Simulium (Hebridosimulium) lucyae Craig., 2006

Craig, Douglas A., Currie, Douglas C., Hunter, Fiona F. & Spironello, Mike, 2006, A taxonomic revision of the southwestern Pacific subgenus Hebridosimulium (Diptera: Simuliidae: Simulium), Zootaxa 1380 (1), pp. 1-90 : 61-63

Simulium (Hebridosimulium) lucyae Craig. n. sp.

( Figs. 5h , 6d )

Types

Holotype. Adult : double-pinned female. Label data— “ NEW HEBRIDES / Aneityum I./Agathis Camp/ 1150 ft. /19.21. vii.1971 ”, “ Holotype (red)”. Coll. G. S. Robinson. ( BM). Condition excellent . Paratypes. Adults: two pinned males; one cleared and in glycerine vial. Label data— as for Holotype, but with “ Paratype (yellow)”. One female; double pinned. Label data— as for males. Condition excellent. Ten females; label data— “ L.E. Cheesman. /B.M. 1955-217”, “ NEW HEBRIDES:/ Aneityum./ Red Crest, 1,200ft. / 3m. N.E. of Anelgauhat./ i.1955 ”, “ Paratype ”. One cleared and in glycerine vial, two with genitalia in glycerine vials, remainder on original points in water-soluble glue. Condition variable. ( BM). One pinned female. Label data— “ NEW HEBRIDES:/ Aneityum I:/ Anelgauhat/ 0–200m, XI.1978 ”, “ N. H. L. Krause Coll. / BISHOP MUSEUM”. Two pinned females; as previously, but with “Acc. #1978. 465”. Condition excellent ( BPBM) .

Diagnosis

Large species. Adults: evenly very dark brown to black. Female: mouthparts substantial, with large mandibles; maxillary palpal sensillum large; scutum markedly broad; genitalia with median region of sternite VII markedly pale, hypogynial valve densely haired, membranous apex pale, narrow, markedly extended dorsomedially. Male: gonocoxa rounded; ventral plate essentially as keel only; dorsal plate shallowly V-shaped; median sclerite stem narrow; cerci distinct.

Description

Adult female (based on numerous pinned specimens). Body: black to very dark brown; total length 2.6–2.9 mm. Head: width 0.90 mm; depth 0.55 mm; postocciput black with sparse vestiture of silvery hairs; frons very dark brown, slightly pruinose; frons-head ratio (narrowest width of frons: greatest width of head) 1.0:4.7. Eye: interocular distance 0.19 mm; ommatidia 0.017 mm in diameter; ca. 34 rows across and 38 down at mid eye. Clypeus: 0.25 mm wide; concolourous with frons; pruinose, vestiture of dense black and pale hairs. Antenna: length 0.66 mm; flagellomeres dark brown; scape and pedicel slightly lighter. Mouthparts: 0.58 length of head depth; mandible distinctly longer than lacinia, well sclerotized with 24 inner teeth; lacinia with 9 inner teeth and 14 outer teeth, robust and larger apically; maxillary palpus evenly dark brown, total length 0.58 mm, proportional length of 3rd, 4th, and 5th articles 1.0:1.0:1.1, sensory vesicle ovoid, 0.6 times width of 3rd article, opening 0.5 times width of vesicle. Thorax: length 1.28 mm; width 1.03 mm; postpronotal lobes slightly paler than scutum; remainder of scutum evenly dark brown to black, vestiture of sparse, short pale hairs; scutellum concolourous with scutum, vestiture of long black hairs, apical angle 110°; postnotum concolourous with scutum; pleural membrane dark brown with sparse, fine pale hairs. Wing: length 2.6–2.7 mm; maximum width 1.2 mm; anterior veins markedly dark. Legs: overall dark brown and black; coxae dark brown; fore leg evenly dark brown except for basal portion of tibia; mid legs, trochanter brownish yellow, remainder dark brown to black; hind leg trochanter brownish yellow, femur darker brown, tarsus with basal region paler, remainder dark brown, tarsus pale yellow, distal region and tarsomeres black. Halter: light brown. Abdomen: overall evenly black; vestiture of moderately dense, long, pale hairs; basal scale dark brown with fringe of pale hairs extended over segment I. Genitalia ( Fig. 5h ): median portion of sternite VIII triangular, as deep as wide, markedly depressed, posterior region pale; hypogynial valves with medial edges slightly concave and divergent, vestiture of dense microtrichia and substantial short hairs, membranous apex very thin and directed posteriorly; genital fork stem narrow, lateral arms clear distally, anteriorly directed apodeme markedly developed and dome-shaped; anal lobes with anterolateral apodeme broadly developed, anteromedian concavity deep; cercus short; spermatheca darkly pigmented.

Adult male (based on 2 pinned specimens). Body: overall black; large, total length 2.97 mm. Head: width 0.87 mm; depth 0.64 mm. Eyes: upper ommatidia orange, 0.047 mm in diameter, ca. 11 across and 13 down; lower ommatidia dark brown, 0.012 mm in diameter, ca. 25 across and down. Clypeus: black, 0.10 times as wide as head; vestiture of sparse substantial black hairs. Antenna: total length 0.57 mm; evenly dark brown. Mouthparts: 0.34 length head depth; mandibles insubstantial, finely tapered with apical hairs; lacinia broad basally, finely tapered apically with terminal hairs; maxillary palpus evenly very dark brown, 0.53 mm long, proportional lengths of 3rd, 4th, and 5th articles 1.0:1.1:1.7, sensory vesicle spherical, occupying 0.5 times width of article, opening 0.3 times width of vesicle. Thorax: length 0.89 mm; width 0.93 mm; postpronotal lobes and scutum evenly very dark brown; vestiture of small fine pale hairs; scutellum concolourous with scutum, apical angle 100°; vestiture of long black hairs with few pale; postnotum concolourous with scutum, shiny; pleuron and pleural membrane medium brown; pleural membrane with fine hairs, not visible at 50x in alcohol. Wing: 2.6 mm in length, 1.2 mm at maximum width. Halter: light brown. Legs: overall dark brown; fore leg coxa, trochanter, femur, and basal half of tibia medium brown, remainder dark brown/black; mid leg coxa brown, trochanter pale brown, remainder dark brown/black; pretarsal claw with ca. 25 grappling hooks dorsally. Abdomen: concolourous with scutum; anterior vestiture of long pale hairs, markedly hirsute laterally, hairs black posteriorly; basal scale dark, hairs markedly long, fine, pale, extended to beyond 2nd segment. Genitalia ( Fig. 6d ): gonocoxa rounded, 1.3 times longer than basal width, markedly pigmented, with long black hairs on distal half, anterolateral apodeme small; gonostyle dark, approximately 3.3 times longer than basal width; mediobasal strengthening ridge not developed; ventral plate reduced, angulate laterally, proximal arms substantial with lateral flange, median keel massive with broad connection to plate, flattened apically; dorsal sclerite thin and more angulate apically; median sclerite elongate with stem 6 times longer than cross piece width. Cerci:

markedly developed.

Pupa. Unknown.

Larva. Unknown.

Additional material examined

Aneityum.?. x.1930. Coll. L. E. Cheesman (16 females; BM); on the hills, 500–1000 ft ,?. xi.1954. Coll. L. E. Cheesman (9 females on 3 pins; BM) .

Etymology

Named for Lucy Evelyn Cheesman, whose account of severe biting by females of this species, while she was stationed in Aneityum, is a classic story of the horrors of bloodthirsty simuliids ( Cheesman 1957 a, Craig 2006).

Distribution VANUATU: Aneityum.

Comments

Simulium lucyae , along with S. subparadisium of Santo, have the largest adults of any simuliid species in Vanuatu. Consistent with the reported vicious biting by females, mandibles of S. lucyae are markedly developed. The females also differ from those of other species in that the scutum is noticeably broader and flattened. The male is easily diagnosed by the unique characteristics of the genitalia. Although an expectation might be that S. lucyae is related to S. johnfrumi of nearby Tanna and Erromango, with no larvae or pupae to indicate otherwise, placement of S. lucyae in the steatopygium species group is based on details of the female genitalia, namely the elongated genital fork stem, enlarged anteriorly directed apodeme, and straightened medial edges of the hypogynial valves. Discovery and characterization of the immature stages of S. lucyae will be of biogeographic interest, because Cheesman (1957b) suggested that the southern three islands of Vanuatu, in particular that of Aneityum, are biogeographically distinct from the others.

Figures

FIGURE 5. Hebridosimulium. Female genitalia. a–d callipygium species group, e–j steatopygium species group. e. Adapted from Craig (1987). Scale bar = 0.1 mm. Abbreviations: an lb — anal lobe; cerc — cercus; gen fk — genital fork; hyp vlv — hypogynial valve; spmth — spermatheca.

FIGURE 6. Hebridosimulium. Male genitalia. a–b callipygium species group, c–f steatopygium species group. e. Paramere spines shown in detail. Scale bar = 0.1 mm. Abbreviations: adg mbm — aedeagal membrane; d plt — dorsal plate; goncx — gonocoxite; gonst — gonostyle; m scl — median sclerite; pm th — paramere teeth; v plt — ventral plate.