Myiopharus Brauer and Bergenstamm, 1889

O’Hara, James E., 2007, A new species of Myiopharus Brauer and Bergenstamm (Diptera: Tachinidae) parasitic on adults of the sunflower beetle, Zygogramma exclamationis (Fabricius), Zootaxa 1521, pp. 31-41 : 32-33

Myiopharus Brauer and Bergenstamm, 1889

Myiopharus Brauer and Bergenstamm, 1889: 161 (also 1890: 93). Type species: Myiopharus metopia Brauer and Bergenstamm, 1889 , by monotypy.

The type species of Myiopharus is M. metopia , described from the Neotropical Region. Reinhard (1945) added the first North American species to Myiopharus , M. dorsalis ( Coquillett, 1898) , and described two additional species, M. canadensis and M. securis . This classification, recognizing three species of Myiopharus in America north of Mexico, was followed by Sabrosky and Arnaud (1965). An earlier synonymy of the North American genus Adoryphorophaga Townsend (1931) with Myiopharus by Mesnil (1960: 653) was either overlooked or disregarded by Sabrosky and Arnaud (1965). Aldrich (1934) described two new species of Myiopharus from Chile, and Guimarães (1971) grouped these and eight other species under Myiopharus in his catalogue of the Tachinidae of America south of the United States.

Wood (1985) re-evaluated the generic concepts of Myiopharus and other blondeliine genera in his revision of the Blondeliini of North and Central America. In an attempt to simplify the oversplit classification of his predecessors, and to bring related species closer together, Wood proposed a revised classification that consisted of fewer, more broadly defined, genera. His intention was to group species based on similarities and shared derived characters, and the result was 55 genera and 177 new generic synonyms for the Blondeliini of North and Central America. Myiopharus remained an exclusively New World genus, but swelled in size from fewer than 15 described species in the New World to 54 described species in just North and Central America (creating over 30 new generic synonyms in the process). Wood (pers. comm.) believes there are about 50 described species in South America that should also be classified in Myiopharus in addition to many undescribed species throughout the Neotropics, making this the largest genus in the Blondeliini . Relatively few species are known from America north of Mexico, where O’Hara and Wood (2004) listed just 14 species. It is suspected that the hosts of Myiopharus species are exclusively beetles in the family Chrysomelidae , with other recorded hosts probably being in error ( Wood 1985). The sister group to Myiopharus within the Blondeliini has not been determined, though Wood (1985) suggested that the monotypic genus Thelyoxynops Townsend from Trinidad might be related to, or possibly congeneric with, Myiopharus .

The monophyly of Myiopharus has not been established, and the genus could possibly be paraphyletic. It does contain species of different appearance; for example, the males of some species have a black thorax and shiny frons ( Fig. 5 ) whereas males of other species are gray like females ( Fig. 1 ), the eye is densely haired in most species and sparsely haired in a few, and the facial ridge is setose along most of its length in some species and on less than lower half in others ( Figs. 2, 4 ). As well, female ovipositors vary from tubular to piercing to laterally flattened ( Figs. 7–8 ). These sorts of differences are often used to separate genera and explain in part why the Myiopharus species of Wood (1985) were once dispersed among many genera. Yet there is also a continuity among species for certain characters and a continuum from one species to the next for others, such that there is no easy way to divide the genus nor any clear indication that it is not monophyletic.

Myiopharus is easily recognizable as a blondeliine tachinid by a combination of character states ( Wood 1985; couplet 119 in Wood 1987): prosternum haired, first postsutural supra-alar seta smaller than first postsutural dorsocentral seta, scutellum with four setae including a pair of large and divergent subapicals, and bend of vein M rounded and obtuse-angled. Myiopharus is less easily characterized, keying out three times in Wood (1987). The genus is diagnosed in Wood (1985). The species described here, M. neilli , can be recognized as a member of Myiopharus by the following features: eye moderately to densely haired, parafacial bare, both sexes with 2 pairs of proclinate orbital setae ( Fig. 4 ), subvibrissal ridge with row of 2–3 setae ( Fig. 2 ), proepisternum bare, vein R 4+5 with just a few hairs basally, middorsal depression on abdominal syntergite 1+2 not extended back to hind margin of syntergite (but close), and body black or almost so in ground color.

Figures

FIGURES 1 – 6. 1. Myiopharus neilli sp. nov., left lateral view of male holotype. Body length = 6.9 mm. 2. M. neilli, oblique view of head of female allotype. Scale bar = 0.5 mm. 3. M. neilli, left lateral view of female allotype. Body length = 6.9 mm. 4. M. dorsalis, oblique view of female head. Scale bar = 0.5 mm. 5. M. canadensis, showing dark thorax and shiny frons that characterizes males of some Myiopharus species (image courtesy of S. A. Marshall). 6. M. neilli, ventral view of female showing tufts of setae on katepisternum in front of mid coxae. Scale bar = 0.3 mm.

FIGURES 7 – 11. Myiopharus neilli sp. nov. 7. Left lateral view of female ovipositor. Scale bar = 0.2 mm. 8. Posterior view of female ovipositor. Scale bar = 0.2 mm. 9. Puparium. Scale bar = 1.0 mm. 10. Posterior and slightly dorsal view of posterior spiracular discs of puparium. Scale bar = 0.2 mm. 11. Puparium within remains of host, Zygogramma exclamationis. Beetle is typically decapitated between prothorax and mesothorax. Scale bar = 1.0 mm.