Revision of eastern Australian ant-mimicking spiders of the genus Myrmarachne (Araneae, Salticidae) reveals a complex of species and forms

Populations of many taxa are polymorphic as a result of interactions between different evolutionary processes. One such taxon is the salticid spider genus Myrmarachne, which is under strong selection for myrmecomorphy resulting in an accurate mimetic resemblance to various ant species. In revising eastern Australian Myrmarachne, we provide descriptions of four new species (Myrmarachne helensmithae sp. nov., Myrmarachne macaulayi sp. nov., Myrmarachne milledgei sp. nov., and Myrmarachne zabkai sp. nov.) and redescriptions of seven species [Myrmarachne bicolor (L. Koch, 1879), Myrmarachne erythrocephala (L. Koch, 1879), Myrmarachne luctuosa (L. Koch, 1879), Myrmarachne lupata (L. Koch, 1879), Myrmarachne macleayana (Bradley, 1876), Myrmarachne smaragdina Ceccarelli, 2010, and Myrmarachne striatipes (L. Koch, 1879)]. Myrmarachne jugularis Simon, 1900 is a junior synonym of M. macleayana; Myrmarachne cognata (L. Koch, 1879) and Myrmarachne simoni (L. Koch, 1879) are synonyms of M. luctuosa; Myrmarachne rubra Ceccarelli, 2010 is a junior synonym of M. bicolor; and Myrmarachne cuprea (Hogg, 1896) is considered nomen dubium. In a few species (M. erythrocephala, M. luctuosa, M. macleayana, M. milledgei sp. nov., and M. striatipes) we recognized at least two (discrete) forms that differ only in colour pattern. Our phylogenetic analysis supports the existence of species groups and forms, but contradicts the designation of some species. At present we find the eastern Australian fauna is thus composed of 11 Myrmarachne species, five of which have forms. (C) 2017 The Linnean Society of London, Zoological Journal of the Linnean Society, 2017