Cryptic Differentiation Research Articles

Dense infraspecific sampling reveals cryptic differentiation in the enigmatic hemiparasitic love vine Cassytha filiformis (Lauraceae)

AbstractSpecies delimitation remains a challenge worldwide, especially in highly diverse tropical and subtropical regions. Here, we use an integrative approach that combines morphology, phylogenomics, and species distribution modeling (SDM) to clarify the cryptic differentiation within the enigmatic hemiparasitic love vine Cassytha filiformis (Lauraceae) in China and adjacent regions. We generated complete plastid genomes and nuclear ribosomal sequences for diverse samples from across the species range and compared results with previously published plastid data, recovering two well‐supported monophyletic clades. Further, the analysis revealed significant differences in two morphological characters and SDM, indicating distinct environmental factors influencing their distributions. Fossil‐calibrated analyses to estimate the origins and diversification patterns for the cryptic species gave divergence age estimates corresponding to the Oligo‐Miocene; a period of new ecological opportunities associated with the prevailing East Asian monsoon. Multivariate analyses support the conclusion that southern China and adjacent regions have a different, previously unknown, cryptic lineage of C. filiformis. Our study highlights the importance of using multivariate approach to characterize plant species, as well as the significant role that past climatic changes have played in driving speciation in parasitic plants in tropical and subtropical zones.

The role of the Sunda shelf biogeographic barrier in the cryptic differentiation of Conus litteratus (Gastropoda: Conidae) across the Indo-Pacific region.

Geographical and oceanographic processes have influenced the speciation of marine organisms. Cone snails are marine mollusks that show high levels of endemism and a wide distributional range across the Indian and Pacific Oceans. Discontinuities in distributions caused by biogeographic barriers can affect genetic connectivity. Here we analysed the connectivity within Conus litteratus using samples from the Lakshadweep archipelago (Arabian Sea, Indian Ocean) and from the Pacific Ocean. Maximum likelihood analyses based on the mitochondrial cytochrome C oxidase subunit I (COI) and on the non-coding 16S ribosomal RNA (16S rRNA) genes revealed cryptic diversity within C. literatus occupying distinct oceanographic regions. The intraspecific genetic distances between the two distinct clades of C. literatus from the Arabian Sea and the Pacific Ocean ranged from 7.4% to 7.6% for COI and from 2.4% to 2.8% for 16S rRNA genes, which is larger than the threshold limit for interspecific differentiation. The haplotype network analysis also corroborated the existence of two different lineages within C. litteratus. The detected genetic discontinuities reflect the effect of the Sunda shelf biogeographic barrier on the allopatric divergence of C. litteratus.

Assessing the origin, genetic structure and demographic history of the common pheasant (Phasianus colchicus) in the introduced European range

The common pheasant, a game species widely introduced throughout the world, can be considered as an ideal model to study the effects of introduction events on local adaptations, biogeographic patterns, and genetic divergence processes. We aimed to assess the origin, spatial patterns of genetic variation, and demographic history of the introduced populations in the contact zone of Central and Southeast Europe, using mitochondrial DNA control region sequences and microsatellite loci. Both types of molecular markers indicated relatively low to moderate levels of genetic variation. The mtDNA analyses revealed that common pheasants across the study area are divided into two distinct clades: B (mongolicus group) and F (colchicus group). Analyses of the microsatellite data consistently suggested a differentiation between Hungary and Serbia, with the pheasant population in Hungary being much more genetically homogeneous, while that of Serbia has much more genetic mixture and admixture. This cryptic differentiation was not detected using a non-spatial Bayesian clustering model. The analyses also provided strong evidence for a recent population expansion. This fundamental information is essential for adequate and effective conservation management of populations of a game species of great economic and ecological importance in the studied geographical region.

Signatures of mitonuclear coevolution in a warbler species complex

Divergent mitonuclear coadaptation could facilitate speciation. We investigate this possibility in two hybridizing species of warblers, Setophaga occidentalis and S. townsendi, in western North America. Inland S. townsendi harbor distinct mitochondrial DNA haplotypes from those of S. occidentalis. These populations also differ in several nuclear DNA regions. Coastal S. townsendi demonstrate mixed mitonuclear ancestry from S. occidentalis and inland S. townsendi. Of the few highly-differentiated chromosomal regions between inland S. townsendi and S. occidentalis, a 1.2 Mb gene block on chromosome 5 is also differentiated between coastal and inland S. townsendi. Genes in this block are associated with fatty acid oxidation and energy-related signaling transduction, thus linked to mitochondrial functions. Genetic variation within this candidate gene block covaries with mitochondrial DNA and shows signatures of divergent selection. Spatial variation in mitonuclear ancestries is correlated with climatic conditions. Together, these observations suggest divergent mitonuclear coadaptation underpins cryptic differentiation in this species complex.

Cryptic speciation and population differentiation in the yellow-nosed albatross species complex

The two species of yellow-nosed albatross, Atlantic (Thalassarche chlororhynchos) and Indian (T. carteri), are morphologically similar, but they differ in breeding behaviour and distribution. Both species are listed as endangered by the IUCN due to the limited number of breeding sites, threats from introduced predators and diseases, and impact of commercial fishing. We quantified genetic variation between and within the two species. Using nuclear (microsatellites and two nuclear sequences) and mitochondrial (control region) markers, we analysed 354 samples from four breeding islands (Atlantic: Nightingale, Inaccessible, and Gough; Indian: Amsterdam) and bycatch samples from South Africa and New Zealand. In addition to all markers separating the two species, nuclear markers showed Atlantic yellow-nosed albatrosses from Gough Island are genetically distinct from those breeding at Nightingale and Inaccessible Islands in the Tristan da Cunha archipelago. Nuclear markers confirmed that all bycatch samples were Indian yellow-nosed albatrosses, however, the bycatch birds from South Africa and New Zealand were distinct from each other and from birds breeding on Amsterdam Island, suggesting colony specific dispersal at sea. Our study supports the current recognition of two yellow-nosed albatross species and recognises genetically distinct groups of both Atlantic and Indian yellow-nosed albatross breeding on different islands, which is important for their conservation and management.

Cryptic differentiation in the Manx shearwater hinders the identification of a new endemic subspecies

The taxonomy of Procellariiformes, particularly petrels and shearwaters, is still unresolved. The Manx shearwaterPuffinus puffinusis one of the best studied seabirds worldwide. Most of the information known on this seabird is focused on the northern core populations where the species is abundant. However, the species shows a high number of peripheral populations, which are extremely small and difficult to study in comparison to central populations. Using an integrative approach, we provided significant evidence of phenological, morphological, acoustic, plumage colour and genetic differentiation of the Canarian Manx shearwaters (the most southern population) from the northern breeding colonies, which is compatible with a long period of isolation. Birds from the Canary Islands breed around 2–3 months earlier, are smaller and lighter and show darker underwing plumage than those from northern populations. In addition, Canarian call features are different from the northern populations. Finally, genetic analyses of the mitochondrial control region indicate an incipient genetic differentiation of Canarian Manx shearwaters from the other breeding populations. The Canarian population holds a small number of breeding colonies and it is declining, so accurate taxonomic recognition critically affects conservation efforts. For all the aforementioned reasons, we propose to rank the Canarian breeding population as a new taxon by presenting the formal description of a new subspeciesPuffinus puffinus canariensisssp. nov.

Single cell transcriptomes of normal endometrial derived organoids uncover novel cell type markers and cryptic differentiation of primary tumours

Endometrial carcinoma, the most common gynaecological cancer, develops from endometrial epithelium which is composed of secretory and ciliated cells. Pathologic classification is unreliable and there is a need for prognostic tools. We used single cell sequencing to study organoid model systems derived from normal endometrial endometrium to discover novel markers specific for endometrial ciliated or secretory cells. A marker of secretory cells (MPST) and several markers of ciliated cells (FAM92B, WDR16, and DYDC2) were validated by immunohistochemistry on organoids and tissue sections. We performed single cell sequencing on endometrial and ovarian tumours and found both secretory-like and ciliated-like tumour cells. We found that ciliated cell markers (DYDC2, CTH, FOXJ1, and p73) and the secretory cell marker MPST were expressed in endometrial tumours and positively correlated with disease-specific and overall survival of endometrial cancer patients. These findings suggest that expression of differentiation markers in tumours correlates with less aggressive disease, as would be expected for tumours that retain differentiation capacity, albeit cryptic in the case of ciliated cells. These markers could be used to improve the risk stratification of endometrial cancer patients, thereby improving their management. We further assessed whether consideration of MPST expression could refine the ProMiSE molecular classification system for endometrial tumours. We found that higher expression levels of MPST could be used to refine stratification of three of the four ProMiSE molecular subgroups, and that any level of MPST expression was able to significantly refine risk stratification of the copy number high subgroup which has the worst prognosis. Taken together, this shows that single cell sequencing of putative cells of origin has the potential to uncover novel biomarkers that could be used to guide management of cancers. © 2020 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

DNA barcoding and molecular phylogeny of Dumasia (Fabaceae: Phaseoleae) reveals a cryptic lineage

Dumasia taxonomy and classification have long been problematic. Species within this genus have few morphological differences and plants without flowers or fruits are difficult to accurately identify. In this study, we evaluated the ability of six DNA barcoding sequences, one nuclear (ITS) and five chloroplast regions (trnH-psbA, matK, rbcL, trnL-trnF, psbB-psbF), to efficiently identify Dumasia species. Most single markers or their combinations identify obvious barcoding gaps between intraspecific and interspecific genetic variation. Most combined analyses including ITS showed good species resolution and identification efficiency. We therefore suggest that ITS alone or a combination of ITS with any cpDNA marker are most suitable for DNA barcoding of Dumasia. The phylogenetic analyses clearly indicated that Dumasia yunnanensis is not monophyletic and is separated as two independent branches, which may result from cryptic differentiation. Our results demonstrate that molecular data can deepen the comprehension of taxonomy of Dumasia and provide an efficient approach for identification of the species.

Conservative plumage masks extraordinary phylogenetic diversity in the Grallaria rufula (Rufous Antpitta) complex of the humid Andes

AbstractThe Grallaria rufula complex is currently considered to consist of 2 species, G. rufula (Rufous Antpitta) and G. blakei (Chestnut Antpitta). However, it has been suggested that the complex, populations of which occur in humid montane forests from Venezuela to Bolivia, comprises a suite of vocally distinct yet morphologically cryptic species. We sequenced nuclear and mitochondrial DNA for 80 individuals from across the distribution of the complex to determine the extent of genetic variation between and within described taxa. Our results revealed 18 geographically coherent clades separated by substantial genetic divergence: 14 within rufula, 3 within blakei, and 1 corresponding to G. rufocinerea (Bicolored Antpitta), a species with distinctive plumage found to be nested within the complex. Neither G. rufula nor G. blakei as presently defined was monophyletic. Although 6 of the 7 recognized subspecies of G. rufula were monophyletic, several subspecies contained substantial genetic differentiation. Genetic variation was largely partitioned across recognized geographic barriers, especially across deep river valleys in Peru and Colombia. Coalescent modeling identified 17 of the 18 clades as significantly differentiated lineages, whereas analyses of vocalizations delineated 16 biological species within the complex. The G. rufula complex seems unusually diverse even among birds of the humid Andes, a prime location for cryptic speciation; however, the extent to which other dispersal-limited Andean species groups exhibit similar degrees of cryptic differentiation awaits further study.

Genetic diversity and population structure of the rockpool shrimp Palaemon elegans based on microsatellites: evidence for a cryptic species and differentiation across the Atlantic\u2013Mediterranean transition

The rockpool shrimp Palaemon elegans is an ecologically important crustacean species within the European coastline fauna. In the present study, genetic diversity and population structure and connectivity were assessed by examining 21 polymorphic microsatellite loci at 13 sampling sites located along the natural distribution range. All localities showed similar levels of genetic variability. Significant deficits of heterozygosity were recorded, most likely due to the presence of null alleles. Genetic structure analyses revealed two clearly genetically distinct groups within P. elegans but without following any geographical or oceanographic basis. Thus, our results provided nuclear evidence for the existence of a Mediterranean cryptic species within P. elegans, highlighting the need to revise its taxonomic status. Regarding P. elegans sensu stricto, population structuring was reported across the Atlantic–Mediterranean transition area, where the Almería-Orán Front restricts the gene flow between the Atlantic and the Mediterranean population. Moreover, while population connectivity was suggested between all Mediterranean localities, some substructure was found within the Atlantic group. Canary Islands exhibited a weak but significant genetic differentiation from all Atlantic mainland localities, consistent with the isolation-by-distance pattern detected throughout the Atlantic population. Overall, all these findings provided new insights into the population biology of P. elegans complex.

Intraspecific Diversity and Phylogeography in Southern Appalachian Dasycerus carolinensis (Coleoptera: Staphylinidae: Dasycerinae)

AbstractThe southern Appalachian Mountains in eastern North America host exceptional diversity, a substantial proportion of which has been generated in place. Yet, beyond broad generalities, bio- and phylogeographical patterns, and the temporal scale of diversification in the region are poorly resolved. Using one mitochondrial and one nuclear marker, we analyze intraspecific diversity patterns in a flightless, litter-inhabiting rove beetle Dasycerus carolinensis Horn. Our goals were to reconstruct the phylogeographical history of this species, producing a dated intraspecific phylogeny, and to examine previous hypotheses of possible cryptic divergence across populations of the species. Samples derive from a mix of old-growth fragments and secondary growth forests, and we also ask whether old-growth remnants host a larger proportion of genetic diversity in the species. We recover a strong primary subdivision among major lineages across the French Broad River basin (dated to ~5.8 MYBP), and a secondary subdivision among western populations dating to ~4.5 MYBP. Most interpopulation uncorrected divergences exceed 5%, strongly suggesting cryptic differentiation. Old-growth populations do not show greater genetic diversity than secondary-growth populations, indicating that most populations have persisted through recent anthropogenic disturbance.

Formal Instatement of Allographa (Graphidaceae): How to Deal with a Hyperdiverse Genus Complex with Cryptic Differentiation and Paucity of Molecular Data

Lucking R. & Kalb K. 2018: Formal instatement of Allographa (Graphidaceae): how to deal with a hyperdiverse genus complex with cryptic differentiation and paucity of molecular data. – Herzogia 31: 535–561. Previous molecular phylogenetic analysis showed that the genus Graphis sensu Staiger (Ascomycota: Ostropales: Graphidaceae) represents two separate, only distantly related lineages. Graphis s.str. comprises the species of the G. scripta and G. subserpentina groups (‘Eugraphis’), as well as part of the G. striatula group. For the segregate genus, the name Allographa is available, and this genus includes the G. acharii, G. dussii, G. marginata, G. nuda, and G. symplecta groups, plus part of the G. striatula group. Allographa is closer to the core Graphidaceae (Diorygma, Glyphis, Pallidogramme, Phaeographis, Platygramme, Platythecium, Sarcographa, Thalloloma, Thecaria), whereas Graphis s.str. is sister to this entire clade and takes a more isolated position on a very long branch. A previously published study of 313 taxa, using morphology-based phylogenetic binning, supported the placement of 103 species of Graphis s.lat. in Allographa. This analysis is here emended to include 453 taxa currently placed in Graphis and Hemithecium, with the result that based on molecular and binning data, 182 species are to be placed in Allographa and 271 to be retained or placed in Graphis. Two species, namely Allographa lutea and A. hypostictica, had already been described in that genus, leaving 180 additional combinations, 28 of which are being proposed in a parallel paper; the remaining new combinations (plus one replacement name) in Allographa and Graphis are proposed here. Two names are validated, namely Allographa anguilliradians Lucking ex Lucking species nova and Allographa uruguayensis Lucking ex Lucking species nova. Two new synonyms are established: Graphis ferrugineodisca Seavey & J.Seavey [= Glyphis atrofusca (Mull.Arg.) Lucking, synonymum novum], and G. mikuraensis Y.Ohmura & M.Nakan. [= Graphis srilankensis Weerakoon, Wijey. & Lumbsch, synonymum novum].

Long-term insitu persistence of biodiversity in tropical sky islands revealed by landscape genomics.

Tropical mountains are areas of high species richness and endemism. Two historical phenomena may have contributed to this: (i) fragmentation and isolation of habitats may have promoted the genetic differentiation of populations and increased the possibility of allopatric divergence and speciation and (ii) the mountain areas may have allowed long-term population persistence during global climate fluctuations. These two phenomena have been studied using either species occurrence data or estimating species divergence times. However, only few studies have used intraspecific genetic data to analyse the mechanisms by which endemism may emerge at the microevolutionary scale. Here, we use landscape analysis of genomic SNP data sampled from two high-elevation plant species from an archipelago of tropical sky islands (the Trans-Mexican Volcanic Belt) to test for population genetic differentiation, synchronous demographic changes and habitat persistence. We show that genetic differentiation can be explained by the degree of glacial habitat connectivity among mountains and that mountains have facilitated the persistence of populations throughout glacial/interglacial cycles. Our results support the ongoing role of tropical mountains as cradles for biodiversity by uncovering cryptic differentiation and limits to gene flow.

Heteromorphism of “Homomorphic” Sex Chromosomes in Two Anole Species (Squamata, Dactyloidae) Revealed by Synaptonemal Complex Analysis

Iguanians (Pleurodonta) are one of the reptile lineages that, like birds and mammals, have sex chromosomes of ancient origin. In most iguanians these are microchromosomes, making a distinction between the X and Y as well as between homeologous sex chromosomes in other species difficult. Meiotic chromosome analysis may be used to elucidate their differentiation, because meiotic prophase chromosomes are longer and less condensed than metaphase chromosomes, and the homologues are paired with each other, revealing minor heteromorphisms. Using electron and fluorescent microscopy of surface spread synaptonemal complexes (SCs) and immunolocalization of the proteins of the SC (SYCP3), the centromere, and recombination nodules (MLH1), we examined sex chromosome synapsis and recombination in 2 species of anoles (Dactyloidae), Anolis carolinensis and Deiroptyx coelestinus, in which the sex chromosomes represent the ancestral condition of iguanians. We detected clear differences in size between the anole X and Y microchromosomes and found an interspecies difference in the localization of the pseudoautosomal region. Our results show that the apparent homomorphy of certain reptile sex chromosome systems can hide a cryptic differentiation, which potentially may influence the evolution of sexual dimorphism and speciation.

Hybridization during altitudinal range shifts: nuclear introgression leads to extensive cyto-nuclear discordance in the fire salamander.

Ecological models predict that, in the face of climate change, taxa occupying steep altitudinal gradients will shift their distributions, leading to the contraction or extinction of the high-elevation (cold-adapted) taxa. However, hybridization between ecomorphologically divergent taxa commonly occurs in nature and may lead to alternative evolutionary outcomes, such as genetic merger or gene flow at specific genes. We evaluate this hypothesis by studying patterns of divergence and gene flow across three replicate contact zones between high- and low-elevation ecomorphs of the fire salamander (Salamandra salamandra) that have experienced altitudinal range shifts over the current postglacial period. Strong population structure with high genetic divergence in mitochondrial DNA suggests that vicariant evolution has occurred over several glacial-interglacial cycles and that it has led to cryptic differentiation within ecomorphs. In current parapatric boundaries, we do not find evidence for local extinction and replacement upon postglacial expansion. Instead, parapatric taxa recurrently show discordance between mitochondrial and nuclear markers, suggesting nuclear-mediated gene flow across contact zones. Isolation with migration models support this hypothesis by showing significant gene flow across all five parapatric boundaries. Together, our results suggest that, while some genomic regions, such as the mitochondria, may follow morphologic species traits and retreat to isolated mountain tops, other genomic regions, such as nuclear markers, may flow across parapatric boundaries, sometimes leading to a complete genetic merger. We show that despite high ecologic and morphologic divergence over prolonged periods of time, hybridization allows for evolutionary outcomes alternative to extinction and replacement of taxa in response to climate change.

Multilocus coalescent species delimitation reveals widespread cryptic differentiation among Drakensberg mountain-living freshwater crabs (Decapoda : Potamonautes)

Cryptic lineages present major challenges for evolutionary and conservation studies, particularly where these lineages remain undiscovered. Freshwater crabs are known to harbour cryptic diversity, in most cases with limited morphological differences. During the present study, we used a multilocus (12S rRNA, 16S rRNA, COI, 28S rRNA, DecapANT and PEPCK) Bayesian species delimitation to examine cryptic diversity within a freshwater crab species complex (Potamonautes clarus/P. depressus). We sampled 25 highland rivers in the Tugela and uMkomazi River drainage systems of the Drakensberg Mountain range, in the KwaZulu–Natal province of South Africa. Our results showed there to be at least eight lineages: six novel potamonautid freshwater crabs, and two described taxa P. clarus and P. depressus. Divergence from the most recent common ancestor occurred between the mid- and late Miocene (12.1 Mya), while divergence within the species complex occurred ~10.3 Mya up until the Holocene (0.11 Mya). The discovery of six novel lineages of freshwater crabs from a seemingly restricted distribution range has conservation implications, but to date most conservation planning strategies have focussed on freshwater vertebrates. By conducting a fine-scale phylogenetic survey using invertebrates, this study provides a platform for the inclusion of freshwater invertebrates in future conservation assessments.

Ecological niche modeling of the rare bee Promelitta alboclypeata reveals possible cryptic differentiation across northern Africa and Arabia (Hymenoptera: Melittidae)

The scarcely collected bee Promelitta alboclypeata with known occurrence across northern Africa and the Arabian Peninsula is a typical example of the bee family Melittidae which encompasses a good number of species with sparse or disjunct distributions and particular flower preferences. Using records for 16 localities, we estimated ecological niche models for P. alboclypeata in Maxent on four sets of occurrences, to represent the disparity of the known records, most of them known from the western section of the range. Our estimates show a predicted area for the species in the northern section of the geographic extent assumed accessible to the species (mainly north Africa and the Arabian Peninsula), signaling feasible regions to survey for the presence of the species; possible ecological niche differentiation between the western and eastern populations is also signaled by the models.

The Southwestern Indian Ocean as a potential marine evolutionary hotspot: perspectives from comparative phylogeography of reef brittle‐stars

AbstractAimThe global biodiversity crisis requires the identification of regions with high evolutionary potential, i.e. evolutionary hotspots (evospots). We created an analytical framework based on comparative phylogeography and coalescent methods to assess the dynamics of diversification and population persistence in the reef ecosystem of a little‐studied region: the Southwestern Indian Ocean (SWIO).LocationCoral reefs of the SWIO, with comparative data from the Pacific Ocean.MethodsWe generated sequences of mitochondrial DNA (COI and 16S) for 10 widespread brittle‐stars (345 specimens) from 21 localities (8 in the SWIO). We analysed them by combining comparative phylogeography approaches, coalescent‐based methods, molecular clocks and the concept of evolutionarily significant units (ESUs) to draw conclusions about the drivers of biodiversity in the region.ResultsCryptic diversity was prevalent, increasing lineage diversity within the 10 nominal species by 70% within the SWIO and by 200% across the Indo‐West Pacific. All seven new SWIO lineages meet the criteria for ESUs and at least six are biological species. We detected likely intraregional diversifications dating to the Plio‐Pleistocene, supporting the SWIO as a generator of biodiversity. Geographical restriction of ESUs, long coalescent times (> 80 ka) and old in situ diversification (> 1 Ma) point to the persistence of populations over multiple glacio‐eustatic cycles. We provide data suggesting demographic expansion during sea‐level high stands. Regional connectivity was lower, and cryptic differentiation higher in lecithotrophs than in planktotrophs.Main conclusionsThe analytical framework based on a biodiversity survey makes it possible to identify evospots by assessing the potential of a region to maintain and generate biodiversity and by evaluating the evolutionary processes and potential drivers at play.

Mimetic host shifts in an endangered social parasite of ants

An emerging problem in conservation is whether listed morpho-species with broad distributions, yet specialized lifestyles, consist of more than one cryptic species or functionally distinct forms that have different ecological requirements. We describe extreme regional divergence within an iconic endangered butterfly, whose socially parasitic young stages use non-visual, non-tactile cues to infiltrate and supplant the brood in ant societies. Although indistinguishable morphologically or when using current mitochondrial and nuclear sequence-, or microsatellite data, Maculinea rebeli from Spain and southeast Poland exploit different Myrmica ant species and experience 100 per cent mortality with each other's hosts. This reflects major differences in the hydrocarbons synthesized from each region by the larvae, which so closely mimic the recognition profiles of their respective hosts that nurse ants afford each parasite a social status above that of their own kin larvae. The two host ants occupy separate niches within grassland; thus, conservation management must differ in each region. Similar cryptic differentiation may be common, yet equally hard to detect, among the approximately 10 000 unstudied morpho-species of social parasite that are estimated to exist, many of which are Red Data Book listed.

Integrative taxonomy successfully resolves the pseudo‐cryptic complex of the disjunct epiphytic moss Orthotrichum consimile s.l. (Orthotrichaceae)

AbstractBroad morphological variation and a complex taxonomic history suggest that Orthotrichum consimile, an epiphytic moss known from oceanic forests of western North America and western Europe, may be a complex of cryptic species rather than a single taxon. This hypothesis was tested through an integrative taxonomic approach combining morphological investigations and phylogenetic inferences from four chloroplast loci. We show that O. consimile is in fact a polyphyletic assemblage of four lineages, which can be diagnosed unambiguously on morphological characters. They are Orthotrichum consimile s.str., O. columbicum (resurrected from synonymy), O. persimile sp. nov. and O. confusum sp. nov. Except for O. columbicum, which has a trans‐Atlantic distribution, these species are endemic to western North America. Phylogenetic inferences increasingly resolve cases of so‐called cryptic speciation within bryophytes exhibiting broad geographic distributions. Almost invariably the hypothesis of cryptic differentiation remains untested. Here we show that parallel morphological and phylogenetic inferences can lead to the resolution of apparent incongruence and lead to the discovery of new, morphologically defined, species.