Reliable species identification provides a sounder basis for use of species in the order Odonata as biological indicators and for their conservation, an urgent concern as many species are threatened with imminent extinction. We generated 134 COI barcodes from 36 morphologically identified species of Odonata collected from Mindanao Island, representing 10 families and 19 genera. Intraspecific sequence divergences ranged from 0 to 6.7% with four species showing more than 2%, while interspecific sequence divergences ranged from 0.5 to 23.3% with seven species showing less than 2%. Consequently, no distinct gap was observed between intraspecific and interspecific DNA barcode divergences. The numerous islands of the Philippine archipelago may have facilitated rapid speciation in the Odonata and resulted in low interspecific sequence divergences among closely related groups of species. This study contributes DNA barcodes for 36 morphologically identified species of Odonata reported from Mindanao including 31 species with no previous DNA barcode records.
The phylogenetic relationships of some taxa in the Platycnemidinae at the species and generic levels have been investigated. Phylogenetic trees were generated from both individual mitochondrial encoded COI, COII, 16S rDNA and nuclear encoded 28S rDNA and also combined sequences; these data indicate that the component taxa of the genus Copera belong to two distinct genetic clades - the marginipes group and the annulata group. There was no distinct genetic difference between the red-legged and yellow-legged morphs of C. vittata. Molecular data showed that the annulata group is considered a member of the genus Platycnemis, as originally proposed. The genus Coeliccia, a member of the subfamily Calicnemiinae (Platycnemididae), is not grouped with the Platycnemidinae. The Disparoneurinae of the 'Protoneuridae' showed a closer relationship to the Platycnemidinae than the Calicnemiinae. The dataset supports the placement of the Disparoneurinae as a subfamily of the Platycnemididae. This resolves the monophyly of Platycnemididae.
Dragonflies of the genus Orthetrum are members of the suborder Anisoptera, family Libellulidae. There are species pairs whose members are not easily separated from each other by morphological characters. In the present study, the DNA nucleotide sequences of mitochondrial and nuclear genes were employed to elucidate the phylogeny and systematics of Orthetrum dragonflies. Phylogenetic analyses could not resolve the various subfamilies of the family Libellulidae unequivocally. The nuclear 28S rRNA gene is highly conserved and could not resolve congeneric species of Orthetrum. Individual mitochondrial genes (COI, COII, and 16S rRNA) and combination of these genes as well as the nuclear ITS1&2 genes clearly differentiate morphologically similar species, such as the reddish species pairs O. chrysis and O. testaceum, and the bluish-coloured species O. glaucum and O. luzonicum. This study also reveals distinct genetic lineages between O. pruinosum schneideri (occurring in Malaysia) and O. pruinosum neglectum (occurring north of Peninsular Malaysia from India to Japan), indicating these taxa are cryptic species.
The final instar larva of Orthetrum borneense Kimmins, 1936, is described and figured for the first time based on exuviae from three male and six female larvae collected in Sarawak, Borneo (East Malaysia). It is compared with an early instar larva, which was matched to the adult O. borneense by DNA barcoding, and the known larvae of other species of this genus that occur in the region.