Although considerable progress has been made in elucidating the relationships within the Chondrichthyes, there is no agreement as it concerns the systematics of Batoidea, the most derived superorder among cartilaginous fishes, and many different interpretations exist. Our investigation provides the first assessment of relationships among the described batoid species using sequences from both mtDNA and nuclear genes as well as karyological morphology. Our work consists primarily in reconstructing the phylogenetic relationships of Batoidea by examining the mtDNA (16S) and nuclear gene (18S) sequences from 11 batoid species. The three analytical methods (NJ, MP and Bayesian analysis) grouped Rajiformes, Myliobatiformes and Rhinobatiformes. In these trees the two torpedoes diverge from the other batoid fishes. We also compare the molecular data with the available karyological evidence, which consist of the diploid number and the karyotype morphology of eight species belonging to the four orders examined. The results show that the karyological structure in the different species is generally consistent with the various phylogenetical trees, and that Torpediniformes confirm their unique genome organization.
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http://dx.doi.org/10.1016/j.gene.2006.09.024 | DOI Listing |
Zootaxa
September 2024
Staatliches Museum für Naturkunde Stuttgart; Gewann Rosenstein 1; 70191 Stuttgart; Germany.
A revised checklist of sharks, batoids, and sturgeons in the Sea of Marmara, Turkey encompasses 41 species across 18 families. It provides a concise historical context and addresses issues related to problematic reports. Furthermore, the paper delves into the analysis of taxonomic changes in other literature reports, aiming to provide a framework for upcoming ichthyological surveys and ecological studies, while also presenting relevant data on the economic significance of select species.
View Article and Find Full Text PDFJ Morphol
September 2024
Departamento de Morfologia, Laboratório de Morfologia Funcional, Universidade Federal do Amazonas, Manaus, Brazil.
This work aimed to describe and quantify the tissue components of the digestive tube of the neotropical freshwater stingray, Potamotrygon wallacei. For this, conventional histology and stereological methods were used to estimate tissue volume. The volumes of the four fundamental layers and the tissue components in the stomach (cardiac and pyloric) and spiral intestine were also estimated.
View Article and Find Full Text PDFMar Environ Res
September 2024
Institut de Ciències del Mar (ICM), CSIC, Barcelona, Spain.
Elasmobranchs play crucial roles as predators in marine ecosystems. Understanding their trophic strategies and interactions is necessary for comprehending food web dynamics and developing ecosystem-based management strategies. Although, feeding strategies can change depending on several factors, including fluctuations in prey availability throughout the year.
View Article and Find Full Text PDFGlob Chang Biol
July 2024
James Cook University, Townsville, Queensland, Australia.
Climate change is an environmental emergency threatening species and ecosystems globally. Oceans have absorbed about 90% of anthropogenic heat and 20%-30% of the carbon emissions, resulting in ocean warming, acidification, deoxygenation, changes in ocean stratification and nutrient availability, and more severe extreme events. Given predictions of further changes, there is a critical need to understand how marine species will be affected.
View Article and Find Full Text PDFAnat Rec (Hoboken)
January 2025
Centro Interdisciplinario de Ciencias Marinas, Instituto Politécnico Nacional, La Paz, Mexico.
Batoids (rays and skates) are cartilaginous fishes whose jaws are not articulated directly to the neurocranium. The only point of contact between them are the hyomandibular cartilages, resulting in a unique mandibular suspension called euhyostyly. Due to this decoupling of the jaws from the skull, muscles play an essential role in modulating mandibular movements during the feeding process, especially during mandibular protrusion.
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