Rachiptera Bigot

Norrbom, Allen L., Sutton, Bruce D., Steck, Gary J. & Monzón, José, 2010, New genera, species and host plant records of Nearctic and Neotropical Tephritidae (Diptera) 2398, Zootaxa 2398, pp. 1-65 : 50

Rachiptera Bigot

Rachiptera Bigot 1859 (type species R. limbata Bigot , by monotypy).

Strobelia Rondani 1868 (type species S. baccharidis Rondani , by designation of Hendel 1914: 93). New synonymy.

Strobelia Rondani is here considered a subjective junior synonym of Rachiptera Bigot , and the following species, all of which were originally described in Strobelia , are transferred to Rachiptera as new combinations: R. alboguttata ( Hendel 1914) , R. baccharidis (Rondani 1868) , R. bimaculata ( Hendel 1914) , R. ferruginea (Hendel 1928) , R. lutulenta ( Hendel 1914) , R. parallela ( Hendel 1914) , and R. rubiginosa (Rondani 1868) .

Rachiptera includes 11 described and various undescribed species from South America ( Argentina, Bolivia, Chile, Colombia, Peru, southern Brazil) that form galls on species of Baccharis , Grindelia , and Heterothalamus ( Asteraceae : Astereae ). The genus is most closely related to Paracantha (see discussion under that genus). Most species form an unusual gall ( Fig. 104) that is surrounded by a white spongy substance secreted by the larva giving it the superficial appearance of a ball of styrofoam ( Aljaro et al. 1984, Frías 2008).

The species previously placed in Rachiptera , R. biarcuata Hendel , R. limbata Bigot , R. percnoptera Hendel , and R. virginalis Hering , along with an undescribed species from Peru and Colombia, probably form a monophyletic group. They share probable apomorphic character states including an elongate wing shape, with the posterior margin at least slightly convex and with a hyaline border (although very small in R. virginalis ), and crossveins r-m and dm-cu at a sharp angle. These characters were used by Hendel (1914) and Foote (1980) to separate Rachiptera from Strobelia , but they, as well as the markings of the face and frons and the scutal setulae pattern, intergrade within Strobelia . Rachiptera parallela and specimens examined from Brazil that are similar to R. virginalis (or perhaps conspecific with it if wing shape and pattern in R. virginalis vary slightly) have elongate, parallel-sided wings without a hyaline area on the posterior margin. In both species the crossveins vary from subparallel to moderately angled. The wings of other species previously included in Strobelia vary from slightly ( R. luculenta ) to broadly oval, with the crossvein orientation more or less correlated with wing shape. The scutal setulae pattern is damaged in many specimens examined, but varies from similar to that in most Paracantha species , with ovoid nonsetulose areas (in at least R. parallela and R. alboguttata ), with more elongate nonsetulose areas (sp. nr. virginalis ), to more evenly distributed ( R. biarcuata , R. limbata , and R. percnoptera ). Finally, R. parallela forms a simple gall (see below), so the behavior of secreting the white material around the gall appears not to be a synapomorphy for all species and is not correlated with wing shape. Although Rachiptera in the sense of previous authors may be monophyletic, Strobelia is not, and there is no clearcut way to divide the entire clade, thus it is preferable to synonymize these names and recognize one genus.