Morphological Delimitation Research Articles

An updated synopsis of Astraea Klotzsch (Crotoneae, Euphorbiaceae) for the State of São Paulo, Brazil

ABSTRACT Euphorbiaceae is one of the richest families in the State of São Paulo, with 37 genera and around 150 species. A synopsis of Astraea was published as part of the treatment for the tribe Crotoneae, but recent taxonomic and systematic advances have brought a more refined knowledge about the genus, especially for the widespread Astraea lobata. This species had its morphological delimitation poorly defined until very recently and, as a result, about five species were distinguished based on morphological characters. In this work, we update the synopsis of Astraea as part of the taxonomic revision of the genus and studies on Euphorbiaceae for the Flora Fanerogâmica do Estado de São Paulo project. We present an identification key, photographs of diagnostic characters, and an updated distribution map for the five species of Astraea found in São Paulo, along with a list of specimens for the state.

The ant genus Rhopalomastix (Hymenoptera: Formicidae: Myrmicinae) in Southeast Asia, with descriptions of four new species from Singapore based on morphology and DNA barcoding.

The true diversity of the Asian ant genus Rhopalomastix Forel is poorly understood. We use an integrated approach to review the known species and subspecies of Rhopalomastix in Southeast Asia. Based on morphology and supporting DNA evidence, we recognize six species. We raise two subspecies of R. rothneyi Forel to species rank (R. johorensis Wheeler stat. n, R. javana Wheeler stat. n.), synonymize R. janeti Donisthorpe (syn. nov.) with R. johorensis, and describe four new species from Singapore: R. glabricephala sp. n., R. murphyi sp. n., R. striata sp. n., and R. tenebra sp. n. All six species found in Southeast Asia are distinct from each other based on morphology; morphological delimitation of these species is further supported by and congruent with mOTUs generated from objective clustering of short fragment COI barcodes using the best close match criteria. Different castes and sexes of most species are described, including redescriptions of the queen of R. javana and male of R. johorensis. A key to the Southeast Asian species based on the worker caste is also provided. Variation among sympatric and also geographically distant populations, and the possibilities of cryptic species, are discussed.

Diversity and conservation of seasonal killifishes of the Hypsolebias fulminantis complex from a Caatinga semiarid upland plateau, São Francisco River basin, northeastern Brazil (Cyprinodontiformes, Aplocheilidae)

A high concentration of endemic species of seasonal killifishes has been recorded for a small area encompassing the highland plateaus associated with the upper section of the Carnaúba de Dentro River drainage and adjacent drainages of the middle section of the São Francisco River basin, northeastern Brazil. The present study is primarily directed to the taxonomy of theH.fulminantisspecies complex in this region, and describes habitat decline and extirpation of natural killifish populations recorded in field studies between 1993 and 2017. Both morphological characters and molecular species delimitation methods using single-locus models (GMYC and bPTP) support recognition of two closely related endemic species,H.fulminantisandH.splendissimusCosta,sp. n.The new species is distinguished from other congeners of theH.fulminantiscomplex by having a red pectoral fin in males, well-developed filamentous rays on the tips of the dorsal and anal fins in adult males, and the second proximal radial of the dorsal fin between the neural spines of the 8thand 9thvertebrae in males. Most recent field inventories indicated possible local extinction of populations ofH.fulminantisandH.splendissimusin the studied area, but additional field studies should be made in other parts of the upper Carnaíba de Dentro River basin to evaluate the current conservation status of these species.

Lectotypification and observations on the morphology, distribution and conservation status of Isoetes luetzelburgii (Isoetaceae)

Isoetes is a worldwide aquatic plant group with ca. 250 species. In South America, Isoetes luetzelburgii is one of the few species that inhabits semi-arid areas. This is an endangered species known from only few collections, which causes uncertainty related to its morphological delimitation, distribution and conservation status. Efforts combining both field and herbarium investigations enabled us to identify several new populations in northern Brazil. In this study, we present a comprehensive assessment of the known distribution of I. luetzelburgii and provide a detailed description of the species. Because the holotype was never properly designated, we also provide the lectotypification for the name. The data presented here contribute to enhance our understanding of the taxonomy and natural history of this species. This understanding may also serve as a conservation tool for the protection of its populations.

Molecular Phylogeny ofAstragalussect.Ammodendron(Fabaceae) Inferred from Chloroplastycf1 Gene

Species of Astragalus section Ammodendron (Fabaceae) are restricted to desert areas in central Asia, Afghanistan, and Iran. In the present study, the variable plastid gene ycf1 was used to reconstruct its phylogeny using parsimony, Bayesian and likelihood methods as well as network analysis. Phylogenetic analyses of ycf1 sequences strongly supported monophyly of the section Ammodendron. The ycf1 phylogeny was congruent with the combined nrDNA ITS, trnH-psbA, trnT-Y and ycf1 data sets. The group assembly in neighbor-net splits graph corresponded to the clades retrieved in the phylogenetic analyses and offered a graphical visualization of relationships between species. Poor phylogenetic resolution within the sect. Ammodendron s. str. may be due to rapid speciation and lower rates of nucleotide evolution. In conclusion, the close relationships among several species can provide pieces of evidence for further investigations on the molecular and morphological delimitation of this section.

Taxonomic revision of West-Alpine cushion plant species belonging to Androsace subsect. Aretia

High-altitude rockjasmines (genus Androsace) are a paramount example of evolutionary radiations in temperate mountains of the Northern Hemisphere. Yet, we show here that their taxonomy is incomplete and has been subject to many historical mistakes, probably due to the lack of exploration of mountains by the classical botanists who described these species. Here we wish to clarify the application of names with regard to four defined morphotypes, typical of high-elevation zones of the Western Alps, in order to set a definitive basis for morphological delimitation of a likely new species discovered in the Mont Blanc range (species not described in this work). To do so, we review the historical taxonomic treatments and positions, carefully reconsider types and species names for these morphotypes, and designate lectotypes and epitypes for each of them. In particular, we confirm the validity of names commonly used to refer to the taxa Androsace alpina, Androsace helvetica, and Androsace pubescens. We show that Androsace vandellii is an invalid name and that Androsace argentea should be used instead. Our work illustrates the utility of historical herbaria to clarify the taxonomy of complex groups of plants growing in inaccessible environments such as high-altitude regions.

Taxonomic implication of embryo micromorphology in the genus Vicia L. (Fabaceae)

In this work, embryos of selected Vicia species were examined to reveal the micromorphological characters that could have taxonomic significance. Experimental results show that morphological characters such as cotyledons shape and colour, radicle shape, colour and position, plumule colour and stipular parts attachments are variable and could be used for taxa identification in the genus Vicia. Numerical analysis based on 38 micromorphological characters was used to build a phenogram that indicated the relationships among the studied taxa. In addition, an identification key using embryo characters was prepared for Vicia species. The variability of embryo characters were discussed in the taxonomic context. Although the embryo characters have only limited phylogenetic signal for Vicia species, they might be used for their morphological delimitation.

Delimitation of the series Laurifoliae in the genus Passiflora (Passifloraceae)

Within the huge diversity of genus Passiflora, series Laurifoliae constitutes a strikingly uniform group, widely distributed in neotropical rain forests, at low to moderate elevations. Given its morphological and ecological unity, Killip mentionned it as an «exceedingly difficult» group. The lack of clear morphological criteria has not helped in delimiting it, and the confusion has grown with the addition of new species and criteria. As a preliminary step in the study of diversity within series Laurifoliae, we re-examine its morphological delimitation, assessing how its current 29 species (including the highly similar P. pachyantha and P. killipiana) conform to 20 criteria from different authors. Three criteria (indumentum on vegetative parts, stipule glands, membranous limen) appear to be irrelevant, because they are either too variable or rarely recorded in the species descriptions. Using the 17 remaining ones, 24 typical species show very limited variations, five of them differing by only one criterion. Among them, we retain terete to angular stem, setaceous or linear stipules soon deciduous, petiolar glands in one pair, leaves oblong, neither peltate nor lobate, three glandular bract over 1 cm long and free, flowers pendent, with two campanulate outer series of filaments (most other series much reduced or aborted). Five species, P. guazumaefolia, P. kikiana, P. odontophylla, P. ischnoclada, and P. maliformis, differ by three to nine traits, not found in the typical representatives of the series, so they can be excluded from it. Passiflora kikiana should be classified into series Kermesinae. For the four other ones, a satisfactory solution implies a more global study, involving other series.

Spatial Trends of Towns in Europe: The Performance of Regions with Low Degree of Urbanisation

AbstractThe paper contributes to the understanding of socio‐spatial trends and urban systems in Europe, with a specific focus on smaller settlements. First, a morphological delimitation of urban settlements as geographical base is used to identify the different settlement structures that characterise regions across Europe. Secondly, an analysis of population and GDP performances of NUTS 3 regions for the 29 countries of the European space (growth rates in 2001–2011) provides evidence of the variety of territorial phenomena that characterise smaller‐settlement regions across Europe. Finally, the paper highlights the diversity and complexity of urbanisation structures in Europe and how general trends observed at larger scale are articulated locally according to prevailing structures of urbanisation. It shows the character of ‘embeddedness’ of smaller settlements within urban systems and territorial structures and how the socio‐economic performances of smaller‐settlement regions are defined by a combination of macro trends, national contextualisation, local dynamics and regional path dependency.

The effectiveness of DNA‐based delimitation inSynchonnusnet‐winged beetles (Coleoptera: Lycidae) assessed, and description of 11 new species

AbstractSynchonnusWaterhouse, 1879 from Australia is revised.AchrasWaterhouse, 1879 andEnylusWaterhouse, 1879 are found to be junior synonyms ofSynchonnusdue to the absence of diagnostic characters and result in the new combinations ofSynchonnus amplus(Kleine, 1930),S. limbatum(Waterhouse, 1877), andS. segregatus(Waterhouse, 1879).Synchonnusis reported from the Australian mesic and monsoon zones, and 11 new species are described:S. flavonotatumsp. nov.,S. masekisp. nov.,S. ailaketoaesp. nov.,S. dubenovaesp. nov.,S. chilvertonensissp. nov.,S. slipinskiisp. nov.,S. monteithisp. nov.,S. eungellensissp. nov.,S. crypticumsp. nov.,S. variabilissp. nov. andS. campestrissp. nov. The morphology‐based species limits are compared with delimitation inferred from the shape of the phylogenetic tree and genetic distance. DNA‐based species limits agree with morphological delimitation in two clades, but a deep conflict was identified in another clade ofSynchonnusconsisting of three species with allopatric distributions and diversified genitalia, but strong similarities incox1mtDNA sequences. The failure of molecular species delimitation in someSynchonnuspoints to our inability to predict the performance of a barcoding approach even in closely related lineages and calls for an integrative taxonomical approach whenever possible. TheSynchonnusfauna of Australia is presented as highly diverse and fragmentation of habitat in the last ~15 million years is hypothesised as the principal factor leading to the observed alpha‐taxonomic diversity.

Molecular and morphological delimitation of Australian Triops species (Crustacea: Branchiopoda: Notostraca)—large diversity and little morphological differentiation

Australia has a very rich and diverse large branchiopod fauna with approximately 140 described or provisionally delimited species, but only one species of Triops, Triops australiensis (Spencer and Hall 1895), is currently recognized. Previous studies identified extensive genetic diversity within T. australiensis that suggested the presence of cryptic species. Herein, we employed an integrative approach to taxonomy to delimit putative species, integrating COI and EF1α sequence data and morphological data. Putative species were initially delimited based on COI by two computational approaches (GMYC and ABGD). The results were interpreted in the light of several species concepts, with particular emphasis on reproductive isolation. Twenty to 27 genetic lineages were delimited. Of these, up to 26 represent species following an evolutionary or phylogenetic species concept. Eighteen are biological species, though reproductive isolation could not be unambiguously established for allopatric species or species without known males. The level of co-occurrences was exceptionally high for Triops, with up to three syntopic and six sympatric species. Species delimitation was impeded by extensive overlap between intraspecific variability and interspecific variation in the genetic as well as morphological datasets. Without prior delimitation of putative species via COI, morphological delimitation would have been impossible. A potential explanation for the morphological variability is the retention of ancestral polymorphisms over long periods of time and across multiple speciation events without subsequent differentiation.

Revision of the Psammothidium germainii complex (Bacillariophyta) in the Maritime Antarctic Region

Psammothidium germainii is a widespread freshwater monoraphid diatom species in the Antarctic Region. Detailed analysis of the populations in the different parts of the Antarctic Region revealed the presence of several species that were lumped under the name 'P. germainii'. The type material of both Achnanthes germainii and Achnanthes ninckei has been investigated to allow a better morphological delimitation of both taxa and to better characterize the new taxa. Two new taxa are proposed: Psammothidium rostrogermainii sp. nov., typical for its rostrate apices and its rather distantly spaced stria pattern, and Psammothidium germainioides sp. nov., formerly identified in Antarctica as Achnanthes ninckei. Both new taxa are illustrated using light and scanning electron micrographs and are compared with similar taxa worldwide. Additionally, two populations of Psammothidium germainii lacking a raphe on the raphevalve are illustrated and discussed.

Circumscription of species of Hodophilus (Clavariaceae, Agaricales) in North America with naphthalene odours

Five North American Hodophilus species with naphthalene-like odours are now recognized based on sequence and (or) morphological data and molecular annotation of type collections. Two well-supported eastern North American species do not match any of the studied types and are described here as new: Hodophilus hesleri and Hodophilus smithii. The previously described Hodophilus paupertinus is found to represent an autonomous species and appears restricted to western North America. Hodophilus subfuscescens is found to be an independent lineage in eastern North America. A morphological type study of Hodophilus peckianus shows that it is a distinct species and not represented among recent collections. Multilocus phylogenetic analyses of European and North American material of species with naphthalene odours reveal no species with transatlantic distributions. Overall, Hodophilus comprises two superclades (the Hodophilus foetens superclade and the Hodophilus micaceus superclade) and 16 terminal clades that correspond to phylogenetic species. This study introduces a new approach for morphological delimitation of agaricoid Clavariaceae combining shape and dimensions of particular elements in the pileipellis and caulocystidia. All previously described taxa included in this study, which were previously treated in the genera Hygrophorus, Camarophyllopsis, or Hygrotrama, are formally transferred to Hodophilus.

Species delimitation of Chinese hop-hornbeams based on molecular and morphological evidence.

Species delimitation through which infers species boundaries is emerging as a major work in modern systematics. Hop‐hornbeam species in Ostrya (Betulaceae) are well known for their hard and heavy woods. Five species were described in China and their interspecific delimitations remain unclear. In this study, we firstly explored their distributions in all recorded field sites distributed in China. We then selected 110 samples from 22 natural populations of five species from this genus and one type specimen of O. yunnanensis, for molecular barcoding analyses. We sequenced four chloroplast (cp) DNA fragments (trnH–psbA, trnL–trnF, rps16, and trnG) and the nuclear internal transcribed spacer (ITS) region for all samples. Sequence variations of Ostrya from four cpDNA fragments identified three groups that showed no correspondence to any morphological delimitation because of the incomplete lineage sorting and/or possible interspecific introgression in the history. However, phylogenetic analyses of ITS sequence variations discerned four species, O. japonica, O. rehderiana, O. trichocarpa, and O. multinervis while O. yunnanensis nested within O. multinervis. Morphological clustering also discerned four species and showed the complete consistency with molecular evidence. Moreover, our phylogenetic analyses‐based ITS sequence variations suggested that O. trichocarpa comprised an isolated lineage different from the other Eurasian ones. Based on these results, hop‐hornbeams in China should be treated as four separate species. Our results further highlight the importance of ITS sequence variations in delimitating and discerning the closely related species in plants.

Integrative taxonomy of Metrichia Ross (Trichoptera: Hydroptilidae: Ochrotrichiinae) microcaddisflies from Brazil: descriptions of twenty new species.

Metrichia is assigned to the Ochrotrichiinae, a group of almost exclusively Neotropical microcaddisflies. Metrichia comprises over 100 described species and, despite its diversity, only one species has been described from Brazil so far. In this paper, we provide descriptions for 20 new species from 8 Brazilian states: M. acuminata sp. nov., M. azul sp. nov., M. bonita sp. nov., M. bracui sp. nov., M. caraca sp. nov., M. circuliforme sp. nov., M. curta sp. nov., M. farofa sp. nov., M. forceps sp. nov., M. formosinha sp. nov., M. goiana sp. nov., M. itabaiana sp. nov., M. longissima sp. nov., M. peluda sp. nov., M. rafaeli sp. nov., M. simples sp. nov., M. talhada sp. nov., M. tere sp. nov., M. ubajara sp. nov., and M. vulgaris sp. nov. DNA barcode sequences (577 bp of the mitochondrial gene COI) were generated for 13 of the new species and two previously known species of Metrichia resulting in 64 sequences. In addition, COI sequences were obtained for other genera of Ochrotrichiinae (Angrisanoia, Nothotrichia, Ochrotrichia, Ragatrichia, and Rhyacopsyche). DNA sequences and morphological data were integrated to evaluate species delimitations. K2P pairwise distances were calculated to generate a neighbor-joining tree. COI sequences also were submitted to ABGD and GMYC methods to assess ‘potential species’ delimitation. Analyses showed a conspicuous barcoding gap among Metrichia sequences (highest intraspecific divergence: 4.8%; lowest interspecific divergence: 12.6%). Molecular analyses also allowed the association of larvae and adults of Metrichia bonita sp. nov. from Mato Grosso do Sul, representing the first record of microcaddisfly larvae occurring in calcareous tufa (or travertine). ABGD results agreed with the morphological delimitation of Metrichia species, while GMYC estimated a slightly higher number of species, suggesting the division of two morphological species, each one into two potential species. Because this could be due to unbalanced sampling and the lack of morphological diagnostic characters, we have maintained these two species as undivided.

Taxonomic relationships among non-macrocystidiate taxa of Lactarius subg. Russularia from Europe with special reference to species from Greece

Members of the ectomycorrhizal genus Lactarius form symbiotic relationships with a wide range of plant species. For the purposes of this study, 29 specimens originally assigned to L. atlanticus, L. serifluus and L. subumbonatus were examined by including all pertinent available material from Greece. The detailed study of macroscopic and microscopic characteristics by using compound optical, differential interference contrast (DIC) and scanning electron microscopy in combination with molecular approaches (ITS1-5.8S-ITS2 rDNA sequencing) permitted a clear separation between L. atlanticus and L. subumbonatus, while their basidiospore shape and height of ornamentation were found to be of diagnostic value. Moreover, the morphological delimitation between the specimens identified as L. serifluus and L. subumbonatus is not clear, and these specimens were intermixed into the same phylogenetic cluster with high support. Thus, the latter name should be considered as a synonym of the former. As concerns other related taxa of L. subg. Russularia, the American L. rubidus and L. subserifluus demonstrated relatively high evolutionary affinity with European collections of L. serifluus/L. subumbonatus and L. atlanticus, respectively.

Integrating DNA barcode data in a monographic study of Convolvulus

AbstractThe stage at which DNA sequence data is incorporated into the taxonomic process and the extent of its contribution has been much discussed, but rarely in the context of assembling a taxonomic revision or monograph of a sizeable group of organisms. We present a new approach, the “foundation monograph”, which incorporates DNA sequence data into a large taxonomic study in a fast and pragmatic way, thereby overhauling the taxonomy of species‐rich, problematic plant groups. In this pilot study we focus on Convolvulus and use this group to exemplify how DNA barcode data can be utilised in the production of a “foundation monograph”. DNA was extracted from 310 accessions, representing 140 species, most of which (285) were herbarium specimens. Samples were sequenced for the proposed plant barcoding markers rbcL, matK and ITS. Sequencing success for each marker was 74%, 49% and 63% respectively. Of the 189 species of Convolvulus recognized to date, 74% (140 species) were sampled and 68% (128 species) were successfully sequenced for at least one region. Specimen age did not impact sequencing success except in the case of matK, the longest region. Eighty percent of the species sampled exhibited combined rbcL + matK barcodes not shared with another species. The addition of ITS increased this proportion to 99%. Phylogenetic analyses of the chloroplast (152 accessions representing 90 Convolvulus species) and nuclear (200 accessions representing 112 Convolvulus species) datasets both resulted in a well‐resolved and well‐supported topology, and revealed four main clades with strong geographical signal. Convolvulus appeared as paraphyletic with respect to Calystegia. Species limits of eight species complexes in which morphological delimitation proved difficult and for which multiple accessions were obtained were evaluated using the phylogenetic framework as a basis. Our study highlights the utility of herbarium specimens as a source of material for DNA extractions as well as the utility of DNA barcode data in the production of a “foundation monograph”, while also providing a robust, well‐sampled and well‐supported framework within which generic relationships, character evolution and biogeography can be investigated.

The Alate Species of <I>Baccharis</I> (Compositae-Astereae) of the North Andes

Abstract Five species and one hybrid of Baccharis with alate stems are recognized in the northern Andes between Colombia and central Peru, of which three species are endemic. A new species, B. woytkowskii, is described from northern Peru. Two species are restricted to northern Peru, and all northern Andean species occur there. Three species also occur in Ecuador and a single species in Colombia. Baccharis subbimera is neotypified and the species endemic to the northern Andes are described and illustrated. Morphological delimitation of species is discussed, and a determination key is provided.

Defining conservation units in a complex of morphologically similar, sexually deceptive, highly endangered orchids

In plants, rapid speciation attributed to pollination strategy is unlikely to lead to obvious morphological traits for identification or large genetic differences among populations. The species-rich Australian orchid genus Caladenia contains numerous taxonomically difficult species complexes, including the reticulata complex comprising 37 species, many of which are highly endangered with narrow-range geographic distributions as a consequence of severe habitat loss. Here, we test morphological species delimitation in the reticulata complex with a multigene phylogenetic analysis, detailed population genetic analysis and comprehensive data on specific sexually deceived pollinators of species within the complex. Phylogenetic analysis revealed limited species-level resolution within the reticulata complex and no difference between species with different pollinators. Microsatellite data confirmed this result for Victorian populations of the reticulata complex but revealed significant isolation by distance between Victorian and South Australian populations. Pollinator preference tests indicated that 10 reticulata complex morphospecies all shared the thynnid wasp pollinator Phymatothynnus nitidus, yet the microsatellite analysis revealed only limited differentiation between those and three species within the reticulata complex shown to employ different pollinators. The combined molecular and ecological approach revealed that morphospecies that share the same pollinator are likely to be the same biological species. Conservation and taxonomic focus should shift from a ‘microspecies’ approach to capturing key populations across the geographic range of the Caladenia reticulata biological species which will greatly assist the allocation of limited conservation resources.

Genetic and morphological diversity of Sphagnum angustifolium, S. flexuosum and S. fallax in Europe

AbstractMolecular and morphological evolution of species may be decoupled which can lead to contrasting delimitation of taxonomic units based on morphological and genetic characters. The moss genus Sphagnum (peat mosses) provides a good example in which morphological and genetic characters often contradict each other. We investigated morphological and genetic variability within a highly polymorphic and taxonomically controversial species complex of the genus Sphagnum in order to reveal the ultimate causes of discordance between morphology and molecular evolution. Specifically, we aimed at addressing the following questions: (1) Are the three closely related European taxa (S. angustifolium, S. fallax, S. flexuosum) of the S. recurvum group morphologically and genetically distinct entities? (2) Are morphological and genetic groups concordant? (3) Is there any sign of hybridization among taxa that might complicate their morphological delimitation? We show that European specimens of the S. recurvum group form three distinct gene pools based on 11 polymorphic microsatellite markers. Individuals defined as morphotype “fallax” appear to be genetically clearly distinct from both morphotype “angustifolium” and “flexuosum”. However, for the latter two morphotypes, traditionally used morphological and genetic markers provide partly incongruent taxonomic delimitations. We show that in about 13% of the accessions 12 traditionally used morphological characters cannot fully distinguish the genetic groups revealed. Our genetic analysis also reveals that only a low proportion of the specimens (3%) is admixed suggesting that hybridization is unlikely to explain the taxonomical controversies observed. Therefore, we hypothesize that taxonomic controversies are likely due to the extreme phenotypic plasticity of morphological characters rather than to porous species boundaries.