Disjunct Distribution Research Articles

Progress in molecular systematics of Caprifoliaceae

AbstractCaprifoliaceae sensu APG IV shows a disjunctive distribution between Eurasia and America, and is an excellent study system for exploring the formation of species with an Eurasian–North American disjunct distribution. Due to widespread hybridization and introgression in Caprifoliaceae sensu APG IV as well as morphological convergence and discontinuous distribution of species, the phylogenetic relationships among subfamilies and the systematic positions of some genera have yet to be fully resolved. Therefore, we present an overview of the classification and molecular phylogenetic studies of Caprifoliaceae sensu APG IV in recent years, aiming to provide a reference for the systematic classification of Caprifoliaceae sensu APG IV and to facilitate discussions of problems and directions of systematic studies in the family.

Revalidation of Enteromius crocodilensis (Fowler, 1934) from synonymy with the disjunctly distributed Enteromius argenteus (Günther, 1868) based on molecular and morphological evidence.

The rosefin barb, Enteromius argenteus, as currently described, is a freshwater fish with a distribution that is geographically separated and divided into the northern population in the Kwanza River system in Angola, and the southern population in the Inkomati River system in South Africa and Eswatini. Due to this disjunct distribution pattern, it is likely that the two populations represent distinct species. mtDNA sequence data and detailed examination of morphometric characters revealed considerable genetic (2.8%-3.5%) and morphological differentiation of the two populations, suggesting their recognition as two distinct species. Enteromius crocodilensis is revalidated and redescribed for the southern population that is readily distinguished from E. argenteus by nonoverlapping circumpeduncular scale counts (12-13 vs. 14) and color pattern (presence of a conspicuous dark band along the midline vs. absence of characteristic melanin patterns). Phylogenetic analysis based on mtDNA cytochrome oxidase subunit I (COI) data places both E. argenteus and E. crocodilensis in a well-supported clade that includes a number of morphologically similar sawfin barb species from southern and central Africa.

Phylogenomic insights into species relationships, reticulate evolution, and biogeographic diversification of the ginseng genus Panax (Araliaceae), with an emphasis on the diversification in the Himalayan‐Hengduan Mountains

AbstractPanax (Araliaceae) is a small genus containing several well known medicinally important species. It has a disjunct distribution between Eastern Asia and Eastern North America, with most species from eastern Asia, especially the Himalayan‐Hengduan Mountains (HHM). This study used the genomic target enrichment method to obtain 358 nuclear ortholog loci and complete plastome sequences from 59 accessions representing all 18 species of the genus. Divergence time estimation and biogeographic analyses suggest that Panax was probably widely distributed from North America to Asia during the middle Eocene. During the late Eocene to Oligocene Panax may have experienced extensive extinctions during global climate cooling. It survived and diverged early in the mountains of Southwest China and tropical Indochina, where some taxa migrated northwestward to the HHM, eastward to central and eastern China, and then onward toward Japan and North America. Gene flow is identified as the main contributor to phylogenetic discordance (33.46%) within Panax. We hypothesize that the common ancestors of the medicinally important P. ginseng + P. japonicus + P. quinquefolius clade had experienced allopolyploidization, which increased adaptability to cooler and drier environments. During the middle to late Miocene, several dispersals occurred from the region of the HHM to contiguous areas, suggesting that HHM acted as a refugium and also served as a secondary diversification center for Panax. Our findings highlight that the interplay of orographic uplift and climatic changes in the HHM greatly contributed to the species diversity of Panax.

Bipolarity and Antitropicality in Marine Taxa: Understanding the Complexities of Latitudinal Distribution

ABSTRACTAimThis systematic review aims to analyse the current status of research on marine bipolar and antitropical distribution patterns by exploring temporal trends, studied taxa, inconsistencies in definitions and the extent of molecular evidence in bipolar and antitropical species.LocationGlobal marine environments, with a special focus on Polar Regions.Time Period1800s to 2024.Major Taxa StudiedMarine taxa across all phyla, ranging from algae and zooplankton groups to fish and cetaceans.MethodsA systematic literature search was conducted using Scopus, PubMed and Google Scholar databases. Studies were screened for relevant publications of marine taxa displaying bipolar or antitropical distributions, and data were extracted in order to perform a numerical summary of aspects including temporal trends, taxa representation and agreement with this article's standardised definitions. Additional data were gathered from The Arctic Register of Marine Species (ARMS) and The Register of Antarctic Marine Species (RAMS) databases. Distribution data were then extracted to verify the potential bipolarity of species present in both databases.ResultsFrom 221 articles, 665 marine taxa records were extracted, of which 517 records were categorised as antitropical and 148 as bipolar. Molecular evidence existed for 25% of non‐paleontological records. A considerable amount of records (44%) did not match the definitions used in this review. The data taken from ARMS and RAMS revealed 408 shared species, of which 41 species were listed as bipolar by the literature collected in this study.Main ConclusionsMarine bipolarity and antitropicality have been topics of interest since the 1800s, especially between 2008 and 2017. However, the discrepancy between the number of potentially bipolar species in publicly available species databases and literature‐based estimates underscores the need for further research of neglected taxa. Future research should prioritise including molecular evidence, transparent terminology and interdisciplinary approaches to address the complexities of marine disjunct distributions.

In splendid isolation: a new cloud forest species expands the distribution of Myrceugenia (Myrtaceae) into Las Yungas and adds a new genus to the flora of Bolivia

Myrceugenia is a temperate or subtropical genus of c. 50 species with a disjunct distribution across South America. The ‘western’ species occur in central Chile and north-western Argentina with one species in the Juan Fernández Islands. The ‘eastern’ species occur in Uruguay, southern Brazil, and marginal regions of Argentina and Paraguay, reaching montane eastern Brazil (two isolated taxa in Central Brazil). It is hypothesized that Myrceugenia once grew across the temperate forests of southern South America, but that oceanic transgressions and the elevation of the Andes during the Miocene divided its populations as the forests retracted from the centre of the continent. The Las Yungas floristic province is a strip of cool, temperate forest that runs along the eastern slopes of the Andes from Venezuela to northern Argentina; Myrceugenia was not known to occur there. We report the discovery of a new species of Myrceugenia in southern Las Yungas (Bosque Tucumano Boliviano). It is distinct from all other species of the genus by the combination of solitary flowers, sub-ancipitate hypanthium, bilocular locules, and 12-13 clustered ovules. The phylogeny of Myrceugenia shows geographic structuring with three basal western clades and one derived eastern clade. The isolated taxa of Myrceugenia from Central Brazil were sisters, respectively, to the rest of the eastern clade and to one of its two subclades, suggesting that isolated taxa are relictual. The discovery of this species has made Myrceugenia the only genus of Myrtaceae to grow in the three cool, humid forests of southern South America.

A revision and addition to Zopheridae (Coleoptera: Tenebrionoidea) in Baltic amber: possible connections between modern Holarctic distributions and Eocene ‘amber forests’

One new extinct genus and six new extinct species of Zopheridae are described and illustrated from Eocene Baltic amber: Usechus andrushchenkoi Alekseev et Bukejs sp. nov., Coxelus carstengroehni Alekseev et Bukejs sp. nov., Paha vanivanitatum Alekseev et Bukejs sp. nov., Lasconotus tenebrisilvarum Alekseev et Bukejs sp. nov., Helioctamenus groehni Alekseev et Bukejs sp. nov., and Thanatoplagia tamutisi Alekseev et Bukejs gen. et sp. nov. These described taxa include the first fossil representatives of five extant genera and two extant tribes of the family Zopheridae. The assumed paleoecology of these taxa within the amber-producing forest paleohabitat, as well as zoogeography of new fossils are discussed. In addition, new fossil records of Xylolaemus legalovi Alekseev et Bukejs, 2016, X. richardklebsi Alekseev et Bukejs, 2016, Endophloeus gorskii Alekseev et Bukejs, 2016, Yantaroxenos colydioides Nabozhenko, Kirejtshuk et Merkl, 2016, and Zopheromimus auriborussiensis Alekseev et Nabozhenko, 2023 from Baltic amber are presented. A catalogue of Zopheridae described from Baltic amber (currently 19 species within 16 genera) is compiled herein, and an identification key for all taxa is provided. The zoogeographical affinities of the Baltic amber zopherid assemblage are assessed. The present-day disjunct distributions of the zopherid genera that have survived since the Eocene and are currently present in the Holarctic region probably resulted from a uniform fauna in the warm temperate regions of the Northern Hemisphere in the first half of the Paleogene. This uniform fauna was followed by independent reduction of distributions within four regions (West Palearctic, East Palearctic, West Nearctic, and East Nearctic). The ‘circum-Arctic quadrants’ schema is proposed for visualisation of this hypothesis. Additionally, a zonal middle to late Eocene ‘amberiferous ring’ is hypothesized as a probable migration pathway for several zopherids in this part of the Eocene. This ‘ring’ is a belt of amber-producing forests in the Northern Hemisphere, with the potential to preserve a wider distribution of taxa that relied on mixed conifer-fagacean forests similar to the Baltic amber forest flora and its faunal assemblage.

Cuban Proserpinidae

The Neotropical landsnails family Proserpinidae comprises the Caribbean genus Proserpina. The Cuban endemic species Proserpina (Despoenella) depressa and P. (D.) globulosa exhibit unique morphological and ecological features still poorly known. We made observations related to morphology and shell coloration, foot and mantle and its variations concerning some extant Cuban and Caribbean populations. Some ecological comments include their defense morphological traits and behavior like foot spasmodic movements. Likewise, we discuss the Cuban species disjunctive distribution. These mollusks inhabit moist karstic areas permanently threatened due to climatic change, forest loss and habitat fragmentation.

Population genetic differentiation and structure of rare plant Anemone shikokiana based on genotyping-by-sequencing (GBS)

BackgroundAnemone shikokiana (Makino) Makino is a perennial herb of the genus Anemone in the family Ranunculaceae. Endemic to the Shandong Peninsula in China and Shikoku Island in Japan, it is a rare and endangered plant with a narrow, disjunct distribution. It is threatened with extinction and is in urgent need of conservation. Evaluating the genetic diversity of species, revealing the population genetic structure and gene flow, and inferring the population history are of great importance for species conservation, especially for rare and endangered plants.ResultsIn our study, 73 samples from eight wild populations in China were sequenced by Super-GBS, yielding a total of 40.59 G clean reads and 52,231 SNPs. Based on the obtained SNP data set, we evaluated the population genetic diversity, genetic structure, and gene flow of A. shikokiana. A low level of genetic diversity was found (He = 0.1925, Ho = 0.1422). The neighbor-joining (NJ) tree, principal component analysis and ADMIXTURE analysis suggested that these 73 A. shikokiana could be considered as two groups. Pairwise genetic differentiation coefficients (Fst) indicated that genetic differentiation was lower between adjacent populations and higher between geographically separated populations. The gene flow between Kunyu Mountain and Lao Mountain was very low. However, neither of the two regions showed evidence of Isolation by Distance.ConclusionsHere, we revealed the population genetic structure and gene flow of A. shikokiana from the Shandong Peninsula, China. This research provides valuable genetic resources for A. shikokiana and contributes to the scientific and effective conservation of the species.

A new record of Dinochloa malayana S.Dransf. (Poaceae, Bambusoideae) from central Sumatra, Indonesia, reveals the continuous distribution of Dinochloa in western Malesia

We report a new record of Dinochloa malayana S.Dransf. (Poaceae, Bambusoideae) from Sumatra, Indonesia, specifically in Sumpur Kudus, Sijunjung, West Sumatra. This discovery expands the known western range of Dinochloa Buse in Malesia. On the mainland of Sumatra, this genus, represented by D. glabrescens Widjaja, was previously only reported from Lampung in the south. Dinochloa was once thought to have a disjunct distribution in western Malesia, limited to the Malay Peninsula and southern Sumatra. Our new data confirm the continuous distribution of Dinochloa throughout western Malesia.

Population isolation in the Plains spadefoot toad: causes and conservation implications.

Range disjunctions appear to be common in nature, although they may be caused by various factors. They may simply be an artefact of inadequate sampling. If real, they may be the result of colonization events or habitat change. With natural habitats showing increasing fragmentation because of human activity, understanding the cause of a disjunction can have important conservation implications. We investigate the geographical range of the Plains spadefoot toad, Spea bombifrons, a widely distributed species in the midwestern and southwestern United States, with a putative disjunct population in southern Texas. We combine GIS mapping, species distribution modeling, and population genetic analysis to investigate this putative disjunction. We establish that this southern Texas population is truly geographically disjunct and genetically distinct. Further, using climate projections we show that this unique population is at high risk of local extinction.

A time-calibrated phylogeny of the diversification of Holoadeninae frogs.

The phylogeny of the major lineages of Amphibia has received significant attention in recent years, although evolutionary relationships within families remain largely neglected. One such overlooked group is the subfamily Holoadeninae, comprising 73 species across nine genera and characterized by a disjunct geographical distribution. The lack of a fossil record for this subfamily hampers the formulation of a comprehensive evolutionary hypothesis for their diversification. Aiming to fill this gap, we inferred the phylogenetic relationships and divergence times for Holoadeninae using molecular data and calibration information derived from the fossil record of Neobatrachia. Our inferred phylogeny confirmed most genus-level associations, and molecular dating analysis placed the origin of Holoadeninae in the Eocene, with subsequent splits also occurring during this period. The climatic and geological events that occurred during the Oligocene-Miocene transition were crucial to the dynamic biogeographical history of the subfamily. However, the wide highest posterior density intervals in our divergence time estimates are primarily attributed to the absence of Holoadeninae fossil information and, secondarily, to the limited number of sampled nucleotide sites.

Revisiting evolutionary relationships of Antrodiaetus (Araneae, Mygalomorphae, Antrodiaetidae) using phylogenomics; implications for species diversity and biogeography of a persistent Holarctic lineage

Antrodiaetus is a lineage of mygalomorph spider (Mygalomorphae: Antrodiaetidae) that has persisted since the late Cretaceous and has a disjunct Holarctic distribution and strong morphological conservatism. These folding-door spiders possess a life history (i.e., limited dispersal, conserved environmental niche) that closely ties their evolution to geology. This study produces a robust, well-supported phylogenomic inference of all currently recognized Antrodiaetus species using UCEs (Ultraconserved Elements), corroborates previous biogeographical hypotheses, and proposes new hypotheses about diversification patterns. We also confirm that previously suspected cryptic diversity within A. pacificus is underestimated, as this nominal species comprises multiple divergent and cryptic lineages. Our phylogeny now serves as a foundation for understanding Antrodiaetus species relationships, biogeography, and speciation.

Phylogenomic insights into the worldwide evolutionary relationships of the stingless bees (Apidae, Meliponini)

Stingless bees (tribe Meliponini) are remarkable for their characteristically large social colonies, their capacity to produce honey and other useful products, and their morphological and behavioral diversity. They have a disjunct pan-tropical distribution, primarily occurring in warm and humid environments in the Neotropical, Afrotropical, and Indo-Australasian regions. Even though phylogenetic hypotheses have been proposed for Meliponini based on morphology and molecular data, many questions are still unsolved regarding the evolutionary relationships and systematics of the tribe. In this contribution, we present a large phylogenomic dataset comprising over 2,500 ultra-conserved element (UCE) loci sequenced for 153 species of Meliponini, representing all known genera of stingless bees. The genera Camargoia, Paratrigonoides, Plectoplebeia, Cleptotrigona, Ebaiotrigona, Papuatrigona, Pariotrigona, Platytrigona, and Sahulotrigona were included in molecular phylogenetic analyses for the first time. Concatenated and species-tree analyses were performed using different partitioning strategies and summary methods. We performed gene-genealogy interrogation (GGI) on several recalcitrant nodes to resolve discordances among recovered tree topologies. Results were mostly consistent among analyses, recovering three main lineages of Meliponini congruent with the biogeographic domains to which they are associated. Within major clades, discordances were found in relation to previous works. The genus Frieseomelitta was recovered as paraphyletic in relation to Trichotrigona, and the genus Lepidotrigona was revealed to be composed of two independent lineages. Even though concatenated and weighted ASTRAL analyses were mostly effective in recovering the relationships favored by GGI, they retrieved different results in relation to the phylogenetic placements of Oxytrigona and Cephalotrigona. The most favored hypothesis in GGI analyses was not found in any other analyses, being more congruent with morphological evidence and highlighting the relevance of exploring the support given to alternative hypotheses through topological tests. Recent advances in our capacity to generate molecular sequences from old specimens using modern sequencing methods allowed for unparalleled sampling across genera, yielding a backbone for the phylogenetic relationships of stingless bees, which will further investigations into their systematics and evolution.

Phylogeny of the Neotropical Hypoctonine Whip-Scorpions (Thelyphonida, Thelyphonidae), with Descriptions of Two New Genera and Species.

Thelyphonida Blanchard, 1852, also known as vinegaroons or whip-scorpions, is a small arachnid order with 140 described species contained in a single family, Thelyphonidae Lucas, 1835. Despite being conspicuous and widely distributed across the tropics and subtropics on four continents, knowledge of the order has been slow to advance. Hypoctoninae Pocock, 1899, one of four subfamilies currently recognized and one of two represented in the New World, comprises five genera. Since its inception, Thelyphonellus Pocock, 1894 has remained the only hypoctonine genus occurring in South America, with only four species described prior to the present contribution. The first detailed morphological study and phylogenetic analysis of Thelyphonellus is presented herein. The morphological phylogenetic analysis-the first for Thelyphonida-includes all except one of the previously described species of Thelyphonellus in addition to two new species described herein; the species of Ravilops Víquez and Armas, 2005 (from the Caribbean island of Hispaniola); and the monotypic Old World genus Etienneus Heurtault, 1984 (from West Africa) scored for 45 morphological characters. A single, most parsimonious phylogenetic hypothesis revealed that Thelyphonellus is paraphyletic with respect to Ravilops. The New World Hypoctoninae comprises four clades with disjunct distributions and well supported by a combination of morphological characteristics, on the basis of which four genera, two of which are new, are recognized: Ravilops, with two species, endemic to Hispaniola; Thelyphonellus, herein restricted to Thelyphonellus amazonicus (Butler, 1872) and Thelyphonellus ruschii Weygoldt, 1979, occurring in Guyana, Suriname, French Guiana, and northern Brazil; Wounaan, gen. n., containing Wounaan vanegasae (Giupponi and Vasconcelos, 2008), comb. n. and Wounaan yarigui, sp. n. from Colombia; and Yekuana, gen. n., containing Yekuana venezolensis (Haupt, 2009), comb. n. and Yekuana wanadi, sp. n. from Venezuela. The two new species are described and illustrated. A key to the identification of the Neotropical genera of Hypoctoninae and a map plotting the known distribution of its species are also presented.

Notes on the taxonomic status and re-lectotypification of Litseaiteodaphne (Lauraceae)

Litseaiteodaphne (Nees) Hook.f., known endemic to Sri Lanka, is now synonymized with L. saligna (Nees) N.P. Balakr. of northeast India and Bangladesh, and thus revealing a curious disjunct distribution. The name Tetrantheraiteodaphne Nees the basionym of L. iteodaphne has been re-lectotypified.

A new superfamily of freshwater mussels Deccanoidea nov. (Mollusca: Unionida) from an intertrappean deposit of Saurashtra province (Gujarat state, western India): An example of disjunct distribution

The Cretaceous-Palaeogene intertrappean deposits of the Deccan Volcanic Province of India comprise vertebrate, invertebrate and plant fossils of the dominantly continental realm. A 3–4 m thick shaly-sandstone lacustrine intertrappean sequence of Early Palaeogene (Palaeocene-Early Eocene) Bamanbor Formation, Chotila Basin (Saurashtra province, Gujarat State, western India) has yielded a collection of molluscans (bivalve and few gastropods) fauna. High-resolution digital photography and radiography of the recovered bivalves allowed us to gain detailed inferences on shell morphology. In a taxonomical context, we herein propose a new unionid molluscan superfamily Deccanoidea nov. represented by a single new family Deccanoidae nov. that includes two new subfamilies, that is, Deccanoinae nov. (represented by two new genera Deccanoida gen. nov. [including four new species: D. conrugis sp. nov., D. aleta sp. nov., and D. costaria sp. nov.] and Bamanboria gen. nov. [including one new species Bamanboria oblongis gen. et sp. nov.] and Chotiloinae nov. [represented by one new genus Chotilia gen. nov. and three new species: Chotilia trappeansis sp. nov., C. tuberculata sp. nov. and C. deccanensis sp. nov.]). Inorganic geochemistry of host (unionid-yielding) lithologies reveals oxic-freshwater conditions, humid-climate and moderate rainfall. The data on historical biogeography reveals that the Indian subcontinent hosted unionids during the late Cretaceous; however, the presence of new (at family/generic level) unionid fauna during the Early Palaeogene (Palaeocene-Early Eocene) in India indicates changes in the geographic position and ecologic condition linked to northward drift and lava outpouring, respectively. A disjunct distribution of unionid fauna in the erstwhile Gondwanan continents and insular India during the Cretaceous-Palaeogene interval can be explained in terms of both vicariance and dispersal.

POPULATION STUDY AND REASSESSMENT OF CONSERVATION STATUS OF AN ENDEMIC DIPTEROCARP, Hopea bilitonensis

Hopea bilitonensis is a rare, endemic Dipterocarp species in the Malesian Region. It has a disjunct distribution pattern, where main populations occur on the sandy soils of Bangka Belitung Islands of Indonesia and some on limestone forest in Perak, Peninsular Malaysia. Current global status of this species based on the IUCN Red List is Critically Endangered (CR) A1c+2c, B1+2c (1998) whilst in Malaysia it is assessed as CR A4c, B1ab(iii) (2010). A reassessment of the conservation status of this species is needed to provide the most current population status and its extinction risk, especially in Indonesia using the IUCN Red List Categories and Criteria version 3.1. This study was conducted to survey and assess the current populations of this species in Belitung Island where most population occurred and subsequently to recommend its current conservation status. The species is in fact still common in the island, stretching along the main roads and surrounding forests. Using the purposive sampling method, we developed a total of 16 plots of 20x20m each in 10 different locations across the Belitung Island. A total of 730 individuals were found with stem diameter at breast height ranged from 2cm to more than 30cm. For global reassessment, based on the current distribution and herbarium records, the calculated extent of occurrence (EOO) is 108,128.642km2, whilst the area of occupancy (AOO) is 84 km2. However, the species clearly has a restricted distribution and is facing high threats due to frequent timber harvesting and continuing decline of the EOO and AOO. The species extinction risk was then assessed by using five quantitative criteria of the IUCN. Therefore, we propose H. bilitonensis category is considered to be Endangered (EN) based on A2c, B2ab(i,ii,iii,iv,v) and C2a(i) criteria.

Repeatome evolution across space and time: Unravelling repeats dynamics in the plant genus Erythrostemon Klotzsch (Leguminosae Juss).

Fluctuations in genomic repetitive fractions (repeatome) are known to impact several facets of evolution, such as ecological adaptation and speciation processes. Therefore, investigating the divergence of repetitive elements can provide insights into an important evolutionary force. However, it is not clear how the different repetitive element clades are impacted by the different factors such as ecological changes and/or phylogeny. To discuss this, we used the Neotropical legume genus Erythrostemon (Caesalpinioideae) as a model, given its ancient origin (~33 Mya), lineage-specific niche conservatism, macroecological heterogeneity, and disjunct distribution in Meso- and South American (MA and SA respectively) lineages. We performed a comparative repeatomic analysis of 18 Erythrostemon species to test the impact of environmental variables over repeats diversification. Overall, repeatome composition was diverse, with high abundances of satDNAs and Ty3/gypsy-Tekay transposable elements, predominantly in the MA and SA lineages respectively. However, unexpected repeatome profiles unrelated to the phylogeny/biogeography were found in a few MA (E. coccineus, E. pannosus and E. placidus) and SA (E. calycinus) species, related to reticulate evolution and incongruence between nuclear and plastid topology, suggesting ancient hybridizations. The plesiomorphic Tekay and satDNA pattern was altered in the MA-sensu stricto subclade with a striking genomic differentiation (expansion of satDNA and retraction of Tekay) associated with the colonization of a new environment in Central America around 20 Mya. Our data revealthat the current species-specific Tekay pool was the result of two bursts of amplification probably in the Miocene, with distinct patterns for the MA and SA repeatomes. This suggests a strong role of the Tekay elements as modulators of the genome-environment interaction in Erythrostemon, providing macroevolutionary insights about mechanisms of repeatome differentiation and plant diversification across space and time.

Holocene Climate Change Promoted Allopatric Divergence and Disjunct Geographic Distribution in a Bee Orchid Species

ABSTRACTAimSpecies with disjunct geographic distributions provide natural opportunities to investigate incipient or recent allopatric divergence. The combination of both genetic and ecological data may be fruitful to decipher the causes of such patterns: (i) actual vicariance, (ii) successful colonisation from one source to a new range (dispersal, biological introduction) or (iii) parallel convergent evolution.LocationSouthern France and Northern Spain.TaxonThe bee orchid Ophrys aveyronensis (and its two recognised subspecies O. a. subsp. aveyronensis and O. a. subsp. vitorica) displays a disjunct geographic distribution with two subranges separated by 600 km on both sides of the Pyrenees mountain range.MethodsAs allopatric divergence is often complex to document in the wild, we used a combination of population genomics and ecological niche modelling (ENM) to investigate the causes of this intriguing biogeographic pattern.ResultsThe population genomic data demonstrate that all the studied populations exhibit similar patterns of genetic diversity and dramatic decrease in effective size compared with the ancestral population. Significant genetic differentiation and reciprocal monophyly exist between populations of the two subranges of O. aveyronensis, despite a very recent divergence time as young as ca. 1500 generations ago. Moreover, paleo‐ENM analyses support that the disjunct geographic distribution of O. aveyronensis is consistent with a range split of a broad ancestral range, contraction and distinct longitudinal and latitudinal shifts in response to climate warming during the Holocene.Main ConclusionThe congruence of the results obtained from both population genomics and ENM approaches documents how very recent continental allopatric divergence initiated speciation in this system. O. aveyronensis provides a promising opportunity to study the onset of reproductive isolation and parallel evolution following an initial stage of geographic separation in a group with high diversification rate.

Past and current climate as a driver in shaping the distribution of the Longitarsus candidulus species group (Coleoptera: Chrysomelidae).

Longitarsus candidulus (Foudras) is a thermophilic flea beetle species widely distributed in the Mediterranean Basin and associated with Daphne gnidium L. and Thymelaea hirsuta (L.). Longitarsus laureolae Biondi and Longitarsus leonardii Doguet, phylogenetically closely related to L. candidulus, show together a peculiar and rare disjunct distribution along the central-southern Apennines and the Cantabrian-Pyrenean mountain system, respectively. Both are associated with Daphne laureola L. in mesophilic habitats. We used "ecological niche modeling" to infer the Pleistocene dynamics in the distribution of the three flea beetle species and their host plants. We interpreted their current distributions, paying particular attention to the presumed time of species divergence as inferred from recent studies. The differentiation of L. laureolae and L. leonardii from L. candidulus likely represents a response to the marked climatic changes during the Late Pliocene. Such a split was likely associated with a trophic niche shift of the laureolae/leonardii ancestor towards the typically mesophilic host plant D. laureola. The subsequent split between L. laureolae and L. leonardii, possibly due at first to the niche competition, was then boosted by an allopatric divergence during the Middle Pleistocene, likely caused by a large area of low environmental suitability for both species, mainly located between the northern Apennines and the south-western Alps.