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Full-Text Articles in Life Sciences
Comparative Brain Anatomy Of Lamniform Sharks (Elasmobranchii: Lamniformes) And Its Implications To Function, Behavioral Ecology, And Evolution, Francesco Guzzo
Comparative Brain Anatomy Of Lamniform Sharks (Elasmobranchii: Lamniformes) And Its Implications To Function, Behavioral Ecology, And Evolution, Francesco Guzzo
College of Science and Health Theses and Dissertations
Understanding the diversity of brain morphology is important to understand the evolution of cognitive ability and how ecology and phylogeny have influenced the variation in brain complexity. I examined the morphological variation of the brain in the shark order Lamniformes based on museum specimens and literature. Where I illustrate a wide range of morphological diversity in lamniform brains, my study shows that there is a strong positive correlation between brain size and body size that sharks with a larger brain tend to have a more foliated cerebellum, but that the body weight over brain weight did not correlate with cerebellar …
Body Forms In Sharks (Chondrichthyes: Elasmobranchii), And Their Functional, Ecological, And Evolutionary Implications, Phillip C. Sternes
Body Forms In Sharks (Chondrichthyes: Elasmobranchii), And Their Functional, Ecological, And Evolutionary Implications, Phillip C. Sternes
College of Science and Health Theses and Dissertations
Sharks are among the oldest vertebrate lineages in which their success has been attributed to their diversity in body shape and locomotor design. In this study, I investigated the diversity of body forms in extant sharks using landmark-based geometric morphometric analyses on lateral view illustrations of nearly all the known (ca. 470) extant sharks in a published guidebook. I ran three different analyses: the ‘full body,' ‘precaudal body,’ and ‘caudal fin' analyses. My study suggests that there are two basic body forms in sharks. The two major body forms are characterized as a ‘shallow-bodied’ form (Group A) and ‘deep-bodied’ form …
Phylogeography Of The Neotropical Fish Genus Rhoadsia (Teleostei: Characidae) In Ecuador, Roberto Valentino Cucalón Tamayo
Phylogeography Of The Neotropical Fish Genus Rhoadsia (Teleostei: Characidae) In Ecuador, Roberto Valentino Cucalón Tamayo
College of Science and Health Theses and Dissertations
Western Ecuador is considered a biodiversity hotspot. Nevertheless, studies of population genetic structure and variation are rare, especially in aquatic species. The genus Rhoadsia is an endemic freshwater fish in this region with two recognized species, Rhoadsia minor and R. altipinna. Little is known about the evolutionary relationships of their populations, and due to morphological similarities, their validity as distinct species has been questioned. The present study uses a phylogeographic approach to examine the evolutionary history of the genus and the validity of the two described species. Furthermore, I investigated the possible geographical origin of the genus based on patterns …