scholarly journals Phylogenetic estimation and morphological evolution of Alsineae (Caryophyllaceae) shed new insight into the taxonomic status of the genus Pseudocerastium

2020 ◽  
Author(s):  
Gang Yao ◽  
Bine Xue ◽  
Kun Liu ◽  
Yuling Li ◽  
Jiuxiang Huang ◽  
...  
Keyword(s):  
Morphological Evolution ◽  
Taxonomic Status ◽  
Phylogenetic Estimation ◽  
Insight Into

scholarly journals Finding the weakest link: mechanical sensitivity in a fish cranial linkage system

2018 ◽  
Vol 5 (10) ◽  
pp. 181003 ◽  
Author(s):  
A. Baumgart ◽  
P. Anderson
Keyword(s):  
Morphological Evolution ◽  
Structural Features ◽  
Mechanical Sensitivity ◽  
Weakest Link ◽  
Lower Jaw ◽  
Single Link ◽  
Evolutionary Level ◽  
Variable Influence ◽  
Physical Mechanics ◽  
Insight Into

Understanding the physical mechanics behind morphological systems can offer insights into their evolution. Recent work on linkage systems in fish and crustaceans has suggested that the evolution of such systems may depend on mechanical sensitivity, where geometrical changes to different parts of a biomechanical system have variable influence on mechanical outputs. While examined at the evolutionary level, no study has directly explored this idea at the level of the mechanism. We analyse the mechanical sensitivity of a fish cranial linkage to identify the influence of linkage geometry on the kinematic transmission (KT) of the suspensorium, hyoid and lower jaw. Specifically, we answer two questions about the sensitivity of this linkage system: (i) What changes in linkage geometry affect one KT while keeping the other KTs constant? (ii) Which geometry changes result in the largest and smallest changes to KT? Our results show that there are ways to alter the morphology that change each KT individually, and that there are multiple ways to alter a single link that have variable influence on KT. These results provide insight into the morphological evolution of the fish skull and highlight which structural features in the system may have more freedom to evolve than others.

scholarly journals New insight into the taxonomic resolution of the genus Bythotrephes Leydig (Crustacea: Cladocera) based on molecular data from Central Europe

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Maciej Karpowicz ◽  
Magdalena Świsłocka ◽  
Joanna Moroz ◽  
Łukasz Sługocki
Keyword(s):  
Genetic Analysis ◽  
Central Europe ◽  
Taxonomic Status ◽  
Molecular Data ◽  
Coi Gene ◽  
Taxonomic Resolution ◽  
Monotypic Genus ◽  
Mtdna Coi ◽  
Xix Century ◽  
Insight Into

AbstractThe taxonomic status of the genus Bythotrephes Leydig (Crustacea: Cladocera) has been debated since the second half of the XIX century. The most widespread view of recent decades has been that Bythotrephes is a monotypic genus, which was support by preliminary molecular data. However, the recent detailed morphological revision of this genus clearly distinguishes at least seven species. Therefore, we performed a multi-lake survey in Central Europe to give new insight into the taxonomic status of Bythotrephes by combining genetic analysis with traditional morphology-based taxonomy. Based on the morphology we identified two species in Central Europe, B. brevimanus and B. lilljeborgi, as well as hybrid forms. For the genetic analysis, we used newly obtained 113 sequences of mtDNA COI gene of the 535-bp length Bythotrephes from Central Europe and sequences downloaded from GenBank. There were no significant differences between all analyzed sequences, which supports the hypothesis that Bythotrephes is a monotypic genus, with only one highly polymorphic species. On the other hand, the results of our work could point out that the COI gene is insufficient to evaluate the taxonomic status of Bythotrephes. Nonetheless, we have identified 29 new haplotypes of mtDNA COI, and one which was the same as the haplotype found in North America and Finland. Furthermore, this haplotype was the source variant from which most other haplotypes were derived.

scholarly journals Segregation and Morphological Evolution of Si Phase during Electromagnetic Directional Solidification of Hypereutectic Al-Si Alloys

Materials ◽  
2018 ◽  
Vol 12 (1) ◽  
pp. 10 ◽  
Author(s):  
Weiyan Jiang ◽  
Wenzhou Yu ◽  
Jie Li ◽  
Zhixiong You ◽  
Chunmei Li ◽  
...  
Keyword(s):  
Directional Solidification ◽  
Morphological Evolution ◽  
Microscopic Analysis ◽  
Solute Concentration ◽  
Constitutional Supercooling ◽  
Metallic Alloys ◽  
Crystal Growth Rate ◽  
Segregation Behavior ◽  
Primary Si ◽  
Insight Into

Understanding the Si segregation behavior in hypereutectic Al-Si alloys is important for controlling the micro- and macrostructures of ingots. The macrosegregation mechanism and morphological evolution of the primary Si phase were investigated during electromagnetic directional solidification (EMDS). Both numerical simulations and experimental results strongly suggested that the severe macrosegregation of the primary Si phase was caused by fluid flow and temperature distribution. Microscopic analysis showed that the morphological evolution of the Si crystal occurred as follows: planar → cellular → columnar → dendritic stages during EMDS. Based on constitutional supercooling theory, a predominance area diagram of Si morphology was established, indicating that the morphology could be precisely controlled by adjusting the values of temperature gradient (G), crystal growth rate (R), and solute concentration (C0). The results provide novel insight into controlling the morphologies of primary Si phases in hypereutectic Al-Si alloys and, simultaneously, strengthen our understanding of the macrosegregation mechanism in metallic alloys.

scholarly journals Macroevolutionary patterns of body plan canalization in euarthropods

Paleobiology ◽  
2020 ◽  
Vol 46 (4) ◽  
pp. 569-593
Author(s):  
Cédric Aria
Keyword(s):  
Regulatory Networks ◽  
Morphological Evolution ◽  
Genetic Regulatory Networks ◽  
Cambrian Explosion ◽  
Adaptive Landscape ◽  
Rates Of Evolution ◽  
History Of ◽  
Optimum Type ◽  
Phylogenetic Framework ◽  
Insight Into

AbstractReconstructing patterns of macroevolution has become a central endeavor in paleobiology, because it offers insight into evolutionary models shaping the history of life. As the most diverse and abundant animals since the Cambrian period, arthropods provide copious data to elucidate the emergence of body plans in metazoan lineages. However, information provided by fossils on the tempo and mode of this phenomenon has lacked a recent synthesis. Here, I investigate macroevolutionary patterns of morphological evolution in Euarthropoda using a combined extinct and extant dataset optimized for multivariate analyses. Overall ordination patterns between the main morphogroups are consistent with another, independently coded, extant-only dataset providing molecular and morphological rates of evolution. Based on a “deep split” phylogenetic framework, total-group Mandibulata and Arachnomorpha emerge as directional morphoanatomical lineages, with basal fossil morphogroups showing heterogeneously spread-out occupations of the morphospace. In addition to a more homogeneous morphological variation, new morphogroups arose by successive reductions of translation distances; this pattern was interrupted only by terrestrialization events and the origin of pancrustaceans. A displaced optimum type of model is proposed to explain the fast assembly of canalized body plans during the Cambrian, with basal fossil morphogroups fitting intermediate fitness peaks in a moving adaptive landscape. Given time constraints imposed by the paleontological evidence, and owing to the interplay between canalization and modularity, as well as a decoupling between molecular and morphological rates, the rise of euarthropods would support the view that the swiftness of the Cambrian explosion was mostly associated with the buildup of genetic regulatory networks.

A molecular analysis of the mysterious Vaurie’s Nightjar Caprimulgus centralasicus yields fresh insight into its taxonomic status

2020 ◽  
Vol 161 (3) ◽  
pp. 635-650
Author(s):  
Manuel Schweizer ◽  
Claudia Etzbauer ◽  
Hadoram Shirihai ◽  
Till Töpfer ◽  
Guy M. Kirwan
Keyword(s):  
Molecular Analysis ◽  
Taxonomic Status ◽  
Fresh Insight ◽  
Insight Into

scholarly journals Genome-based classification of Burkholderia cepacia complex provides new insight into its taxonomic status

2020 ◽  
Vol 15 (1) ◽  
Author(s):  
Yuan Jin ◽  
Jianglin Zhou ◽  
Jing Zhou ◽  
Mingda Hu ◽  
Qi Zhang ◽  
...  
Keyword(s):  
Burkholderia Cepacia ◽  
Taxonomic Status ◽  
Burkholderia Cepacia Complex ◽  
Insight Into

scholarly journals Continental-scale patterns of hyper-cryptic diversity within the freshwater model taxon Gammarus fossarum (Crustacea, Amphipoda)

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Remi Wattier ◽  
Tomasz Mamos ◽  
Denis Copilaş-Ciocianu ◽  
Mišel Jelić ◽  
Anthony Ollivier ◽  
...  
Keyword(s):  
Evolutionary Ecology ◽  
Taxonomic Status ◽  
Model Organisms ◽  
Cryptic Diversity ◽  
Gammarus Fossarum ◽  
Continental Scale ◽  
Operational Taxonomic Units ◽  
Freshwater Crustacean ◽  
High Level ◽  
Insight Into

Abstract Traditional morphological diagnoses of taxonomic status remain widely used while an increasing number of studies show that one morphospecies might hide cryptic diversity, i.e. lineages with unexpectedly high molecular divergence. This hidden diversity can reach even tens of lineages, i.e. hyper cryptic diversity. Even well-studied model-organisms may exhibit overlooked cryptic diversity. Such is the case of the freshwater crustacean amphipod model taxon Gammarus fossarum. It is extensively used in both applied and basic types of research, including biodiversity assessments, ecotoxicology and evolutionary ecology. Based on COI barcodes of 4926 individuals from 498 sampling sites in 19 European countries, the present paper shows (1) hyper cryptic diversity, ranging from 84 to 152 Molecular Operational Taxonomic Units, (2) ancient diversification starting already 26 Mya in the Oligocene, and (3) high level of lineage syntopy. Even if hyper cryptic diversity was already documented in G. fossarum, the present study increases its extent fourfold, providing a first continental-scale insight into its geographical distribution and establishes several diversification hotspots, notably south-eastern and central Europe. The challenges of recording hyper cryptic diversity in the future are also discussed.

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