Phylogenetic relationships inferred from ribosomal ITS sequences and biogeographic patterns in representatives of the genus Calopteryx (Insecta : Odonata) of the West Mediterranean and adjacent West European zone

Western Europe is a reinvasion zone for the riverine dragonfly genus Calopt eryx (Insecta: Odonata). Reinvasion may have been from central West Asia or from the West Mediterranean refugium, Phylogenetic relationships of West M editerranean and West European tars of the genus Calopteryx from different localities were inferred from sequences of the internal transcribed spacers (ITS1 and ITS2) of the nuclear ribosomal RNA genes. Twenty-six taxa belong ing to the species groups C, splendens, C. meridionalis, C. haemorrhoidalis , C. virgo, C. xanthostoma, and C. exul were analyzed, with two North Ameri can species, C. amata and C. aequabilis, as outgroup. Sequence data and phy logenetic analyses were used to infer biogeographical patterns. The ribosom al spacers (ITS1 and ITS2) and the intervening 5.8S rDNA gene were amplifie d by PCR and sequenced. The ITS2 sequences of the West Mediterranean and We st European calopterygids show no length variation but the ITS1 region was slightly variable in length. The sequence variation for ITS1 and ITS2 regio ns between different West Mediterranean and West European calopterygids was 14.5 and 6.1%, respectively. Phylogenetic relationships inferred from ITS sequences only partly confirm morphological data. A monophyletic origin of all West Mediterranean and West European species emerged. They are separate d into two main clades; the splendens-like forms and the virgo/meridionalis /haemorrhoidalis group. Intraspecific variability, indicating different sta ges of speciation, was detected only in West Mediterranean representatives (e.g., C. xanthostoma) but not in invasive representatives in West Europe. The North African endemic C. exul is more closely related to the Italian C. s. caprai than to C. splendens sensu strictu, Based on the present informa tion, Cretan populations are the only splendens-like tars in addition to C. s. caprai that deserve subspecies status. (C) 2001 Academic Press.