Ommatius : synonyms , new record , redescription of Ommatius erythropus and description of the female of Ommatius trifidus ( Diptera : Asilidae : Ommatiinae )

Ommatius erythropus Schiner, 1867 is redescribed and a lectotype is established. The female of Ommatius trifidus Vieira, Bravo & Rafael, 2010 is described and a new record is provided. Ommatius ruficaudus Curran, 1928 is established as a new synonym of Ommatius pulcher (Engel, 1885). An identification key is presented to the Ommatius costatus species group. A map with the geographic records is provided.


INTRODUCTION
Ommatiinae Hardy, 1927, one of the 14 subfamilies of Asilidae, is characterized by the setae on the anterior surface of the antennal stylus (Dikow 2009).The most species-rich genus of Ommatiinae is Ommatius Wiedemann, 1821.Ommatius has wide geographic distribution, and is currently broadly defined by the character states of the subfamily (Scarbrough 2005), being the only included genus occurring in the Neotropical Region.Currently, there are 318 valid species in the world (Vieira 2015), 118 of which are from the Neotropics (Papavero 2009, Vieira 2015).
The New World species of Ommatius are divided into eight species groups (ampliatus and holosericeus (holosericeus complex), costatus, hanebrinki, lucidatus, normus, pumilus and tibialis) (Scarbrough 1990, 1993, 2000, 2002, 2008, Scarbrough and Perez-Gelabert 2006).The normus species group is currently restricted to South America, occurring in Venezuela, Guyana, Suriname, French Guiana, Brazil and Paraguay (Scarbrough 2008, Vieira et al. 2010), while the costatus species group is more widely distributed in the Neotropical Region.Males of the Ommatius costatus species group can be recognized by the presence of a long, thin, preapical, dorsoposterior seta on the mid femora; additionally, veins M 1 and M 2 are slightly sigmoid (Scarbrough 1993).The Ommatius normus species group is characterized mainly by the swollen hind femo-ra, usually < 4.5 times longer than wide in anterior view, row of posteroventral bristles on the femur divided into basal and apical groups, separated by a wide bare space; epandrium with 2-3 long setae or macrosetae laterally; base of m1 narrow, at most 1/2 as wide as diameter at basal 1/3; distiphallus usually horizontal, only slightly depressed or elevated, tubular, wide in cross-section apically; spermathecae usually 3-5 times longer than wide, often strongly constricted medially (Scarbrough 2008).
The morphological terminology follows Cumming and Wood (2009).The techniques of Vieira (2012) were used to examine the terminalia.Photographs of the specimens were taken with a Leica DFC500 digital camera attached to a Leica M205C stereomicroscope, connected to a computer with the Leica Application Suite LAS V3.6 software, which includes an Auto-Montage module (Syncroscopy software).After examination and illustration, the detached parts were stored in microvials with glycerin and pinned with their respective specimen.The label data are cited in full, with the original spelling, punctuation and dates.Information presented within square brackets are complementary data not included in the labels.Data from the same specimen but from different labels are separated by slashes (/).The distribution map was generated on the website SimpleMappr.Geographical coordinates were obtained from specimen labels.If they were not available, approximate coordinates were obtained from gazetteers and maps.

TAXONOMY
Two treatments are proposed to the normus group: the female of Ommatius trifidus Vieira, Bravo & Rafael, 2010 is described and a new record is provided, and O. ruficaudus Curran, 1928 is established as a new synonym of O. pulcher (Engel, 1885).Ommatius erythropus Schiner, 1867 is redescribed and a lectotype is established.Furthermore, O. erythropus Schiner is allocated in the O. costatus species group.A map with the geographic records of the species, including those of the synonym O. ruficaudus Curran, is provided (Fig. 1).
Wing (Figs 6,7).Brown hyaline; dark brown veins; with costal dilatation; crossvein r-m just before middle of cell d; R 4+5 bifurcation at level of apex of cell d; microtrichia on posterior wing margin arranged in single row; halter pale yellow, stalk base and bulb light brown.
Remarks.Ommatius erythropus is a typical species of the O. costatus species group.It has the following characteristics of this group: preapical, dorsoposterior seta on the mid femora; hind femora more slender, usually 5-6 times longer than wide in anterior view, row of posteroventral bristles not divided into two groups or separated by wide bare space; M 1 and M 2 veins slightly sigmoid (Scarbrough 1993(Scarbrough , 2008)).Ommatius erythropus is similar to O. spatulatus Curran, 1928, but differs by the presence of six yellow dorsocentral macrosetae, apical scutellar yellow setae and mid femur with a brown, moderately thick, preapical, dorsoposterior seta.By contrast, O. spatulatus does not have dorsocentral macrosetae, apical scutellar setae and the mid femur has a pale, long, thin, preapical, dorsoposterior seta.Furthermore, O. erythropus differs from O. spatulatus by the combined characters of the terminalia.
Lectotype condition.Thorax with a hole on posterior portion of scutum.