Taxonomic Delimitation Research Articles

Coalescent-based species delimitation meets deep learning: Insights from a highly fragmented cactus system.

Delimiting species boundaries is a major goal in evolutionary biology. An increasing volume of literature has focused on the challenges of investigating cryptic diversity within complex evolutionary scenarios of speciation, including gene flow and demographic fluctuations. New methods based on model selection, such as approximate Bayesian computation, approximate likelihoods, and machine learning are promising tools arising in this field. Here, we introduce a framework for species delimitation using the multispecies coalescent model coupled with a deep learning algorithm based on convolutional neural networks (CNNs). We compared this strategy with a similar ABC approach. We applied both methods to test species boundary hypotheses based on current and previous taxonomic delimitations as well as genetic data (sequences from 41loci) in Pilosocereus aurisetus, a cactus species complex with a sky-island distribution and taxonomic uncertainty. To validate our method, we also applied the same strategy on data from widely accepted species from the genus Drosophila. The results show that our CNN approach has a high capacity to distinguish among the simulated species delimitation scenarios, with higher accuracy than ABC. For the cactus data set, a splitter hypothesis without gene flow showed the highest probability in both CNN and ABC approaches, a result agreeing with previous taxonomic classifications and in line with the sky-island distribution and low dispersal of P.aurisetus. Our results highlight the cryptic diversity within the P.aurisetus complex and show that CNNs are a promising approach for distinguishing complex evolutionary histories, even outperforming the accuracy of other model-based approaches such as ABC.

Resolving the Tetrastigma loheri s. l. Species Complex (Vitaceae) in the Philippines: No Evidence for Recognizing More than One Species

Abstract— Tetrastigma loheri (Vitaceae) is a vine species native to Borneo and the Philippines. Because it is a commonly encountered forest species in the Philippines, T. loheri is potentially suitable for studying patterns of genetic diversity and connectivity among fragmented forest ecosystems in various parts of this country. However, previous research suggests that T. loheri is part of a species complex in the Philippines (i.e. the T. loheri s. l. complex) that potentially also contains Philippine plants identified as T. diepenhorstii, T. philippinense, T. stenophyllum, and T. trifoliolatum. This uncertainty about its taxonomic delimitation can make it challenging to draw conclusions that are relevant to conservation from genetic studies using this species. Here, we tested the hypothesis that T. loheri s. l. is composed of more than one species in the Philippines. For this, we used generalized mixed Yule coalescent (GMYC) and Poisson tree process (PTP) species delimitation models to identify clades within DNA sequence phylogenies of T. loheri s. l. that might constitute species within this complex. Although these methods identified several putative species, these are statistically poorly supported and subsequent random forest analyses using a geometric morphometric leaf shape dataset and several other vegetative characters did not result in the identification of characters that can be used to discriminate these putative species morphologically. Furthermore, the results of principal component and principal coordinates analyses of these data suggest the absence of morphological discontinuities within the species complex. Under a unified species concept that uses phylogenetic and morphological distinction as operational criteria for species recognition, we therefore conclude that the currently available data do not support recognizing multiple species in the T. loheri s. l. complex. This implies that T. loheri is best considered as a single, morphologically variable species when used for studying patterns of genetic diversity and connectivity in the Philippines.

Taxonomic study of some species of the subfamily Dipsacoideae Eaton (Caprifoliaceae) by phenolic acid profiles

Dipsacoideae has always been problematic for taxonomic delimitation of the taxa because of their morphological similarities and diversity amongst the taxa. Phenolic compounds are found in various organs of plants and are important in terms of chemotaxonomy and pharmacognosy. In this study, the phenolic acid compounds of 12 species of Dipsacoideae were analyzed using high-performance liquid chromatography photodiode array detection (HPLC-PDA) and also evaluated their significances as chemotaxonomic markers. The main phenolic acids were found to be caffeic acid, p-coumaric acid, ferulic acid and salicylic acid. The principal components analysis (PCA) bi-plot indicated that ferulic acid, caffeic acid, cinnamic acid, p-coumaric acid and rosmaric acid were principal components in the studied species dispersion. The species were separated from each other in a principal coordinate analysis (PCoA) plot in terms of their phenolic acid profile. Regarding the results, the high amount of caffeic acid and cinnamic acid could be considered a chemotaxonomic marker for genus Pterocephalus Vaill. and Cephalaria Schrad. respectively. The results indicated that Scabiosa koelzii Rech. and S. amoena Jacq. were placed as a distinct group regarding their phenolic acid profile and established the opinion supported by Greuter and Raus. Consequently, phenolic contents could be applied as a significant marker in the chemotaxonomy of Dipsacoideae. Considering it, we suggest the study of interaction among ecological and genetically factors as well as the studied chemical compounds.

Delimitation despite discordance: Evaluating the species limits of a confounding species complex in the face of mitonuclear discordance.

The delimitation of species is an essential pursuit of biology, and proper taxonomies are crucial for the assessment and conservation management of organismal diversity. However, delimiting species can be hindered by a number of factors including highly conserved morphologies (e.g., cryptic species), differences in criteria of species concepts, lineages being in the early stages of the speciation or divergence process, and discordance between gene topologies (e.g., mitonuclear discordance). Here we use a taxonomically confounded species complex of toads in Central America that exhibits extensive mitonuclear discordance to test delimitation hypotheses. Our investigation integrates mitochondrial sequences, nuclear SNPs, morphology, and macroecological data to determine which taxonomy best explains the divergence and evolutionary relationships among these toads. We found that a three species taxonomy following the distributions of the nuclear SNP haplotypes offers the best explanation of the species in this complex based off of the integrated data types. Due to the taxonomic instability of this group, we also discuss conservation concerns in the face of improper taxonomic delimitation. Our study provides an empirical and integrative hypothesis testing framework to assess species delimitation hypotheses in the face of cryptic morphology and mitonuclear discordance and highlights the importance that a stable taxonomy has over conservation‐related actions.

Deciphering the Taxonomic Delimitation of Ottelia acuminata (Hydrocharitaceae) Using Complete Plastomes as Super-Barcodes

Accurate species delimitation and identification, which is a challenging task in traditional morphology-based taxonomy, is crucial to species conservation. Ottelia acuminata (Hydrocharitaceae) is a severely threatened submerged macrophyte endemic to southwestern China. The taxonomy of O. acuminata, which has long been in dispute, remains unresolved, impeding effective conservation and management practices. Here, we aim to address the long-standing issues concerning species boundary and intraspecific subdivision of O. acuminata using complete plastome sequences as super-barcodes. The taxonomic delimitation of O. acuminata was explored using phylogenetic inference and two independent sequence-based species delimitation schemes: automatic barcode gap discovery (ABGD) and multi-rate Poisson tree processes (mPTP). The reciprocally reinforcing results support the reduction of the closely related congeneric species, O. balansae and O. guanyangensis, as two conspecific varieties of O. acuminata. Within the newly defined O. acuminata, accurate varietal identification can be achieved using plastome super-barcodes. These findings will help inform future decisions regarding conservation, management and restoration of O. acuminata. This case study suggests that the use of plastome super-barcodes can provide a solution for species delimitation and identification in taxonomically difficult plant taxa, thus providing great potential to lessen the challenges of inventorying biodiversity, as well as biologically monitoring and assessing threatened species.

Taxonomic significance of anatomical characters in some species of Caryophyllaceae Family in Iraq

The anatomical characters of the leaves, trichomes and stems of 12 species of Caryophyllaceae family were studied. The results showed that the average of epidermal cells length in the adaxial surface ranged between 95.00 µm in Agrostemma githago and 29.5 µm in Agrostemma gracile, while in the abaxial surface, it ranged between 92.5 µm in A. githago and 35.62 µm in A. gracile. Stomatal complex was circular and elliptic-shaped. All species have four types of stomata: diacytic, anomocytic, paracytic and hemiparacytic. Trichome and their distribution does play significant role in the taxonomic delimitation, A. gracile trichomes have non-glandular hairs, while Arenaria balansae has non-glandular and glandular hairs. Two types of mesophyll appear to be a good diagnostic characteristic isobilateral in the Agrostemma species and dorsiventral (bifacial) in the remaining species as well as several sclerenchyma layers including thick and thin-walled cells that surrounded vascular bundle and also the petiole contains many layers of sclerenchyma cells. Stem shape and size were different between species. The stems had the greatest size (1064.50 µm) in Acanthophyllum bracteatum, while the smallest stem cross section (450.46 µm) in A. balansae. Cells were rich in druses crystals. Sclerenchymatous layers were observed in all species. The number of sclerenchyma was different between the species, so that, 12-23 layers in A. gracile and 4-7 in A. crassifolium. Size of pith was different. The greatest was 280.22 mm in Agrostemma githago, while no pith was found in Polycarpon tetraphyllum and Arenaria balansae.

Incipient speciation in Calceolaria polyrhiza complex (Calceolariaceae): cytogenetic analysis supports molecular and morphological data

ABSTRACT Calceolaria polyrhiza is a perennial herb distributed in southern South America. The species is highly polymorphic and includes four described morphotypes that were previously considered different species. We performed a detailed study of the karyotype of each morphotype considering at least two localities for each one, with the aim of contributing to the taxonomic delimitation of the Calceolaria polyrhiza complex. In addition, a principal component analysis and a mapping of chromosome traits onto a phylogeny of nuclear DNA sequences were performed. This detailed karyotypic study has revealed specific markers, which have allowed to characterize each morphotype. ‘Prichardii’ morphotype was consistently polyploid. ‘Mendocina’ and ‘Lanceolata’ morphotypes had the highest total heterochromatin amount, with two pairs of chromosomes carrying NORs. ‘Mendocina’ samples showed the most asymmetrical karyotypes. ‘Polyrhiza’ morphotype had the most symmetrical karyotypes of the four morphotypes and the simplest fluorescent chromosome banding pattern. Thus, the four morphotypes could be characterized by chromosomal data and, together with the phylogenetic analysis of molecular data, could be considered taxonomic units in the process of diversification.

Resolving phylogenetic and classical nomenclature: A revision of Seraphsidae Jung, 1974 (Gastropoda: Neostromboidae).

This revision demonstrates that an integrated taxonomic approach to classical taxonomic practice can lead to increased internal cladistic resolution within a clade, including the recognition of new taxa at all nomenclatural levels. In particular, this revision has two aims: 1) to complete an α-taxonomic revision of Seraphsidae (Stromboidea); and 2) to resolve the infrafamilial relationships within Seraphsidae using morphological cladistics. An annotated synonymy was generated for each taxon, the precedence of names determined, and revised descriptions formulated. Character sets that reflect the synapomorphies within the major subclades of Seraphsidae were coded and a cladogram generated using maximum likelihood within the tnt program with default settings. Four forms of material and evidence were used in this systematic review: 1) the type material for each taxon; 2) non-type physical material; 3) published images; and 4) literary references for specimen localities without illustration. The current morphologically-based classification of Seraphsidae was found to be sound in terms of current species delimitations. Regardless of this, the use of an integrated taxonomy improved understanding of the internal cladistic relationships within Seraphsidae, which led to higher resolution of the internal cladistic arrangements and taxonomic delimitation. Furthermore, this increased resolution is now reflected in the family nomenclature. Two new subfamilies are proposed, Seraphsinae and Pseudoterebellinae, which are used to distinguish the two clades within Seraphsidae based on form: members of Seraphsinae are involute, while members of Pseudoterebellinae are evolute. Pseudoterebellum is proposed as a new genus to show the discontinuity in the fossil record and highlight the structural differences between it and Terebellum. A new species from Jamaica, Seraphs kaindraperi, is described, being the first record from that location and that geological period and is morphologically distinct from other described taxa. This revision included Mauryna within Seraphsidae on the grounds that it provides a basal link to the Seraphsidae sister taxa Semiterebellum and Terebellopsis, all of which are currently contained within Rostellariidae, and all three clades may in time be brought together under one family. All clades have been constructed to be in compliance with both the ICZN and PhyloCode. It was not possible within the context of this revision to test the results of the α-taxonomic findings against phylogenies generated with molecular data. This was due to the high number of extinct taxa within the Seraphsidae.

Reusing Old and Producing New Data Is Useful for Species Delimitation in the Taxonomically Controversial Iberian Endemic Pair Petrocoptis montsicciana/P. pardoi (Caryophyllaceae)

Petrocoptis montsicciana and P. pardoi are two Iberian endemic taxa of Caryophyllaceae family with an unclear taxonomic delimitation, being variously treated as independent species, subspecies or even synonyms. In the present study, allozyme raw data obtained in the early 2000s have been reused with improved tools to survey genetic structure, and complemented with modeling and niche comparative analyses to shed light on species delimitation. Genetic structure was investigated using four approaches: Bayesian clustering, Monmonier’s algorithm, Principal Coordinate Analysis (PCoA), and Analysis of Molecular Variance (AMOVA). Ecological niche differences have been assessed through Ecological Niche Modeling (ENM) using MaxEnt, and Principal Component Analysis using both occurrence records and background climate (PCA-env). Genetic analysis confirms the distinction between both taxa, and the scenario of a progenitor–derivative (P–D) is suggested. In agreement with genetic data, niche analysis shows clear differences between their climate regarding species occurrences and background spaces. Climate divergence could be explained, at least partially, by the abundance of rocks where species live although differences at the microclimate instead of the regional climate should be explored in future research. Given the genetic distinction between P. montsicciana and P. pardoi, both taxa should be regarded as separate ‘Management Units’ (MUs).

Comparative floral surface micromorphology helps to discriminate between species of Paphiopedilum (Orchidaceae: Cypripedioideae) from Peninsular Malaysia

Abstract. The floral micromorphology of critically endangered Paphiopedilum Pfitzer [P. barbatum (Lindl.) Pfitzer, P. callosum var. sublaeve (Rchb.f.) P.J.Cribb and P. niveum (Rchb.f.) Stein] were analyzed concerning either infrageneric taxonomy or physioecological demands. The first two species are phylogenetically close and superficially identical but occur with distinct phytogeographical distributions in the region. The third species is a phylogenetically distant congener that inhabits limestone areas in the northern part of Peninsular Malaysia. Using scanning electron microscopy (SEM), we investigated the surface of the dorsal sepal, synsepal, lateral petals, pouch or labellum, and staminode. Amongst the investigated features were epicuticular waxes, epicuticular ornamentation, trichome distribution and type, pustular glands, and papillae. Our study supports the distinction of P. barbatum from P. callosum var. sublaeve, which belong to subgenus Paphiopedilum, and from P. niveum, a species belonging to subgenus Brachypetalum, a separated monophyletic clade. Comparatively, P. barbatum has Type III non-glandular trichomes on the margin of its lateral petals, which are absent in P. callosum var. sublaeve. Paphiopedilum callosum var. sublaeve and P. niveum are distinguishable from P. barbatum by a confined distribution of papillae. The epicuticular ornamentation and distribution of trichomes on staminode discriminate between P. barbatum and P. callosum var. sublaeve and differentiates them from P. niveum. Compared to P. barbatum and P. niveum, stomata in P. callosum var. sublaeve were superficial with prominently raised guard cells. From the physioecological view, the absence of glandular trichomes, and the low occurrence of papillae and stomata on the floral parts explain the unscented flowers of P. barbatum and P. callosum var. sublaeve. A combination of the features examined is taxonomically valuable for delimitation of the species at the infrageneric level, although the diagnostic characters are far inadequate for a generic taxonomic revision. A study with a more extensive sampling from the three subgenera of Paphiopedilum, including subgenus Parvisepalum, is anticipated to elucidate the level of variation of the analyzed microcharacters.
 Key Words: physioecological importance, Peninsular Malaysia, subgenus Brachypetalum, subgenus Paphiopedilum, scanning electron microscopy, taxonomic delimitation

Comparative morpho-anatomical characteristics and phytochemical constituents of Aloe vera Barbadensis miller and Aloe vera var. Chinensis (haw) Berger

This study was set to investigate the comparative morphological and anatomical characteristics of Aloe vera barbadensis Miller and Aloe vera var. chinensis(Haw) Berger. These are evergreen perennials belonging to Asphodelaceae Juss. in the Order Asparagales Link. The former measures up to 80±20cm in height with lanceolate leaves and rosette habit. The leaves have spiny margins decorated with whitish spots on both foliar surfaces which disappear at maturity. The tubular flowers are orange and densely clustered at the stem apex; corolla is yellowish, tubular and up to 2.5±0.5cm in length whereas the latter is 40±10cm in height with rather lightly green rosette leaves and foliar white spots on foliar surfaces maintained at maturity. The two plants are fleshy and succulent with mild bitter taste. Leaves are amphistomatic with tetracytic sunken stomata. The cells of the epidermal layer are nucleated mostly hexagonal and includepentagonal, heptagonal to square or rounded. Stomatal indices for Aloe vera barbadensis adaxial foliar layer is 7.92 % and abaxial 4.76% while Aloe vera var. chinensis adaxial surface is 7.92% and abaxial 3.85%, not significant. Anatomical studies revealed the cell types from the epidermis, hypodermis, general cortex to the pith are similar in mid-ribs, petioles, stems and nodes. The roots have piths and vasculation is closed type. Phytochemical studies showed the presence of Alkaloids, flavonoids, saponins and tannins in both species, whereas combined anthraquinone was observed absent in both plants. Cardenolide, phlobatannins and free anthraquinones were present in Aloe vera var. chinesis but absent in Aloe vera barbadensis while cyanogenic glycoside was absent in Aloe vera var chinensis but present in Aloe vera barbadensis. The species are used in natural medicine. The information contained in this research would further aid in the taxonomic delimitations of these plants.
 Keywords: Comparative, Aloe vera, phytochemistry, morphology, anatomy, Asphodelaceae.

EDNA in a bottleneck: Obstacles to fish metabarcoding studies in megadiverse freshwater systems

AbstractThe current capacity of environmental DNA (eDNA) to provide accurate insights into the biodiversity of megadiverse regions (e.g., the Neotropics) requires further evaluation to ensure its reliability for long‐term monitoring. In this study, we first evaluated the taxonomic resolution capabilities of a short fragment from the 12S rRNA gene widely used in fish eDNA metabarcoding studies, and then compared eDNA metabarcoding data from water samples with traditional sampling using nets. For the taxonomic discriminatory power analysis, we used a specifically curated reference dataset consisting of 373 sequences from 258 neotropical fish species (including 47 newly generated sequences) to perform a genetic distance‐based analysis of the amplicons targeted by the MiFish primer set. We obtained an optimum delimitation threshold value of 0.5% due to lowest cumulative errors. The barcoding gap analysis revealed only a 51.55% success rate in species recovery (133/258), highlighting a poor taxonomic resolution from the targeted amplicon. To evaluate the empirical performance of this amplicon for biomonitoring, we assessed fish biodiversity using eDNA metabarcoding from water samples collected from the Amazon (Adolpho Ducke Forest Reserve and two additional locations outside the Reserve). From a total of 84 identified Molecular Operational Taxonomic Units (MOTUs), only four could be assigned to species level using a fixed threshold. Measures of α‐diversity analyses within the Reserve showed similar patterns in each site between the number of MOTUs (eDNA dataset) and species (netting data) found. However, β‐diversity revealed contrasting patterns between the methods. We therefore suggest that a new approach is needed, underpinned by sound taxonomic knowledge, and a more thorough evaluation of better molecular identification procedures such as multi‐marker metabarcoding approaches and tailor‐made (i.e., order‐specific) taxonomic delimitation thresholds.

Conservation in the face of hybridisation: genome-wide study to evaluate taxonomic delimitation and conservation status of a threatened orchid species

This study assessed inter- and intraspecific relationships and genetic structure in an Australian species complex in the helmet orchids (Corybas) to clarify the taxonomic and conservation status of the threatened species Corybas dowlingii, a narrow endemic from southeast Australia. Taxonomic delimitation between the three closely related species C. aconitiflorus, C. barbarae, and C. dowlingii has been mainly based on floral traits which exhibit varying degrees of overlap, rendering species delimitation in the complex difficult. Genome-wide data for the species complex was generated using double-digest restriction-site associated DNA (ddRAD) sequencing. Phylogenomic, genetic network and genetic structure analysis were carried out as well as co-ancestry analysis and hybridisation detection analysis. The ddRADseq results exhibited fine scale genetic structure within the C. acotiniflorus complex and provided evidence for hybridisation and introgression within the complex, resulting in blurred taxonomic boundaries between the three species. Implications of the results for conservation management in the face of hybridisation are discussed.

<strong>A new and threatened species of <em>Trichaptum</em> (Basidiomycota, Hymenochaetales) from urban mangroves of Santa Catarina Island, Southern Brazil</strong>

Trichaptum comprises around 36 polypore species, with variable morphology and worldwide distribution. During polypore surveys in Santa Catarina Island (Southern Brazil), specimens of a remarkable species, with large, mostly resupinate basidiomata, large (6–11µm long) spores and two kinds of cystidia, were collected in mangrove forests and their vicinities. Morphological and phylogenetic analysis (rDNA ITS) revealed it as new, and is described herein as T. fissile sp. nov. Moreover, the species is proposed as Vulnerable according to the IUCN criteria. The taxonomic placement and delimitation of Trichaptum are also discussed.

Phylogeny and biogeography of the Japanese rhinoceros beetle, Trypoxylus dichotomus (Coleoptera: Scarabaeidae) based on SNP markers.

The Japanese rhinoceros beetle Trypoxylus dichotomus is one of the largest beetle species in the world and is commonly used in traditional Chinese medicine. Ten subspecies of T. dichotomus and a related Trypoxylus species (T. kanamorii) have been described throughout Asia, but their taxonomic delimitations remain problematic. To clarify issues such as taxonomy, and the degree of genetic differentiation of Trypoxylus populations, we investigated the genetic structure, genetic variability, and phylogeography of 53 specimens of Trypoxylus species from 44 locations in five Asian countries (China, Japan, Korea, Thailand, and Myanmar). Using specific‐locus amplified fragment sequencing (SLAF‐seq) techniques, we developed 330,799 SLAFs over 114.16M reads, in turn yielding 46,939 high‐resolution single nucleotide polymorphisms (SNPs) for genotyping. Phylogenetic analysis of SNPs indicated the presence of three distinct genetic groups, suggesting that the various subspecies could be treated as three groups of populations. PCA and ADMIXTURE analysis also identified three genetic clusters (North, South, West), which corresponded to their locations, suggesting that geographic factors were important in maintaining within population homogeneity and between population divergence. Analyses of SNP data confirmed the monophyly of certain subspecies on islands, while other subspecies (e.g., T. d. septentrionalis) were found to be polyphyletic and nested in more than one lineage. AMOVA demonstrated high level of differentiation among populations/groups. Also, pairwise F ST values revealed high differentiation, particularly between South and West, as well as between North and South. Despite the differentiation, measurable gene flow was inferred between genetic clusters but at varying rates and directions. Our study demonstrated that SLAF‐seq derived markers outperformed 16S and COII sequences and provided improved resolution of the genetic differentiation of rhinoceros beetle populations from a large part of the species’ range.

Population genetic structure and species delimitation in theCryptanthus zonatuscomplex (Bromeliaceae)

AbstractMorphological variations of individuals and populations of plants have hampered taxonomists from understanding whether such variations are intra- or interspecific. In this research, we study Cryptanthus burle-marxii and C. zonatus, the morphological variations of which overlap, making it difficult to identify them. Both taxa are restricted to the north of the Brazilian Atlantic Forest and are included in the C. zonatus species complex. We applied different methods such as morphological comparison, population genetics using ten nuclear microsatellite markers and ecological niche modelling to study population genetic structure and species delimitation of this species complex. Our analysis revealed that the two genetic clusters were formed possibly because of the presence of a historical geographical barrier in a region called ‘depressão do Abiaí’. The two genetic clusters were concordant with the northern and southern distribution of the complex but incongruent with a morphological variation or current taxonomic delimitation. Thus, we synonymize C. burle-marxii with C. zonatus and re-evaluate its conservation status as endangered.

Distribution models and morphometric analyses in Deyeuxia velutina, an Andean grass species

Rúgolo de Agrasar recognized two varieties of Deyeuxia velutina (D. velutina var. velutina and D. velutina var. nardifolia) based on leaf sheath indumentum, lemma length, and leaf blade direction. However, taxonomic delimitation has been difficult due to occasional overlapping characters. To assess the infraspecific delimitation of D. velutina, we present a comprehensive study combining morphometric analyses and a potential distribution model. To explore morphological variation and select diagnostic characters, we measured 124 morphological characters in 52 specimens of both varieties and performed a principal coordinate analysis and univariate analyses (Analysis of variance and Kruskal-Wallis non-parametric test). Both taxa resolved as separate morphological groups. Additionally, a Discriminant Analysis was performed to classify the individuals in the predetermined morphological groups. For modeling the species distribution, 26 specimens of D. velutina var. nardifolia and 68 of D. velutina var. velutina were georeferenced and 20 environmental variables were analyzed through a Maximum Entropy model. Deyeuxia velutina extends in the high Andean region from Peru to southern Argentina and Chile. Both varieties differed in their geographical limits, a result supported by regression analyses of latitude and longitude on the principal coordinates of the PCoA. Deyeuxia velutina var. nardifolia is restricted to the northern area of distribution while D. velutina var. velutina showed a higher habitat suitability in the southern region. Moreover, D. velutina var. nardifolia is here reported for the first time in San Juan province (Argentina), constituting the austral limit of its geographical distribution. Additional reliable morphological characters were considered in an updated key to the varieties.

Fruit and seed micromorphology of the genus Iberis L. (Brassicaceae) in Turkey and its utility in taxonomic delimitation

Background: This paper investigates whether the fruit and seed micromorphology of eight Turkish Iberis (Brassicaceae) species can be used as a further aid in their taxonomic delimitation.
 Questions: Are the micro-morphological characters of the fruits and seeds of Iberis useful to support the taxonomic delimitation of its species?
 Studied species / data description /Mathematical model: The eight species of Iberis present in Turkey were examined. The fruit and seed characteristics were obtained and statistical analysis was performed using UPGMA.
 Study site and dates: Fifteen localities in Turkey, from 2015 to 2019.
 Methods: Samples of fruit and seed of eight species of Iberis were collected, stored, and later measured and described with aid of light and scanning electron microscopies.
 Results: All eight species had different fruit and seed characters; particularly differing from each other with respect to fruit and seed size, seed shape and seed ornamentation. Two fruit ornamentation types were evident, smooth and striated. The seed coat surface were separated into three types: reticulate, reticulate-rugose and reticulate-papillate, being reticulate the most common. Further differences were noted for the seed surface epidermal structures, notably species had rectangular, tetragonal, or pentagonal patterning. An identification key was constructed based on a similarity analysis.
 Conclusions: Fruit morphology, seed dimensions, colour, and epidermal cell patterning are useful microcharacters that enabled species-level determinations in the Iberis species sampled.

Methods and approaches to advance soil macroecology

AbstractMotivation and aimSoil biodiversity is central to ecosystem function and services. It represents most of terrestrial biodiversity and at least a quarter of all biodiversity on Earth. Yet, research into broad, generalizable spatial and temporal patterns of soil biota has been limited compared to aboveground systems due to complexities of the soil system. We review the literature and identify key considerations necessary to expand soil macroecology beyond the recent surge of global maps of soil taxa, so that we can gain greater insight into the mechanisms and processes shaping soil biodiversity. We focus primarily on three groups of soil taxa (earthworms, mycorrhizal fungi and soil bacteria) that represent a range of body sizes and ecologies, and, therefore, interact with their environment at different spatial scales.ResultsThe complexities of soil, including fine‐scale heterogeneity, 3‐D habitat structure, difficulties with taxonomic delimitation, and the wide‐ranging ecologies of its inhabitants, require the classical macroecological toolbox to be expanded to consider novel sampling, molecular identification, functional approaches, environmental variables, and modelling techniques.Main conclusionsSoil provides a complex system within which to apply macroecological research, yet, it is this property that itself makes soil macroecology a field ripe for innovative methodologies and approaches. To achieve this, soil‐specific data, spatio‐temporal, biotic, and abiotic considerations are necessary at all stages of research, from sampling design to statistical analyses. Insights into whole ecosystems and new approaches to link genes, functions and diversity across spatial and temporal scales, alongside methodologies already applied in aboveground macroecology, invasion ecology and aquatic ecology, will facilitate the investigation of macroecological processes in soil biota, which is key to understanding the link between biodiversity and ecosystem functioning in terrestrial ecosystems.

<p><strong>Checklist of Lycopodiaceae in Vietnam with three new records and one lectotypification</strong></p>

An updated checklist of the family Lycopodiaceae in Vietnam is provided. The checklist is based on the most recent taxonomic delimitation of this family. It comprises three subfamilies, six genera and 20 species. Three species, Huperzia nanlingensis, Phlegmariurus henryi and Phlegmariurus tetrastichus, are reported from Vietnam for the first time, which is mainly a result of floristic exploration of the country during the last 15 years. Detailed descriptions and photographs are provided for the newly recorded species, as well as a map showing their distribution in Vietnam. Taxonomy of these and related species is briefly discussed. Type material of P. tetrastichus was analyzed and a specimen from G (G00349152) was designated as a lectotype. It was demonstrated that the combination Huperzia tetrasticha has never been validly published.