A review of tangle-veined flies (Nemestrinidae, Diptera) in Egypt

Abstract The Egyptian fauna of the genus Nemestrinus Latreille, 1802 is revised. In 1967, Steyskal and El-Bialy listed 12 species from the region, but only six species are now recognized. The primary type specimens of the species N.aegyptiacus (Wiedemann, 1828), N.rufipes (Olivier, 1810), and N.lateralis Wiedemann, 1828 (N.lateralis being a synonym of N.rufipes) deposited in the Museum für Naturkunde, Berlin, Germany were examined. Two species (N.abdominalis Olivier, 1811 and N.fascifrons (Bigot, 1888) are placed as new synonyms of N.ater (Olivier, 1811), and N.ruficornis Macquart, 1840 is synonymized with N.rufipes (Olivier, 1811). Nemestrinusjullieni (Efflatoun, 1925) is confirmed as a synonym of N.aegyptiacus. Furthermore, three species (N.caucasicus Fischer, 1806, N.pallipes (Olivier, 1811), and N.persicus Lichtwardt, 1909) have been removed and are doubtful records from Egypt. A key to the species, lists of specimens examined, and Illustrations and distributions for each species are provided. The status of species of doubtful occurrence in Egypt is discussed.


Introduction
Nemestrinidae (tangle-veined flies) are a small dipteran family belonging to the suborder Brachycera-Orthorrhapha and occur all over the world, but are most abundant and diverse in the Palaearctic, Australian and Afrotropical Regions (Richter 1997;Pape et al. 2011). The family is classified into five subfamilies and comprises approximately 300 species worldwide in 23 genera, while 77 species in eight genera are known from the Palaearctic region (Richter 1997;Narchuk 2007;Papavero and Bernardi 2009;Pape et al. 2011).
The Nemestrininae comprise ca. 175 species worldwide in six genera (Bernardi 1973;Papavero and Bernardi 2009). In the Palaearctic Region, the Nemestrininae currently include approximately 67 species in two genera (Nemestrinus Latreille, and Stenopteromyia Lichtwardt) according to the last published catalogue by Richter (1988).
The genus Nemestrinus was described by Latreille in 1802 based on specimens collected from Egypt and Syria. It comprises 66 species in the Palaearctic Region (Bernardi 1973;Richter 1988Richter , 1997Narchuk 2007) and is characterized by the wing venation: The apical part of the wing occasionally has supernumerary transverse veins, R 3 is present, R 3+4 and R 5 are free, M 1 and M 2 are free, the diagonal vein reaches the wing margin, and the proboscis is well developed and longer than the head. One of the important tools to separate nemestrinid species is the genitalia, composed of the well-developed hypandrium, partly fused with the gonocoxites with a linguiform apical projection bearing numerous hairs; and the elongate gonocoxal apodemes, which are sinuate and fused medially forming a dorsal bridge (Richter and Ovtshinnikova 1996;Richter 1997).
There is no modern comprehensive work identifying and cataloguing the Egyptian nemestrinine fauna. The subfamily in Egypt has never been monographed, and the genus is very much in need of a modern revision. This study was undertaken to revise, update, and clarify the taxonomic status of the species of genus Nemestrinus Latreille in the Egyptian fauna.

Materials and methods
Specimens examined in this study are deposited in the following collections: The Museum für Naturkunde, Germany, Berlin (ZMHB) is the depository of type specimens of N. aegyptiacus, N. rufipes, and N. lateralis Wiedemann, 1828 (the latter is a synonym of the second species). We obtained this information by personal communication with Mr. Sven Marotzke and Ms. Elena Grigoryeva.
We could not access the types of other species because some are missing, as in the Egyptian Society of Entomology, wherein type specimens of the species N. jullieni have apparently been destroyed, and it is not known where the other types are. We examined and revised the original descriptions of all Egyptian nemestrinid species.
The Smithsonian National Museum of Natural History (USNM) has specimens of Nemestrinidae from Egypt: N. abdominalis, N. aegyptiacus, and N. rufipes that have all been identified by Dr. Torsten Dikow using our key. Redescriptions are based on series of specimens of each of these species and body measurements include genitalia.
Remarks. After examining the female type specimen of Nemestrinus aegyptiacus (Fig. 1) and comparing it with a large series of specimens identified as Nemestrinus jullieni Efflatoun (some specimens were by seen by him but it is not clear who determined the identification), we confirm this identification, and it is clear that both are the same species. Hence, N. julieni is placed as a synonym instead of a subspecies based on examination of the series of specimens and dissections of genitalia of both N. aegyptiacus and N. julieni and the female type specimen of N. aegyptiacus, and comparisons with the genitalia figures of Bernardi's (1973: figs 54- (27), and abdomen (28). 29-32 male genitalia: epandrium, proctiger, and cerci (29) Diagnosis. Frons shiny black with a transverse white band; wing with small cells extending forward from R1 to hind margin; abdomen orange with longitudinal black vitta in male but entirely black in female.
Thorax black or blackish brown, with blackish to yellowish brown hairs, pleurae with long and dense black hairs; leg blackish or dark yellow; claws well developed; pulvilli almost rudimentary. Wing blackish brown, but apex and postero-apical margin pale brown; wing with many small cells extend forward from R1 to hind margin (Fig. 27). Abdomen short, wide, reddish to orange with longitudinal black strip that is narrow posteriorly and sometimes absent at apex (Fig. 28). Male genitalia with gonocoxite having two processes, inner process short and slender, whereas the outer process is longer, thicker and subapically curved; gonostyli longer than the inner gonocoxal processes but shorter than the outer one, with subapical cleft and small projection ( 29, 30); aedeagus free, narrow distally and fused proximally with parameres; parameres slightly sinuate; parameral apodeme a long, while aedeagal tine is short; ejaculatory apodeme slender and narrow (Figs 31, 32). Female. Similar as male (Figs 33-37), except: eyes widely separated more than in male. Abdomen entirely black or at least with reddish black lateral margins (Fig. 38). Head in male slightly wider than thorax but in female narrower than thorax. Female genitalia with quadrate subgenital plate, bilobed distally (Fig. 39); genital furca with furcated arms and serrated laterally (Fig.  40); uterus small, with terminal accessory process; spermathecal ducts narrow and long with oval medium spermathecae (Fig. 41).  (Sack 1933;Bernardi, 1973;Richter 1988).
Remarks. Nemestrinus abdominalis and N. fascifrons are newly synonymized with N. ater. The earlier works of Lichtwardt (1909Lichtwardt ( , 1919, Villeneuve (1912), and Bequaert (1938) suggested that N. ater, N. abdominalis, and N. fascifrons were closely related to each other based on Egyptian, Tunisian, and Palestinian material. We observed that N. ater has sexually dimorphic abdominal color. We also discovered that all the specimens previously identified by Efflatoun as N. fascifrons are males and we confirm these identifications. We also confirm that all the specimens that were previously identified by the same author as N. ater are females and confirmed by us as N. fascifrons. The two "species" of Efflatoun were captured from approximately the same locality and time of year by the same collector, i.e., "Efflatoun collected males at W.  (Figs 50, 51). Female differentiated from male by the eyes that are more dichoptic. Female genitalia with rectangular subgenital plate, excavated proximally to approx. 1/2 length of plate (Fig. 58); genital furca with small genital aperture, between projections with broad ends, and curved posteromedially with small curve on upper and lower margins (Fig. 59); uterus large and flatted, spermathecae long (Fig. 60). Local distribution. Eastern Desert, Lower Nile. Geographical distribution. Egypt, Iran, and Israel (Sack 1933;Bernardi, 1973;Richter 1988).
Diagnosis. Frons and face with dense whitish hairs and pollinose; inner ends of transverse suture with two white spots; wing hyaline with brownish base, veins yellowish, without additional small cells; abdomen black with transverse white bands, slightly curved medially; gonocoxite with inner and outer processes, the inner tapered apically, outer slightly curved subapically; gonostyli broader than gonocoxal processes with broad subapical projection; aedeagal complex narrow, aedeagus slightly broader distally.
Head triangular in profile, ventrally with dense, short, whitish hairs; frons and face with dense whitish hairs and pollinosity (Figs 61-63, 71-73); antenna distinctly jointed, stylus is brown (Figs 64, 74). Thorax slightly shiny black; inner parts of transverse suture with two white spots; scutellum and mesonotum with grayish yellow hairs; pleurae with long white hairs. Leg with blackish femora covered with whitish hairs; tibiae and tarsi brown with brownish red hairs; pulvilli orange, nearly as long as claws. Wing hyaline with brownish infuscate base; veins yellowish, without additional small cells (Figs 65, 75). Abdomen black with transverse white bands, whi slightly curved medially; basal segments with long yellowish hairs but subsequent segments with white hairs; venter of abdomen with dense white hairs that fold on the lateral margins (Figs 66, 76). Gonocoxite with inner and outer processes, inner tapered apically, outer slightly curved subapically; gonostyli broader than gonocoxal processes with broad projection subapically (Figs 67, 68); aedeagal complex narrow, aedeagus slightly broader apically (Figs 69, 70). Female: eyes separated in both sexes but considerably broader than in male at vertex; genitalia with sub-rectangular subgenital plate (Fig. 77); genital furca narrower anteriorly with four incurved posterolateral projections (Fig. 78); uterus with terminal accessory process; spermathecae rather long (Fig. 79).

Nemestrinus reticulatus Latreille, 1802 Figures 80-85
Nemestrinus reticulatus Latreille, 1802: 437. Type locality: not given but according to Latreille (1809: 307), it is Egypt and Syria. Rhynchocephalus latreillei Fischer, 1812: 195. Nemestrina cinctus Macquart, 1840: 16. Nemestrina kindermanni Bischof, 1905 Diagnosis. Frons with shiny yellow or black spot below ocelli; mesonotum with two gray spots at inner ends of the transverse suture, between them there is a thin longitudinal stripe; wing hyaline in posterior 1/2 and apex but brownish on anterior 1/2 and slightly infuscate at base; wing with small cells that extend forward from R 2 to hind margin; abdomen gray, matte, with incomplete transverse black stripes; tergite II bears shiny black spots divided in the middle by a transverse longitudinal gray strip; black spots on tergites III-V more or less fused into bands with an emargination along the posterior margin; on tergite III, gray emargination varies from very deep to nearly absent; abdominal venter with dense gray pollinosity, the second sternite with central black spot.
Description. Length: body 14-15 mm. Head black with dense gray pollinosity and whitish hairs; frons with shiny yellow or black spot below ocelli, in male frons at vertex nearly as wide as eye width (Figs 80, 83), while in female nearly twice as eye width (Fig. 81); antenna with orange scape and pedicel, first flagellomere brown to blackish brown with some gray pollinosity (Fig. 82), basal two segments of stylus subequal in length and segment III 2/3 × longitudinal eye diameter; palpi yellow or brown with black apices. Thorax pale black with yellowish white or grayish white hairs, but longer and denser on scutellum and pleurae; mesonotum with two gray spots at inner ends of transverse suture and between them is a thin longitudinal stripe. Leg rusty red; in females, only hind tarsi blackish or hind leg entirely blackish; in males, all femora black; hind tibiae and tarsi blackish. Wing hyaline over posterior 1/2 and at apex, but somewhat brown over anterior 1/2 and slightly infuscate at base; wing with small cells that extend forward from R 2 to hind margin (Fig. 85). Abdomen gray, matte, with incomplete transverse black stripes; tergite II with shiny black spots divided in the middle by a transverse longitudinal gray strip; black spots on tergites III-V are more or less fused into bands with an emargination along the posterior margin; on tergite III, gray emargination varies from very deep to nearly absent; abdominal venter with dense gray pollinosity, sternite II with black central spot (Fig. 84).

Redescription.
Length: male body13.5-18.5 mm, wing 11.5-16 mm. Female body 14-21 mm, wing 12-17.5 mm. Head short, wider than thorax; frons covered with dense orange-yellow pollinosity except with shiny blackish brown transverse oval callus (96)(97)(98); face shiny brownish orange with short yellow hairs; antenna orange (Figs 89, 99); proboscis black, as long as thorax, upper surface of base with short yellow hairs; palpi orange. Thorax shiny black with yellow hairs, longer and denser on the sides and in front; mesonotum with indistinct spots at inner ends of transverse suture. Leg orange, coxae and base of femora somewhat brown, pulvilli light yellow and nearly 1/2 length of claw. Wing with yellowish brown band in the middle, but clear apically and along posterior margin; wing with small cells extending forward from R2 to M1 or M2 (Figs 90, 100). Halter brown with light yellow pedicel. Abdomen orange to reddish orange with longitudinal black median vitta; tergite I entirely black, tergite II with transverse white band; abdomen with short and golden yellow hairs but longer laterally; abdominal venter orange and with black lateral margins (Figs 91,101). Gonocoxite with inner process slightly tapered; gonostyli longer than gonocoxal process, curved subapically with small projection (Fig. 93); aedeagus fused proximally with parameres and separated distally, parameres and aedeagus with small indentations distally in lateral view (Figs 94,95). Female genitalia: rectangular subgenital plate with large curve (Fig. 102); genital furca with large aperture surrounded by narrow and slightly curved posterolaterally projections (Fig. 103); uterus with small terminal accessory; spermathecae nearly as long as the uterus (Fig. 104).
Remarks. Bernardi (1973) and Richter (1988) considered N. rufipes and N. ruficornis to be valid species but, in contrast, Lichtwardt (1909) and Bequaert (1938) synonymized the two. We agree with this decision based on a comparison of the original description of N. ruficornis (no material was examined) with the male type specimen of N. rufipes (Fig. 2) and the female type specimen of N. lateralis (Fig. 3), both in ZMHB, in addition to both sexes of many old Egyptian specimens of N. rufipes. Thus, we confirm that N. rufipes and N. ruficornis are conspecific and the first is the valid name, and Nemestrinus ruficornis is here synonymized with N. rufipes.
List of doubtful species. In the present study, three species are treated as doubtful and are excluded from the list of Egyptian Nemestrinidae: Nemestrinus caucasicus, Nemestrinus pallipes, and Nemestrinus persicus.

Discussion
As a result of this revision, we can confirm six species of Nemestrinus present in Egypt. This is lower than the 12 taxa (eleven species and one subspecies) listed by Steyskal and El-Bialy (1967) but three species are treated as doubtfully occurring including N. pallipes added by Bernardi (1973) and Richter (1988) as Egyptian species and three species that are newly synonymized (N. abdominalis, N. fascifrons, and N. ruficornis).
Furthermore, N. jullieni, a subspecies designated by Steyskal and El-Bialy (1967), is confirmed as a synonym of N. aegyptiacus.
The second species (N. pallipes) is not represented in Egyptian collections. This species was previously considered to be an Egyptian species based on an erroneous interpretation of its type locality (Java) by Bequaert (1932), Bernardi (1973), andRichter (1988), for reasons unknown. The type locality was given by Olivier (1811) in his original description as Java, while describing seven new species from Egypt, although two of them were from Arabia and around the Caspian Sea. Olivier (1811) based his paper on material collected from different areas in the Middle East and his "Java" evidently refers to a place near Tel-Aviv in Israel currently known as Jaffa, not an Egyptian locality. We communicated with managers in Tel Aviv museum (Steinhardt museum), Diptera collection (Dr. Elizabeth Morguilis and Dr. Ariel-Leib Frieman), who checked the nemestrinid group and they do not have any specimens of this species in their collections. This species is also not mentioned in the list of Steyskal and El-Bialy (1967). Although it is believed that this species does not occur in Egypt, it may yet be found and recorded from the country.
The third species (N. persicus) is reported in Sack (1933) and Paramonov (1945) as an Egyptian species, but without any listing of Egyptian material. It is also mentioned as an Egyptian species by Steyskal and El-Bialy (1967) but is not represented in Egyptian reference collections; however, Bequaert (1932), Bernardi (1973), and Richter (1988) excluded it as an Egyptian species. The type locality in the original description was given as Iran by Lichtwardt (1909) and, consequently, this species is excluded from the Egyptian fauna.
Nemestrinus reticulatus is stated here as not having any specimens in Egyptian collections and is not excluded from the Egyptian fauna in our study because we trust the descriptions of Latreille (1809) who originally reported the species in Egypt. Our drawings of this species are reproduced from Bequaert (1938), Sack (1933), andSeguy (1926).
As we observed on the maps there are similarities in the distributions of N. aegyptiacus and N. rufipes, which are longitudinally scattered from Lower to Upper Egypt and the western and eastern deserts, while N. faciatus is concentrated only in some localities on the coastal strip in Alexandria. Nemestrinus exalbidus is dispersed around the lower Egyptian delta and a few localities in the western and eastern deserts. Nemestrinus ater has a crosswise distribution in the northern area of Egypt including Sinai, and the lower and upper Nile valley (see Map 1), and one record in the eastern desert, in addition to one locality near Libya.
The species of Nemestrinus are concentrated in the semiarid areas around the Nile delta, especially around Lower Egypt and in some arid areas in western, eastern, and the Egyptian Sinai deserts. The wider geographical distribution of Nemestrinus in the adjacent countries includes North Africa (Algeria, Libya, Morocco, and Tunisia) which all have a large percentage of the arid deserts that these nemestrinid species prefer. And at nearly the same latitude are Israel, Saudi Arabia, and Syria which also have arid areas (deserts) and may support species.
We found based that the seasonal imago flight activity of all Nemestrinus species in Egypt is in the spring season (March, April, and May) and only the species N. ater and N. exalbidus may also be activate in February.