Print
A new species of Systenus Loew (Diptera, Dolichopodidae) from Croatia
expand article infoStefan Naglis
‡ University of Zurich, Zurich, Switzerland
Open Access

Abstract

Systenus bartaki sp. n. is described from Croatia. The new species is similar to S. tener Loew and S. vasilii Grichanov but it differs by characters of the antennae and the male genitalia.

Key Words

Dolichopodidae, Systenus, Croatia, new species

Introduction

The genus Systenus Loew, 1857 is present in all biographical regions and includes worldwide 36 species (Yang et al. 2006, Bickel 2015). In the Palaearctic region 10 species are known and a revised key was provided by Negrobov (2005). The systematic position of the genus is still differently treated – Negrobov (1991, 2005) placed the genus in the Systeninae while Bickel (1986, 2015) proposed a placement in the Medeterinae. Species of the genus are known to be tree-trunk associated and the larvae develop in tree-hole debris (Vaillant 1978, Oboňa et al. 2012). Since members of the genus Systenus are usually rare in collections, examples of rich local sympatry are of special interest. For example six species were collected at the same locality near Manaus, Brazil (Naglis 2000), five species were collected from a single tree in Germany (Diestelhorst and Lunau 2001), three species were collected at the same collecting site in Switzerland (Naglis 2014), and eight species were collected at the same locality in Costa Rica (Bickel 2015).

The material was collected by means of a Malaise trap situated in the village of Gornji Muć, located 15 km from the Adriatic coast in the hinterland of the city of Split. The trap was placed on a sunny hill slope named Grudina at 500 m a.s.l., in an orchard, at position 43°41'27"N, 16°29'44"E on the southeast foothills of the Svilaja mountain. The cold and dry mountain air from the northeast is mitigated with moist and warmish southern winds creating the Submediterranean climate vegetation zone with dominant Quercus pubescens communities. To the south the collecting place was close to the fields and slopes planted with vineyards and orchards and to the north it was open to a small wood and pasture

Material and methods

Dipterans were sorted by means of morphospecies method and voucher specimens were dried and mounted on cards. The material examined is deposited in the collection of the Czech University of Life Sciences Prague (CULSP).

Body length is measured from the base of the antennae to the tip of abdominal segment 6; wing length from wing base to wing apex. The positions of features on elongate structures such as leg segments are given as a fraction of the total length, starting from the base. The following ratios are used: relative podomere ratios: femur, tibia, tarsomere 1/2/3/4/5; length of crossvein dm-cu to distal section of CuA (= CuAx ratio); distance between veins R2+3 and R4+5 to distance between R4+5 and M at costal margin (= RMx ratio). Describing the hypopygium, dorsal and ventral refer to the position prior to rotation and flexion, i.e. in figures top is morphologically ventral and bottom is dorsal. If not otherwise indicated, the coloration of hairs and setae is black. Morphological terminology follows Cumming and Wood (2009).

Morphological abbreviations: ac = acrostichal setae; ad = anterodorsal; dc = dorsocentral setae; pd = posterodorsal; ppls = proepisternal setae.

Systematic account

Description of the new species

Systenus bartaki sp. n.

Fig. 1

Type material

Holotype ♂: Croatia, Gorni Muć, 500 m, abandoned garden, MT [malaise trap], 43°41'27"N, 16°29'44"E, 24.viii.-14.ix.2014, B. Kokan leg. (to be deposited at CULSP).

Diagnosis

Antennal scape and pedicel yellow, postpedicel black, but basoventral 1/3 yellow, 3 times as long as basal height; arista 1/5 as long as postpedicel; veins R4+5 and M parallel in distal part; apical section of CuA 2.5 times as long as crossvein dm-cu; hypandrium curved, with a pair of long sinuous setae; cercus long and broad, triangular.

Description

Male. Body length (holotype): 2.0 mm, wing length 2.0 mm. Head: frons and face metallic green, with dense greyish pruinosity, narrowest distance between eyes about equal to the distance between ocellar setae; palpus yellow; proboscis dark brown; antennal scape and pedicel yellow; postpedicel (Fig. 1A) black, except basoventral 1/3 yellow, 3 times as long as basal height, with dense short hairs; arista apical, bare, 1/5 as long as postpedicel; postocular setae white. Thorax: mesonotum metallic blue-green shining, with grey pruinosity; thoracic setae black; 6 pairs of strong dc; ac short, consisting of 10-12 pairs; scutellum with a pair of strong marginal setae and 2 smaller lateral setae; 2-3 yellow ppls; pleura same coloration as mesonotum. Legs: including coxae pale yellow, hind femur with a brown dorsoapical patch, setae and hairs black except as noted. Fore leg: coxa with pale yellow anterior setae; femur, tibia and tarsomeres lacking major setae; relative podomere ratios: 40:40:20:10:7:4:5. Mid leg: coxa with pale yellow anterior setae; femur bare; tibia with a pair of ad/pd setae at 1/4; tarsomeres bare; relative podomere ratios: 49:51:27:16:10:7:5. Hind leg: coxa with a strong pale lateral seta; femur bare; tibia with a row of 5-6 short pd setae; tarsomeres bare; relative podomere ratios: 50:64:13:25:14:10:6. Wing: hyaline, veins brownish-yellow; R3+4 and M parallel in apical half; CuAx ratio: 0.4; RMx ratio: 1.5; lower calypter pale yellow, with yellow setae; halter pale yellow. Abdomen: metallic blue-green shining; hairs and setae brown. Hypopygium (Fig. 1B): epandrium dark brown; cercus and surstylus white, hypandrium yellowish-brown. Epandrium rectangular; hypandrium curved, with acute apex, bearing a pair of long sinuous setae; surstylus narrow and straight, with a basoventral and a basodorsal projection and with two subapical setae; cercus long, triangular, broadened medially.

Figure 1. 

Systenus bartaki sp. n. holotype male. A antenna, left lateral B hypopygium, left lateral. Cer = cercus; Epa = epandrium; Hyp = hypandrium; Pha = phallus; Sur = surstylus. Scale bars: 0.1 mm.

Female: unknown.

Etymology

The new species is dedicated to the Czech dipterist Miroslav Barták.

Discussion

Systenus bartaki is similar to S. tener Loew, 1859 and S. vasilii Grichanov, 2002. All species share the following characters: veins R4+5 and M parallel in distal half; antennal scape and pedicel yellow. S. bartaki can be separated from the other two species by the short arista which is only 1/5 as long as the postpedicel, and by the postpedicel which is 3 times as long as high. In S. tener and S. vasilii the arista is at least 1/2 as long as the postpedicel and the postpedicel is 2-2.5 times as long as high. The male genitalia of S. bartaki are similar to that of S. vasilii, but differ by the broadened, triangular cercus which is longer than the surstylus, and by the curved hypandrium bearing a pair of long, sinuous setae. In S. vasilii the cercus is ribbon-shaped, shorter than the surstylus, and the hypandrium is not curved and bears short setae (see fig. 3 in Grichanov 2002).

Acknowledgements

I am thankful to Miroslav Barták (CULSP) for the loan of the material and for information about collecting site and methods and to Bože Kokan (Natural History Museum Split) for collecting the material. Dan Bickel (Sidney), Oleg Negrobov (Voronezh) and Andreas Sanchez (Neuchatel) provided useful comments on the manuscript.

References

  • Cumming JM, Wood DM (2009) Adult morphology and terminology [Chapter] 2. In: Brown BV, Borkent A, Cumming JM, Wood DM, Woodley NE, Zumbado MA (Eds) Manual of Central American Diptera. Volume 1, 9–50.
  • Diestelhorst O, Lunau K (2001) Leben in der Krone. Farbschalenfänge von Dolichopodiden im Kronenraum einer Buche. Mitteilungen der Deutschen Gesellschaft für allgemeine und angewandte Entomologie 13: 543–546.
  • Grichanov IYa (2002) A new species of Systenus Loew (Diptera: Dolichopodidae) from Israel. Studia dipterologica 9: 219–223.
  • Naglis S (2000) Six new species of Systenus (Diptera: Dolichopodidae) from Brazil, with a key to the Neotropical species. Studia dipterologica 7(1): 59–68.
  • Naglis S (2014) Systenus tener Loew (Diptera, Dolichopodidae), neu für die Schweiz. Entomo Helvetica 7: 157–159.
  • Negrobov OP (2005) Species of the genus Systenus (Dolichopodidae, Diptera) from the Palaearctic region. Entomological Review 85(7): 826–830. [Translated from Zoologicheskii Zhurnal 2005 84(11): 1421–1424]
  • Oboňa J, Pollet M, Naglis S (2012) First records of one genus and three species of long-legged flies (Diptera: Dolichopodidae) from Slovakia. Folia faunistica Slovaca 17(4): 357–360.
  • Vaillant F (1978) Les Systenus et leur habitat dendrotelme (Dipt. Dolichopodidae). Bulletin de la Société entomologique de France 83(3–4): 73–85.
  • Yang D, Zhu Y, Wang M, Zhang L (2006) World Catalog of Dolichopodidae (Insecta: Diptera). China Agricultural University, 704 pp.