Systematics of the Gracilariales (Rhodophyta) including new subfamilies, tribes, subgenera, and two new genera, Agarophyton gen. nov. and Crassa gen. nov.

Phytotaxa ◽  
2018 ◽  
Vol 374 (1) ◽  
pp. 1 ◽  
Author(s):  
CARLOS FREDERICO D. GURGEL ◽  
JAMES N. NORRIS ◽  
WILLIAM E. SCHMIDT ◽  
HAU NHU LE ◽  
SUZANNE FREDERICQ

The Gracilariales is a red macroalgal order and the main global source of the economically important agar, a marine phycocolloid. Independent comparative morphological and molecular phylogenetic studies over the last 20 years have revealed the existence of seven major clades recognizable as distinct genera. Of these major clades only four free-living genera have been widely accepted taxonomically: Curdiea, Melanthalia, Gracilariopsis, and Gracilaria. Three other clades comprise the reinstatement of the genus Hydropuntia and the proposal of two new genera, Agarophyton and Crassa, described herein. Based on new rbcL DNA sequences, and along with a reassessment of published comparative morphological and molecular phylogenetic studies, we argue that the latter three genera represent distinct evolutionary lineages in the Gracilariaceae, and propose a new classification for the order Gracilariales. Our new proposal incorporates the most current understanding of the evolutionary history of the order, establishes a natural and stable classification system, and provides the basis for the recognization of intra-family ranks. Our classification scheme reconciles all molecular phylogenetic studies published to date.

2015 ◽  
Vol 84 (4) ◽  
pp. 275-287 ◽  
Author(s):  
Ole E. Heie

Abstract Several characters of the Lachnidae are discussed, and it is explained why some of them are not plesiomorphies as previously believed, but apomorphies. This applies e.g. to the absence of host alternation in the extant genera, to the short cauda and to the presence of compound eyes in the nymphs and the apterous adults. Some characters are adaptations to attention by ants or ways of feeding. It is concluded that many characters show that the family is relatively young and probably originally had host alternation of the same kind as Aphididae, which is regarded as the sister group. The results of some molecular phylogenetic studies are discussed.


Phytotaxa ◽  
2015 ◽  
Vol 218 (3) ◽  
pp. 201 ◽  
Author(s):  
Ashley N. Egan ◽  
Bo Pan

Recent molecular phylogenetic studies (Egan et al., in prep.) have demonstrated widespread polyphyly within the genus Pueraria. A new classification is presented here that delineates monophyletic groups previously considered congeneric with Pueraria. This taxonomic treatment provides several new species combinations and a more natural circumscription of Pueraria by reinstating the genus Neustanthus, transferring one species to Teyleria and establishing two new genera: Haymondia and Toxicopueraria.


2019 ◽  
Vol 186 (4) ◽  
pp. 1067-1096 ◽  
Author(s):  
Elyse S Freitas ◽  
Aniruddha Datta-Roy ◽  
Praveen Karanth ◽  
L Lee Grismer ◽  
Cameron D Siler

AbstractThe genera Lepidothyris, Lygosoma and Mochlus comprise the writhing or supple skinks, a group of semi-fossorial, elongate-bodied skinks distributed across the Old World Tropics. Due to their generalized morphology and lack of diagnostic characters, species- and clade-level relationships have long been debated. Recent molecular phylogenetic studies of the group have provided some clarification of species-level relationships, but a number of issues regarding higher level relationships among genera still remain. Here we present a phylogenetic estimate of relationships among species in Lygosoma, Mochlus and Lepidothyris generated by concatenated and species tree analyses of multilocus data using the most extensive taxonomic sampling of the group to date. We also use multivariate statistics to examine species and clade distributions in morpho space. Our results reject the monophyly of Lygosoma s.l., Lygosoma s.s. and Mochlus, which highlights the instability of the current taxonomic classification of the group. We, therefore, revise the taxonomy of the writhing skinks to better reflect the evolutionary history of Lygosoma s.l. by restricting Lygosoma for Southeast Asia, resurrecting the genus Riopa for a clade of Indian and Southeast Asian species, expanding the genus Mochlus to include all African species of writhing skinks and describing a new genus in Southeast Asia.


2005 ◽  
Vol 1 (3) ◽  
pp. 291-295 ◽  
Author(s):  
Jennifer A Leonard ◽  
Nadin Rohland ◽  
Scott Glaberman ◽  
Robert C Fleischer ◽  
Adalgisa Caccone ◽  
...  

Twenty years ago, the field of ancient DNA was launched with the publication of two short mitochondrial (mt) DNA sequences from a single quagga ( Equus quagga ) museum skin, an extinct South African equid ( Higuchi et al . 1984 Nature 312 , 282–284). This was the first extinct species from which genetic information was retrieved. The DNA sequences of the quagga showed that it was more closely related to zebras than to horses. However, quagga evolutionary history is far from clear. We have isolated DNA from eight quaggas and a plains zebra (subspecies or phenotype Equus burchelli burchelli ). We show that the quagga displayed little genetic diversity and very recently diverged from the plains zebra, probably during the penultimate glacial maximum. This emphasizes the importance of Pleistocene climate changes for phylogeographic patterns in African as well as Holarctic fauna.


Science ◽  
2021 ◽  
Vol 373 (6556) ◽  
pp. 792-796 ◽  
Author(s):  
Paul K. Strother ◽  
Clinton Foster

Molecular time trees indicating that embryophytes originated around 500 million years ago (Ma) during the Cambrian are at odds with the record of fossil plants, which first appear in the mid-Silurian almost 80 million years later. This time gap has been attributed to a missing fossil plant record, but that attribution belies the case for fossil spores. Here, we describe a Tremadocian (Early Ordovician, about 480 Ma) assemblage with elements of both Cambrian and younger embryophyte spores that provides a new level of evolutionary continuity between embryophytes and their algal ancestors. This finding suggests that the molecular phylogenetic signal retains a latent evolutionary history of the acquisition of the embryophytic developmental genome, a history that perhaps began during Ediacaran-Cambrian time but was not completed until the mid-Silurian (about 430 Ma).


2012 ◽  
Vol 2012 ◽  
pp. 1-9 ◽  
Author(s):  
Masahiko Muraji ◽  
Norio Arakaki ◽  
Shigeo Tanizaki

The phylogenetic relationship, biogeography, and evolutionary history of closely related two firefly species,Curtos costipennisandC. okinawanus, distributed in the Ryukyu Islands of Japan were examined based on nucleotide sequences of mitochondrial (2.2 kb long) and nuclear (1.1-1.2 kb long) DNAs. In these analyses, individuals were divided among three genetically distinct local groups,C. costipennisin the Amami region,C. okinawanusin the Okinawa region, andC. costipennisin the Sakishima region. Their mtDNA sequences suggested that ancestralC. costipennispopulation was first separated between the Central and Southern Ryukyu areas, and the northern half was then subdivided betweenC. costipennisin the Amami andC. okinawanusin the Okinawa. The application of the molecular evolutionary clocks of coleopteran insects indicated that their vicariance occurred 1.0–1.4 million years ago, suggesting the influence of submergence and subdivision of a paleopeninsula extending between the Ryukyu Islands and continental China through Taiwan in the early Pleistocene.


2002 ◽  
Vol 93 (4) ◽  
pp. 333-353 ◽  
Author(s):  
Julia J. Day

ABSTRACTThe Eocene sparid fauna (Teleostei: Percoidei) from Monte Bolca, Italy and from the London Clay, U.K. is revised based on re-examination of the type material and phylogenetic analyses of primarily osteological data. Two phylogenetic analyses, one of the Eocene taxa and a combined analysis of fossil and extant taxa, were performed. The addition of fossils to the extant data greatly increased numbers of most parsimonious trees, destabilising and obscuring basal relationships within the Sparidae. Combination of the data from fossil and extant data also affected relationships among the fossil taxa, changing some from those recovered using fossil data alone and destabilising others. Successive approximations character weighting supported the inclusion of the Eocene taxa within a monophyletic Sparidae. The genus Sparnodus, as previously conceived, is paraphyletic and is partitioned to remove the paraphyly. Five monotypic genera are recognised, including three new genera, Abromasta, Ellaserrata and Pseudosparnodus. Inclusion of the fossils in the phylogenetic analysis implies a minimum age of origin for the Sparidae of 55 Ma with most Recent sparid fauna in place no later than the Miocene, and provides further evidence that the diversification of feeding strategies occurred early on in the evolutionary history of the group.


2019 ◽  
Vol 190 (4) ◽  
pp. 389-404 ◽  
Author(s):  
Kálmán Könyves ◽  
John David ◽  
Alastair Culham

Abstract Hoop-petticoat daffodils are a morphologically congruent group comprised of two distinct lineages in molecular phylogenetic trees of Narcissus. It is possible that the morphological similarity is a product of both historic and current low-level gene flow between these lineages. For the first time, we report population sampling from across the entire range of distribution covering the Iberian Peninsula and Morocco. In total, 455 samples were collected from 59 populations. Plastid DNA sequences of matK and ndhF were generated alongside 11 microsatellite loci to permit comparison between plastid and nuclear lineage histories. The plastid DNA phylogenetic tree was highly congruent with previous molecular studies and supported the recognition of these two lineages of hoop-petticoat daffodils as separate sections. Assignment of samples to sections sometimes differed between plastid DNA and (nuclear) microsatellite data. In these cases, the taxa had previously been the focus of dissent in taxonomic placement based on morphology. These discrepancies could be explained by hybridization and introgression among the two lineages during the evolution of hoop-petticoat daffodils, and shows that placement of species in sections is dependent on the source of data used. This study underlines the complex evolutionary history of Narcissus and highlights the discrepancies between floral morphology and phylogeny, which provides a continuing challenge for the systematics of Narcissus.


2019 ◽  
Vol 158 (2) ◽  
pp. 98-105 ◽  
Author(s):  
Suziane A. Barcellos ◽  
Rafael Kretschmer ◽  
Marcelo S. de Souza ◽  
Alice L. Costa ◽  
Tiago M. Degrandi ◽  
...  

As in many other bird groups, data on karyotype organization and distribution of repetitive sequences are also lacking in species belonging to the family Hirundinidae. Thus, in the present study, we analyzed the karyotypes of 3 swallow species (Progne tapera, Progne chalybea, and Pygochelidon cyanoleuca) by Giemsa and AgNOR staining, C-banding, and FISH with 11 microsatellite sequences. The diploid chromosome number was 2n = 76 in all 3 species, and NORs were observed in 2 chromosome pairs each. The microsatellite distribution pattern was similar in both Progne species, whereas P. cyanoleuca presented a distinct organization. These repetitive DNA sequences were found in the centromeric, pericentromeric, and telomeric regions of the macrochromosomes, as well as in 2 interstitial blocks in the W chromosome. Most microchromosomes had mainly telomeric signals. The Z chromosome displayed 1 hybridization signal in P. tapera but none in the other species. In contrast, the W chromosome showed an accumulation of different microsatellite sequences. The swallow W chromosome is larger than that of most Passeriformes. The observed enlargement in chromosome size might be explained by these high amounts of repetitive sequences. In sum, our data highlight the significant role that microsatellite sequences may play in sex chromosome differentiation.


Author(s):  
Ryan Kyger ◽  
Agusto Luzuriaga-Neira ◽  
Thomas Layman ◽  
Tatiana Orli Milkewitz Sandberg ◽  
Devika Singh ◽  
...  

Abstract DNA cytosine methylation is central to many biological processes, including regulation of gene expression, cellular differentiation, and development. This DNA modification is conserved across animals, having been found in representatives of sponges, ctenophores, cnidarians, and bilaterians, and with very few known instances of secondary loss in animals. Myxozoans are a group of microscopic, obligate endoparasitic cnidarians that have lost many genes over the course of their evolution from free-living ancestors. Here, we investigated the evolution of the key enzymes involved in DNA cytosine methylation in 29 cnidarians and found that these enzymes were lost in an ancestor of Myxosporea (the most speciose class of Myxozoa). Additionally, using whole-genome bisulfite sequencing, we confirmed that the genomes of two distant species of myxosporeans, Ceratonova shasta and Henneguya salminicola, completely lack DNA cytosine methylation. Our results add a notable and novel taxonomic group, the Myxosporea, to the very short list of animal taxa lacking DNA cytosine methylation, further illuminating the complex evolutionary history of this epigenetic regulatory mechanism.


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