Taxon Delineation in Gelechioid Moths: From Phylogenetics to Dna Barcoding
Year: 2014
Type: dissertation
Abstract: Systematics, phylogenetics and taxonomy are the scientific fields of species discovery, delimitation, description, classification and evolutionary history. The major task of these fields is to form meaningful groups, such as species and higher taxa, based on certain rules and characters. Species and higher taxa create the units of the Linnean hierarchic classification system, which is needed as the basis of all knowledge on biodiversity. Indeed, there is a great need for a complete classification, covering every species on earth, because all subsequent studies and applications are hindered as long as species remain undescribed. However, the estimated count of nine million species on earth, of which ca. 86% are currently unknown to science, together with the numerous threats to biodiversity pose a real challenge to taxonomy, and efficient tools and procedures are strongly needed. In order to be both effective and high-quality, the taxonomic workflow needs to be divided into different steps in the correct sequence. A sampling scheme, the choice of characters and analytical tools are dependent on the phase performed along the workflow. The main aim of Mari Kekkonen s doctoral thesis is to study and conduct different steps along this taxonomic flowchart by using various gelechioid moths as focal species. Specifically, the thesis includes four chapters: a phylogenetic examination of the superfamily Gelechioidea based on combined data of multi-locus DNA and morphology, and three studies focusing on delineation of putative species (i.e., operational taxonomic units, OTUs) based on single-locus DNA barcodes. The delineation studies cover various topics, from testing different OTU delineation methods (BIN, TCS, ABGD, GMYC) with reference species, developing criteria for discordant results and a protocol for associating short sequences from type specimens to delineated groups, to employing the methods, criteria and protocols in practice. The first chapter presents a phylogenetic hypothesis for the Gelechioidea with the best support for families to date. This was achieved mainly due to the use of both molecular and morphological data. We also provide a new family-level classification with redefined 16 families. The three OTU delineation studies revealed taxon-dependent performance within the four datasets (Finnish Gelechiinae, Australian Elachistinae, Australian Hypertrophinae, European Elachista dispunctella complex), but otherwise rather congruent results between the methods. The third chapter provides 120 putative species for poorly-known hypertrophine moths and criteria for evaluating discordant delineation results. Finally, in the last chapter, the E. dispunctella group with a high number of poorly-defined species is re-examined based on DNA barcodes from both fresh non-type and old type specimens. This doctoral thesis is a part of a long-term study of the Hypertrophinae, aiming to provide well-supported phylogeny and species boundaries for the group. The results here not only enhance the study on hypertrophines, but also offer tools to benefit the taxonomic research in general. As a result of the great challenge of taxonomy to describe all species, every new innovation to speed up the workflows without compromising the quality is of crucial importance.
Source: Työväentutkimus Vuosikirja
Author: Mari Kekkonen
Language: English
Subfield: Insect Science
Domain: Life Sciences
Open Access status: green
OpenAlex ID: W1480326435