Systematics of Clupeomorpha (Osteichthyes:Teleostei) with methodological considerations for morphological phylogenetics

  • Author / Creator
    Vernygora, Oksana V
  • Here I conduct a systematic revision of Clupeomorpha, a group of bony fishes that includes over 500 living and extinct species of herrings, sardines, anchovies, and their relatives. Despite a long history of research on clupeomorph fishes, evolutionary relationships within the group remain poorly understood. To provide an updated phylogeny and classification for Clupeomorpha, I begin by addressing methodological issues pertinent to morphological phylogenetics and species delimitation in palaeontological and neontological studies and conclude by using a combined evidence approach to analyze morphological, molecular, and concatenated data sets employing multiple methods of phylogenetic inference. In the chapters discussing methodological issues in morphological phylogenetics, I assess the performance of widely used probabilistic algorithms of phylogenetic inference (Bayesian inference and maximum likelihood), and also develop and test a new model of discrete morphological trait evolution (FreqMorph) that uses empirical character state frequencies. Results of simulation studies indicate that Bayesian inference applications are the most consistent and robust to variations in taxonomic sampling and amount of missing data. Additionally, using empirical character state frequencies, as implemented in FreqMorph, can improve accuracy of phylogenetic reconstructions in cases when the number of taxa is large and branch lengths are of particular importance. Delimiting taxonomic units is another pertinent issue in systematic studies. In a case study of the extant genus Alosa, I show that an integrative approach combining genetic and morphological data provides a reliable framework for delimiting closely related and morphologically similar species. In palaeontological studies, species delimitation relies heavily on morphological data. In a case study of the extinct genus †Armigatus, I conduct a comparative examination of multiple specimens to seek morphological traits that allow more reliable species delimitation within the genus. Lastly, I bring together morphological and molecular data to perform a combined evidence phylogenetic analysis of the Clupeomorpha. Synthesis of the multiple phylogenetic results suggests that Clupeomorpha can be subdivided into three orders, Denticipitiformes, †Ellimmichthyiformes, and Clupeiformes, with Denticipitiformes being the basalmost clupeomorph lineage. Interrelationships within †Ellimmichthyiformes and Clupeiformes are overall consistent with the current classification. I assign a family rank to previously recognized clupeid subfamilies that have been consistently recovered as monophyletic groups, Clupeidae (new usage), Dorosomatidae, and Alosidae, and provide a list of morphological features that can be used to diagnose members of these groups.

  • Subjects / Keywords
  • Graduation date
    Fall 2020
  • Type of Item
  • Degree
    Doctor of Philosophy
  • DOI
  • License
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