Migration, speciation, and the evolution of diadromy in anguillid eels

2002 ◽  
Vol 59 (12) ◽  
pp. 1989-1998 ◽  
Author(s):  
K Tsukamoto ◽  
J Aoyama ◽  
M J Miller

Recent findings and hypotheses about the migration, spawning ecology, phylogenetic relationships, and possible mechanisms of speciation of anguillid eels are overviewed. The offshore distribution and otolith microstructure of small leptocephali suggest that the Japanese eel Anguilla japonica may spawn at seamounts west of the Mariana Islands in the western North Pacific during the new moon of each month from April to November. Some temperate eels have been found to remain in coastal areas after recruitment without a freshwater growth phase (ocean residents or "sea eels"), showing flexible patterns of migratory histories. Recent molecular phylogenetic studies suggest that the tropical eel Anguilla borneensis from the Borneo Island region is the most ancestral species. Every eel species or population has its own migration loop (migration route or life cycle) that connects their spawning area and growth habitats. Spatial and temporal shifts in these migration loops could cause separation into subpopulations, or speciation. Therefore, the large-scale migration of temperate eels probably evolved from local migrations of tropical eels as a result of long-distance dispersal of leptocephali from spawning sites in tropical waters of low latitude to temperate growth habitats at higher latitudes.

2019 ◽  
Author(s):  
Nicolás N. Moreyra ◽  
Julián Mensch ◽  
Juan Hurtado ◽  
Francisca Almeida ◽  
Cecilia Laprida ◽  
...  

AbstractThe Drosophila repleta group is an array of more than 100 cactophilic species endemic to the “New World”. The acquisition of the ability to utilize decaying cactus tissues as breeding and feeding sites is a key aspect that allowed the successful diversification of the repleta group in the American deserts. Within this group, the Drosophila buzzatii cluster is a South American clade of seven cactophilic closely related species in different stages of divergence, a feature that makes it a valuable model system for evolutionary research. However, even though substantial effort has been devoted to elucidating the phylogenetic relationships among members of the D. buzzatii cluster, the issue is still controversial. In effect, molecular phylogenetic studies performed to date generated ambiguous results since tree topologies depend on the kind of molecular marker employed. Curiously, even though mitochondrial DNA has become a popular marker in evolutionary biology and population genetics, none of the more than twenty Drosophila mitogenomes assembled so far belongs to this cluster. In this work we report the assembly of six complete mitogenomes of five species: D. antonietae, D. borborema, D. buzzatii, D. seriema and two strains of D. koepferae, with the aim to revisit the phylogenetic relationships and divergence times by means of a mitogenomic approach. The recovered topology using complete mitogenomes gives support to the hypothesis of the monophyly of that the D. buzzatii cluster and shows two main clades, one including D. buzzatii and D. koepferae (both strains) and the other the remaining species. These results are in agreement with previous reports based on a few mitochondrial and/or nuclear genes but in conflict with the results of a recent large-scale nuclear phylogeny, suggesting that nuclear and mitochondrial genomes depict different evolutionary histories.


PeerJ ◽  
2016 ◽  
Vol 4 ◽  
pp. e2160 ◽  
Author(s):  
Soowon Cho ◽  
Samantha W. Epstein ◽  
Kim Mitter ◽  
Chris A. Hamilton ◽  
David Plotkin ◽  
...  

Butterflies and moths (Lepidoptera) comprise significant portions of the world’s natural history collections, but a standardized tissue preservation protocol for molecular research is largely lacking. Lepidoptera have traditionally been spread on mounting boards to display wing patterns and colors, which are often important for species identification. Many molecular phylogenetic studies have used legs from pinned specimens as the primary source for DNA in order to preserve a morphological voucher, but the amount of available tissue is often limited. Preserving an entire specimen in a cryogenic freezer is ideal for DNA preservation, but without an easily accessible voucher it can make specimen identification, verification, and morphological work difficult. Here we present a procedure that creates accessible and easily visualized “wing vouchers” of individual Lepidoptera specimens, and preserves the remainder of the insect in a cryogenic freezer for molecular research. Wings are preserved in protective holders so that both dorsal and ventral patterns and colors can be easily viewed without further damage. Our wing vouchering system has been implemented at the University of Maryland (AToL Lep Collection) and the University of Florida (Florida Museum of Natural History, McGuire Center of Lepidoptera and Biodiversity), which are among two of the largest Lepidoptera molecular collections in the world.


2013 ◽  
Vol 58 (1) ◽  
pp. 149-177 ◽  
Author(s):  
S. Robbert Gradstein

AbstractIn 1983, Gradstein, Pócs and Váňa discussed the disjunct Afro-American ranges of 41 liverwort species and 8 genera. Since the appearance of this paper much progress has been made in the study of tropical liverworts and knowledge of the neotropical and African floras has improved considerably. The new investigations have raised the number of Afro-American hepatics to 74 species, 13 genera and one family (Oxymitraceae). Afro-American species constitute about 5% of the neotropical liverwort flora and 8% of the flora of Africa. The percentages of species shared by the two continents are doubled when pantropical species are added. Five Afro-American species are newly recognized in this paper: Calypogeia peruviana Nees & Mont. (= C. afrocaerulea E. W. Jones, syn. nov.), Ceratolejeunea coarina (Gottsche) Steph. (= C. diversicornua Steph., syn. nov.), C. ornithocephala Herzog (= C. kilimanjarica Pócs & Ast, syn. nov.), Odontoschisma variabile (Lindenb. & Gottsche) Trevis. (= O. africanum Steph., syn. nov.) and Syzygiella manca (Mont.) Steph. [= S. geminifolia (Mitt.) Steph., syn. nov.]. Spore dispersal experiments and molecular-phylogenetic studies have shown that the intercontinental ranges of liverwort species, and of the majority of genera, should have resulted from long-distance dispersal events, not from vicariance.


Author(s):  
Ron Harris

Before the seventeenth century, trade across Eurasia was mostly conducted in short segments along the Silk Route and Indian Ocean. Business was organized in family firms, merchant networks, and state-owned enterprises, and dominated by Chinese, Indian, and Arabic traders. However, around 1600 the first two joint-stock corporations, the English and Dutch East India Companies, were established. This book tells the story of overland and maritime trade without Europeans, of European Cape Route trade without corporations, and of how new, large-scale, and impersonal organizations arose in Europe to control long-distance trade for more than three centuries. It shows that by 1700, the scene and methods for global trade had dramatically changed: Dutch and English merchants shepherded goods directly from China and India to northwestern Europe. To understand this transformation, the book compares the organizational forms used in four major regions: China, India, the Middle East, and Western Europe. The English and Dutch were the last to leap into Eurasian trade, and they innovated in order to compete. They raised capital from passive investors through impersonal stock markets and their joint-stock corporations deployed more capital, ships, and agents to deliver goods from their origins to consumers. The book explores the history behind a cornerstone of the modern economy, and how this organizational revolution contributed to the formation of global trade and the creation of the business corporation as a key factor in Europe's economic rise.


Author(s):  
D. G. Melnikov ◽  
L. I. Krupkina

Based on the published data of molecular phylogenetic studies of the tribe Cariceae Dumort. genera (Cyperaceae), obtained by an international collaboration (The Global Carex Group, 2016; et al.), and morphological characters of the genera (Kukkonen, 1990; and others), new nomenclatural combinations and replacement names in the genus Carex L. are published for 11 species, one subspecies and two sections previously included in the genus Kobresia Willd.


Author(s):  
Richard W. Jobson ◽  
Paulo C. Baleeiro ◽  
Cástor Guisande

Utricularia is a morphologically and ecologically diverse genus currently comprising more than 230 species divided into three subgenera—Polypompholyx, Utricularia, and Bivalvaria—and 35 sections. The genus is distributed worldwide except on the poles and most oceanic islands. The Neotropics has the highest species diversity, followed by Australia. Compared to its sister genera, Utricularia has undergone greater rates of speciation, which are linked to its extreme morphological flexibility that has resulted in the evolution of habitat-specific forms: terrestrial, rheophytic, aquatic, lithophytic, and epiphytic. Molecular phylogenetic studies have resolved relationships for 44% of the species across 80% of the sections. Scant data are available for phylogeography or population-level processes such as gene flow, hybridization, or pollination. Because nearly 90% of the species are endemics, data are urgently needed to determine how to protect vulnerable species and their habitats.


2021 ◽  
Vol 13 (4) ◽  
pp. 2225
Author(s):  
Ralf Peters ◽  
Janos Lucian Breuer ◽  
Maximilian Decker ◽  
Thomas Grube ◽  
Martin Robinius ◽  
...  

Achieving the CO2 reduction targets for 2050 requires extensive measures being undertaken in all sectors. In contrast to energy generation, the transport sector has not yet been able to achieve a substantive reduction in CO2 emissions. Measures for the ever more pressing reduction in CO2 emissions from transportation include the increased use of electric vehicles powered by batteries or fuel cells. The use of fuel cells requires the production of hydrogen and the establishment of a corresponding hydrogen production system and associated infrastructure. Synthetic fuels made using carbon dioxide and sustainably-produced hydrogen can be used in the existing infrastructure and will reach the extant vehicle fleet in the medium term. All three options require a major expansion of the generation capacities for renewable electricity. Moreover, various options for road freight transport with light duty vehicles (LDVs) and heavy duty vehicles (HDVs) are analyzed and compared. In addition to efficiency throughout the entire value chain, well-to-wheel efficiency and also other aspects play an important role in this comparison. These include: (a) the possibility of large-scale energy storage in the sense of so-called ‘sector coupling’, which is offered only by hydrogen and synthetic energy sources; (b) the use of the existing fueling station infrastructure and the applicability of the new technology on the existing fleet; (c) fulfilling the power and range requirements of the long-distance road transport.


2021 ◽  
Vol 307 (2) ◽  
Author(s):  
Pau Carnicero ◽  
Núria Garcia-Jacas ◽  
Llorenç Sáez ◽  
Theophanis Constantinidis ◽  
Mercè Galbany-Casals

AbstractThe eastern Mediterranean basin hosts a remarkably high plant diversity. Historical connections between currently isolated areas across the Aegean region and long-distance dispersal events have been invoked to explain current distribution patterns of species. According to most recent treatments, at least two Cymbalaria species occur in this area, Cymbalaria microcalyx and C. longipes. The former comprises several intraspecific taxa, treated at different ranks by different authors based on morphological data, evidencing the need of a taxonomic revision. Additionally, some populations of C. microcalyx show exclusive morphological characters that do not match any described taxon. Here, we aim to shed light on the systematics of eastern Mediterranean Cymbalaria and to propose a classification informed by various sources of evidence. We performed molecular phylogenetic analyses using ITS, 3’ETS, ndhF and rpl32-trnL sequences and estimated the ploidy level of some taxa performing relative genome size measures. Molecular data combined with morphology support the division of traditionally delimited C. microcalyx into C. acutiloba, C. microcalyx and C. minor, corresponding to well-delimited nrDNA lineages. Furthermore, we propose to combine C. microcalyx subsp. paradoxa at the species level. A group of specimens previously thought to belong to Cymbalaria microcalyx constitute a well-defined phylogenetic and morphological entity and are described here as a new species, Cymbalaria spetae. Cymbalaria longipes is non-monophyletic, but characterized by being glabrous and diploid, unlike other eastern species. The nrDNA data suggest at least two dispersals from the mainland to the Aegean Islands, potentially facilitated by marine regressions.


2006 ◽  
Vol 63 (8) ◽  
pp. 1752-1762 ◽  
Author(s):  
Matthew L Keefer ◽  
Christopher C Caudill ◽  
Christopher A Peery ◽  
Theodore C Bjornn

Upstream-migrating adult salmon must make a series of correct navigation and route-selection decisions to successfully locate natal streams. In this field study, we examined factors influencing migration route selections early in the migration of 4361 radio-tagged adult Chinook salmon (Oncorhynchus tshawytscha) as they moved upstream past dams in the large (~1 km wide) Columbia River. Substantial behavioral differences were observed among 11 conspecific populations, despite largely concurrent migrations. At dams, Chinook salmon generally preferred ladder passage routes adjacent to the shoreline where their natal tributaries entered, and the degree of preference increased as salmon proximity to natal tributaries increased. Columbia River discharge also influenced route choices, explaining some route selection variability. We suggest that salmon detect lateral gradients in orientation cues across the Columbia River channel that are entrained within tributary plumes and that these gradients in cues can persist downstream for tens to hundreds of kilometres. Detection of tributary plumes in large river systems, using olfactory or other navigation cues, may facilitate efficient route selection and optimize energy conservation by long-distance migrants.


2021 ◽  
Vol 7 (12) ◽  
pp. eabe2741
Author(s):  
Paschalia Kapli ◽  
Paschalis Natsidis ◽  
Daniel J. Leite ◽  
Maximilian Fursman ◽  
Nadia Jeffrie ◽  
...  

The bilaterally symmetric animals (Bilateria) are considered to comprise two monophyletic groups, Protostomia (Ecdysozoa and the Lophotrochozoa) and Deuterostomia (Chordata and the Xenambulacraria). Recent molecular phylogenetic studies have not consistently supported deuterostome monophyly. Here, we compare support for Protostomia and Deuterostomia using multiple, independent phylogenomic datasets. As expected, Protostomia is always strongly supported, especially by longer and higher-quality genes. Support for Deuterostomia, however, is always equivocal and barely higher than support for paraphyletic alternatives. Conditions that cause tree reconstruction errors—inadequate models, short internal branches, faster evolving genes, and unequal branch lengths—coincide with support for monophyletic deuterostomes. Simulation experiments show that support for Deuterostomia could be explained by systematic error. The branch between bilaterian and deuterostome common ancestors is, at best, very short, supporting the idea that the bilaterian ancestor may have been deuterostome-like. Our findings have important implications for the understanding of early animal evolution.


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