scholarly journals Endocranial preservation of a Carboniferous actinopterygian from Lancashire, UK, and the interrelationships of primitive actinopterygians

1999 ◽  
Vol 354 (1382) ◽  
pp. 435-462 ◽  
Author(s):  
Michael I. Coates
Keyword(s):  
Brain Structure ◽  
Morphological Characters ◽  
Taxonomic Group ◽  
Brain Morphology ◽  
Monophyletic Clade ◽  
Upper Carboniferous ◽  
Fossil Material ◽  
Muscle Insertion ◽  
Fossil Data ◽  
Enamel Composition

The gross brain structure of an Upper Carboniferous ( ca . 310 Myr ago) ray–finned fish (Actinopterygii) is described from exceptionally well–preserved fossil material from the Burnley region of Lancashire, UK. Previously identified as ‘ Rhadinichthys ’ planti , the species is reassigned to the genus Mesopoma . Morphological characters derived from these data are combined with reviews of cranial skeletal anatomy, enamel composition, oculomoter muscle insertion and paired fin morphology to test and reanalyse hypotheses of primitive actinopterygian interrelationships. Results indicate that ancestral chondrostean (sturgeon and paddlefish) and neopterygian (teleost, amiid and gar) lineages diverged earlier than current theories suggest. Palaeonisciformes, a taxonomic group widely used to include most Palaeozoic actinopterygians, include a significant number of primitive neopterygians, several of which may form a distinct monophyletic clade. Within this revised phylogenetic context, changes in gross brain morphology from primitive conditions, as revealed by fossil data, highlight likely specializations in extant non–teleostean actinopterygians.

Phylogeny and Biogeography of Chara (Charophyta) Inferred from 18S rDNA Sequences

1999 ◽  
Vol 47 (3) ◽  
pp. 347 ◽  
Author(s):  
S. T. Meiers ◽  
V. W. Proctor ◽  
R. L. Chapman
Keyword(s):  
Maximum Likelihood ◽  
Morphological Characters ◽  
Small Subunit ◽  
Monophyletic Clade ◽  
Rdna Sequences ◽  
Extant Species ◽  
Likelihood Analysis ◽  
18S Rdna Sequences ◽  
Break Up ◽  
Fossil Data

Competing hypotheses concerning the relationships among subsections of the genus Chara were tested with parsimony and maximum likelihood analysis of small subunit (18S) ribosomal DNA gene (rDNA) sequences. The traditional hypothesis as stated by Wood and Imahori (1965) separates Chara into subgenera and subsections based primarily on stipulode and cortication characters, whereas Proctor’s (1980) hypothesis proposed subgenera based on the break-up of Pangea into Laurasia and Gondwana, and subsections based on the subsequent break-up of these two supercontinents. Both parsimony and maximum likelihood analyses strongly refuted Wood and Imahori’s hypothesis, as well as the importance traditionally placed on stipulode and cortication characters. Partial or total loss of cortication may occur within a subsection, as demonstrated by C. imperfecta, C. braunii, C. muelleri and C. brittonii. Although the nodal stem cell gives rise to the branchlets, stipulodes and axial cortex, stipulodes can be retained despite the loss of cortication as demonstrated by C. hydropitys, which is placed solidly within Willdenowia by both analyses. Proctor’s hypothesis was supported with Gondwanan subsections basal (except for C. tomentosa) and Laurasian subsections placed together in a monophyletic clade in both analyses, although the placement of subsection Grovesia is uncertain. Monophyly of subsections Wallmania and Willdenowia and Lamprothamnium are strongly supported. Lamprothamnium is placed within the genus Chara, which disagrees with previous (McCourt et al. 1996) rbcL analyses. Further studies are needed to identify phylogenetically informative morphological characters for extant taxa, and a method is needed to link extant species to the extensive fossil data for a fuller understanding of the phylogeny and biogeography of this distinctive genus.

scholarly journals Empirical examination of the replicability of associations between brain structure and psychological variables

eLife ◽  
2019 ◽  
Vol 8 ◽  
Author(s):  
Shahrzad Kharabian Masouleh ◽  
Simon B Eickhoff ◽  
Felix Hoffstaedter ◽  
Sarah Genon ◽  
Keyword(s):  
Brain Structure ◽  
Gray Matter Volume ◽  
Brain Morphology ◽  
Empirical Examination ◽  
Psychological Variables ◽  
Psychological Measures ◽  
Exploratory Approach ◽  
Wide Range ◽  
Cognitive Neurosciences ◽  
Brain Behavior

Linking interindividual differences in psychological phenotype to variations in brain structure is an old dream for psychology and a crucial question for cognitive neurosciences. Yet, replicability of the previously-reported ‘structural brain behavior’ (SBB)-associations has been questioned, recently. Here, we conducted an empirical investigation, assessing replicability of SBB among heathy adults. For a wide range of psychological measures, the replicability of associations with gray matter volume was assessed. Our results revealed that among healthy individuals 1) finding an association between performance at standard psychological tests and brain morphology is relatively unlikely 2) significant associations, found using an exploratory approach, have overestimated effect sizes and 3) can hardly be replicated in an independent sample. After considering factors such as sample size and comparing our findings with more replicable SBB-associations in a clinical cohort and replicable associations between brain structure and non-psychological phenotype, we discuss the potential causes and consequences of these findings.

scholarly journals Advances in studying brain morphology: The benefits of open-access data

2017 ◽  
Author(s):  
Christopher R Madan
Keyword(s):  
Open Access ◽  
Brain Structure ◽  
Large Scale ◽  
Open Data ◽  
Brain Morphology ◽  
Subcortical Structures ◽  
Open Access Data ◽  
Age Related ◽  
Neuroimaging Data ◽  
Access Data

Until recently, neuroimaging data for a research study needed to be collected within one’s own lab. However, when studying inter-individual differences in brain structure, a large sample of participants is necessary. Given the financial costs involved in collecting neuroimaging data from hundreds or thousands of participants, large-scale studies of brain morphology could previously only be conducted by well-funded laboratories with access to MRI facilities and to large samples of participants. With the advent of broad open-access data-sharing initiatives, this has recently changed–here the primary goal of the study is to collect large datasets to be shared, rather than sharing of the data as an afterthought. This paradigm shift is evident as increase in the pace of discovery, leading to a rapid rate of advances in our characterization of brain structure. The utility of open-access brain morphology data is numerous, ranging from observing novel patterns of age-related differences in subcortical structures to the development of more robust cortical parcellation atlases, with these advances being translatable to improved methods for characterizing clinical disorders (see Figure 1 for an illustration). Moreover, structural MRIs are generally more robust than functional MRIs, relative to potential artifacts and in being not task-dependent, resulting in large potential yields. While the benefits of open-access data have been discussed more broadly within the field of cognitive neuroscience elsewhere (Gilmore et al., 2017; Poldrack and Gorgolewski, 2014; Van Horn and Gazzaniga, 2013; Voytek, 2016), as well as in other fields (Ascoli et al., 2017; Choudhury et al., 2014; Davies et al., 2017), the current paper is focused specifically on the implications of open data to brain morphology research.

Integrative approach reveals underestimated Peyssonneliales diversity in Brazil: registering the first occurrence of Ramicrusta and Incendia, with the description of three new species

Phytotaxa ◽  
2020 ◽  
Vol 439 (1) ◽  
pp. 39-55
Author(s):  
EDILENE MARIA DOS SANTOS PESTANA ◽  
GOIA DE MATTOS LYRA ◽  
GABRIEL DO NASCIMENTO SANTOS ◽  
CIBELE CONCEIÇÃO DOS SANTOS ◽  
VALÉRIA CASSANO ◽  
...  
Keyword(s):  
New Species ◽  
Original Description ◽  
Morphological Characters ◽  
Type Locality ◽  
Integrative Approach ◽  
Brazilian Coast ◽  
Monophyletic Clade ◽  
Sister Relationship ◽  
First Occurrence ◽  
Three New Species

Peyssonneliaceae represents a monophyletic clade of red encrusting algae classified Peyssonneliales. Molecular analyses have been important for revealing unknown diversity in this family, which includes small, cryptic organisms, frequently distinguished solely by discrete anatomical characters. Brazil however, remains virtually unknown. To assess this diversity, phylogenetic and barcoding analyses using rbcL, COI-5P and SSU data, as well as morpho-anatomical analyses were performed. Here we report the first occurrence of two genera on the Brazilian coast: Ramicrusta and Incendia, and describe three new species: Ramicrusta fujiiana sp. nov., Ramicrusta paradoxa sp. nov. and Incendia yoneshigueana sp. nov. Ramicrusta was resolved as a monophyletic clade in the three reconstructed phylogenies, and had congruent topologies. In the rbcL phylogeny, Ramicrusta fujiiana formed a well-supported clade sister to a well-supported clade including R. aranea (Vanuatu, type locality) and R. textilis (Jamaica, type locality). Morphological characters of R. paradoxa are not in agreement with the original description of the genus. Therefore, we present an updated and broader concept of Ramicrusta. Incendia was resolved as a monophyletic clade with full support for rbcL. Incendia yoneshigueana is in a sister relationship with I. glabra (Vanuatu, type locality). This study extends the distributions of Ramicrusta and Incendia, proposes three new species, and confirms the effectiveness of rbcL, COI-5P and SSU in inferring phylogenetic relationships and delimiting species in the Peyssonneliales. The integrative approach established clear taxonomic concepts for the studied genera and species, and identified useful characters for genera delimitation in Peyssonneliaceae.

Where Fossils Dare and Males Matter: combined morphological and molecular analysis untangles the evolutionary history of the spider ant genus Leptomyrmex Mayr (Hymenoptera : Dolichoderinae)

2017 ◽  
Vol 31 (6) ◽  
pp. 765 ◽  
Author(s):  
Phillip Barden ◽  
Brendon Boudinot ◽  
Andrea Lucky
Keyword(s):  
Evolutionary History ◽  
Morphological Evolution ◽  
Sister Group ◽  
Morphological Characters ◽  
Fossil Material ◽  
First Case ◽  
History Of ◽  
The Impact ◽  
Surprising Discovery

The distinctive ant genus Leptomyrmex Mayr, 1862 had been thought to be endemic to Australasia for over 150 years, but enigmatic Neotropical fossils have challenged this view for decades. The present study responds to a recent and surprising discovery of extant Leptomyrmex species in Brazil with a thorough evaluation of the Dominican Republic fossil material, which dates to the Miocene. In the first case study of direct fossil inclusion within Formicidae Latreille, 1809, we incorporated both living and the extinct Leptomyrmex species. Through simultaneous analysis of molecular and morphological characters in both Bayesian and parsimony frameworks, we recovered the fossil taxon as sister-group to extant Leptomyrmex in Brazil while considering the influence of taxonomic and character sampling on inferred hypotheses relating to tree topology, biogeography and morphological evolution. We also identified potential loss of signal in the binning of morphological characters and tested the impact of parameterisation on divergence date estimation. Our results highlight the importance of securing sufficient taxon sampling for extant lineages when incorporating fossils and underscore the utility of diverse character sources in accurate placement of fossil terminals. Specifically, we find that fossil placement in this group is influenced by the inclusion of male-based characters and the newly discovered Neotropical ‘Lazarus taxon’.

scholarly journals Shared genetic etiology between cortical brain morphology and tobacco, alcohol, and cannabis use

2021 ◽  
Author(s):  
Jill A. Rabinowitz ◽  
Adrian I. Campos ◽  
Jue-Sheng Ong ◽  
Luis M. García-Marín ◽  
Sarael Alcauter ◽  
...  
Keyword(s):  
Substance Use ◽  
Surface Area ◽  
Brain Structure ◽  
Genetic Correlations ◽  
Cannabis Use ◽  
Brain Morphology ◽  
Equation Modeling ◽  
Genetic Etiology ◽  
Genetic Overlap ◽  
Shared Genetic

ABSTRACTGenome-wide association studies (GWAS) have independently identified hundreds of genomic regions associated with brain morphology and substance use. However, the genetic overlap between brain structure and substance use has not been characterized. Here we leverage GWAS summary data of 71 brain imaging measures and alcohol, tobacco, and cannabis use to investigate their genetic overlap using LD score regression. We also used genomic structural equation modeling to model a ‘substance use common genetic factor’ and examined its genetic overlap with brain structure. After accounting for multiple testing, we identified eight significant negative genetic correlations, including between alcoholic drinks per week and average cortical thickness and intracranial volume with the age of smoking initiation; and five positive genetic correlations, including between insula surface area and lifetime cannabis use, and between the common factor with pericalcarine surface area. Our findings highlight a shared genetic etiology between variation in cortical brain morphology and substance use.

A new species of habitat–forming Suberites (Porifera, Demospongiae, Suberitida) in the Benguela upwelling region (South Africa)

Zootaxa ◽  
2017 ◽  
Vol 4254 (1) ◽  
pp. 49
Author(s):  
TOUFIEK SAMAAI ◽  
SESHNEE MADURAY ◽  
LIESL JANSON ◽  
MARK J GIBBONS ◽  
BENEDICTA NGWAKUM ◽  
...  
Keyword(s):  
South Africa ◽  
New Species ◽  
Morphological Characters ◽  
Specimen Size ◽  
Unconsolidated Sediments ◽  
Monophyletic Clade ◽  
African Region ◽  
The West ◽  
Benguela Upwelling ◽  
A New Species

S. dandelenae sp. nov. is described from the west coast of South Africa and occurs at depths of 80–500 m among unconsolidated sediments. Specimens can reach 40 cm in length and in some areas off South Africa, up to 18 tons/km2 can be collected in a single demersal trawl. Morphologically, the sponge is straw yellow, massive with rounded lobes and has a velvety surface: it is characterized by subradiate, irregular reticulation of bundles of tylostyles and tylostrongyles. Specimens of S. dandelenae sp. nov. have three size classes of tylostyles with the largest tylostyle lengths being 516 μm (441–614 μm), medium tylostyle lengths being 352 μm (307–422 μm) and the shortest tylostyle lengths being 215 μm (153–288 μm). Apart from the presence of tylostyles, some specimens of S. dandelenae sp. nov. also possess centrotylostongyles/oxeas, tylostrongyles and microacanthostrongyles spicules. We have used morphological characters to distinguish this species and a molecular marker (cox1) to conform that all specimens are the same species. At the spicular level, S. dandelenae sp. nov. is characterized by a complex of spicule types that vary with specimen size. Following a histological investigation and re–description of the holotypes of S. ficus (Johnston, 1842) and S. tylobtusus Lévi, 1958, and comparisons with S. carnosus (Johnston, 1842), S. stilensis Burton, 1933, and other Suberites species described from the African region, it is clear that the new species is different in spicule morphology, spicule size and external morphology. For example, microacanthostrongyles are not present in S. tylobtusus and S. carnosus, whilst S. ficus possesses a second, non–spinose category of microstrongyles. Suberites tylobtusus has tylostyles that are sometimes polytylote, with heads either well formed, pear shaped or reduced, in only one size catogory. The 'tylobtuse' condition of the tylostyles is also different to the kidney–shaped and centrotylostrongyles found in S. dandelenae sp. nov. Suberites stilensis Burton, 1933 has larger and thicker tylostyles (800 μm length x 10 μm thick) than those of S. dandelenae sp. nov. A comparative analysis of partial cox1 sequences from morphologically diverse specimens of S. dandelenae sp. nov. with published material indicates that all specimens comprise a monophyletic clade. The combined morphological and genetic data support the designation of Suberites dandelenae sp. nov. 

scholarly journals Altered cortical development and psychiatric symptom risk in adolescents exposed to maternal stress in utero

2019 ◽  
Author(s):  
Goldie A. McQuaid ◽  
Valerie L. Darcey ◽  
Melissa F. Avalos ◽  
Diana H. Fishbein ◽  
John W. VanMeter
Keyword(s):  
Gray Matter ◽  
Prenatal Stress ◽  
Brain Structure ◽  
Maternal Stress ◽  
In Utero ◽  
Brain Morphology ◽  
Maternal Report ◽  
Increased Risk ◽  
Adolescent Risk ◽  
Parietal Lobule

ABSTRACTObjectiveMaternal exposure to stress during pregnancy is associated with increased risk for cognitive and behavioral sequelae in offspring. Animal research demonstrates exposure to stress during gestation has effects on brain structure. In humans, however, little is known about the enduring effects of in utero exposure to maternal stress on brain morphology. We examine whether maternal report of stressful events during pregnancy is associated with brain structure and behavior in adolescents.MethodWe compare gray matter morphometry of typically-developing early adolescents (11-14 years of age, mean 12.7) based on presence/absence of maternal report of stressful event(s) during pregnancy: prenatal stress (PS; n=28), no prenatal stress (NS; n=55). The Drug Use Survey Index Revised (DUSI-R) assessed adolescent risk for problematic behaviors. Exclusionary criteria included pre-term birth, low birth weight, and maternal substance use during pregnancy. Groups were equivalent for demographic (age, sex, IQ, SES, race/ethnicity), and birth measures (weight, length).ResultsCompared to NS peers, adolescents in the PS group exhibited increased gray matter volume in bilateral posterior parietal cortex (PPC): bilateral intraparietal sulcus, left superior parietal lobule and inferior parietal lobule. Additionally, the PS group displayed greater risk for psychiatric symptoms and family system dysfunction, as assessed via DUSI-R subscales.ConclusionThis study provides evidence for the enduring neurodevelopmental effects of exposure to maternal stress while in utero, suggesting the dynamic alterations in brain structure that occur during the adolescent critical period may unmask the latent effects of gestational stress on brain morphology and increase subsequent risk for psychiatric symptomatology.

scholarly journals Advances in studying brain morphology: The benefits of open-access data

2017 ◽  
Author(s):  
Christopher R Madan
Keyword(s):  
Open Access ◽  
Brain Structure ◽  
Large Scale ◽  
Open Data ◽  
Brain Morphology ◽  
Subcortical Structures ◽  
Open Access Data ◽  
Age Related ◽  
Neuroimaging Data ◽  
Access Data

Until recently, neuroimaging data for a research study needed to be collected within one’s own lab. However, when studying inter-individual differences in brain structure, a large sample of participants is necessary. Given the financial costs involved in collecting neuroimaging data from hundreds or thousands of participants, large-scale studies of brain morphology could previously only be conducted by well-funded laboratories with access to MRI facilities and to large samples of participants. With the advent of broad open-access data-sharing initiatives, this has recently changed–here the primary goal of the study is to collect large datasets to be shared, rather than sharing of the data as an afterthought. This paradigm shift is evident as increase in the pace of discovery, leading to a rapid rate of advances in our characterization of brain structure. The utility of open-access brain morphology data is numerous, ranging from observing novel patterns of age-related differences in subcortical structures to the development of more robust cortical parcellation atlases, with these advances being translatable to improved methods for characterizing clinical disorders (see Figure 1 for an illustration). Moreover, structural MRIs are generally more robust than functional MRIs, relative to potential artifacts and in being not task-dependent, resulting in large potential yields. While the benefits of open-access data have been discussed more broadly within the field of cognitive neuroscience elsewhere (Gilmore et al., in press; Poldrack and Gorgolewski, 2014; Van Horn and Gazzaniga, 2013; Van Horn and Toga, 2014; Vogelstein et al., 2016; Voytek, 2016), as well as in other fields (Ascoli et al., 2017; Choudhury et al., 2014; Davies et al., 2017), this opinion paper is focused specifically on the implications of open data to brain morphology research.

scholarly journals Phylogeny of the Anomura (Decapoda, Crustacea): Spermatozoa and spermatophore morphological evidence

1997 ◽  
Vol 67 (2) ◽  
pp. 125-141 ◽  
Author(s):  
Christopher C. Tudge
Keyword(s):  
Phylogenetic Analysis ◽  
Decapod Crustacean ◽  
Sister Group ◽  
Morphological Characters ◽  
The Other ◽  
Monophyletic Group ◽  
Morphological Evidence ◽  
Monophyletic Clade ◽  
The Family ◽  
Single Clade

A phylogenetic analysis of selected anomuran, thalassinidean, and other decapod crustacean taxa, based on spermatozoal ultrastructural characters and spermatophore morphological characters, was performed and the following relationships of the taxa are elucidated from the trees produced. The Anomura are not a monophyletic assemblage, with the lomoid Lomis being exclusive of the remainder of the anomuran taxa, and the thalassinid Thalassina included in the anomuran clade. The synapomorphy joining the majority of the conventional anomuran taxa (Lomis excluded) is the cytoplasmic origin of the microtubular arms. When the palinurid and thalassinoid representatives are separately designated as outgroups, the Astacidea and Brachyura jointly formed a sister group to the Anomura. The superfamilies Thalassinoidea, Paguroidea, and Galatheoidea are not monophyletic groups. In all analyses the anomuran families Coenobitidae and Porcellanidae each form a monophyletic group. The paguroid family Diogenidae is paraphyletic, with the genera Clibanarius and Cancellus separate from a single clade containing the remaining diogenid genera. The families Paguridae and Parapaguridae form a monophyletic clade with the exception of Porcellanopagurus. The two representatives of the family Chirostylidae (Eumunida and Uroptychus) fail to associate with the other species in the Galatheoidea. The taxa in the family Galatheidae are not a monophyletic assemblage. The only investigated hippoid Hippa is portrayed as the sister group to the remainder of the anomuran taxa (with the exception of Lomis).

Sign in / Sign up

Export Citation Format

Share Document