Taxonomic Interpretation Research Articles

Morphotype and Multivariate Analysis of the Occlusal Pattern of the First Lower Molar in European and Asian Arvicoline Species (Rodentia, Microtus, Alexandromys)

We studied the morphotypic variation of the occlusal pattern of m1 in 13 arvicoline species (genera Microtus and Alexandromys). As a result, 22 m1 morphotypes were identified. In Alexandromys, five morphotypes of m1 were found, while in Microtus only seven. The morphological diversity of m1 morphotypes (H) in voles of the genus Microtus is significantly lower compared to Alexandromys. The largest number of m1 morphotypes and the highest morphological diversity of m1 were revealed in the Mongolian vole (14 morphotypes and H = 2.134), while the lowest values (two morphotypes and H = 0.285) occur in the population of M. levis from Orlov Island. An attempt of ecological and taxonomical interpretation of interspecific differences was made based on the m1 morphotypes.

Linking karyotypes with DNA barcodes: proposal for a new standard in chromosomal analysis with an example based on the study of Neotropical Nymphalidae (Lepidoptera).

Chromosomal data are important for taxonomists, cytogeneticists and evolutionary biologists; however, the value of these data decreases sharply if they are obtained for individuals with inaccurate species identification or unclear species identity. To avoid this problem, here we suggest linking each karyotyped sample with its DNA barcode, photograph and precise geographic data, providing an opportunity for unambiguous identification of described taxa and for delimitation of undescribed species. Using this approach, we present new data on chromosome number diversity in neotropical butterflies of the subfamily Biblidinae (genus Vila Kirby, 1871) and the tribe Ithomiini (genera Oleria Hübner, 1816, Ithomia Hübner, 1816, Godyris Boisduval, 1870, Hypothyris Hübner, 1821, Napeogenes Bates, 1862, Pseudoscada Godman et Salvin, 1879 and Hyposcada Godman et Salvin, 1879). Combining new and previously published data we show that the species complex Oleria onega (Hewitson, [1852]) includes three discrete chromosomal clusters (with haploid chromosome numbers n = 15, n = 22 and n = 30) and at least four DNA barcode clusters. Then we discuss how the incomplete connection between these chromosomal and molecular data (karyotypes and DNA barcodes were obtained for different sets of individuals) complicates the taxonomic interpretation of the discovered clusters.

Learning from beautiful monsters: phylogenetic and morphogenetic implications of left-right asymmetry in ammonoid shells

BackgroundMany pathologies that modify the shell geometry and ornamentation of ammonoids are known from the fossil record. Since they may reflect the developmental response of the organism to a perturbation (usually a sublethal injury), their study is essential for exploring the developmental mechanisms of these extinct animals. Ammonoid pathologies are also useful to assess the value of some morphological characters used in taxonomy, as well as to improve phylogenetic reconstructions and evolutionary scenarios.ResultsWe report on the discovery of an enigmatic pathological middle Toarcian (Lower Jurassic) ammonoid specimen from southern France, characterized by a pronounced left-right asymmetry in both ornamentation and suture lines. For each side independently, the taxonomic interpretations of ornamentation and suture lines are congruent, suggesting a Hildoceras semipolitum species assignment for the left side and a Brodieia primaria species assignment for the right side. The former exhibits a lateral groove whereas the second displays sinuous ribs. This specimen, together with the few analogous cases reported in the literature, lead us to erect a new forma-type pathology herein called “forma janusa” for specimens displaying a left-right asymmetry in the absence of any clear evidence of injury or parasitism, whereby the two sides match with the regular morphology of two distinct, known species.ConclusionsSince “forma janusa” specimens reflect the underlying developmental plasticity of the ammonoid taxa, we hypothesize that such specimens may also indicate unsuspected phylogenetic closeness between the two displayed taxa and may even reveal a direct ancestor-descendant relationship. This hypothesis is not, as yet, contradicted by the stratigraphical data at hand: in all studied cases the two distinct taxa correspond to contemporaneous or sub-contemporaneous taxa. More generally, the newly described specimen suggests that a hitherto unidentified developmental link may exist between sinuous ribs and lateral grooves. Overall, we recommend an integrative approach for revisiting aberrant individuals that illustrate the intricate links among shell morphogenesis, developmental plasticity and phylogeny.

Diversity and temporal variations of the Hemiptera Auchenorrhyncha fauna in the Ajaccio region (France, Corsica)

SummaryDuring a one-year survey of the Auchenorrhyncha fauna in a maquis habitat of the Ajaccio region (Corsica), 37 species were listed including three alien species recorded in Europe in the last decades. The standard 658 bp mitochondrial COI barcode was obtained for 32 species, including 14 species never previously barcoded. Neighbor-joining analyses confirmed the delineation for all the species. However, comparisons with available sequences from mainland Europe showed that four species presented a significant intraspecific divergence (>3%), whereas a reduced interspecific divergence was found for another set of species. Complementary studies may therefore be necessary to better assess their taxonomic levels. Three species – Euscelis lineolata Brullé, 1832 (Cicadellidae), Philaenus spumarius (Linnaeus, 1758) (Aphrophoridae) and Latilica maculipes (Melichar, 1906) (Issidae) – accounted for up to 74.3% of the total insects collected. Although taxonomic interpretations using restricted sampling and COI sequences alone are not robust, the proportion of new sequences highlight the global lack of knowledge about the Auchenorrhyncha as a whole and the potentially presence of cryptic taxa in different clades.

Fossil Sea Cow Remains (Mammalia: Sirenia) on Paving Stones in the City of Girona (Catalonia, Spain)

Remains of an extinct sea cow are identified on several paving stones in the city of Girona (Catalonia, NE Spain). The limestone slabs are of middle Eocene age, making the fossil one of the oldest representatives of its group in Europe. Based on macroscopic and CT scan data, our study provides first results on the individual age and taxonomic identification of the find. The sea cow remains represent a single specimen. The relative position and degree of wear of the third upper molar indicate a subadult or young adult. Analysis of basicranial sutures and of the third upper molar indicate a young adult. Morphological comparisons focusing on Eocene taxa from Europe that are considered valid and belong to the Dugongidae argue for a closer relationship of the Girona specimen with the genus Prototherium. Given the palaeobiogeographic and stratigraphic distribution of the species available for comparison, the Girona sea cow is tentatively assigned to P. ausetanum. Ongoing post-processing of the CT scans and subsequent 3D reconstruction of the preserved bones are expected to enhance the morphological and taxonomic interpretation and will provide new insights into the evolutionary history and diversity of Eocene sirenians. For this reason, the city of Girona, which already maintains a system of touristic routes for explaining the local geology and palaeontology, will include the scientifically significant site of discovery in its cultural tourism programme. The sea cow remains will be included in the “Inventory of Areas of Geological Interest”, a catalog summarizing the geological history of Catalonia.

Typification of the Linnaean name Iris pumila (Iridaceae)

The typification of the Linnaean name Iris pumila (Iridaceae) is discussed. Original material conserved in the Clifford Herbarium (BM), agreeing with the current usage of the name, is designated as the lectotype. An epitype is also designated in order to avoid any ambiguity in the taxonomic interpretation of the lectotype specimen and hence the application of the name.Citation: Boltenkov E. V. 2019: Typification of the Linnaean name Iris pumila (Iridaceae). — Willdenowia 49: 147 – 150. doi: https://doi.org/10.3372/wi.49.49202Version of record first published online on 20 May 2019 ahead of inclusion in August 2019 issue.

A new genus of Proterotheriinae (Mammalia, Litopterna) from the Pleistocene of Uruguay

ABSTRACTWe describe a new genus and species of Proterotheriinae from the Pleistocene of Uruguay. Several taxonomic, biostratigraphic, paleoecological, and paleoenvironmental analyses and interpretations have been performed in a detailed study of the Litopterna (Mammalia, ‘Meridiungulata’) of Uruguay. The Proterotheriidae is the most diverse family of the Litopterna. In Uruguay, the record of the Proterotheriidae, although in many cases fragmentary, includes interesting specimens in particular contexts and different ages in the late Oligocene–late Pleistocene. The aim of this work is to reassess the specimens primarily assigned four decades ago to ‘Licaphrium’ aff. floweri, redescribing them, evaluating their taxonomic status in the context of the Proterotheriidae, and establishing the characters that allow the determination of this taxon as a new genus and species of Proterotheriinae: Uruguayodon alius. We redescribe two specimens of this new taxon, which include dental and postcranial remains. The diagnostic element is the last lower molar, which shows, among other characters, paraconid and paralophid in a very lingual position, smoothed metaflexid, and absence of entoflexid. The individuals were excavated from a sandy level of the San José Member of the Raigón Formation, a unit that has an endemic fauna, a pattern discussed here in a paleogeographic framework. The provenance of the analyzed specimens from Pleistocene layers is indicated by mammalian content and absolute ages, which support the presence of another genus of Proterotheriidae surviving into the Quaternary, in addition to Neolicaphrium recens.

Morphological and Taxonomical Interpretation of Schugura and Orestovia, Enigmatic Plants from the Devonian of Russia

Morphological and Taxonomical Interpretation of Schugura and Orestovia, Enigmatic Plants from the Devonian of Russia

Morphological and Taxonomic Interpretation of Orestovia and Schuguria, Enigmatic Devonian Plants from Russia.

A detailed study of the external and internal surfaces of the cuticle of Orestovia and Schuguria using scanning electron microscopy and confocal laser microscopy has shown that the structures formerly interpreted as stomata or reproductive organs are most likely to be gland cells producing mucilage. Each structure represents a single large cell with a complex aperture on the external wall. In addition, a reproductive organ similar to multilocular sporangia known in brown algae of the order Ectocarpales has been found in attachment to a compression fossil of Orestovia. These data suggest similarity of the genera studied with brown algae.

Paleobiology of a three-dimensionally preserved paropsonemid from the Devonian of New York

A three-dimensionally preserved stellate fossil from the Middle-Upper Devonian of New York is described. Although it shares gross similarities with oral cones of anomalocaridids, we interpret it as the mold of the dorsal portion of the segmented alimentary canal of the rare, soft-bodied animal Paropsonema cryptophya. Together with two other dorsally preserved P. cryptophya specimens, such fossils strengthen the hypothesized link between two primitive deuterostome stem groups - the paropsonemids and the eldonids. Although the taxonomic affinities of these groups remain uncertain, it is important to illustrate fossils like these because they provide paleontologists with a ‘search image’ for more material that may elucidate patterns in early animal evolution or may help revise taxonomic interpretations. The new specimen of Paropsonema is also the youngest described occurrence of the paropsonemids and its sediment-filled gut is consistent with an epibenthic lifestyle for that group.

Do Antarctic populations represent local or widespread phylogenetic and ecological lineages? Complicated fate of bipolar moss concepts with Drepanocladus longifolius as a case study

Bipolar moss species, extreme examples of large and disjunctive geographical ranges, belong to the most important components of the vegetation cover in Antarctica. Their appropriate taxonomic interpretations are essential for fine-scale biogeographical considerations but our knowledge on their phylogenetic affinities still remains limited. Here, we address the history of the Antarctic populations of Drepanocladus longifolius, a moss species widely considered a bipolar taxon. First, based on a worldwide sampling, we verify its assumed bipolar status. Then, we ask whether its current Antarctic populations have persisted throughout at least the last major glaciation in situ or, alternatively, are they a recent, postglacial element. Phylogenetic analyses together with investigation of morphological characters were used to infer relationships among accessions representing the whole distribution range of the taxon. Morphological and phylogenetic data strictly segregated specimens from the Southern and the Northern Hemisphere, with an exception of Australian populations that were included in the latter group. The Antarctic, sub-Antarctic and South American populations belong to a single clade and are treated as D. longifolius s. str., which consequently is not a bipolar taxon. All Northern Hemisphere populations and the ones from Australia represent D. capillifolius, a lately neglected taxon, which thus displays a true bipolar distribution pattern but not comprising the Antarctic and South American populations. These results provide a sound example of key importance of a detailed taxonomical and phylogenetic treatment as a basis for biogeographical studies. In D. longifolius s. str., a homogeneity in all non-coding nuclear and plastid regions was observed throughout the whole range. It contrasted with the presence of one missense mutation in the rps4 gene in all examined Antarctic populations, which correlated with their distinct ecological situation. While identity of non-coding sequences in D. longifolius populations indicates a postglacial recruitment of extant Antarctic populations from extra-regional locations rather than a long-term in situ survival, the mutation in the rps4 gene may be hypothesised to reflect an adaptive response of plants to the Antarctic environment.

Metagenomic insights into diazotrophic communities across Arctic glacier forefields.

Microbial nitrogen fixation is crucial for building labile nitrogen stocks and facilitating higher plant colonisation in oligotrophic glacier forefield soils. Here, the diazotrophic bacterial community structure across four Arctic glacier forefields was investigated using metagenomic analysis. In total, 70 soil metagenomes were used for taxonomic interpretation based on 185 nitrogenase (nif) sequences, extracted from assembled contigs. The low number of recovered genes highlights the need for deeper sequencing in some diverse samples, to uncover the complete microbial populations. A key group of forefield diazotrophs, found throughout the forefields, was identified using a nifH phylogeny, associated with nifH Cluster I and III. Sequences related most closely to groups including Alphaproteobacteria, Betaproteobacteria, Cyanobacteria and Firmicutes. Using multiple nif genes in a Last Common Ancestor analysis revealed a diverse range of diazotrophs across the forefields. Key organisms identified across the forefields included Nostoc, Geobacter, Polaromonas and Frankia. Nitrogen fixers that are symbiotic with plants were also identified, through the presence of root associated diazotrophs, which fix nitrogen in return for reduced carbon. Additional nitrogen fixers identified in forefield soils were metabolically diverse, including fermentative and sulphur cycling bacteria, halophiles and anaerobes.

Re-description of the lectotype of “Spatangus cortestudinarium Goldfuss, 1829” (Late Cretaceous) and its implications for the phylogeography of Micraster (Spatangoida, Echinoidea)

A detailed re-description of the lectotype of “Spatangus cortestudinarium Goldfuss, 1829” [currently used as Micraster cortestudinarium (Goldfuss, 1829)], (designated by Stokes 1975), was undertaken and compared to previous taxonomic interpretations of this species. Comparisons with additional known material from across Europe allowed the more reliable identification of the provenance of the type specimen than previously postulated, which most likely originates from the Chalk of the Anglo-Paris Basin (southern England, northern France). Hitherto it was frequently accepted that the geographic distribution of M. cortestudinarium occurred in large parts of Europe and western Asia. Accordingly, the evolutionary succession (including M. cortestudinarium), recognised in the Anglo-Paris-Basin, was assumed to be also traceable outside of the Anglo-Paris Basin. The re-assessment of M. cortestudinarium, resulting in a distribution restricted to the Anglo-Paris Basin, has implementations for the biogeography and interpretation of the evolution of Micraster. The evolution within Micraster must thus have occurred differently in the various Cretaceous realms and been more diverse than thought so far.

A new species of Xotodon (Notoungulata, Toxodontidae) from northwestern Argentina

ABSTRACTXotodon caravela, a new species of toxodontid from northwestern Argentina, is presented. The material studied consists of a well-preserved and nearly complete mandible and a maxillary fragment, recovered in the Aconquija Formation (late Miocene-early Pliocene) at the El Molino locality (Tucumán Province, Argentina). The fossil diversity of the levels is concordant with an early Pliocene fauna. The general features of the dentition and mandible (e.g., concave ectoloph and single lingual fold on upper molars, anterior fold mesially displaced relative to the hypoflexid in the lower molars, sigmoid lateral outline of chin, and continuous enamel on M3) allow the inclusion of this specimen in the genus Xotodon. In turn, some traits indicate unequivocally that this is a new species, such as the anterior region without constriction at the premolar level, the approximately 13° angle of implantation of the i3 in relation to the ventral edge of the mandibular body (without lateral divergence), and the presence of an intra-alveolar projection of the incisive crown extending laterally below the premolars to the level of the p4 and forming a robust projection or lateral ledge. The new taxon was included in a matrix of 59 characters and compared with 32 notoungulate genera. The phylogenetic position and comparative analysis support the taxonomic interpretation of the studied specimen as a new species of Xotodon. This represents the first record of a toxodontid in the Neogene lowlands of northwestern Argentina and contributes to our knowledge of this family in the region.Citation for this article: Armella, M. A., D. A. García-López, and L. Dominguez. 2018. A new species of Xotodon (Notoungulata, Toxodontidae) from northwestern Argentina. Journal of Vertebrate Paleontology. DOI: 10.1080/02724634.2017.1425882.

Oral Biofilm Sampling for Microbiome Analysis in Healthy Children.

Oral biofilm and its molecular analysis provide a basis for investigating various dental research and clinical questions. Knowledge of biofilm composition leads to a better understanding of cariogenic and periopathogenic mechanisms. Microbial changes taking place in the oral cavity during childhood are of interest for several reasons. The evolution of the child oral microbiota and shifts in its composition need to be analyzed further to understand and possibly prevent the onset of disease. At the same time, advanced knowledge of the natural composition of oral biofilm is needed. Early stages of caries-free permanent dentition with healthy gums provide a widely unaffected subgingival habitat that can serve as an in situ baseline for studying features of oral health and disease. Analysis of children's oral biofilm during different stages in life is thus an important theme in the field. Modern molecular analysis methods can provide comprehensive information about the bacterial diversity of such biofilms. To enable microbiota data comparison, it is important to standardize each step in the procedure for molecular data generation. This procedure spans from clinical sampling, Next Generation Sequencing (NGS), bioinformatic data processing, to taxonomic interpretation. One of the most critical factors here is biofilm sampling. Sampling in children is even more challenging in particular due to limited space in subgingival areas. We thus focus on the use of paper points for subgingival sampling. This article provides a detailed protocol for oral biofilm sampling of the subgingival sulcus, the mucosa, and saliva in children.

Oral Biofilm Sampling for Microbiome Analysis in Healthy Children

Oral biofilm and its molecular analysis provide a basis for investigating various dental research and clinical questions. Knowledge of biofilm composition leads to a better understanding of cariogenic and periopathogenic mechanisms. Microbial changes taking place in the oral cavity during childhood are of interest for several reasons. The evolution of the child oral microbiota and shifts in its composition need to be analyzed further to understand and possibly prevent the onset of disease. At the same time, advanced knowledge of the natural composition of oral biofilm is needed. Early stages of caries-free permanent dentition with healthy gums provide a widely unaffected subgingival habitat that can serve as an in situ baseline for studying features of oral health and disease. Analysis of children's oral biofilm during different stages in life is thus an important theme in the field. Modern molecular analysis methods can provide comprehensive information about the bacterial diversity of such biofilms. To enable microbiota data comparison, it is important to standardize each step in the procedure for molecular data generation. This procedure spans from clinical sampling, Next Generation Sequencing (NGS), bioinformatic data processing, to taxonomic interpretation. One of the most critical factors here is biofilm sampling. Sampling in children is even more challenging in particular due to limited space in subgingival areas. We thus focus on the use of paper points for subgingival sampling. This article provides a detailed protocol for oral biofilm sampling of the subgingival sulcus, the mucosa, and saliva in children.

Phylogenomic support for evolutionary relationships of New World direct-developing frogs (Anura: Terraranae)

Phylogenomic approaches have proven able to resolve difficult branches in the tree of life. New World direct-developing frogs (Terraranae) represent a large evolutionary radiation in which interrelationships at key points in the phylogeny have not been adequately determined, affecting evolutionary, biogeographic, and taxonomic interpretations. We employed anchored hybrid enrichment to generate a data set containing 389 loci and >600,000 nucleotide positions for 30 terraranan and several outgroup frog species encompassing all major lineages in the clade. Concatenated maximum likelihood and coalescent species-tree approaches recover nearly identical topologies with strong support for nearly all relationships in the tree. These results are similar to previous phylogenetic results but provide additional resolution at short internodes. Among taxa whose placement varied in previous analyses, Ceuthomantis is shown to be the sister taxon to all other terraranans, rather than deeply embedded within the radiation, and Strabomantidae is monophyletic rather than paraphyletic with respect to Craugastoridae. We present an updated taxonomy to reflect these results, and describe a new subfamily for the genus Hypodactylus.

Recent species name changes in the European Lymnaeidae: two tales with unhappy end?

Two doubtful cases of species name replacements in the family Lymnaeidae Rafinesque, 1815 (pond snails) proposed in 1990-2000s are discussed. These are: Radix labiata (Rossmäßler, 1835) vs. R. peregra (O.F. Müller, 1774), and Stagnicola fuscus (C. Pfeiffer, 1821) vs. S. vulneratus (Küster, 1862). It is shown that in both instances the name alterations were not based on the conclusive evidence and thus seem to be proposed without substantial reasons. I argue that the name Radix peregra cannot be ruled out and replaced by R. labiata. The type series of the latter has been identified in collection of the Natural History Museum of Vienna and it is shown that R. labiata is a junior synonym of R. balthica (Linnaeus, 1758). The lectotype of Limnaeus pereger var. labiatus Rossmäßler, 1835 is designated. The resurrection of the species name Limnaeus fuscus (Pfeiffer, 1821) for application to a certain species of Stagnicola is also very doubtful since this name must be treated as a nomen dubium , and any taxonomic interpretation of it is inevitable based on more or less reliable hypothesis, not on the total evidence. The replacement of S. vulneratus by its alleged senior synonym adds little to our knowledge on lymnaeid taxonomy and evolutionary relationships. It is desirable that the nomenclatorial principle of priority must not be applied to nomina dubia .

Species abundance, richness and body size evolution of kangaroos (Marsupialia: Macropodiformes) throughout the Oligo-Miocene of Australia

The Riversleigh World Heritage Area, northwestern Queensland, Australia, contains numerous Oligo-Miocene and Pleistocene fossil bearing deposits. Species of the suborder Macropodiformes (kangaroos and allies) described from Oligo-Miocene sediments at Riversleigh include representatives of all three macropodiform families: Macropodidae, Hypsiprymnodontidae and Balbaridae, a family of extinct fanged kangaroos. Despite extensive taxonomic study, few studies have focused on the ecology of balbarids that are present in Late Oligocene to Late Miocene faunal assemblages. Recently, several macropodiform species from Riversleigh have been described or revised that significantly alter previous interpretations of species richness and abundance at Riversleigh. In this study, Riversleigh macropodiform species richness and relative abundance is explored against a framework of recently revised taxonomic interpretations and biostratigraphy. With the exception of the Early Miocene, our results suggest that balbarids were less abundant than macropodids at Riversleigh. Balbarid species richness declined by the Early Miocene while macropodid species diversity declined from the Early Miocene to Middle Miocene and again in the Late Miocene. We also estimate body mass for macropodiform taxa throughout the Oligo-Miocene. A statistically significant increase in body mass is evident for most taxa through time. A number of ancestral macropodid genera suffer extinction in the Middle Miocene and are replaced by larger sthenurine macropodids around the time of the Miocene Climatic Optimum. Trends in faunal turnover (extinction and replacement of several macropodiform species) in the Middle Miocene are consistent with trends for other mammalian groups both from Riversleigh and globally.

The ranking of fungi: a tribute to David L. Hawksworth on his 70th birthday

The history of assigning ranks to fungi, as well as the relative importance of using divergence time estimates is reviewed. The paper pays tribute to the major mycological players, and especially to David Hawksworth on his 70th birthday and his contribution to fungal ranking in Systema Ascomycetum from 1982 to 1998. Following the conclusion of the latter series, the ranking continued with the Outlines of Ascomycota in 2007 and 2010 and more recently with specific classes in 'Towards an outline of Sordariomycetes' and 'Families of Dothideomycetes'. Earlier classifications based on phenotype were certainly more subjective; however, remarkably many of these old arrangements have stood the test of time. More recently, phylogenetic analyses have provided evidence towards a natural classification, resulting in significant changes in many lineages. The classification arrangements however, are still subjective and dependent on the taxa analysed, resulting in different taxonomic interpretations and schemes, particularly when it comes to ranking. Thus, what have been considered as genera by some, have been introduced as families by others. More recently, estimation of divergence times using molecular clock methods have been used as objective evidence for higher ranking of taxa. A divergence period (i.e. 200-300 MYA) can be used as a criterion to infer when a group of related taxa evolved and what rank they should be given. We compiled data on divergence times for various higher ranking taxa in the Kingdom Fungi. The kingdom evolved 1000-1600 MYA (Stenian-Calymmian), while the presently accepted phyla evolved between 358 and 541 MYA (Devonian-Cambrian). Divergence times for subphyla are generally between 358 and 485 MYA (Devonian-Ordovician), those of classes 145-358 MYA (Jurassic-Carboniferous), subclasses 66-358 MYA (Cretaceous-Carboniferous), orders 23-252 MYA (Paleogene-Triassic), families 2.8-145 MYA (Neogene-Cretaceous), and genera 2.8-66 MYA (Neogene-Paleogene). Thus, there are wide discrepancies in the times different taxa diverged. We provide an overview over Ascomycota, showing how application of temporal banding could affect the recognition of higher taxa at certain rank levels. We then use Sordariomycetes as an example where we use divergence times to provide additional evidence to stabilize ranking of taxa below class level. We propose a series of evolutionary periods that could be used as a guide to determine the various higher ranks of fungi: phyla[550 MYA, subphyla 400-550 MYA; classes 300-400 MYA; subclasses 250-300 MYA, orders 150-250 MYA, and families 50-150 MYA. It is proposed that classification schemes and ranking of taxa should, where possible, incorporate a polyphasic approach including phylogeny, phenotype, and estimate of divergence times.