Morphological and genetic variation in Southern Ocean Echinoderms with main focus on brittle stars (Ophiuroidea)

• Main Author: Guzzi, Alice
• Other Authors: CORSOLINI, SIMONETTA
• Format: Doctoral or Postdoctoral Thesis
• Language: English
• Published: Università degli Studi di Siena 2024
• Subjects: DNA barcoding; Echinoderms; Reverse taxonomy; Settore BIO/05 - Zoologia; Antarctic; Southern Ocean; Ross Sea; Terra Nova Bay; Antarc*; Antarctica
• Online Access: https://hdl.handle.net/11365/1259175

In recent years, changes to traditional taxonomic methods to incorporate new technologies and techniques have greatly improved the quality of species hypotheses, but more work can be done to improve the speed of new species discovery and documentation. The mitochondrial COI DNA barcode has been successfully used to identify species with high accuracy since the early 2000s and is now currently used in conjunction with morphological examinations to detect and delimit new species. The first aim of this thesis was the definition of a general standard sampling protocol to be applied in remote and extreme areas such as the Southern Ocean to pinpoint new species and the establishment of a procedural approach for samples treatment to obtain and record all the metadata and information associated with the collected organisms that will undergo molecular identification based on DNA barcoding. Distributional information’s regarding the Ross Sea quadrant are still scarce and sparse, despite the continued research that has been held in the area since the 50’s of the past century. To fill this gap, the second objective of the thesis concerns the production of distributional data and species lists of taxa belonging to the phylum Echinodermata from the Terra Nova Bay area (Ross Sea, Antarctica) for which there is still no information in the scientific literature, i.e. the classes Holothuroidea and Crinoidea. To assess this objective, a “Reverse taxonomy” approach was applied to echinoderms samples stored in the permanent biological collections of the Italian National Antarctic Museum (MNA, Section of Genoa). According to this approach, analysis of morphological features (e.g. skeletal elements) was performed only after having obtained molecular data and a robust phylogeny, to assess the congruence between morphological and molecular data. In order to do that, all the available organisms belonging to the phylum Echinodermata suitable for molecular investigation were gathered and analyzed. A collection of cytochrome c oxidase ...