A new genus from Chile and the origins of armored scale insects (Diaspididae)

We discuss a newly discovered genus of scale insects from Chile, comprising four newly discovered species. They have large ribosomal subunit (28S rDNA) sequences that place them outside of all the recently recognized subfamilies of Diaspididae. We treat them as members of Xanthophthalminae, a heretofore monotypic taxon restricted to the Caribbean basin and recently regarded as belonging in Halimococcidae, here regarded as a subfamily of Diaspididae with a center of distribution in Chile. The host plants of the new genus are Araucaria araucana (Araucariaceae) and Drimys winteri (Winteraceae), which both have fossil records indicating relatively little morphological change since the Mesozoic. The new genus is morphoolgically extraordinary, with a series of multilobulate lobes on abdominal segments, becoming less sclerotized anteriorly, and grading into a series of submarginal gland tubercles on the cephalothorax. We hypothesize that the new genus resembles the common ancestor of Diaspididae, with relatively undifferentiated, serially homologous lobules similar to those that differentiated to form the diversity of marginal appendages seen in modern armored scale insects.