Molecular taxonomy and phylogenetic relationships among Australian Nasutitermes and Tumulitermes genera (Isoptera, Nasutitermitinae) inferred from mitochondrial COII and 16S sequences.

The subfamily Nasutitermitinae Hare (1937) is a tropical and subtropical group, generally considered as the most specialised subfamily of Termitidae. To highlight some taxonomic inconsistencies, the phylogenetic relationships among seven Australian species, morphologically ascribed to the genera Nasutitermes and Tumulitermes, were studied through the analyses of the mitochondrial markers cytochrome oxidase II and 16S ribosomal RNA genes. In our trees, N. longipennis samples clearly pertain to two different specific entities with an apparently parapatric distribution. Further, the phylogenetic analysis performed on separated and combined data sets shows the placement of Tumulitermes species within a clade grouping Nasutitermes ones, and vice versa. Tests for alternative topologies do not support the monophyly of the genera Nasutitermes and Tumulitermes. Our results confirm the hypothesis that the morphological features used to establish relationships among these species are not phylogenetically decisive.

Karyology, mitochondrial DNA and the phylogeny of Australian termites.

A comprehensive karyological characterization of 20 Australian and three European species of Isoptera, together with a mitochondrial gene analysis is presented. Higher termites appear karyotypically very uniform, while lower termites are highly variable. The differences in chromosome number are explained through Robertsonian changes or multiple translocation events. An ancestral acrocentric karyotype can be suggested as the most primitive one. In Kalotermitidae chromosomal repatterning has repeatedly arisen with the X0-male type possibly representing a XY-derived condition. This argues against a simple origin of termites from cockroaches. The fixed chromosome number of Rhinotermitidae and Termitidae (2n=42, XY/XX) may be explained with the non-random nature of chromosomal evolution. A sex-linked multivalent, either with a ring or a chain structure, is found in the majority of species. Phylogenetic analyses on COII sequences recognize Mastotermitidae as the basal lineage and define the Rhinotermitidae+Termitidae cluster with a good bootstrap support. Kalotermitidae fail to be joined in a single cluster in agreement with the detected chromosomal variability. On the other hand, the karyotypic conservation of the Termitidae family contrasts with the polytomy evidenced at the subfamily level.