Browsing by Subject "Evolutionary Biology"
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Item Open Access A classification for extant ferns(Taxon, 2006-01-01) Smith, AR; Pryer, KM; Schuettpelz, E; Korall, P; Schneider, H; Wolf, PGWe present a revised classification for extant ferns, with emphasis on ordinal and familial ranks, and a synopsis of included genera. Our classification reflects recently published phylogenetic hypotheses based on both morphological and molecular data. Within our new classification, we recognize four monophyletic classes, 11 monophyletic orders, and 37 families, 32 of which are strongly supported as monophyletic. One new family, Cibotiaceae Korall, is described. The phylogenetic affinities of a few genera in the order Polypodiales are unclear and their familial placements are therefore tentative. Alphabetical lists of accepted genera (including common synonyms), families, orders, and taxa of higher rank are provided.Item Open Access A diploids-first approach to species delimitation and interpreting polyploid evolution in the fern genus astrolepis (pteridaceae)(Systematic Botany, 2010-04-01) Beck, James B; Windham, Michael D; Yatskievych, George; Pryer, Kathleen MPolyploidy presents a challenge to those wishing to delimit the species within a group and reconstruct the phylogenetic relationships among these taxa. A clear understanding of the tree-like relationships among the diploid species can provide a framework upon which to reconstruct the reticulate events that gave rise to the polyploid lineages. In this study we apply this "diploids-first" strategy to the fern genus Astrolepis (Pteridaceae). Diploids are identified using the number of spores per sporangium and spore size. Analyses of plastid and low-copy nuclear sequence data provide well-supported estimates of phylogenetic relationships, including strong evidence for two morphologically distinctive diploid lineages not recognized in recent treatments. One of these corresponds to the type of Notholaena deltoidea, a species that has not been recognized in any modern treatment of Astrolepis. This species is resurrected here as the new combination Astrolepis deltoidea . The second novel lineage is that of a diploid initially hypothesized to exist by molecular and morphological characteristics of several established Astrolepis allopolyploids. This previously missing diploid species is described here as Astrolepis obscura. © Copyright 2010 by the American Society of Plant Taxonomists.Item Open Access A plastid phylogeny of the cosmopolitan fern family cystopteridaceae (Polypodiopsida)(Systematic Botany, 2013-06-01) Rothfels, CJ; Windham, MD; Pryer, KMAmong the novel results of recent molecular phylogenetic analyses are the unexpectedly close evolutionary relationships of the genera Acystopteris, Cystopteris, and Gymnocarpium, and the phylogenetic isolation of these genera from Woodsia. As a consequence, these three genera have been removed from Woodsiaceae and placed into their own family, the Cystopteridaceae. Despite the ubiquity of this family in rocky habitats across the northern hemisphere, and its cosmopolitan distribution (occurring on every continent except Antarctica), sampling of the Cystopteridaceae in phylogenetic studies to date has been sparse. Here we assemble a three-locus plastid dataset (matK, rbcL, trnG-R) that includes most recognized species in the family and multiple accessions of widespread taxa from across their geographic ranges. All three sampled genera are robustly supported as monophyletic, Cystopteris is strongly supported as sister to Acystopteris, and those two genera together are sister to Gymnocarpium. The Gymnocarpium phylogeny is deeply divided into three major clades, which we label the disjunctum clade, the robertianum clade, and core Gymnocarpium. The Cystopteris phylogeny, similarly, features four deeply diverged clades: C. montana, the sudetica clade, the bulbifera clade, and the fragilis complex. Acystopteris includes only three species, each of which is supported as monophyletic, with A. taiwaniana sister to the japonica/tenuisecta clade. Our results yield the first species-level phylogeny of the Cystopteridaceae and the first molecular phylogenetic evidence for species boundaries. These data provide an essential foundation for further investigations of complex patterns of geographic diversification, speciation, and reticulation in this family. © Copyright 2013 by the American Society of Plant Taxonomists.Item Open Access A revised family-level classification for eupolypod II ferns (Polypodiidae: Polypodiales)(Taxon, 2012-01-01) Rothfels, CJ; Sundue, MA; Kuo, L; Larsson, A; Kato, M; Schuettpelz, E; Pryer, KMWe present a family-level classification for the eupolypod II clade of leptosporangiate ferns, one of the two major lineages within the Eupolypods, and one of the few parts of the fern tree of life where family-level relationships were not well understood at the time of publication of the 2006 fern classification by Smith & al. Comprising over 2500 species, the composition and particularly the relationships among the major clades of this group have historically been contentious and defied phylogenetic resolution until very recently. Our classification reflects the most current available data, largely derived from published molecular phylogenetic studies. In comparison with the five-family (Aspleniaceae, Blechnaceae, Onocleaceae, Thelypteridaceae, Woodsiaceae) treatment of Smith & al., we recognize 10 families within the eupolypod II clade. Of these, Aspleniaceae, Thelypteridaceae, Blechnaceae, and Onocleaceae have the same composition as treated by Smith & al. Woodsiaceae, which Smith & al. acknowledged as possibly non-monophyletic in their treatment, is circumscribed here to include only Woodsia and its segregates; the other "woodsioid" taxa are divided among Athyriaceae, Cystopteridaceae, Diplaziopsidaceae, Rhachidosoraceae, and Hemidictyaceae. We provide circumscriptions for each family, which summarize their morphological, geographical, and ecological characters, as well as a dichotomous key to the eupolypod II families. Three of these families- Diplaziopsidaceae, Hemidictyaceae, and Rhachidosoraceae-were described in the past year based on molecular phylogenetic analyses; we provide here their first morphological treatment.Item Open Access A revised generic classification of vittarioid ferns (Pteridaceae) based on molecular, micromorphological, and geographic data(Taxon, 2016-08-01) Schuettpelz, E; Chen, C; Kessler, M; Pinson, JB; Johnson, G; Davila, A; Cochran, AT; Huiet, L; Pryer, KM© International Association for Plant Taxonomy (IAPT) 2016. Vittarioid ferns compose a well-supported clade of 100-130 species of highly simplified epiphytes in the family Pteridaceae. Generic circumscriptions within the vittarioid clade were among the first in ferns to be evaluated and revised based on molecular phylogenetic data. Initial analyses of rbcL sequences revealed strong geographic structure and demonstrated that the two largest vittarioid genera, as then defined, each had phylogenetically distinct American and Old World components. The results of subsequent studies that included as many as 36 individuals of 33 species, but still relied on a single gene, were generally consistent with the early findings. Here, we build upon the previous datasets, incorporating many more samples (138 individuals representing 72 species) and additional plastid markers (atpA, chlN, rbcL, rpoA). Analysis of our larger dataset serves to better characterize known lineages, reveals new lineages, and ultimately uncovers an underlying geographic signal that is even stronger than was previously appreciated. In our revised generic classification, we recognize a total of eleven vittarioid genera. Each genus, including the new genus Antrophyopsis (Benedict) Schuettp., stat. nov., is readily diagnosable based on morphology, with micromorphological characters related to soral paraphyses and spores complementing more obvious features such as venation and the distribution of sporangia. A key to the currently recognized vittarioid genera, brief generic descriptions, and five new species combinations are provided.Item Open Access A worldwide phylogeny of Adiantum (Pteridaceae) reveals remarkable convergent evolution in leaf blade architecture(Taxon, 2018-06-01) Huiet, L; Li, F; Kao, T; Prado, J; Smith, AR; Schuettpelz, E; Pryeri, KM© International Association for Plant Taxonomy (IAPT) 2018, All rights reserved. Adiantum is among the most distinctive and easily recognized leptosporangiate fern genera. Despite encompassing an astonishing range of leaf complexity, all species of Adiantum share a unique character state not observed in other ferns: sporangia borne directly on the reflexed leaf margin or “false indusium” (pseudoindusium). The over 200 species of Adiantum span six continents and are nearly all terrestrial. Here, we present one of the most comprehensive phylogenies for any large (200+ spp.) monophyletic, subcosmopolitan genus of ferns to date. We build upon previous datasets, providing new data from four plastid markers (rbcL, atpA, rpoA, chlN) for 146 taxa. All sampled taxa can be unequivocally assigned to one of nine robustly supported clades. Although some of these unite to form larger, well-supported lineages, the backbone of our phylogeny has several short branches and generally weak support, making it difficult to accurately assess deep relationships. Our maximum likelihood-based ancestral character state reconstructions of leaf blade architecture reveal remarkable convergent evolution across multiple clades for nearly all leaf forms. A single unique synapomorphy—leaves once-pinnate, usually with prolonged rooting tips—defines the philippense clade. Although a rare occurrence in Adiantum, simple leaves occur in three distinct clades (davidii, philippense, peruvianum). Most taxa have leaves that are more than once-pinnate, and only a few of these (in the formosum and pedatum clades) exhibit the distinct pseudopedate form. Distributional ranges for each of the terminal taxa show that most species (75%) are restricted to only one of six major biogeographical regions. Forty-eight of our sampled species (nearly one-third) are endemic to South America.Item Open Access Adaptive wear-based changes in dental topography associated with atelid (Mammalia: Primates) diets(Biological Journal of the Linnean Society, 2018-06-28) Pampush, JD; Spradley, JP; Morse, PE; Griffith, D; Gladman, JT; Gonzales, LA; Kay, RFItem Open Access Are there too many fern genera?(Taxon, 2018-06-01) Schuettpelz, E; Rouhan, G; Pryer, KM; Rothfels, CJ; Prado, J; Sundue, MA; Windham, MD; Moran, RC; Smith, ARItem Open Access Baja: A New Monospecific Genus Segregated from Cheilanthes s. l. (Pteridaceae)(Systematic Botany, 2019-09-06) George, LO; Pryer, KM; Kao, T; Huiet, L; Windham, MDItem Open Access Complexity by Subtraction(Evolutionary Biology, 2013) McShea, DW; Hordijk, WThe eye and brain: standard thinking is that these devices are both complex and functional. They are complex in the sense of having many different types of parts, and functional in the sense of having capacities that promote survival and reproduction. Standard thinking says that the evolution of complex functionality proceeds by the addition of new parts, and that this build-up of complexity is driven by selection, by the functional advantages of complex design. The standard thinking could be right, even in general. But alternatives have not been much discussed or investigated, and the possibility remains open that other routes may not only exist but may be the norm. Our purpose here is to introduce a new route to functional complexity, a route in which complexity starts high, rising perhaps on account of the spontaneous tendency for parts to differentiate. Then, driven by selection for effective and efficient function, complexity decreases over time. Eventually, the result is a system that is highly functional and retains considerable residual complexity, enough to impress us. We try to raise this alternative route to the level of plausibility as a general mechanism in evolution by describing two cases, one from a computational model and one from the history of life. © 2013 Springer Science+Business Media New York.Item Open Access DNA barcoding exposes a case of mistaken identity in the fern horticultural trade.(Molecular ecology resources, 2010-11) Pryer, Kathleen M; Schuettpelz, Eric; Huiet, Layne; Grusz, Amanda L; Rothfels, Carl J; Avent, Tony; Schwartz, David; Windham, Michael DUsing cheilanthoid ferns, we provide an example of how DNA barcoding approaches can be useful to the horticultural community for keeping plants in the trade accurately identified. We use plastid rbcL, atpA, and trnG-R sequence data to demonstrate that a fern marketed as Cheilanthes wrightii (endemic to the southwestern USA and northern Mexico) in the horticultural trade is, in fact, Cheilanthes distans (endemic to Australia and adjacent islands). Public and private (accessible with permission) databases contain a wealth of DNA sequence data that are linked to vouchered plant material. These data have uses beyond those for which they were originally generated, and they provide an important resource for fostering collaborations between the academic and horticultural communities. We strongly advocate the barcoding approach as a valuable new technology available to the horticulture industry to help correct plant identification errors in the international trade.Item Open Access Evolution of altruism under group selection in large and small populations in fluctuating environments(Theoretical Population Biology, 1979-01-01) Uyenoyama, MKA continuous, graded form of group selection which does not involve extinction of demes can effectively oppose selection on the individual level against an altruistic allele under fluctuating environments in infinitely large demes among which uniform mixing occurs every generation. Although group selection cannot alter the conditions necessary for the initial increase of altruistic alleles, group selection can significantly influence the stationary distribution of gene frequency which is attained once stochastic forces have allowed theirintroduction. Drift is a more effective source of variation than fluctuations in selection when the variance in selection is moderate to small. High numbers of demes promote polymorphism under both graded group selection and extinction group selection. © 1979.Item Open Access Fern phylogeny inferred from 400 leptosporangiate species and three plastid genes(Taxon, 2007-01-01) Schuettpelz, E; Pryer, KMIn an effort to obtain a solid and balanced approximation of global fern phylogeny to serve as a tool for addressing large-scale evolutionary questions, we assembled and analyzed the most inclusive molecular dataset for leptosporangiate ferns to date. Three plastid genes (rbcL, atpB, atpA), totaling more than 4,000 bp, were sequenced for each of 400 leptosporangiate fern species (selected using a proportional sampling approach) and five outgroups. Maximum likelihood analysis of these data yielded an especially robust phylogeny: 80% of the nodes were supported by a maximum likelihood bootstrap percentage ≥ 70. The scope of our analysis provides unprecedented insight into overall fern relationships, not only delivering additional support for the deepest leptosporangiate divergences, but also uncovering the composition of more recently emerging clades and their relationships to one another.Item Open Access Is morphology really at odds with molecules in estimating fern phylogeny?(Systematic Botany, 2009-07-01) Schneider, H; Smith, AR; Pryer, KMUsing a morphological dataset of 136 vegetative and reproductive characters, we infer the tracheophyte phylogeny with an emphasis on early divergences of ferns (monilophytes). The dataset comprises morphological, anatomical, biochemical, and some DNA structural characters for a taxon sample of 35 species, including representatives of all major lineages of vascular plants, especially ferns. Phylogenetic relationships among vascular plants are reconstructed using maximum parsimony and Bayesian inference. Both approaches yield similar relationships and provide evidence for three major lineages of extant vascular plants: lycophytes, ferns, and seed plants. Lycophytes are sister to the euphyllophyte clade, which comprises the fern and seed plant lineages. The fern lineage consists of five clades: horsetails, whisk ferns, ophioglossoids, marattioids, and leptosporangiate ferns. This lineage is supported by characters of the spore wall and has a parsimony bootstrap value of 76%, although the Bayesian posterior probability is only 0.53. Each of the five fern clades is well supported, but the relationships among them lack statistical support. Our independent phylogenetic analyses of morphological evidence recover the same deep phylogenetic relationships among tracheophytes as found in previous studies utilizing DNA sequence data, but differ in some ways within seed plants and within ferns. We discuss the extensive independent evolution of the five extant fern clades and the evidence for the placement of whisk ferns and horsetails in our morphological analyses. © 2009 by the American Society of Plant Taxonomists.Item Open Access Isozymic and Chromosomal Evidence for the Allotetraploid Origin of Gymnocarpium dryopteris (Dryopteridaceae)(Systematic Botany, 1993-01) Pryer, KM; Haufler, CHItem Open Access Low-copy nuclear data confirm rampant allopolyploidy in the cystopteridaceae (Polypodiales)(Taxon, 2014-10-01) Rothfels, CJ; Johnson, AK; Windham, MD; Pryer, KM© International Association for Plant Taxonomy (IAPT) 2014. Here we present the first nuclear phylogeny for Cystopteridaceae (Polypodiales), using the single-copy locus gapCp “short”. This phylogeny corroborates broad results from plastid data in demonstrating strong support for the monophyly of the family’s three genera—Cystopteris, Acystopteris, and Gymnocarpium—and of the major groups within Cystopteris (C. montana, the sudetica and bulbifera clades, and the C. fragilis complex). In addition, it confirms the rampant hybridization (allopolyploidy) that has long been suspected within both Cystopteris and Gymnocarpium. In some cases, these data provide the first DNA-sequence-based evidence for previous hypotheses of polyploid species origins (such as the cosmopolitan G. dryopteris being an allotetraploid derivative of the diploids G. appalachianum and G. disjunctum). Most of the allopolyploids, however, have no formal taxonomic names. This pattern is particularly strong within the C. fragilis complex, where our results imply that the eight included accessions of “C. fragilis” represent at least six distinct allopolyploid taxa.Item Open Access Maidenhair ferns, adiantum, are indeed monophyletic and sister to shoestring ferns, vittarioids (Pteridaceae)(Systematic Botany, 2016-01-01) Pryer, KM; Huiet, L; Li, F; Rothfels, CJ; Schuettpelz, E© 2016 by the American Society of Plant Taxonomists. Across the tree of life, molecular phylogenetic studies often reveal surprising relationships between taxa with radically different morphologies that have long obscured their close affiliations. A spectacular botanical example is Rafflesia, a holoparasite that produces the largest flowers in the world, but that evolved from tiny-flowered ancestors within the Euphorbiaceae. Outside of parasitic lineages, such abrupt transformations are rarely seen. One exception involves the "maidenhair ferns" (Adiantum), which are quintessential ferns: beautifully dissected, terrestrial, and shade loving. The closely related "shoestring ferns" (vittarioids), in contrast, have an extremely simplified morphology, are canopy-dwelling epiphytes, and exhibit greatly accelerated rates of molecular evolution. While Adiantum and the vittarioids together have been shown to form a robust monophyletic group (adiantoids), there remain unanswered questions regarding the monophyly of Adiantum and the evolutionary history of the vittarioids. Here we review recent phylogenetic evidence suggesting support for the monophyly of Adiantum, and analyze new plastid data to confirm this result. We find that Adiantum is monophyletic and sister to the vittarioids. With this robust phylogenetic framework established for the broadest relationships in the adiantoid clade, we can now focus on understanding the evolutionary processes associated with the extreme morphological, ecological, and genetic transitions that took place within this lineage.Item Open Access Metaxya lanosa, a second species in the genus and fern family Metaxyaceae(Systematic Botany, 2001-10-11) Smith, AR; Tuomisto, H; Pryer, KM; Hunt, JS; Wolf, PGWe describe and illustrate Metaxya lanosa, the second known species in the genus and the fern family Metaxyaceae (Pteridophyta). It is currently known from four different watersheds in Amazonian Peru and Venezuela. It can be distinguished readily from M. rostrata by the noticeably woolly-hairy stipes and rachises (hairs red-brown or orange-brown and easily abraded), broader, more elliptic pinnae, cartilaginous and whitish pinna margins, more distinct veins abaxially, and longer pinna stalks, especially on the distal pinnae, rbcL data from a very limited sampling are ambiguous but do not reject support for the recognition of at least two species within Metaxya.Item Open Access Molecular phylogenetic relationships and morphological evolution in the heterosporous fern genus Marsilea(Systematic Botany, 2007-01-01) Nagalingum, NS; Schneider, H; Pryer, KMUsing six plastid regions, we present a phylogeny for 26 species of the heterosporous fern genus Marsilea. Two well-supported groups within Marsilea are identified. Group I includes two subgroups, and is relatively species-poor. Species assignable to this group have glabrous leaves (although land leaves may have a few hairs), sporocarps lacking both a raphe and teeth, and share a preference for submerged conditions (i.e., they are intolerant of desiccation). Group II is relatively diverse, and its members have leaves that are pubescent, sporocarps that bear a raphe and from zero to two teeth, and the plants are often emergent at the edges of lakes and ponds. Within Group II, five subgroups receive robust support: three are predominantly African, one is New World, and one Old World. Phylogenetic assessment of morphological evolution suggests that the presence of an inferior sporocarp tooth and the place of sporocarp maturation are homoplastic characters, and are therefore of unreliable taxonomic use at an infrageneric level. In contrast, the presence of a raphe and superior sporocarp tooth are reliable synapomorphies for classification within Marsilea. © Copyright 2007 by the American Society of Plant Taxonomists.Item Open Access Norman Myers (1934-2019).(Nature ecology & evolution, 2020-02) Pimm, Stuart L; Raven, Peter H