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Goethe Universitat Frankfurt (2017)

Taxonomy, phylogeny and zoogeography of the hexaploid Torini of the Middle East and North Africa

Borkenhagen Kai

Titre : Taxonomy, phylogeny and zoogeography of the hexaploid Torini of the Middle East and North Africa

Auteur : Borkenhagen Kai

Université de soutenance : Goethe Universitat Frankfurt

Grade : Doktorgrade der Naturwissenschaften 2017

Résumé partiel
ishes of the tribe Torini Karaman, 1971 (Teleostei : Cyprinidae) are a diverse group of primary freshwater fishes, distributed in Africa, the Middle East, and Indomalaya. They are an important component of the native freshwater-fish fauna of the Middle East and North Africa, and occur in most large river systems of the Levant, Arabia, Mesopotamia, southern Iran, and Morocco. They belong to the subfamily Cyprininae, are characterised by being tetraploid or hexaploid, having large scales, and a smooth and ossified last unbranched ray in the dorsal fin. As primary freshwater fishes they are not able to tolerate marine conditions and depend on direct freshwater connections for their dispersal. This makes them an ideal model for zoogeographic studies. Prior to this study, the diversity of the Torini species in the Middle East and North Africa was not well understood. The validity of several genera and species was unclear, and the generic assignment of several species changed frequently. In this PhD project the taxonomy, phylogeny, and zoogeography of the Torini of the Middle East and North Africa were investigated with morphological, as well as molecular methods. More than 1550 fish specimens were examined morphologically. Some of the specimens, including the types of most nominal species, were already available from museum collections. The remaining specimens were collected during expeditions to Ethiopia, Iran, Jordan, Morocco and Syria. Tissue samples were collected for molecular genetic analyses. The mitochondrial genes for cytochrome b, NADH dehydrogenase subunit 4 and the tRNAs for serine and histidine were sequenced from more than 120 specimens, representing 20 species of Torini and two small, diploid African barbs (Cyprinidae, tribe Smiliogastrini). Molecular data were analysed with Bayesian inference and other methods. The analyses confirmed that the hexaploid Torini of Africa and the Middle East form a monophyletic group. In the Middle East and North Africa the Torini are represented by the genera Arabibarbus, Carasobarbus, Mesopotamichthys, and Pterocapoeta. These genera are each morphologically diagnosable, monophyletic, and genetically distinct. The species ’Labeobarbus’ reinii cannot be assigned to any of these genera, because it is morphologically dissimilar and genetically clearly separated from each of them. A generic name for this species is presently not available and until the description of a new genus it is preliminarily assigned to the genus ’Labeobarbus’. Out of the 28 species-group taxa described from the Middle East and North Africa until now, 15 are valid : Arabibarbus arabicus, A. grypus, A. hadhrami, Carasobarbus apoensis, C. canis, C. chantrei, C. exulatus, C. fritschii, C. harterti, C. kosswigi, C. luteus, C. sublimus, Mesopotamichthys sharpeyi, Pterocapoeta maroccana, and ’Labeobarbus’ reinii. The phylogenetic relationships between the Middle Eastern and North African Torini are well resolved, based on the analysis of mitochondrial DNA sequences from nearly all relevant species.

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Page publiée le 11 janvier 2019