Hebridosimulium Grenier & Rageau, 1961

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 : 16

Subgenus Hebridosimulium Grenier & Rageau

Hebridosimulium Grenier & Rageau 1961: 96 (as genus). Type species: Simulium jolyi Roubaud 1906 (by original designation)

Simulium (Hebridosimulium) : Crosskey, 1967: 27 (new status); Crosskey 1974:156; Craig 1987: 381; Crosskey & Howard 2004: 29

Diagnosis (revised)

Adults: wing with basal section of radius haired; vein R 1 with hairs only, spinules absent. Cibarial pump without armature. Mandible lacking outer teeth. Distal article of maxillary palpus short. Base of wing vein Rs slightly pigmented. Pleural membrane haired ( Fig. 4 ), sparsely so in some species. Katepisternum bare. Fore tarsus slender, fore basitarsus about 6–7 times as long as greatest width. Hind basitarsus parallel sided in both sexes, with markedly expanded calcipala extended almost to second hind tarsomere. Scutum without pattern. Female (e.g., Fig. 1a ): thorax not markedly domed; tarsal claw simple, basal tooth absent. Abdomen with thick pale scales laterally, dark scales medially and on terminal segments. Seventh sternite very weakly developed. Genitalia ( Fig. 5 ): hypogynial valves produced apically as flattened membranous processes; anal lobes with anterior extension; spermatheca pigmented with distinct reticulate pattern, small clear area around junction of sperm duct. Male: upper ommatidia enlarged, but not markedly so ( Fig. 1c ). Genitalia ( Fig. 6 ): gonostyle long, slender, tapered with single apical tooth, slightly shorter than gonocoxa; gonocoxite not produced beyond base of gonostyle, with welldeveloped anterior apodeme; ventral plate complex, produced medially as large haired spatulate process with constricted neck, anterior arms subparallel to curved; parameres weakly developed, parameral spines well developed, complex, about 10 on each side, 1 larger slightly recurved and 2 narrower apical spines with 6–8 smaller basal spines on concertinaed cuticle; dorsal plate cone- to V-shaped with vestiture of microtrichia; median sclerite variously T-shaped with convex larger end; aedeagal membrane with triads of microtrichia. Cerci: distinct. Pupa: gill approximately half as long as body, with 8 or 10 elongate filaments on each side, occasionally 9, mostly branched in pairs, diverging basally and converging apically, dorsal filaments often shorter than other filaments ( Fig. 7 ). Dorsal thoracic granules generally present, either large and coarsely scattered, or smaller and densely packed, rarely absent ( Fig. 8 ). Abdomen with normal complement of hooks, lacking spinecombs dorsally on terminal segments, second segment dorsally with row of 4 hairs each side; grapnel hooks absent; terminal spines short, thick, smooth laterally. Cocoon: closely woven, no fenestrae; boot-shaped with conspicuous raised anterior margin, or almost slipper-shaped with short raised anterior margin; opening circular ( Fig. 7 ). Larva: head capsule with head spots variable, cephalic apotome sometimes darkened in midline posteriorly and posterolaterally; cephalic setae and sockets small; cuticle smooth; cervical sclerites separate from postocciput or lightly attached. Antenna: distal article extended completely beyond labral fan stalk, or antenna subequal in length to stalk. Mandible without supernumerary serrations. Mandibular phragma lacking ventral extension. Labral fan with 36–53 fine rays, fan stalk markedly unpigmented, with posterobasal notch more or less strongly developed, anterior palatal bar often projected anteromedially. Hypostoma: 11 teeth, either not prominent, or moderately prominent lateral and median teeth and small distinct sublateral teeth; paralateral teeth very poorly developed; hypostomal serrations poorly developed or absent; 9–12 substantial setae subparallel to lateral margin of hypostoma. Postgenal cleft of medium size, acutely Vshaped; longer than postgenal bridge, occasionally with anterior apical extension. Abdomen: posterodorsal cuticle smooth; with or without dorsolateral tubercles; posterior abdomen either callipygous or steatopygous; posteroventral tubercles poorly developed or absent. Rectal papillae: 3 simple lobes. Rectal scales absent. Anal sclerite: X-shaped; anterodorsal arms substantial and splayed at apices; subequal in length to posterolateral arms that extend 0.3 distance around circlet of hooks; accessory sclerite absent ( Fig. 22 ). Posterior circlet with 154–214 rows of 20–35 hooks; directed either ventrally or posteriorly.

Figures

FIGURE 1. Typical examples of Hebridosimulium. a. Female Simulium callipygium (Santo). b. Head of male S. laciniatum (Fiji). c. Head of female S. pankumuense (Malekula). Scale bar = 0.5 mm.

FIGURE 4. Hebridosimulium. Female adult right pleural membranes. Dorsal to the left, anterior up. Scale bar = 0.1 mm.

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.

FIGURE 7. Hebridosimulium. Pupal cocoons. a & b. Lateral and dorsal views. c & d. Lateral view. Scale bar = 0.5 mm.

FIGURE 8. Hebridosimulium. Pupal thoracic cuticle. Scale bar = 0.1 mm.

FIGURE 22. Anal sclerite and circlet of hooks of larvae of Hebridosimulium species. Last instar. Ca. 2800 and 7300 hooks, respectively. Scale bar = 0.2 mm.