taxa co-occur geographically but are ecologically distinct. We fitted niche and spatial distribution models based on extensive field surveys to quantify geographic and ecological divergence among taxa integrated in a phylogenetic context. Contrary to our expectation, phylogenetically closely related species tend to occupy similar ecological niches, revealing that ecological niche divergence among species accumulates slowly, even in sympatry. This suggests that evolutionary young taxa may be partially reproductively isolated due to subtle phenotypic differences, such as reproductive morphology and phenology, rather than by ecological niche and may putatively exacerbate divergence among populations. Thus, allopatry and sympatry are complementary speciation mechanisms on oceanic islands, jointly spurring this enigmatic radiation.

Key innovations and niche variation promoted rapid diversification of the widespread Juniperus (Cupressaceae)

The processes of forming lineages undergoing widespread radiations remain a knowledge gap that is fundamental to our understanding of the geographic distributions of species. Although early studies emphasized the importance of dispersal ability and historical migration events, key innovations that promote rapid diversification and/or adaptation to new habitats may also strongly influence distribution ranges. Juniperus is the second largest genus of conifers and is widely distributed throughout the Northern Hemisphere. Here, we used phylogenetic, phenotypic, and climatic data to investigate the contributions of these processes to the wide distribution and rapid diversification of Juniperus. Combining a time-scaled phylogeny and macroevolutionary theory, we show that the key innovations of berry-like seed cones and dioecy promoted the rapid diversification of Juniperus and that increased dispersal ability promoted allopatric speciation. Ecological niches had significant divergence among different clades of Juniperus. Biogeographic results supported multiple long-distance dispersal events and niche variation that contributed to the modern range of Juniperus, while both phenotypic adaptation and ecological opportunity probably drove its distribution range. Our findings suggest that the current widespread distribution is likely the result of significant divergence driven by niche variation in which ecological opportunities from key innovation and phenotypic divergence.

Distinct phylogeographic and population genetic patterns of decapod species across Mediterranean biogeographic barriers

Abstract The Mediterranean Sea is a semi-enclosed oceanic basin that communicates with the Atlantic Ocean and can be subdivided into seven geographical regions. It is considered a hotspot of biodiversity and is characterised by high rates of endemism. Over the past decades, many studies showed the presence of potential geographical breaks both across the Atlanto-Mediterranean transition and within the Mediterranean Sea. These investigations led to the identification of three distinct types of population genetic structures: (1) populations characterized by panmixia; (2) Atlanto-Mediterranean geographical partitioning; and (3) possible further subdivision between East and West Mediterranean basins. In this review, mainly focused on Christoph Schubart’s works and interests, we summarize the different patterns of gene flows across the Atlanto-Mediterranean transition and within the Mediterranean Sea, recorded for decapod species living in littoral zones. Although some species share similar biological traits, larval dispersal mechanisms and habitat preferences, differences in their phylogeographic and population genetic structures do emerge. These findings confirm the complex nature of gene flows across the Atlanto-Mediterranean transition and within the Mediterranean basin and how difficult it is to achieve a generalised picture of the phylogeographical patterns of Atlantic-Mediterranean species.

Global pattern of conodont similarity and faunal constraints during the highstand of the Evae eustatic event (late Floian, Lower Ordovician)

One of the largest Ordovician sea-level rises is the Evae transgression, which occurs in the lower part of the Oepikodus evae Biozone, indicative of a late Floian age. Specifically, the characteristics associated with the highstand of this event included: a higher proportion of specimens of the index species O. evae than other species, a diversity acme in the evae Biozone, and a reduction of biogeographic barriers that resulted in a high proportion of species with cosmopolitan distribution. In the present contribution, the pattern of species similarity among Laurentia, Argentine Precordillera, Baltica, Kazakhstania, South China, and Australia is evaluated with a multiple coefficient analysis including only the sections that recorded the highstand of the Evae transgression. Moreover, the effect of possible terrestrial, latitudinal, physicochemical barriers and palaeogeographic distance on the species distribution is statistically analysed. Our results show a global pattern of conodont species distribution that is highly constrained by the tested palaeoenvironmental factors. This suggests that contrary to what was expected for a prominent transgression, faunal barriers did not decrease significantly during the Evae drowning peak.

Across a phylogeographic break in the Qinling Mountains-Huaihe River Line: Quaternary evolutionary history of a medicinal and edible homologous plant (Allium macrostemon) in China

Biogeographic barriers to gene flow are central to studies of plant phylogeography. There are many physical and geographic barriers in China, but few studies have used molecular ecological evidence to investigate the natural geographic isolation barrier of the Qinling Mountains-Huaihe River Line (QHL). Allium macrostemon is a precious Chinese perennial herb belonging to the Amaryllidaceae family. It is used as a food and medicine, with a variety of health and healing properties. Five SSR markers, three chloroplast DNA (cpDNA) markers (psbA-trnH, rps16 and trnL-F), one nuclear ribosomal DNA (nrDNA) marker (ITS), and simplified genome GBS sequencing were used to analyse the genetic diversity and structure of A. macrostemon. Combining SSR, cpDNA, nrDNA ITS data and GBS analysis results, we divided A. macrostemon populations into northern and southern groups, with the southern group further divided into southwestern and central-southeastern groups. Niche simulation results reveal that the distribution area of A. macrostemon will reach its maximum in the future. These data indicate that the regional separation of A. macrostemon has been maintained by the combined influence of a geographical barrier and Quaternary climate, and that the back-and-forth fluctuations of QHL and Quaternary climate have played an important role in this process. QHL acts as a north-south dividing line in phylogeography and population genetic structure, promoting physical geographic isolation. This study provides a theoretical basis for the conservation, development, and utilization of A. macrostemon resources. It further provides a reference for understanding the systematic geographical pattern of the large-scale spatial distribution of plants in China and enriches our understanding of Quaternary plant evolution in areas with complex terrain.

Electronic Newsletters as a Professional Development Tool for Rural Educators

Rural educators need access to evidence-based instructional practices and technologies that meet the needs of our communities. Difficulty accessing quality professional development due to geographic isolation, limited access to specialists, cost constraints, staffing shortages, lack of access to resources and technology, and less time to participate in meaningful professional development are common barriers facing rural teachers. One way to disseminate evidence-based practices is through an electronic newsletter. This article shares how a behavior analyst developed an online newsletter to build relationships, offer resources, highlight staff achievement, provide instruction, and model evidence-based behavior interventions for school staff.

Population genetic diversity and environmental adaptation of Tamarix hispida in the Tarim Basin, arid Northwestern China.

Arid ecosystems, characterized by severe water scarcity, play a crucial role in preserving Earth's biodiversity and resources. The Tarim Basin in Northwestern China, a typical arid region isolated by the Tianshan Mountains and expansive deserts, provides a special study area for investigating how plant response and adaptation to such environments. Tamarix hispida, a species well adapted to saline-alkaline and drought conditions, dominates in the saline-alkali lands of the Tarim Basin. This study aims to examine the genetic diversity and environmental adaptation of T. hispida in the Tarim Basin. Genomic SNPs for a total of 160 individuals from 17 populations were generated using dd-RAD sequencing approach. Population genetic structure and genetic diversity were analyzed by methods including ADMIXTURE, PCA, and phylogenetic tree. Environmental association analysis (EAA) was performed using LFMM and RDA analyses. The results revealed two major genetic lineages with geographical substitution patterns from west to east, indicating significant gene flow and hybridization. Environmental factors such as Precipitation Seasonality (bio15) and Topsoil Sand Fraction (T_SAND) significantly shaped allele frequencies, supporting the species' genetic adaptability. Several genes associated with environmental adaptation were identified and annotated, highlighting physiological and metabolic processes crucial for survival in arid conditions. The study highlights the role of geographical isolation and environmental factors in shaping genetic structure and adaptive evolution. The identified adaptive genes related to stress tolerance emphasize the species' resilience and highlight the importance of specific physiological and metabolic pathways.

Conservation implications of a genomic‐based taxonomy for threatened allopatric Agriades butterflies

Abstract A good knowledge of the evolutionary history of organisms and an accurate taxonomic framework are keys for efficient biodiversity conservation measures. This is particularly relevant for European butterflies, which are often used as bioindicator organisms and umbrella species for conservation. The Holarctic butterfly genus Agriades includes seven European arctic‐alpine species of which several have a debated taxonomic status. They are localized and allopatric, and at least two of them are of high conservation concern, namely A. aquilo (in Europe, restricted to northern Scandinavia) and A. zullichi (endemic to southern Spain). Despite high conservation value and taxonomic uncertainty, molecular studies on these taxa are limited to DNA barcodes. We investigated the evolutionary history and species delimitation of West Palearctic Agriades using double‐digest RAD sequencing (ddRADseq). Various analyses using genomic data suggested the presence of one species in the glandon species group and one or two in the pyrenaicus species group. The differentiation within the former group (i.e., glandon, aquilo, zullichi) appears to be relatively recent, although the main allopatric populations represent evolutionary significant units (ESUs). Notable geographic structure was found within the pyrenaicus species group, with four allopatric ESUs detected. Wolbachia screening highlighted the presence of several allele combinations, some associated with particular Agriades populations. Genomic data revealed the evolutionary trajectory of European Agriades and a tendency for taxonomic oversplitting within this genus. These findings aid conservation by providing genetic background for region or population prioritization (including ESUs), and for the management of potential population reinforcement or reintroductions.

BIOGEOGRAPHIC PATTERNS OF COLOMBIAN FROGS AND TOADS

Using the data provided in Ruiz-Carranza et al. (1996) the distributions of the 540 species of frogs and toads are partitioned among ten ecogeographic units of Colombia defined on the basis of precipitation and elevation. Sorne lowlands areas (Pacific lowlands, Amazonia) exhibit high diversity (85-94 species) but lowlands areas in general are impoverished (30-52 species), especially when contrasted with upland areas. The three Andean cordilleras harbor between 87 and 121 species of frogs and toads, demonstrating that the biodiversity of Colombia resides primarily in its montane components, not in its lowland rainforests. When biological endemicity is separated from political endemicity, five areas of high endemicity remain (the three Andean cordilleras, the Sierra Nevada de Santa Marta, and the Pacific lowlands). We endeavor to explain this description by recourse to cladistic analyses of several groups of leptodactylid frogs where we find that the general pattem of diversification is by meaos of horizontal diversification (allopatric speciation) with a minor contribution from vertical diversification.

Whole genome resequencing reveals the evolutionary history and geographic isolation of the eastern Asian Hickory (Carya)

Societal Impact StatementUnraveling the genetic intricacies and evolutionary history of Asian Hickories through advanced genome sequencing gives valuable insights into their ecological adaptations. Understanding the impact of historical dynamics, climate fluctuations, and geographical barriers on Asian hickories not only contributes to scientific knowledge but also empowers policymakers with evidence‐based decisions and guides conservationists in their efforts to protect vulnerable species. The identification of potential habitats, especially for the endangered Carya kweichowensis, offers a promising avenue for targeted conservation efforts, aligning with global initiatives to preserve Earth's precious biodiversity, but also ensures the conservation of a vital genetic reservoir for nut‐bearing economic tree species.SummaryBiogeographic characteristics of disjunct distribution play a vital role in plant geography and the endangered mechanism. The whole genome resequencing provides an opportunity to study the genetic relationship, population diffusion, and floristic evolution of disjunctive‐distribution flora. Based on the SNPs (single nucleotide polymorphisms) data generated by the whole genome deep resequencing of five EA (Eastern Asian) Carya species, we constructed the phylogenetic tree, genetic structure, and species distribution modeling to clarify the phylogenetic relationships and to predict the potential distribution area of EA Carya. Phylogenetic analysis of Carya revealed two distinct clades, separating EA Carya from NA (North America) Carya. C. kweichowensis, an endangered species, showed the lowest nucleotide diversity and the earliest divergence among studied EA Carya species. Species distribution modeling predicted suitable habitats for five EA Carya species, revealing the potential distribution of endangered C. kweichowensis. Importantly, minimal spatial overlap was observed among distribution regions of EA Carya species during different time periods. The uneven regional distribution of EA Carya is believed to be a consequence of Quaternary climate fluctuations, mountain barriers hindering species dispersal, and the limited cold tolerance of these trees. EA Carya highlights the significant role of climate and geological changes in their regional distribution and migration routes in Asia. Furthermore, the discovery of potential habitats offers a promising avenue for the conservation of C. kweichowensis.

Panmixia and local endemism: a revision of the Eubranchus rupium species complex with a description of new species.

Species of the genus Eubranchus Forbes, 1838 (Mollusca: Gastropoda: Nudibranchia) are common faunistic elements of boreal benthic ecosystems, associated with hydroid communities. Recent studies have suggested that the widely distributed trans-Arctic E. rupium (Møller, 1842) constitutes a complex of at least three candidate species, but the detailed taxonomy of the complex remains unresolved. The purpose of the present paper is to conduct an integrative taxonomic study including molecular genetic methods (a phylogenetic analysis using COI , 16S rRNA and histone H3 with application of species delimitation methods) and morphological study (light and scanning electron microscopy) of E. rupium and closely related species. The specific aims of this study were to establish the species boundaries, morphological variability, and the phylogeographic structure within this group. The phylogeographic analysis included a TCS -based network analysis, an analysis of molecular variance (AMOVA), divergence time estimations, and ancestral area reconstructions. We demonstrate that specimens initially identified as E. rupium included three distinctive species: the nominal E. rupium with an amphiboreal range, the new species Eubranchus novik sp. nov. from the Sea of Japan, for which a taxonomic description is provided in this paper, and Eubranchus sp. from the northern Kuril Islands, which requires the collection and study of additional material for formal description. Our results confirm the amphiboreal distribution of E. rupium , as no geographic structure was found across Pacific, Arctic and Atlantic populations, and the results of the AMOVA analysis showed no differences between groups of samples from different geographic regions. The divergence of the 'Eubrancus rupium species complex' is estimated from the late Miocene or the Miocene-Pliocene boundary to the late Pliocene. It is hypothesised that the most probable ancestral region for the Eubranchus rupium species complex is the north-western Pacific, and the subsequent speciation likely occurred due to dispersal followed by allopatric speciation. ZooBank: urn:lsid:zoobank.org:pub:228E0C46-0BF7-4DDD-9C00-67B50E298D65.