A second Scirtothrips species with a hind-femoral comb in males (Thysanoptera, Thripidae)

Amongst the 100 described species worldwide of the genus Scirtothrips, the South African Citrus Thrips, S. aurantii Faure, has been considered unique because the males possess a comb of stout setae on the hind femora (Hoddle & Mound, 2003). A new species that shares this character state is described here from Cedrus (Pinaceae) in Kenya, although no information is available for either species concerning the functional significance of this comb. The host association of this new species is interesting, because Scirtothrips species are generally considered to be associated with the young leaves of dicot plants, on which some are important pests (Mound & Palmer, 1981). Despite this, several relatively unrelated species within the genus have radiated onto various unrelated Gymnospermae. Two are associated with Juniperus (S. brevipennis in eastern North America, and S. juniperinus in Central Asia), one with Libocedrus (S. solaris in California), and one with Taxodium (S. taxodii in eastern North America), and in Australia two species are associated with the young fronds of cycads (S. litotetes on Lepidozamia and S. tenor on Cycas). Moreover, two species are known from different tree ferns (S. pteridis in Costa Rica, and S. frondis in Australia). Scirtothrips is thus yet another example of radiation within a genus of Thysanoptera that involves exploitation of unrelated plants (Mound, 2005), such as Cranothrips Bagnall (Pereyra & Mound, 2009) and Echinothrips Moulton (Mound & Marullo, 1996), rather than fidelity to any particular plant lineage. For full nomenclatural details of all taxa mentioned here see Mound (2010).