Phylogenetics of Darwiniothamnus (Asteraceae: Astereae) – molecular evidence for multiple origins in the endemic flora of the Galápagos Islands

Aim The aims of this study were (1) to investigate whether the two growth forms of Darwiniothamnus Harling (Asteraceae) originated from the colonization of a single ancestor, (2) to identify the closest relative(s) of Darwiniothamnus, and (3) to review molecular phylogenies from other plant groups to infer the origin of Galápagos endemics. Location Darwiniothamnus is endemic to the Galápagos Islands. Methods All putative relatives of Darwiniothamnus plus 38 additional species were included. Nucleotide sequences of the internal transcribed spacers of the nuclear ribosomal DNA were used for Bayesian and parsimony analyses. Results Darwiniothamnus is polyphyletic. Two species (D. lancifolius (Hook. f.) Harling and D. tenuifolius (Hook. f.) Harling) are woody shrubs that usually grow to 1–2 m in height; they belong to a clade composed of species otherwise restricted to the Caribbean. These two species are sister to Erigeron bellidiastroides Griseb., a herbaceous species endemic to Cuba. The third species (D. alternifolius Lawesson & Adsersen) is a perennial herbaceous plant, woody at the base and reaching only up to 50 cm in height. It is sister to two Chilean (Coquimbo–Valparaiso region) species that also have a perennial herbaceous habit: E. fasciculatus Colla and E. luxurians (Skottsb.) Solbrig. They are placed in an assemblage restricted to South America. The review of previous molecular phylogenetic studies revealed that two of the endemic genera and endemic species of three non‐endemic genera have their closest relatives in South America. Endemic species belonging to three non‐endemic genera have sister species in North America or the West Indies. One endemic genus and endemic species in three non‐endemic genera have sister taxa with a widespread continental distribution, or their molecular phylogenies yielded equivocal results. Main conclusions The flora of Galápagos has affinities with both North America (including the Antilles) and South America. Darwiniothamnus exhibits both patterns: two species of this genus are sister to a taxon endemic to Cuba, supporting a connection between the Cocos plate and the West Indies; the third species, D. alternifolius, provides a link with the Coquimbo–Valparaiso region, suggesting a biogeographical connection between the Nazca plate and southern South America.     

Historical Biogeography of endemic seed plant genera in the Caribbean: Did GAARlandia play a role?

The Caribbean archipelago is a region with an extremely complex geological history and an outstanding plant diversity with high levels of endemism. The aim of this study was to better understand the historical assembly and evolution of endemic seed plant genera in the Caribbean, by first determining divergence times of endemic genera to test whether the hypothesized Greater Antilles and Aves Ridge (GAARlandia) land bridge played a role in the archipelago colonization and second by testing South America as the main colonization source as expected by the position of landmasses and recent evidence of an asymmetrical biotic interchange. We reconstructed a dated molecular phylogenetic tree for 625 seed plants including 32 Caribbean endemic genera using Bayesian inference and ten calibrations. To estimate the geographic range of the ancestors of endemic genera, we performed a model selection between a null and two complex biogeographic models that included timeframes based on geological information, dispersal probabilities, and directionality among regions. Crown ages for endemic genera ranged from Early Eocene (53.1 Ma) to Late Pliocene (3.4 Ma). Confidence intervals for divergence times (crown and/or stem ages) of 22 endemic genera occurred within the GAARlandia time frame. Contrary to expectations, the Antilles appears as the main ancestral area for endemic seed plant genera and only five genera had a South American origin. In contrast to patterns shown for vertebrates and other organisms and based on our sampling, we conclude that GAARlandia did not act as a colonization route for plants between South America and the Antilles. Further studies on Caribbean plant dispersal at the species and population levels will be required to reveal finer‐scale biogeographic patterns and mechanisms.     

Origin and differentiation of endemism in the flora of China

The present paper analyzed 239 endemic genera in 67 families in the flora of seed plants in China. The results showed that there are five families containing more than ten endemic genera, namely, Gesneriaceae (27), which hereafter refers to the number of endemic genera in China, Composite (20), Labiatae (12), Cruciferae (11), and Umbelliferae (10), 15 families with two endemic genera, and another 30 families with only one endemic genus. Four monotypic families (Ginkgoaceae, Davidiaceae, Eucommiaceae and Acanthochlamydaceae) are the most ancient, relict and characteristic in the flora of seed plants in China. Based on integrative data of systematics, fossil history, and morphological and molecular evidence of these genera, their origin, evolution and relationships were discussed. In gymnosperms, all endemic genera are relicts of the Arctic-Tertiary flora, having earlier evolutionary history, and can be traced back to the Cretaceous or to the Jurassic and even earlier. In angiosperms, the endemic genera are mostly relicts, and are represented in all lineages in the “Eight-Class System of Classification of Angiosperms”, and endemism can be found in almost every evolutionary stage of extant angiosperms. The relict genera once occupied huge areas in the northern hemisphere in the Tertiary or the late Cretaceous, while neo-endemism mostly originated in the late Tertiary. They came from Arctic-Tertiary, Paleo-tropical-Tertiary and Tethys-Tertiary florisitic elements, and the blend of the three elements with many genera of autochthonous origin. The endemism was formed when some dispersal routes such as the North Atlantic Land Bridge, and the Bering Bridge became discontinuous during the Tertiary, as well as the climate change and glaciations in the late Tertiary and the Quaternary. Therefore, the late Tertiary is the starting point of extant endemism of the flora in China. __________ Translated from Acta Botanica Yunnanica, 2005, 27(6): 577–604 [译自: 云南植物研究]     

Molecular phylogenetic studies of Lachnum and its allies based on the Japanese material

Molecular phylogenetic studies were carried out based on ITS-5.8S rDNA, the D1–D2 region of the large subunit rRNA gene, RPB2, and combined data of D1–D2 and RPB2 as well as these three genes on 36 species among 7 genera for Lachnum and allied genera in the family Hyaloscyphaceae. In the combined data of all three regions, seven strongly supported clades were obtained. The same clades were also recognized in most of the trees based on each gene, and the combined data of D1–D2 and RPB2, although some of them were not strongly supported. Four clades represented Albotricha, Brunnipila, Incrucipulum, and Lachnellula, respectively, whereas Lachnum was distributed to the remaining three clades. The molecular phylogenies strongly supported a group of species with granulate hairs, and we suggest the concept of Lachnaceae should be restricted to these species. Based on the molecular phylogenetic analysis, three new combinations—Incrucipulum longispineum, I. radiatum, and Lachnellula pulverulentum from Lachnum—are proposed.     

Are phylogenies resolved at the genus level appropriate for studies on phylogenetic structure of species assemblages?

Phylogenies are essential to studies investigating the effect of evolutionary history on assembly of species in ecological communities and geographical and ecological patterns of phylogenetic structure of species assemblages. Because phylogenies well resolved at the species level are lacking for many major groups of organisms such as vascular plants, researchers often generate a species-level phylogenies using a phylogeny well resolved at the genus level as a backbone and attaching species to their respective genera in the phylogeny as polytomies or by using a megaphylogeny well resolved at the genus level as a backbone and adding additional species to the megaphylogeny as polytomies of their respective genera. However, whether the result of a study using species-level phylogenies generated in these ways is robust, compared to that based on phylogenies fully resolved at the species level, has not been assessed. Here, we use 1093 angiosperm tree assemblages (each in a 110 × 110 km quadrat) in North America as a model system to address this question, by examining six commonly used metrics of phylogenetic structure (phylogenetic diversity and phylogenetic relatedness) and six climate variables commonly used in ecology. Our results showed that (1) the scores of phylogenetic metrics derived from species-level phylogenies resolved at the genus level with species being attached to their respective genera as polytomies are very strongly or perfectly correlated to those derived from a phylogeny fully resolved at the species level (the mean of correlation coefficients is 0.973), and (2) the relationships between the scores of phylogenetic metrics and climate variables are consistent between the two sets of analyses based on the two types of phylogeny. Our study suggests that using species-level phylogenies resolved at the genus level with species being attached to their genera as polytomies is appropriate in studies exploring patterns of phylogenetic structure of species in ecological communities across geographical and ecological gradients.     

The Bahamian Flora: Plant Exploration,Living Collections,and DNA – A Journey Started in 1963

Dr. John Popenoe was Director of Fairchild Tropical Botanic Garden (FTBG) between 1963 and 1989. Dr. Popenoe was a strong supporter of the Bahamian flora, and in 1963 he obtained extramural funds to develop a living collection focusing on Bahamian plants that was established in FTBG. During his tenure FTBG supported the publication of the latest comprehensive flora of this archipelago. A project initiated by the first FTBG herbarium curator, William Gillis, but published by Donovan and Helen Correll (with illustrations of Priscilla Fawcett) in 1982. This living collection of Bahamian plants has supplied plant material for molecular phylogenetic studies worldwide. There are DNA phylogenies for only 10 of the 89 Bahamian endemics; most of the material of these phylogenies came from plants from these collections (three species) and/or from fragments of herbarium specimens collected by Donovan Correll (six species). Only two of the species included in these phylogenies are from collections unrelated to FTBG. Excluding species restricted to the Bahamas, material from 14 Caribbean Island endemics that are part of these collections has been used in phylogenetic studies. The available molecular phylogenies show that the Bahamian endemics are closely related to species from the West Indies or continental areas of the Caribbean Basin. There is also a paucity of population genetic studies based on DNA markers focusing on Bahamian plants. Only two of the four available population genetic studies are for a Bahamian endemic taxon.     

Mitochondrial DNA Phylogeny of the Family Cichlidae: Monophyly and Fast Molecular Evolution of the Neotropical Assemblage

A mitochondrial DNA (mtDNA) phylogeny of cichlid fish is presented for the most taxonomically inclusive data set compiled to date (64 taxa). 16S rDNA data establish with confidence relationships among major lineages of cichlids, with a general pattern congruent with previous morphological studies and less inclusive molecular phylogenies based on nuclear genes. Cichlids from Madagascar and India are the most basal groups of the family Cichlidae and sister to African–Neotropical cichlids. The cichlid phylogeny suggests drift-vicariance events, consistent with the fragmentation of Gondwana, to explain current biogeographic distributions. Important phylogenetic findings include the placement of the controversial genus Heterochromis basal among African cichlids, the South American genus Retroculus as the most basal taxon of the Neotropical cichlid assemblage, and the close relationship of the Neotropical genera Cichla with Astronotus rather than with the crenicichlines. Based on a large number of South American genera, the Neotropical cichlids are defined as a monophyletic assemblage and shown to harbor significantly higher levels of genetic variation than their African counterparts. Relative rate tests suggest that Neotropical cichlids have experienced accelerated rates of molecular evolution. But these high evolutionary rates were significantly higher among geophagine cichlids. Received: 18 September 1998 / Accepted: 16 December 1998     

The phylogenetic position of some Philippine "babblers" spans the muscicapoid and sylvioid bird radiations

The Philippines is characterized by a high rate of endemism among its terrestrial vertebrates, including enigmatic genera with uncertain affinities. In a recent comprehensive study of the avian family of Timaliidae (babblers), it was shown that three putative babbler genera endemic to the Philippines (Leonardina, Robsonius, and Micromacronus) are distant relatives of Timaliidae. With additional DNA sequences from new samples and data from Genbank, we attempt to determine the phylogenetic affinities of these three genera and examine the resulting implications for biogeography and avian endemism in the Philippines. Well-supported phylogenies recover the three genera in three different families spanning the sylvioid and muscicapoid radiations of passerine birds. Leonardina groups with Muscicapidae and is most closely related to other isolated montane endemic species in Southeast Asia. Robsonius appears to be an early offshoot of Locustellidae. Micromacronus belongs in Cisticolidae, but its position in the family is unresolved. Contrary to implications based on traditional taxonomy, the Philippine archipelago appears to have played a minor role in the diversification of babblers.     

Morphology and molecular phylogeny of a marine interstitial tetraflagellate with putative endosymbionts: <Emphasis Type="Italic">Auranticordis quadriverberis</Emphasis> n. gen. et sp. (Cercozoa)

Background  

Comparative morphological studies and environmental sequencing surveys indicate that marine benthic environments contain a diverse assortment of microorganisms that are just beginning to be explored and characterized. The most conspicuous predatory flagellates in these habitats range from about 20–150 μm in size and fall into three major groups of eukaryotes that are very distantly related to one another: dinoflagellates, euglenids and cercozoans. The Cercozoa is a diverse group of amoeboflagellates that cluster together in molecular phylogenies inferred mainly from ribosomal gene sequences. These molecular phylogenetic studies have demonstrated that several enigmatic taxa, previously treated as Eukaryota insertae sedis, fall within the Cercozoa, and suggest that the actual diversity of this group is largely unknown. Improved knowledge of cercozoan diversity is expected to help resolve major branches in the tree of eukaryotes and demonstrate important cellular innovations for understanding eukaryote evolution.     

CLADISTIC REAPPRAISAL OF NEOTROPICAL STENODERMATINE BAT PHYLOGENY

Abstract— Several phylogenies have been proposed for neotropical stenodermatine fruit-eating bats (Phyllostomidae), based on detention, external morphology, osteology and chromosomes. However, these previous analyses did not incorporate fully the idea that relationships should be identified based solely on shared derived characteristics. A critique of past methodology and results, and an alternative phylogeny using a morphological data set supplemented with karyotypic information, is presented. In my analysis, there appear two main lineages. The eight genera of white-shouldered bats form a monophyletic clade based on three synapomorphies (white patch of fur on shoulders, lack of a palatial extension with varying degrees of emargination and modified upper incisors); previous work suggested a paraphyletic relationship for this group. Furthermore, the monophyly of the four genera endemic to the Antilles is supported by two synapomorphies, suggesting a common origin as opposed to a multiple invasion for these genera. The appearance of the derived 2n = 30 and FN = 56 standard karyotype suggests that the morphologically distinct Sturnira forms the sister taxon to the remaining genera which are united by the synapomorphy of white facial stripes. This supports the inclusion of Sturnira within the stendodermatines and not in its own monotypic higher-level taxon. My results do not refute the traditional systematic view of Artibeus (including Dermanura, Koopmania and Enchisthenes ) being monophyletic, and supports Mesophylla and Vampyressa being distinct non-sister genera.     

A synopsis of Jacquinia (Theophrastaceae) in the Antilles and South America

Stål, B. 1995. A synopsis of Jacquinia (Theophrastaceae) in the Antilles and South America. — Nord. J. Bot. 15: 493–511. Copenhagen. ISSN 0107–055X.
The genus Jacquinia in the Antilles and South America is revised. Twenty-two native and one introduced species are recognised. In the Greater Antilles, 11 species (six endemic) occur in Cuba, eight in Hispaniola (two endemic), five in Jamaica (two endemic), and four in Puerto Rico (none endemic). Two species (none endemic) occur in the Lesser Antilles and five (four endemic) in South America. Eighteen species are native to the Antilles and of these one, J. arborea , is shared with Central America and one, J. amzillaris , is shared with South America. No species is shared between South and Central America. One new combination, J. frutescens , is made. Several species are illustrated and distribution maps for all species are presented. A key to the species in the Antilles and South America and an index to all combinations published in Jacquinia are provided.     

Fish fauna of Chalakudy River,part of Western Ghats biodiversity hotspot,Kerala, India: patterns of distribution,threats and conservation needs

Seventy one fish species belonging to 27 families and 50 genera were collected from various sampling sites spread along the upstream and downstream parts of the Chalakudy river, in the Western Ghats biodiversity hotspot in Kerala, South India. Cyprinids were the most dominant group represented by 24 species belonging to 13 genera, followed by the catfishes of the family Bagridae (7 species from 2 genera) and loaches belonging to the family Balitoridae (5 species from 5 genera). Of the 71 species, 4 belong to the ‘critically endangered’ (CR) and 16 to the ‘endangered’ (EN) category. 3 of the critically endangered species are strictly endemic to the Chalakudy river system. We also collected 5 exotic species several of them categorized as potential pest. Fish species richness (FSR) showed a direct relationship with increasing stream order with maximum values observed in the downstream/low elevation regions. Considerable differences were observed in the FSR between different microhabitats with maximum values observed in bed rock and pool riffle and the lowest in regimes followed by step pools. Diversity and species richness decreased with increasing altitude and higher diversity and species richness were observed in sampling sites located between 0–200 m above sea level. A definite temporal partitioning was also observed with regard to FSR with higher richness during the day time and the lowest observed at dawn. Indiscriminate collection of endemic and threatened ornamental fish species for export, exploitation of endangered food fishes by forest-dwelling communities and local fisher folk, pollution, loss of riparian cover, damming and exotic species threaten the rich ichthyofaunal diversity of Chalakudy River. An urgent need exists for studying the life history traits and demography of the most important endemic and threatened fishes, as lack of information on these aspects have significantly affected conservation efforts. The implementation of strong management strategies like fixing total allowable catch (TAC), and the use of quotas are needed to reduce the overall collection pressure with regard to the trade in native ornamental species from the river.     

Notes on the Poaceae of the Robinson Crusoe (Juan Fernández) Islands, Chile

Notes on the Poaceae of the Robinson Crusoe (Juan Fernández) Islands, Chile, Brittonia 54: 154–163. 2001.—Poaceae in the Robinson Crusoe (=Juan Fernández) Islands number 53 species in 32 genera, of which 9% of the species are endemic, 9% indigenous, and 81% adventitious. The endemic taxa (and their conservation status) are:Agrostis masafuerana (rare),Chusquea fernandeziana (not endangered),Megalachne berteroana (not endangered),M. masafuerana (not endangered), andPodophorus bromoides (extinct).Megalachne andPodophorus are endemic genera. Comparisons with Poaceae in the Bonin and Volcano Islands, Canary Islands, Galápagos Islands, and Hawaiian Islands show different levels of endemism: number of endemic taxa, respectively, 5, 10, 12, 40; percent specific endemism, 8, 6, 21, 19. No endemic genera occur.Anthoxanthum odoratum, Avena barbata andHordeum murinum are noxious weeds in the Robinson Crusoe Islands. Many adventives are shared among floras of the archipelagos, with the highest ties of Robinson Crusoe being to the Canaries (53% of total Poaceae known in Juan Fernández) and the Hawaiian Islands (47%). Low levels of adventives occur within the Bonin (5%) and Galápagos (7%) Islands. In contrast, there are many endemic genera of Asteraceae in these same archipelagos: Bonin and Volcano Islands (1), Canary Islands (8), Galápagos Islands (5), and Hawaiian Islands (6); percent of specific endemism is also higher (20, 53, 54 and 56, respectively). Hypotheses for greater levels of endemics among oceanic island Asteraceae include more efficient dispersal mechanisms by wind and birds, animal pollination systems that result in greater degrees of geographic populational genetic isolation, and a vascular cambium that offers enhanced growth-form evolutionary opportunities.     

The Taxonomic and Evolutionary History of Fossil and Modern Balaenopteroid Mysticetes

Balaenopteroids (Balaenopteridae + Eschrichtiidae) are a diverse lineage of living mysticetes, with seven to ten species divided between three genera (Megaptera, Balaenoptera and Eschrichtius). Extant members of the Balaenopteridae (Balaenoptera and Megaptera) are characterized by their engulfment feeding behavior, which is associated with a number of unique cranial, mandibular, and soft anatomical characters. The Eschrichtiidae employ suction feeding, which is associated with arched rostra and short, coarse baleen. The recognition of these and other characters in fossil balaenopteroids, when viewed in a phylogenetic framework, provides a means for assessing the evolutionary history of this clade, including its origin and diversification. The earliest fossil balaenopterids include incomplete crania from the early late Miocene (7–10 Ma) of the North Pacific Ocean Basin. Our preliminary phylogenetic results indicate that the basal taxon, “Megaptera” miocaena should be reassigned to a new genus based on its possession of primitive and derived characters. The late late Miocene (5–7 Ma) balaenopterid record, except for Parabalaenoptera baulinensis and Balaenoptera siberi, is largely undescribed and consists of fossil specimens from the North and South Pacific and North Atlantic Ocean basins. The Pliocene record (2–5 Ma) is very diverse and consists of numerous named, but problematic, taxa from Italy and Belgium, as well as unnamed taxa from the North and South Pacific and eastern North Atlantic Ocean basins. For the most part Pliocene balaenopteroids represent extinct species and genera and reveal a greater degree of morphological diversity than at present. The Pleistocene record is very limited and, unfortunately, fails to document the evolutionary details leading to modern balaenopteroid species diversity. It is evident, however, that most extant species evolved during the Pleistocene. Morphological and molecular based phylogenies support two competing hypotheses concerning relationships within the Balaenopteroidea: (1) balaenopterids and eschrichtiids as sister taxa, and (2) eschrichtiids nested within a paraphyletic Balaenopteridae. The addition of fossil taxa (including a new Pliocene species preserving a mosaic of balaenopterid and eschrichtiid characters) in morphological and “total evidence” analyses, offers the potential to resolve the current controversy concerning the possible paraphyly of Balaenopteridae.     

A synopsis of the endemic plant genera of Borneo

The large, tropical island of Borneo has some of the world's richest habitats for plant life, but faces increasing pressures from anthropogenic activities that threaten its biodiversity. With a good portion of the Bornean flora not critically studied, a comprehensive documentation of the numerous endemic taxa expected for the island is not yet complete. It is not known what the relative significance of endemic genera is compared to Bornean centres of endemism documented or predicted through modelling, and if they can inform current conservation plans. As a first step, we here present a synopsis of the endemic genera of Borneo, based on a comprehensive study of literature, herbarium specimens and distributional data, and an investigation of whether the genera have been included in molecular phylogenetic studies that confirm their monophyly. Such a review is timely since many generic delimitations have been shaped by molecular evidence used to test morphology-based taxonomy, while botanical collection and revisionary efforts continue. Our findings suggest that 65 vascular plant genera from 25 families may be considered endemic to Borneo. More than two-thirds (48) of these genera have had at least one species included in molecular phylogenetic studies, but of these, only 39 have been sufficiently sampled to be considered monophyletic with high confidence, or they are monotypic. Slightly over half (38) of the endemic genera are herbaceous. A majority of the genera have fruits or seeds specialised for dispersal by abiotic vectors, or unspecialised seeds. Almost two-thirds (42) of the endemic genera are monotypic, and some of these could represent relict lineages. We expect the current list of endemic genera to be relatively stable and aligned with recent taxonomic concepts, and that it serves to illuminate an interesting aspect of Borneo's unique assemblage of endemic species.     

Molecular Systematics of Threatened Seed Plant Species Endemic in the Caribbean Islands

A review of available Caribbean Island red-lists species (CR and EN categories based on the IUCN guidelines from 2001, and E category established according to the IUCN guidelines from 1980) is presented. A database of over 1,300 endemic species that are either Critically Endangered or Endangered sensu IUCN was created. There are molecular systematic studies available for 112 of them. Six of these species (in six genera) are the only members of early divergent lineages that are sister to groups composed of a large number of clades. Seven of the species (in seven genera) belong to clades that have a small number of taxa but are sister to species/genus-rich clades. Ten of the species (in six genera) are sister to taxa restricted to South America or nested in clades endemic to this region. Fifty-seven of the species (in 35 genera) are sister to Caribbean Island endemic species. Erigeron belliastroides, an Endangered (EN) Cuban endemic, is sister to the Galapagos genus Darwiniothamnus. The phylogenetic placement of four of the threatened species resulted in changes in their taxonomic placement; they belong to polyphyletic or paraphyletic genera.     

A reptilian smoking gun: first record of invasive Jackson’s chameleon (<Emphasis Type="Italic">Chamaeleo jacksonii</Emphasis>) predation on native Hawaiian species

Here we report the first conclusive evidence of an introduced reptile (Chamaeleo jacksonii) feeding on Hawaiian taxa, including 11 snails in four endemic genera from two families, including four individuals of an endangered species (Achatinella mustelina), and native insects in five genera. Native Hawaiian invertebrates were discovered in the dissected stomachs of wild caught Jackson’s chameleons collected from June to November 2009 on the island of Oahu. Although Jackson’s chameleons were introduced to the Hawaiian Islands in the early 1970s, ecological impacts have never been documented. Of particular concern is the fact that chameleons have previously only rarely been found in native Hawaiian habitat, although 12 were recently collected in a mid-elevation native forest, an area that is not likely to be suitable for their long-term persistence, but that is adjacent to higher elevation pristine forest where endemic prey are abundant and favorable climatic conditions exist for chameleon persistence. One concern is that Jacksons’s chameleons may be undergoing a range expansion into upper elevation pristine forests. If chameleons reach and establish populations in these areas, devastating impacts to the native ecosystem are possible. A thorough understanding of the impacts of chameleons on Hawaiian fauna will require additional evaluation and sampling, but dissemination of this discovery in a timely fashion is important as it provides new information regarding this threat. Monitoring and collection of chameleons is ongoing, particularly in native Hawaiian forest habitats at mid and upper elevations (600–1,300 m).     

An analysis of altitudinal behavior of tree species in Subansiri district,Eastern Himalaya

Plant species diversity and endemism demonstrate a definite trend along altitude. We analyzed the (i) pattern of tree diversity and its endemic subset (ii) frequency distribution of altitudinal range and (iii) upper & lower distributional limits of each tree species along altitudinal gradients in eastern Himalaya. The study was conducted in Subansiri district of Arunachal Pradesh. Data on the tree species (cbh ≥ 15 cm) were gathered every 200 m steps between 200 m and 2200 m gradients. Tree diversity demonstrated a greater variation along the gradients. A total of 336 species (of which 26 are endemic) were recorded belonging to 185 genera and 78 families. The alpha diversity demonstrated a decreasing pattern with two maxima (i.e., elevational peaks) along the gradients; one in 601–1000 m and the other in 1601–1800 m, corresponding to transition zones between tropical-subtropical and subtropical-temperate forests. Pattern diversity revealed a narrow range along the gradients. Frequency of altitudinal range was distributed between 1 and 41. Only one species (Altingia excelsa) showed widest amplitude, occurring over the entire range. Highest level of species turnover was found in 400–600 m step at lower elevational limit whereas for upper elevational limit, the highest turn over was recorded between 800 and 1000 m. Tree diversity decreased and its endemic subset increased along the gradients. Two maximas in tree diversity pattern correspond to forest transition zones with subtropical-temperate transition is narrower than tropical-subtropical. The pattern observed here could be attributed to varied microclimates or environmental heterogeneity. If altitudinal amplitude of a species is considered as an aspect of its niche breadth, it is clear from these results that niche breadth in these organisms is in fact independent of the diversity of the assemblage in which they occur. This analysis calls for detailed floristic studies to determine the breadth of changes between adjacent forest types and details of local species richness in high diversity areas.     

A Total Evidence Phylogeny of the Arctoidea (Carnivora: Mammalia): Relationships Among Basal Taxa

A total evidence phylogenetic analysis was performed for 14 extant and 18 fossil caniform genera using a data matrix of 5.6 kbp of concatenated sequence data from six independent loci and 80 morphological characters from the cranium and dentition. Maximum parsimony analysis recovered a single most parsimonious cladogram (MPC). The topology of the extant taxa in the MPC agreed with previous molecular phylogenies. Phylogenetic positions for fossil taxa indicate that several taxa previously described as early members of extant families (e.g., Bathygale and Plesictis) are likely stem taxa at the base of the Arctoidea. Taxa in the “Paleomustelidae” were found to be paraphyletic, but a monophyletic Oligobuninae was recovered within this set of taxa. This clade was closely related to the extant genera Gulo and Martes, therefore, nested within the extant radiation of the family Mustelidae. This analysis provides a resolution to several discrepancies between phylogenies considering either fossil taxa or extant taxa separately, and provides a framework for incorporating fossil and extant taxa into comprehensive combined evidence analyses.     

The evolutionary radiation of Arvicolinae rodents (voles and lemmings): relative contribution of nuclear and mitochondrial DNA phylogenies

Background  

Mitochondrial and nuclear genes have generally been employed for different purposes in molecular systematics, the former to resolve relationships within recently evolved groups and the latter to investigate phylogenies at a deeper level. In the case of rapid and recent evolutionary radiations, mitochondrial genes like cytochrome b (CYB) are often inefficient for resolving phylogenetic relationships. One of the best examples is illustrated by Arvicolinae rodents (Rodentia; Muridae), the most impressive mammalian radiation of the Northern Hemisphere which produced voles, lemmings and muskrats. Here, we compare the relative contribution of a nuclear marker – the exon 10 of the growth hormone receptor (GHR) gene – to the one of the mitochondrial CYB for inferring phylogenetic relationships among the major lineages of arvicoline rodents.