ON THE PHYLOGENY OF LAKE BAIKAL AMPHIPODS IN THE LIGHT OF MITOCHONDRIAL AND NUCLEAR DNA SEQUENCE DATA

• Published in: Crustaceana Vol. 72; no. 8; pp. 911 - 919
• Main Authors: Sherbakov, D. Yu, Kamaltynov, Ogarkov, Vainola, Vainio, Verheyen
• Format: Journal Article
• Language: English
• Published: The Netherlands Brill 1999; BRILL
• Subjects: Acanthogammarus; Amphipoda; Ancient Lakes; Biological taxonomies; Estimated taxes; Evolution; Freshwater; Genera; Lakes; Macrohectopus branickii; Micruropus; Nucleotide sequences; Pallasea; Phylogenetics; Phylogeny; Russia, Siberia, Baikal L; Taxa; Topology; Russia, Siberia, Baykal L
• ISSN: 0011-216X; 1568-5403
• DOI: 10.1163/156854099503816

Abstract
Two DNA sequence data sets, one from the nuclear 18S rRNA gene (520 bp long), the other from the mitochondrial COI gene (540 bp), are used to characterize the evolutionary history of the endemic Baikalian amphipod species assemblage. The observed differentiation suggests that the initial radiation of Baikalian lineages was ancient, probably older than the emergence of the initial large paleolake within the current lake basin in the mid-Tertiary. The mtDNA data suggest a principal division between the smooth fossorial genus Micruropus and the remaining Baikalian amphipod taxa included in the study. The monophyly of the Baikalian taxa with respect to the non-Baikalian Gammarus cannot be conclusively inferred from the mitochondrial sequences. The 18S rRNA data, however, suggest that the pelagic Baikalian species Macrohectopus branickii is closer to the European Gammarus pulex than to any other gammarid studied, and give an indication of a polyphyletic origin of the Baikalian amphipod fauna. Also, within the Baikalian assemblage, the major genera with strongly developed body armature, Acanthogammarus and Pallasea, may be polyphyletic. Deux ensembles de donnees de sequences du DNA, l'un concernant le 18S rRNA nucleaire (520 pb), l'autre le gene mitochondrial COI (540 pb) sont utilises pour caracteriser l'histoire evolutive de l'assemblage des especes d'amphipodes endemiques du Baikal. La differenciation observee suggere que la radiation initiale des lignees baikaliennes est ancienne, probablement plus ancienne que l'emergence du grand paleolac initial a l'interieur du bassin lacustre du tertiaire moyen. Les donnees du mtDNA suggerent une division principale entre le genre fouisseur lisse Micruropus et les taxa baikaliens restants, inclus dans l'etude. La monophylie des taxons baikaliens par rapport aux Gammarus non baikaliens ne peut pas etre deduite de facon concluante des sequences mitochondriales. Les donnees du 18S rRNA, cependant, suggerent que l'espece pelagique baikalienne Macrohectopus branickii est plus proche du Gammarus pulex europeen que de n'importe quel autre gammaride etudie, et donnent une indication de l'origine polyphyletique de la faune baikalienne d'amphipodes. De meme, dans l'assemblage baikalien, les genres majeurs aavec une armature du corps fortement developpee, Acanthogammarus et Pallasea , pourraient etre ppolyphyletiques.