Nomenclatural changes in the Australasian gall-inducing genus Apiomorpha Rübsaamen (Hemiptera: Coccomorpha: Eriococcidae).

Apiomorpha Rübsaamen, 1894 was erected as a replacement name for Brachyscelis Schrader, 1863 that was preoccupied in the Coleoptera (Chrysomelidae: Brachyscelis Germar, 1834). Apiomorpha is a genus of eriococcid scale insects that induce galls on Eucalyptus (Myrtaceae) in Australia and New Guinea (Szent-Ivany & Womersley 1962; Gullan 1984; Gullan et al. 2005). In his original description of the genus, Schrader (1863a) included six species, of which B. citricola Schrader was subsequently recognised as a nomen nudum (Froggatt 1921). Among the other five, B. pileata Schrader was later designated as the type species of Apiomorpha by Lindinger (1937). Also amongst these five was B. ovicola Schrader, for which Schrader described and illustrated galls of males and females on twigs and leaves of Eucalyptus haemastoma (Schrader 1863a, plate II, figs a, e) in or near Sydney, New South Wales (NSW). He stated that his species names reflected the shape of the galls of adult females; hence those of B. ovicola can be interpreted as being egg-shaped and were illustrated as such by Schrader (1863a). Galls of males of B. ovicola he described and illustrated as trumpet-shaped.

Rapid chromosomal evolution in a morphologically cryptic radiation.

Cryptic species occur within most of the major taxonomic divisions, and a current challenge is to determine why some lineages have more cryptic species than others. It is expected that cryptic species are more common in groups where there are life histories or genetic architectures that promote speciation in the absence of apparent morphological differentiation. Chromosomal rearrangements have the potential to lead to post-zygotic isolation and might be an important factor leading to cryptic species. Here we investigate the potential role of chromosomal change in driving speciation in the karyotypically diverse scale insect genus Apiomorpha, focussing on four species placed in the same species group (the A. minor species group Gullan, 1984). Using mitochondrial and nuclear DNA sequence data, we find that Apiomorpha minor is not monophyletic and consists of at least nine cryptic species. Diploid chromosome counts range from 2n=4 to 2n=84 across the four currently recognized species, and some of the chromosomal variation exists in the absence of other genetic or host use differences, consistent with karyotypic changes being involved in lineage divergence and the generation of cryptic species.