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In this ecomorphological study, we investigate how the ventral pectoral girdle morphology of anurans correlates with their locomotor modes, habitat preferences, and phylogenetic relationships. We analysed 18 morphometric variables of the pectoral girdle's ventral region across 19 anuran species, encompassing diverse locomotion modes (jumping, hopping, walking, and swimming) and habitats (arboreal, bushy, terrestrial, and aquatic). Our findings, predominantly explained by the Ornstein–Uhlenbeck model, reveal evolutionary adaptations in pectoral girdle morphology driven by habitat‐specific demands. Notably, bushy and walker‐jumper species exhibit large clavicles, coracoids, and sternums, along with a broad medial pectoral girdle and bigger epicoracoid. Terrestrial and arboreal‐ jumpers have a larger omosternum area compared to predominantly swimming species. Arboreal walkers show shorter epicoracoid horns and narrower coracoids. Interestingly, bushy and terrestrial species have a higher proportion of bone tissue in their pectoral girdles. This indicates a potential adaptation to support the additional to adaptation to participate in shock absorption. The patterns recovered underscore the intricate relationship between anatomical evolution and environmental adaptation in anurans. [ABSTRACT FROM AUTHOR]

In anurans, the vertebral column diverges widely from that of other tetrapods; yet the molecular mechanisms underlying its morphogenesis remain largely unexplored. In this study, we investigate the role of the homeologous uncx.L and uncx.S genes in the vertebral column morphogenesis of the allotetraploid frog Xenopus laevis. We initiated our study by cloning the uncx orthologous genes in the anuran Xenopus and determining their spatial expression patterns using in situ hybridization. Additionally, we employed gain‐of‐function and loss‐of‐function approaches through dexamethasone‐inducible uncx constructs and antisense morpholino oligonucleotides, respectively. Comparative analysis of the messenger RNA sequences of homeologous uncx genes revealed that the uncx.L variant lacks the eh1‐like repressor domain. Our spatial expression analysis indicated that in the presomitic mesoderm and somites, the transcripts of uncx.L and uncx.S are located in overlapping domains. Alterations in the function of uncx genes significantly impact the development and differentiation of the sclerotome and myotome, resulting in axial skeleton malformations. Our findings suggest a scenario where the homeologous genes uncx.L and uncx.S exhibit antagonistic functions during somitogenesis. Specifically, uncx.S appears to be crucial for sclerotome development and differentiation, while uncx.L primarily influences myotome development. Postallotetraploidization, the uncx.L gene in X. laevis evolved to lose its eh1‐like repressor domain, transforming into a "native dominant negative" variant that potentially competes with uncx.S for the same target genes. Finally, the histological analysis revealed that uncx.S expression is necessary for the correct formation of pedicles and neural arch of the vertebrae, and uncx.L is required for trunk muscle development. HIGHLIGHTS: After allotetraploidization of X. laevis the uncx.L gene lost its eh1‐like repressor domain to making it a "native negative dominant".uncx homeologues genes are required for normal sclerotomal and myogenic differentiation.Alterations in the expression levels uncx homeologues genes leads to severe malformations in the axial skeleton. [ABSTRACT FROM AUTHOR]

Evolutionary tempo and mode summarize ancient and controversial subjects of theoretical biology such as gradualism, convergence, contingence, trends, and entrenchment. We employed an integrative methodological approach to explore the evolutionary tempo and mode of Lepidosaurian phalangeal formulae (PFs). This approach involves quantifying the frequencies of morphological changes along an evolutionary trajectory. The five meristic characters encoded by PFs are particularly valuable in revealing evolutionary patterns, owing to their discrete nature and extensive documentation in the literature. Based on a pre-existing dataset of PFs from 649 taxa (35 Lepidosauria families, including fossils), from which there exists a unique repertoire of 53 formulations, our approach simultaneously considers phenetic and phylogenetic data. This culminates in a diagram accounting for the phylogenetic dynamic of evolution traversing across different regions of morphospace. The method involves enumerating phenotypical options, reconstructing phenotypes across the phylogeny, projecting phenotypes onto a morphospace, and constructing a flow network from the frequency of evolutionary transitions between unique phenotypic conditions. This approach links Markovian chains and evolutionary trajectories to formally define parameters that describe the underlying transitions of morphological change. Among other results, we found that (a) PF evolution exhibits a clear trend towards reduction in the phalangeal count and that (b) evolutionary change tends to occur significantly between morphologically similar PFs. Notwithstanding, although minor but not trivial, transitions between distant formulas -jumps- occur. Our results support a pluralistic view including stasis, gradualism, and saltationism discriminating their prevalence in a target character evolution. [ABSTRACT FROM AUTHOR]

The present work aims to analyze the processes of shaping the career of teachers in Biological Sciences of the Faculty of Natural Sciences and the Miguel Lillo Institute of the National University of Tucumán. These processes cover both changes in the organization and administration of the academic study units as well as aspects related to the disciplinary fields that structure the curriculum. In order to carry out this research, an analysis of documents referring to the origin and implementation of the different curricula and of curricular documents from the creation of the university career in 1937 to the current plan was made. In the same sense, the files and resolutions produced regarding issues related to the shaping of organizational and training proposals were located and studied as well. [ABSTRACT FROM AUTHOR]