islands
Igor Ya. GRICHANOV
Grichanov, I.Ya. Bickelia (Diptera: Dolichopodidae),
a new genus from Indian Ocean islands
Bickelia, a new genus of the dolichopodid subfamily
Sciapodinae is described. B. subparallela sp.n., B. parallela
(Macquart) and B. guerini (Parent) are included.
I.Ya. Grichanov, All-Russian Institute of Plant Protection,
Podbelskogo 3, St.Petersburg-Pushkin, 189620, Russia.
Key words: Diptera, Dolichopodidae, Bickelia gen.n., Chagos
Archipelago, Seychelles, Mauritius.
Bickelia gen.n.
Type-species: Bickelia subparallela sp.n., here designated
Description. Male head wider than high; vertex shallow excavated.
Occiput and frons not concave, mat bronze-green, grey pollinose. One
pair of well developed ocellar, postvertical and proclinate vertical
bristles present in both sexes. Upper postocular bristles black, in
one row. Ventral postcranium covered with irregular pale hairs. Eyes
bare, not joined across face. Face and clypeus narrow, female face
wider, with slightly indicated suture, densely silvery pollinose; face
does not come down eyes, clypeus slightly bulging. Cheeks undeveloped.
Palpi and proboscis short. Antennae mostly black, with short articles,
inserted in the upper third of head; scape bare, short, pedicel
sphaeroidal, with short dorsal and ventral subapical setae, without
appendices. First flagellomere as long as high, subtriangle, with
rounded apex, haired. Arista dorsal, simple, with microscopic setulae,
shorter than head height.
Mesonotum metallic green, pleura dark-green or black, grey
pollinose; 1 h, 1 ph, 2 ntpl, 2-3 ia, 1 sa, 1 pa. Five pairs of strong
dorsocentral bristles, with a few hairs in front of them, not sexually
dimorphic; short biseriate acrostichals. Scutellum with two strong
bristles and usually with one pair of marginal hairs. Postnotum
developed. Propleuron with 2 fine ventral setae.
Legs mostly yellow, simple. Male fore and middle coxae with
sparse hairs and with 2-3 fine apical bristles, hind coxae with strong
bristle; female fore coxae usually with additional row of strong
lateral spines. Male fore legs without strong bristles or spines;
female fore femora usually with group of 3-5 strong ventral bristles
in basal third, each bristle arising from a distinct mound-like
pedicel. Middle and hind femora with strong anterior preapical
bristle. Tibiae with developed bristles in both sexes.
Wings elongate, slightly darkened. Veins simple. Costa reaches M
1 before apex; M 1 and R 4+5 almost parallel; M 1 and M 2 slightly
diverged; M 1 not recurved basad, with right angle bend; M 2 straight;
crossvein m-cu straight, placed in the middle of wing. Anal vein
usually reduced. Anal lobe small or undeveloped. Anal angle lost in
males and reduced in females.
Abdomen dark bronze-green, cylindrical, tergal overlap of segments
mat black; unmodified segments together nearly twice as long as
mesonotum. 1st-6th abdominal tergits and sternits well developed,
simple. Hypopygium pedicillate, epandrium attached to the tip of 7th
tergit; 7th segment slightly longer than epandrium. Appendices short,
strongly sclerotized. Surstylus bifurcated.
Diagnosis. Bickelia is similar to Sciapus Zeller (sensu Bickel,
1994) and Mascaromyia Bickel in thoracic chaetotaxy, and overall
habitus. It is clearly distinguished from other genera of Sciapodinae
by distinct anterior preapical seta on middle and hind femora, narrow
tomentous face and frons, presence of vertical setae in both sexes,
presence of 2 fine ventral propleural setae, branched vein M, modified
hypopygium. Bickelia should be included in the key to world genera of
Sciapodinae (Bickel, 1994) as follows:
1. FII and/or FIII with distinct anterior preapical setae ..........2
- Femora without strong anterior preapical setae ..................4
2. FIII only with anterior preapical setae; propleuron without strong
ventral seta ......................................... Sciapus Zeller
- Both FII and FIII with anterior preapical setae; propleuron with
more or less strong ventral seta ..................................2a
2a. Lateral scutellar setae hairlike; ac usually present, short and
numerous; propleuron with 2 fine black ventral setae; M bifurcated ..
................................................... Bickelia gen.nov.
- Lateral scutellar setae strong; ac present as 2-4 long pairs;
propleuron with strong ventral seta; M 2 usually absent (Negrobovia
Bickel & Amesorhaga Bickel).........................................3
Etymology. The genus is named in honour of the Australian dipterologist
Dr. Daniel J. Bickel.
Included species:
guerini Parent, 1935:86 (Sciopus); Bickel, 1994:101 (Mascaromyia);
Mauritius, n.comb.
Parent described damaged female with some male secondary sex
characters (setation of fore coxae and femora, wing
shape). Indication of strong femoral preapical bristles attributes the
species to Bickelia.
parallela Macquart, 1842:175 (Psilopus); Parent, 1935:88 (Sciopus);
Bickel, 1994:101 (Mascaromyia); Mauritius, n.comb.
Parent redescribed extremely damaged female type-specimen using
indistinct characters. Indication of strong femoral preapical
bristles attributes it also to Bickelia.
subparallela sp.n.
Holotype and paratypes of the new species are conserved in the
Natural History Museum (London).
Bickelia subparallela sp.n. (Fig. 1, 2, 3)
Holotype. Male, Chagos Archipelago: Diego Garcia, East Point,
7.V.1971 / A.M. Hutson, B.M. 1971-346. Paratypes. 7 males and 9
females with the same label as holotype but with catching dates 6 &
8.V.1971; 2 males and 1 female, Chagos Archipelago: Diego Garcia,
Eclipse Point, 26.III & 1.IV.1971 / A.M. Hutson, B.M. 1971-346; 2
females, Chagos Archipelago: Diego Garcia, Eclipse Point, 3 &
10.IV.1971 / A.M. Hutson, B.M. 1971-346 / At light; 2 males and 3
females, Chagos Archipelago: Diego Garcia, Trois Picquet, 4.IV.1971 /
A.M. Hutson, B.M. 1971-346 / coconut woodland; 2 males and 3 females,
Chagos Archipelago: Diego Garcia, Trois Picquet, 5.IV.1971 / A.M.
Hutson, B.M. 1971-346 / open coconut grove; 1 male, Chagos
Archipelago: Diego Garcia, Simpson's Point, 2.IV.1971 / A.M. Hutson,
B.M. 1971-346; 1 male, Chagos Archipelago: Diego Garcia, Simpson's
Point, 2.IV.1971 / A.M. Hutson, B.M. 1971-346 / freshwater pool; 1
male and 3 females, Chagos Archipelago: Diego Garcia, Simpson's Point,
20.IV.1971 / A.M. Hutson, B.M. 1971-346 / At light; 1 male, Chagos
Archipelago: Diego Garcia, Pointe Marianne, 13.IV.1971 / A.M. Hutson,
B.M. 1971-346 / lagoon coast; 1 female, Chagos Archipelago: Diego
Garcia, Pointe Marianne, 17.IV.1971 / A.M. Hutson, B.M. 1971-346 / At
light; 1 male, Seychelles Is., Cascade, 10.III.1965, Tams and Nye,
B.M. 1966-72.
Description. Frons mat bronze-green, grey pollinose. Strong
vertical bristle bends forward, smaller postvertical one presents
nearly at end of postocular row. Face silvery-white, pollinose,
narrow, 4 times as high as wide in the middle. Epistome twice as wide
as clypeus. Palpi and proboscis very short, brown, covered with small
hairs, palpi also with a small black bristle. Antennae black, scape
brown. First flagellomere as long as heigh at base, subtriangle, with
rounded apex, slightly pubescent. Arista dorsal, microscopically
haired. Length ratio of scape to pedicel to first flagelomere to
arista - 0.3:0.4:0.6:3.5.
Mesonotum metallic green, with two mat black postalary spots and
with brownish reflection between dorsocentral bristles, slightly grey
polinose; pleura bronze-olive-green, grey pollinose. Five dorsocentral
bristles with 3d bristle somewhat smaller, with a few hairs in front
of them; at least 10 pairs of short acrostichals, slightly increasing
backwards. Scutellum with two strong bristles and two hairs from the
outside.
Legs yellow, simple, middle and hind coxae and apical segments of
tarsi mostly brown. Fore coxae from the front with yellow hairs and
three black apical bristles. Middle coxae from the front with a few
dark hairs and with two or three fine black bristle, from the outside
bare. Hind coxae with one long black external bristle, with several
dark anteroventral hairs. Hind trochanter with a dark hair. Fore
femora usually with short fine basoventral and posterior preapical
hairs. Fore tibiae with one anterodorsal, two posterodorsal and one -
three apical bristles. Fifth tarsomere slightly flattened. Length
ratio of fore coxa to femora to tibia to tarsus (segments from first
to fifth) - 3.3 : 5.1 : 5.0 : 3.2 : 1.5 : 1.1 : 0.7 : 0.7. Middle and
hind femora with a few black ventral preapical hairs and one strong
anterior preapical bristle. Middle tibiae with three strong
anterodorsal, three posterodorsal, one or two ventral, four or five
apical bristles. Length ratio of middle coxa to femora to tibia to
tarsus (segments from first to fifth) - 2.2 : 5.2 : 6.4 : 3.8 : 1.9 :
1.0 : 0.9 : 0.7. Hind tibiae with three anterodorsal, three
posterodorsal, two short ventral bristles. Hind basitarsomere usually
with short basoventral bristle. Length ratio of hind coxa to femora to
tibia to tarsus (segments from first to fifth) - 1.7 : 6.5 : 7.9 : 2.7
: 1.5 : 1.2 : 1.1 : 0.8.
Wings slightly darkened, veins brown. Costa with short simple
setulae, posterior border with short hairs. Ratio of parts of costa
between R 2+3 and R 4+5 to those between R 4+5 and M 1 - 1.7 : 0.7. M 1
arises perpendicularly from M 2, with rounded right angle bend, then
straight; M 1 and M 2 slightly diverged; crossvein m-cu straight,
forming obtuse external angle with M 1+2. Ratio of crossvein m-cu to
apical part of M1+2 (fork-handle) to apical part of M 3+4 - 1.5 : 2.6
: 1.5. Anal vein and lobe reduced. Anal angle absent. Halteres yellow.
Squamae yellow, with brown edging and dark bristles.
Hypopygium black-brown, with short hairs, pedicillate, attached
to the tip of 7th sternit. Epandrial lobe short, with 3 setae.
Appendices short, brown, strongly sclerotized. Cercus broad, hooked,
with 4 long and some short external setae and with 3 long apicoventral
thorns. Surstylus with ventral arm slightly larger than dorsal arm;
ventral arm with a few short apical setulae; dorsal arm also with 2 or
3 long setae.
Female. Similar to male except lacking male secondary sexual
characters, otherwise as follows: face grey pollinose, wide, with
parallel edges, 2.5 times as high as wide. Legs usually dark-yellow,
sometimes partly brownish; fore coxae with additional 2-4 black
basoventral bristles; fore femora with 3-5 ventral spines of various
length in basal half. Oviscapt: ninth hemitergit with 1 acanthophorite
and 2 long setae; cercus short and broad, with 1 apical seta. Anal
lobe slightly developed; anal angle obtuse.
Length: body 2.4-3.1 mm; body with antennae 2.9-3.6 mm;
wing-length 2.1-2.7 mm; wing-width 0.7-0.8 mm.
Distribution: Chagos Archipelago,
Seychelles.
Diagnosis. Males of Bickelia subparallela sp.n. appear closely
related to B. guerini, and females - to B. parallela. Most paratypes
of new species were collected from Chagos Archipelago, although a male
was found in Seychelles, while other species were described from
Mauritius. Keeping in mind poor differentiation between females of
related sciapodine genera, I can propose the next key to the species
of Bickelia:
1. Fore femora without strong bristles...............................2
- Fore femora with four strong black anteroventral bristles
(females).........................................................3
2. Distinct acrostichal setae in two rows (male).......B. subparallela
- Acrostichals absent (female).............................B. guerini
3. Anal vein present, two scutellar bristles only.........B. parallela
- Anal vein reduced, two strong scutellars and two lateral hairs
from the outside....................................B.
subparallela
Acknowledgements
I am sincerely grateful to Dr Brian Pitkin for his kindness in
giving me the opportunity to study the collection of the Natural
History Museum (London). I appreciate the help I have received from
Mrs Galina Grichanova in doing
the illustrations.
References
Bickel D.J. 1994. The Australian Sciapodinae (Diptera: Dolichopodidae),
with a review of the Oriental and Australasian faunas, and a world
conspectus of the subfamily. - Rec. Austral. Mus., 1994, Suppl. 21: 1-394.
Parent O. 1935. Dipteres Dolichopodides nouveaux. - Encycl.
Entomol. (B) Diptera, 8: 59-96.
Remark under figures
Fig. 1. Bickelia subparallela sp.n., habitus.
Fig. 2. Bickelia subparallela sp.n., hypopygium.
Fig. 3. Bickelia subparallela sp.n., oviscapt (dry specimen).