Rhaphium curvitarsus Negrobov, Maslova et Selivanova, 2020

Negrobov, O. P., Maslova, O. O. & Selivanova, O. V., 2020, A NEW SPECIES OF THE GENUS RHAPHIUM (DIPTERA: DOLICHOPODIDAE) FROM SAKHALIN ISLAND, Far Eastern Entomologist 409, pp. 21-25 : 22-24

Rhaphium curvitarsus Negrobov, Maslova et Selivanova , sp. n.

http://zoobank.org/NomenclaturalActs/ F2F9BECE-2787-47C6-8EDE-2DBEC3895E42

Figs 1–5

TYPE MATERIAL, Holotype – ♂, Russia: Sakhalin, 41 km N Yuzhno-Sakhalinsk ,

village Pokrovka, 8.VII 1982 (Shamshev leg.). The type is deposited in the collection of the

Zoological Institute of the Russian Academy of Sciences in St. Petersburg.

DESCRITION. Male. Body length 2.7 mm, wing length 2.5 mm.

Face white with silver tint, its width in middle part approximately half as wide as postpedicel. Proboscis dark-brown. Palpus black. Frons green, shining without dusting. Antennae black. Postpedicel elongated triangular, with a pointed apex; its length longer than width.

Arista located closer to top of postpedicel, without enlargement, covered with short hairs.

The ratio of length and width of postpedicel to length of arista – 2.2: 0.9: 2.9. Postocular bristles yellow below.

Thorax green with metallic bronze shade. Mesonotum metallic shiny, pleura with grey dusting. Propleura with group of white hairs. 5 pairs of dorsocentral setae. Acrostichal setae arranged in 2 rows. Scutellum with 2 strong marginal bristles. Legs mostly yellow, bases of fore coxa, mid and hind coxae, most of fore femur, apical part of hind femur, apical segments of mid and hind tarsi dark. Coxae with long white hairs, mid coxa below with a group of black setae forming spike. Mid and hind femora with 1 strong preapical bristle. Fore tibiae with 4

anterodorsal setae. Fore basitarsus at base with 4 black ventral setae. 2nd tarsomere of fore tarsus curved ventrally, on apex ventrally thickened. 4th tarsomere of fore tarsus ventrally on apex thickened, on apex with black thick curved ventral seta and yellow transparent flat seta. 5th tarsomere of fore tarsus with group of long setae from dorsal and apical sides, their length is greater than diameter of joint. 5th tarsomere with dorsal process. black claws and white pulvillus. Relative length of fore tibia and 5 tarsomeres (from 1st to 5th) is 4.7: 2.4:

2.6: 0.9: 1.0: 0.9. Mid tibia with 4 anterodorsal, 1 posterodorsal and 3 anteroventral bristles.

Mid basitarsus with long ventral setae. 2nd tarsomere of mid tarsus at base with 1 long and 1

short ventral setae. Relative length of mid tibia and 5 tarsomeres (from 1st to 5th) is 6.2: 3.3:

1.6: 1.5: 0.7: 0.5. Hind tibia not swollen, with 4 anterodorsal and 1 posterodorsal bristles.

Hind basitarsus swollen. Relative length of hind tibiae and 5 tarsomeres (from 1st to 5th) is

7.4: 2.4: 2.6: 1.7: 1.1: 0.7.

Wings not darkened, without spots. Costa at apex of subcostal vein without thickening.

R 4+5 and M 1 hardly convergent at tip of wing. M 1 weakly curved. Apical part of M 4 longer than posterior transverse vein (dm-m), their length ratio is 3.6: 1.5. Anal angle of wing obtuse. Lower calypter yellow with white hairs. Halter yellow.

Abdomen green, shiny, with bronze tint, with black hairs, below at base with white hairs.

Hypopygium brown. Hypandrium oval, slightly longer than wide. Surstyli long, rhomboid at apex, with two long tooth-like processes at base. Cerci long, two times longer than epandrium,

forked at base, with wide lateral lobe.

Female unknown.

ETYMOLOGY. The species is named for the curved segments of the fore tarsus.

NOTES. New species is similar to Rh. firsovi Stackelberg et Negrobov, 1976, known from Primorsky Krai (Russia) and Alaska (USA), but differs from the latter in morphology of apical segments of the fore tarsi, by color of the fore femur, and by morphology of hypopygium. In Rh. firsovi, fore femur yellow; 4th tarsomere of fore tarsus not widened, 5th tarsomere without group of long setae; surstyli straight (see Negrobov, 1979: figs 1761–1764),

while in Rh. curvitarsus sp. n., fore femur mostly dark, 4th tarsomere of fore tarsus widened,

5th tarsomere with a group of long setae ( Fig. 2 ), and surstyli as in Fig. 3 .

lateral view; 3 – surstyli, ventral view; 4 – hypopygium, lateral view; 5 – hypopygium,

ventral view.

Key to species and subspecies of Rhaphium estimated or recorded from Sakhalin and Kuril Islands

1. Mesonotum and abdomen with silver dusting. Fore basitarsus with a number of ventral black setae (Holarctic species recorded from Primorye and Japan) ……………………… ………..…………………………………………………..…. Rh. dispar Coquillett, 1898

– Mesonotum and abdomen without silver dusting. Fore basitarsus without a group of bristles ………………………………………………..……..………………………….. 2

2. Face black or grey-black …………………………………....……………………………. 3

– Face silvery white ……………………………………………………………..…..……… 6

3. Face wider than postpedicel (Sakhalin) ………….. Rh. neolatifacies Yang et Wang, 2006

– Face much narrower than width of the postpedicel ……………………………..……..…. 4

4. Cerci divided into two lobes (Sakhalin) ………....……… Rh. macalpini Negrobov, 1986

– Cerci not divided into lobes …………………………...……………….….……………… 5

5. Surstyli short, their length approximately equal to width, at apex with two lateral processes (Holarctic species recorded from Primorye and Japan) …. Rh. boreale (Van Duzee, 1923)

– Surstyli long, more than 3 times longer than width, tapering to apex (Sakhalin) …….…… ………………………………..……………..…. Rh. terminale igoriani Negrobov, 1986

6. Hind coxae with strong lateral setae. Surstyli with a group of long bristles (Primorsky Krai) ………………………………………………………….... Rh. flavilabre Negrobov, 1979

– Hind coxae outside with thin hairs. Surstyli without group long bristles …………...…… 7

7. Mid coxae from below with a spike made of black setae (Sakhalin) …………………….. ………………………………………………………………….… Rh. curvitarsus sp. n.

– Mid coxae from below without spike ………………..………………………………….... 8

8. 5th tarsomere of fore tarsus without group of long setae (Kuril Islands: Kunashir) ……… ……………………………………………………………... Rh. richterae Negrobov1977

– 5th tarsomere of fore tarsus with group of long setae ………..…………………………… 9

9. Fore and mid femora and basal part of hind femur black. Cerci long, straight, longer than epandrium (Sakhalin) ……………………………….. Rh. sachalinense Negrobov, 1979

– Femora yellow. Cerci short, curved, shorter than epandrium (Kuril Islands: Iturup) ……… …………………………………..……. Rh. gussakovskii Stackelberg et Negrobov, 1976

Figures

Figs 1–5. Rhaphium curvitarsus sp. n. 1 – antenna; 2 – 1st-5th segments of fore tarsus,