Integrative Taxonomy Reveals a New Species of the Genus Lejeunea (Marchantiophya: Lejeuneaceae) from Peninsular Malaysia.

Prior to the advent of molecular work, the observable variation in vegetative reproduction has been used to classify Lejeunea into subgenera and sections. Thereby, the ability of developing caducous leaves was regarded as major factor. A reexamination of several Lejeunea specimens revealed that L. cocoes with caducous leaves shows considerable morphological differences with non-caducous leaved plants of L. cocoes. Phylogenetic analyses based on a three-marker dataset (rbcL, trnLF and the nuclear ribosomal ITS region) indicated two independent and robust lineages of the morpho-species L. cocoes. We consider both clades as two distinct species and therefore describe the new species, L. malaysiana for L. cocoes morpho-species with caducous leaves. Lejeunea malaysiana is characterized by its caducous leaves with ribbon-like and plantlet regenerants, strongly reduced leaf lobules, distant and deeply bilobed underleaves, long-keeled obovoid perianth, and autoicy and ranges from tropical Asia to the Pacific region.

A study of community structure and beta diversity of epiphyllous liverwort assemblages in Sabah, Malaysian Borneo.

We evaluated the species richness and beta diversity of epiphyllous assemblages from three selected localities in Sabah, i.e. Mt. Silam in Sapagaya Forest Reserve, and Ulu Senagang and Mt. Alab in Crocker Range Park. A total of 98 species were found and a phytosociological survey was carried out based on the three study areas. A detailed statistical analysis including standard correlation and regression analyses, ordination of species and leaves using centered principal component analysis, and the SDR simplex method to evaluate the beta diversity, was conducted. Beta diversity is very high in the epiphyllous liverwort assemblages in Sabah, with species replacement as the major component of pattern formation and less pronounced richness difference. The community analysis of the epiphyllous communities in Sabah makes possible their detailed description and comparison with similar communities of other continents.

An ancient tropical origin, dispersals via land bridges and Miocene diversification explain the subcosmopolitan disjunctions of the liverwort genus Lejeunea.

Understanding the biogeographical and diversification processes explaining current diversity patterns of subcosmopolitan-distributed groups is challenging. We aimed at disentangling the historical biogeography of the subcosmopolitan liverwort genus Lejeunea with estimation of ancestral areas of origin and testing if sexual system and palaeotemperature variations can be factors of diversification. We assembled a dense taxon sampling for 120 species sampled throughout the geographical distribution of the genus. Lejeunea diverged from its sister group after the Paleocene-Eocene boundary (52.2 Ma, 95% credibility intervals 50.1-54.2 Ma), and the initial diversification of the crown group occurred in the early to middle Eocene (44.5 Ma, 95% credibility intervals 38.5-50.8 Ma). The DEC model indicated that (1) Lejeunea likely originated in an area composed of the Neotropics and the Nearctic, (2) dispersals through terrestrial land bridges in the late Oligocene and Miocene allowed Lejeunea to colonize the Old World, (3) the Boreotropical forest covering the northern regions until the late Eocene did not facilitate Lejeunea dispersals, and (4) a single long-distance dispersal event was inferred between the Neotropics and Africa. Biogeographical and diversification analyses show the Miocene was an important period when Lejeunea diversified globally. We found slight support for higher diversification rates of species with both male and female reproductive organs on the same individual (monoicy), and a moderate positive influence of palaeotemperatures on diversification. Our study shows that an ancient origin associated with a dispersal history facilitated by terrestrial land bridges and not long-distance dispersals are likely to explain the subcosmopolitan distribution of Lejeunea. By enhancing the diversification rates, monoicy likely favoured the colonisations of new areas, especially in the Miocene that was a key epoch shaping the worldwide distribution.

Geographical structure, narrow species ranges, and Cenozoic diversification in a pantropical clade of epiphyllous leafy liverworts.

The evolutionary history and classification of epiphyllous cryptogams are still poorly known. Leptolejeunea is a largely epiphyllous pantropical liverwort genus with about 25 species characterized by deeply bilobed underleaves, elliptic to narrowly obovate leaf lobes, the presence of ocelli, and vegetative reproduction by cladia. Sequences of three chloroplast regions (rbcL, trnL-F, psbA) and the nuclear ribosomal ITS region were obtained for 66 accessions of Leptolejeunea and six outgroup species to explore the phylogeny, divergence times, and ancestral areas of this genus. The phylogeny was estimated using maximum-likelihood and Bayesian inference approaches, and divergence times were estimated with a Bayesian relaxed clock method. Leptolejeunea likely originated in Asia or the Neotropics within a time interval from the Early Eocene to the Late Cretaceous (67.9 Ma, 95% highest posterior density [HPD]: 47.9-93.7). Diversification of the crown group initiated in the Eocene or early Oligocene (38.4 Ma, 95% HPD: 27.2-52.6). Most species clades were established in the Miocene. Leptolejeunea epiphylla and L. schiffneri originated in Asia and colonized African islands during the Plio-Pleistocene. Accessions of supposedly pantropical species are placed in different main clades. Several monophyletic morphospecies exhibit considerable sequence variation related to a geographical pattern. The clear geographic structure of the Leptolejeunea crown group points to evolutionary processes including rare long-distance dispersal and subsequent speciation. Leptolejeunea may have benefitted from the large-scale distribution of humid tropical angiosperm forests in the Eocene.

Crown Group Lejeuneaceae and Pleurocarpous Mosses in Early Eocene (Ypresian) Indian Amber.

Cambay amber originates from the warmest period of the Eocene, which is also well known for the appearance of early angiosperm-dominated megathermal forests. The humid climate of these forests may have triggered the evolution of epiphytic lineages of bryophytes; however, early Eocene fossils of bryophytes are rare. Here, we present evidence for lejeuneoid liverworts and pleurocarpous mosses in Cambay amber. The preserved morphology of the moss fossil is inconclusive for a detailed taxonomic treatment. The liverwort fossil is, however, distinctive; its zig-zagged stems, suberect complicate-bilobed leaves, large leaf lobules, and small, deeply bifid underleaves suggest a member of Lejeuneaceae subtribe Lejeuneinae (Harpalejeunea, Lejeunea, Microlejeunea). We tested alternative classification possibilities by conducting divergence time estimates based on DNA sequence variation of Lejeuneinae using the age of the fossil for corresponding age constraints. Consideration of the fossil as a stem group member of Microlejeunea or Lejeunea resulted in an Eocene to Late Cretaceous age of the Lejeuneinae crown group. This reconstruction is in good accordance with published divergence time estimates generated without the newly presented fossil evidence. Balancing available evidence, we describe the liverwort fossil as the extinct species Microlejeunea nyiahae, representing the oldest crown group fossil of Lejeuneaceae.

World checklist of hornworts and liverworts.

A working checklist of accepted taxa worldwide is vital in achieving the goal of developing an online flora of all known plants by 2020 as part of the Global Strategy for Plant Conservation. We here present the first-ever worldwide checklist for liverworts (Marchantiophyta) and hornworts (Anthocerotophyta) that includes 7486 species in 398 genera representing 92 families from the two phyla. The checklist has far reaching implications and applications, including providing a valuable tool for taxonomists and systematists, analyzing phytogeographic and diversity patterns, aiding in the assessment of floristic and taxonomic knowledge, and identifying geographical gaps in our understanding of the global liverwort and hornwort flora. The checklist is derived from a working data set centralizing nomenclature, taxonomy and geography on a global scale. Prior to this effort a lack of centralization has been a major impediment for the study and analysis of species richness, conservation and systematic research at both regional and global scales. The success of this checklist, initiated in 2008, has been underpinned by its community approach involving taxonomic specialists working towards a consensus on taxonomy, nomenclature and distribution.

Molecular phylogeny of the leafy liverwort Lejeunea (Porellales): evidence for a neotropical origin, uneven distribution of sexual systems and insufficient taxonomy.

BACKGROUND: Lejeunea is a largely epiphytic, subcosmopolitan liverwort genus with a complex taxonomic history. Species circumscriptions and their relationships are subject to controversy; biogeographic history and diversification through time are largely unknown. METHODOLOGY AND RESULTS: We employed sequences of two chloroplast regions (trnL-trnF, rbcL) and the nuclear ribosomal ITS region of 332 accessions to explore the phylogeny of the Harpalejeunea-Lejeunea-Microlejeunea complex. Lejeunea forms a well-supported clade that splits into two main lineages corresponding to L. subg. Lejeunea and L. subg. Crossotolejeunea. Neotropical accessions dominate early diverging lineages of both main clades of Lejeunea. This pattern suggests an origin in the Neotropics followed by several colonizations from the Neotropics into the Paleotropics and vice versa. Most Afro-Madagascan clades are related to Asian clades. Several temperate Lejeunea radiations were detected. Eighty two of the 91 investigated Lejeunea species could be identified to species level. Of these 82 species, 54 were represented by multiple accessions (25 para- or polyphyletic, 29 monophyletic). Twenty nine of the 36 investigated species of L. subg. Lejeunea were monoicous and 7 dioicous. Within L. subg. Crossotolejeunea, 15 of the 46 investigated species were monoicous and 31 dioicous. Some dioicous as well as some monoicous species have disjunct ranges. CONCLUSIONS/SIGNIFICANCE: We present the first global phylogeny of Lejeunea and the first example of a Neotropical origin of a Pantropical liverwort genus. Furthermore, we provide evidence for the Neotropics as a cradle of Lejeunea lineages and detect post-colonization radiations in Asia, Australasia, Afro-Madagascar and Europe. Dioicy/monoicy shifts are likely non-randomly distributed. The presented phylogeny points to the need of integrative taxonomical studies to clarify many Lejeunea binomials. Most importantly, it provides a framework for future studies on the diversification of this lineage in space and time, especially in the context of sexual systems in Lejeuneaceae.

Tramps, narrow endemics and morphologically cryptic species in the epiphyllous liverwort Diplasiolejeunea.

Diplasiolejeunea is a pantropical, epiphytic genus of leafy liverworts that occurs from the lowlands to more than 4000m altitude. Phylogenetic analyses of a molecular dataset consisting of three markers (nuclear ribosomal ITS region, plastidic trnL-F region and rbcL gene) and 122 accessions (plus two outgroups, Colura and Cololejeunea) indicate that the evolutionary diversity of Diplasiolejeunea is underestimated by current morphology-based classification. Four morphologically semi-cryptic species have been recovered. The molecular phylogenies support a deep split into a Neotropical and a Paleotropical clade, the latter structured into Australasian, Asian and Afromadacascan lineages. Presented results confirm the ranges of two pantropical species (D. cavifolia, D. rudolphiana), provide evidence for dispersal from the Neotropics into the Paleotropics, indicate speciation along altitudinal gradients and demonstrate extensive morphological homoplasy. We propose a revised supraspecific classification of Diplasiolejeunea into a predominantly Paleotropical subgenus Physolejeunea and predominantly Neotropical subgenera Austrolejeuneopsis and Diplasiolejeunea, the former containing mainly epiphytic species, the latter mainly epiphylls. Several clades are supported by combinations of morphological character states, and could be assigned to sections at some later point. This is the first comprehensive phylogeny of a largely epiphyllous genus of liverworts.

Analysis of dark albedo features on a southern polar dune field of Mars.

We observed 20-200 m sized low-albedo seepage-like streaks and their annual change on defrosting polar dunes in the southern hemisphere of Mars, based on the Mars Orbiter Camera (MOC), High Resolution Stereo Camera (HRSC), and High Resolution Imaging Science Experiment (HiRISE) images. The structures originate from dark spots and can be described as elongated or flowlike and, at places, branching streaks. They frequently have another spotlike structure at their end. Their overall appearance and the correlation between their morphometric parameters suggest that some material is transported downward from the spots and accumulates at the bottom of the dune's slopes. Here, we present possible scenarios for the origin of such streaks, including dry avalanche, liquid CO(2), liquid H(2)O, and gas-phase CO(2). Based on their morphology and the currently known surface conditions of Mars, no model interprets the streaks satisfactorily. The best interpretation of only the morphology and morphometric characteristics is only given by the model that implies some liquid water. The latest HiRISE images are also promising and suggest liquid flow. We suggest, with better knowledge of sub-ice temperatures that result from extended polar solar insolation and the heat insulator capacity of water vapor and water ice, future models and measurements may show that ephemeral water could appear and flow under the surface ice layer on the dunes today.

Molecular insights into the phylogeny and subgeneric classification of Frullania Raddi (Frullaniaceae, Porellales).

With an estimated 300-375 species, Frullania is the largest genus of Porellales and forms a major clade of leafy liverworts. The cosmopolitan genus includes mostly epiphytes and represents an important component of the cryptogamic vegetation in various, especially tropical, habitats. There have been abundant changes and modifications to the infrageneric classification of Frullania, with up to fifteen subgenera and numerous sections solely based on morphology. Here we present the first molecular phylogeny of Frullania using four markers (rbcL, psbA, trnL-trnF region of cp DNA, nr5.8S-ITS-2 region) and 171 accessions from throughout the range. The molecular data provide evidence for the monophyly of several subgenera and support intercontinental ranges of these clades. Previous subgeneric assignment for a suite of taxa based on morphological evidence is not supported by the molecular data. Representatives of the genera Amphijubula, Neohattoria and Schusterella are nested in robust subclades of Frullania. Basal relationships within Frullania are largely unsupported. Based on the outcome of the phylogenetic analyses we present a revised supraspecific classification and provide evidence for the monophyly of some morphological species. Disjunct distributional patterns within Frullania cannot be explained by Gondwanan vicariance.