Descriptions of little-known and unknown morphs ofZelkovaphis caucasica(Hemiptera: Aphididae: Eriosomatinae), with an analysis of its phylogenetic position

Zelkovaphis caucasica is a little-known Caucasian species of leaf-rolling aphids on Zelkova carpinifolia, and was not included in a previous morphological phylogenetic analysis of the tribe Eriosomatini. We redescribe little-known emigrants of Z. caucasica and describe first instars borne by the emigrants, with keys to species for these morphs of the genus Zelkovaphis. Based on the present specimens and a previously published description, we added Z. caucasica to a published data matrix for Eriosomatini species, and re-analysed the phylogenetic relationships of the tribe Eriosomatini. Successive weighting analysis indicated that Z. caucasica branched off at the base of the Eriosomatini phylogeny, as well as other leaf-rolling species on Zelkova. It is therefore suggested that, like other leaf rollers on Zelkova, Z. caucasica is a relict that has survived in glacial refugia.