A new tribe in the Chironominae (Diptera: Chironomidae) validated by rst immature stages of Xiaomyia Sæther & Wang and a phylogenetic review

The newly discovered larva and previously unassociated pupa of Xiaomyia Saether & Wang, a distinctive outlier in the subfamily Chironomidae, allows description, illustration and comparison with its proposed closest relative, Shangomyia Saether & Wang. A previously described bizarre pupal exuviae, 'Taxon 2' sensu Coffman et al. (1988) from south India belongs to Xiaomyia. Molecular data from other sources allows review of the phylogeny and an estimate of the evolutionary tempo. As proposed for the pupa, and independently from adult male morphology, molecular data locate the two genera in a clade that is the sister group to the three other named tribes combined, warranting tribal status within the subfamily Chironominae. Expanded and revised diagnoses for larva, pupa, and adults of Xiaomyiini new tribe are provided. A novel ribbed and spinulose plate-like lobe associated with the ventral larval maxilla in Shangomyia and Xiaomyia is a major synapomorphy for the tribe.