Cyanobacterial diversity and taxonomic uncertainty: polyphasic pathways to improved resolution

After many years of taxonomic uncertainty, Albertosaurus was established as a new genus in 1905, the year Alberta became a province of Canada. Gorgosaurus is a closely related tyrannosaurid from the Judithian beds of southern Alberta that was subsequently synonymized with Albertosaurus. Although most researchers consider the genera as distinct, there has been considerable confusion over the temporal and geographic range of Albertosaurus. Albertosaurus sarcophagus is only known from 13 skulls and (or) skeletons of varying completeness, and one (possibly two) bonebeds, all from the Horseshoe Canyon Formation (Campanian–Maastrichtian) of Alberta. Many of the major Albertosaurus specimens are scientifically compromised due to poor collection techniques, incomplete locality and stratigraphic information, politics, vandalism, accidents, gunplay, and landowner issues. The background of each specimen is discussed to eliminate some of the sources of confusion and to document how much of each specimen is preserved.

Download Full-text

Culture-dependent characterization of cyanobacterial diversity in the intertidal zones of the Portuguese coast: A polyphasic study

Systematic and Applied Microbiology ◽

10.1016/j.syapm.2011.07.003 ◽

2012 ◽

Vol 35 (2) ◽

pp. 110-119 ◽

Cited By ~ 31

Author(s):

Ângela Brito ◽

Vitor Ramos ◽

Rui Seabra ◽

Arlete Santos ◽

Catarina L. Santos ◽

...

Keyword(s):

Intertidal Zones ◽

Portuguese Coast ◽

Cyanobacterial Diversity ◽

Culture Dependent

Download Full-text

Taxonomy of Farrea (Porifera, Hexactinellida, Hexactinosida) from the southwestern Atlantic, with description of a new species and a discussion on the recognition of subspecies in Porifera

Canadian Journal of Zoology ◽

10.1139/z10-105 ◽

2011 ◽

Vol 89 (3) ◽

pp. 169-189 ◽

Cited By ~ 4

Author(s):

D. A. Lopes ◽

E. Hajdu ◽

H. M. Reiswig

Keyword(s):

New Species ◽

Comparative Analysis ◽

Video Recording ◽

First Record ◽

Historical Overview ◽

Southwestern Atlantic ◽

Campos Basin ◽

Taxonomic Uncertainty ◽

Coral Banks ◽

A New Species

The present study reports three species of Farrea Bowerbank, 1862 from Campos Basin (southwestern Atlantic): Farrea herdendorfi Duplessis and Reiswig, 2004, Farrea occa Bowerbank, 1862, and Farrea campossinus sp. nov. This is the first record of F. herdendorfi for the South Atlantic and only the second record of the species worldwide. Farrea occa is described and reported to form mass occurrences in the area’s sponge and coral banks, as seen in extensive video recording undertaken between 900 and 1100 m depth. The new species approaches Farrea foliascens Topsent, 1906 very closely, but differs in that its hooked anchorate clavules are much larger and the meshes of its dictyonal framework rather more irregular. Our thoughts on whether the proposed new species deserved species or subspecies rank led to an investigation on the usage of subspecies rank in Porifera. A historical overview, mainly contrasting Demospongiae and Hexactinellida is offered here. We concluded that no rule of thumb is readily made out from the comparative analysis of various authors’ taxonomic decisions. Until one such agreement is achieved, it appears to us that naming new subspecies should be objectively argued for, or better, totally avoided, as a useless further dimension to taxonomic uncertainty in poriferan classification.

Download Full-text

Genetic structure and historical and contemporary gene flow of Astyanaxmexicanus in the Gulf of Mexico slope: a microsatellite-based analysis

PeerJ ◽

10.7717/peerj.10784 ◽

2021 ◽

Vol 9 ◽

pp. e10784

Author(s):

Rodolfo Pérez-Rodríguez ◽

Sarai Esquivel-Bobadilla ◽

Adonaji Madeleine Orozco-Ruíz ◽

José Luis Olivas-Hernández ◽

Francisco Javier García-De León

Keyword(s):

Gene Flow ◽

Gulf Of Mexico ◽

Microsatellite Loci ◽

Evolutionary History ◽

Population Analysis ◽

Morphological Variability ◽

High Capacity ◽

Genetic Population ◽

Contemporary Gene Flow ◽

Taxonomic Uncertainty

Background Astyanax mexicanus from the river basins of the Gulf of Mexico slope are small freshwater fish that usually live in large groups in different freshwater environments. The group is considered successful due to its high capacity for dispersal and adaptation to different habitats, and the species present high morphological variability throughout their distribution in Mexico. This has produced the most extreme morphotype of the group; the hypogeous or troglobite, which has no eyes or coloration, and is probably the cause of taxonomic uncertainty in the recognition of species across the entire range. Most studies of A. mexicanus have mainly focused on cave individuals, as well as their adjacent surface locations, providing an incomplete evolutionary history, particularly in terms of factors related to dispersal and the potential corridors used, barriers to gene flow, and distribution of genetic variability. The aim of the present study is to determine the population structure and the degree and direction of genetic flow in this complex taxonomic group, incorporating geographic locations not previously included in analyses using microsatellite loci. Our aim is to contribute to the knowledge of the intricate evolutionary history of A. mexicanus throughout most of its range. Methods The present study included a set of several cave and surface locations of A. mexicanus, which have been widely sampled along the Gulf of Mexico slope, in a genetic population analysis using 10 microsatellite loci. Results Ten genetic populations or lineages were identified. In these populations, gene flow was recorded at two time periods. Historical gene flow, both inter and intra-basin, was observed among surface populations, from surface to cave populations, and among cave populations, whereas recording of contemporary gene flow was limited to intra-basin exchanges and observed among surface populations, surface to cave populations, and cave populations.

Download Full-text

Taxonomic Uncertainty and the Anomaly Zone: Phylogenomics Disentangle a Rapid Radiation to Resolve Contentious Species (Gila robusta complex) in the Colorado River

10.1101/692509 ◽

2019 ◽

Cited By ~ 2

Author(s):

Tyler K. Chafin ◽

Marlis R. Douglas ◽

Max R. Bangs ◽

Bradley T. Martin ◽

Steven M. Mussmann ◽

...

Keyword(s):

Colorado River ◽

Nominal Species ◽

Rapid Radiation ◽

Evolutionary Mechanisms ◽

Phylogenetic Discordance ◽

The Status ◽

Taxonomic Uncertainty ◽

Morphological Differences ◽

Phylogenetic Models ◽

Methodological Difficulties

AbstractSpecies is an indisputable unit for biodiversity conservation, yet their delimitation is fraught with both conceptual and methodological difficulties. A classic example is the taxonomic controversy surrounding the Gila robusta complex in the lower Colorado River of southwestern North America. Nominal species designations were originally defined according to weakly diagnostic morphological differences that conflicted with traditional genetic analyses. Consequently, the complex was re-defined as a single polytypic unit, with the proposed ‘threatened’ status of two being withdrawn at the federal level. Here, we utilized dense spatial and genomic sampling (N=387 and >22k loci) to re-evaluate the status of the complex, based on SNP-based coalescent and polymorphism-aware phylogenetic models. In doing so, all three species were supported as evolutionarily independent lineages, despite widespread phylogenetic discordance. To understand this discrepancy with past studies, we categorized evolutionary mechanisms driving discordance. We tested (and subsequently rejected) prior hypotheses suggesting that phylogenetic discord in the complex was hybridization-driven. Instead, we found the G. robusta complex to have diverged within the ‘anomaly zone’ of tree space and, as such, have accumulated inconsistent patterns of diversity which have confounded prior studies. After extending these analyses with phylogeographic modeling, we propose that this is reflective of a rapid radiation promoted by Plio-Pleistocene tectonism. Our results not only support resurrection of the three species as distinct entities, but also offer an empirical example of how phylogenetic discordance can be categorized in other recalcitrant taxa where variation is primarily partitioned at the species-level.

Download Full-text

The curse of taxonomic uncertainty in biogeographical studies of free-living terrestrial protists: a case study of testate amoebae from Amsterdam Island

Journal of Biogeography ◽

10.1111/j.1365-2699.2009.02094.x ◽

2009 ◽

Vol 36 (8) ◽

pp. 1551-1560 ◽

Cited By ~ 31

Author(s):

T. J. Heger ◽

E. A. D. Mitchell ◽

P. Ledeganck ◽

S. Vincke ◽

B. Van de Vijver ◽

...

Keyword(s):

Testate Amoebae ◽

Free Living ◽

Taxonomic Uncertainty

Download Full-text

Cyanophycean (Cyanobacterial) diversity from the Lakhimpur-Khiri District of Northern Uttar Pradesh, India

International Journal of Science and Technology Research Archive ◽

10.53771/ijstra.2021.1.2.0040 ◽

2021 ◽

Vol 1 (2) ◽

pp. 1-2

Author(s):

Digvijay Verma ◽

Vinay Kumar Singh ◽

Rinku Bharati ◽

Shyam Kishore ◽

Seshu Lavania

Keyword(s):

Methylene Blue ◽

Microscopic Study ◽

Standard Method ◽

Uttar Pradesh ◽

Water Bodies ◽

Methylene Blue Solution ◽

Different Seasons ◽

Blue Solution ◽

Cyanobacterial Diversity ◽

First Time

In the present study, the cyanophycean diversity of the Lakhimpur-Khiri district, northern Uttar Pradesh, India, has been investigated for the first time. Algae samples were collected in plastic bottles and preserved in 3-4% formalin from Lakhimpur-Khiri district of northern Uttar Pradesh in different seasons from 2015 to 2016. The field photographs of the selected localities were also taken and the location of each site noted down. For the Microscopic study of Cyanophycean algae, the samples were stained with 1 % aqueous methylene blue solution according to the standard method. The observations and photomicrography were done with help of Nikon Labophot-11 microscope. A total of 31 cyanophycean algal taxa have been recorded from different water bodies of Lakhimpur-Khiri. These algal taxa belong to 14 genera and 9 families of the division Cyanophyata. Of these, Oscillatoria (7), Phormidium (4) and Lyngbya (3) are abundant.

Download Full-text

Cyanobacterial Diversity in the Hypersaline Environment of the Saltpans of Southeastern Coast of India

Asian Journal of Plant Sciences ◽

10.3923/ajps.2008.473.478 ◽

2008 ◽

Vol 7 (5) ◽

pp. 473-478 ◽

Cited By ~ 8

Author(s):

A. Nagasathya ◽

N. Thajuddin

Keyword(s):

Hypersaline Environment ◽

Southeastern Coast ◽

Cyanobacterial Diversity

Download Full-text

Epiphytic cyanobacterial diversity in the sub-Himalayan belt of Garhwal region of Uttarakhand, India

Botanica Orientalis Journal of Plant Science ◽

10.3126/botor.v8i0.5955 ◽

2012 ◽

Vol 8 ◽

pp. 77-89 ◽

Cited By ~ 3

Author(s):

Mukesh Kumar ◽

Rajan Kumar Gupta ◽

AB Bhatt ◽

SC Tiwari

Keyword(s):

Significant Variation ◽

Principal Component ◽

Climatic Conditions ◽

Oxygenic Photosynthesis ◽

Plant Science ◽

Himalayan Belt ◽

Different Seasons ◽

Cyanobacterial Diversity ◽

Species Study ◽

Properties Of Soil

Cyanobacteria constitute the largest, most diverse and widely distributed group of prokaryotes that perform oxygenic photosynthesis. These are known to comprise a diverse flora of morphologically distinct forms. Some species are epiphytic occurring on a variety of plants. The present study was undertaken to study the distribution pattern of epiphytic cyanobacterial flora in the foot-hills of Garhwal Himalaya. An extensive survey was carried out in different seasons at four cyanobacteria-rich localities (Dakpatthar, Kotdwar, Rishikesh and Laldhang) of Uttarakhand state of India. A total of 39 epiphytic cyanobacterial taxa (12 heterocystous and 27 non-heterocystous) belonging to 2 orders, 7 families and 17 genera were recorded from this region. Highest number of species (25) was reported from Rishikesh, followed by Kotdwar with 14 species and Laldhang and Dakpatthar each with 12 species. Principal Component Analysis showed significant variation for epiphytic cyanobacterial diversity among studied sites, whereas cluster analysis categorized epiphytic cyanobacterial diversity under two categories, viz. Cluster I with 9 species and Cluster II with 30 species. Study concludes that variation in epiphytic cyanobacterial diversity might be compared to physicochemical properties of soil and climatic conditions along altitudes.doi: http://dx.doi.org/10.3126/botor.v8i0.5955 Botanica Orientalis – Journal of Plant Science (2011) 8: 77-89

Download Full-text