Simulium (Hebridosimulium) spiroi Craig, Currie &amp; Hunter 2006, n. sp.
Creators: name: Craig, Douglas A.
name: Currie, Douglas C.
name: Hunter, Fiona F.
name: Spironello, Mike
Publisher: name: Zenodo
Year: 2006
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Diptera
Simuliidae
Simulium
Simulium spiroi

description: <i>Simulium</i> (<i>Hebridosimulium</i>) <i>spiroi</i> Craig, Currie &amp; Hunter, n. sp. (Figs. 10f, 11n, 14f, 17f, 19f, 21f) <i>Types</i> <b>Holotype</b>. Larva: last instar in alcohol. Label data – " <i>Simulium</i> (<i>Hebridosimulium</i>) <i>spiroi</i> <i>.</i> VANUATU, Malekula, Wesso River Cascade. S16.37880° E167.76663°, alt. 34 m, 2.ix.2004. Coll. D. A. &amp; R. Craig. HOLOTYPE. No. 16606" (BPBM). <b>Paratypes</b>. Larvae: last instars in alcohol (BPBM, DAC, ROM). Penultimate and earlier instar in alcohol (BPBM, DAC, LCNZ, ROM). Label data as for Holotype, but with " PARATYPE ". <i>Diagnosis</i> Larva: head evenly dark brown; body markedly lighter gray, posterolateral diagonal gray stripes on sixth segment. Pupa: gill petioles short. <i>Description</i> <b>Adult female.</b> Unknown. <b>Adult male.</b> Unknown. <b>Pupa</b> (based on pharate material). Thorax: cuticle with numerous granules present. Gill (Fig. 10f): petioles short and thick; branching pattern (2+2) +2 +2 +2, occasionally (2+2) +2 +2 +1+1; filaments noticeably tapered; maximum length 1.4–1.8 mm. <b>Larva</b> (based on 6 mature last-instar larvae). Body (Fig. 11n): total length 6.5–6.9 mm; females evenly pale grey dorsally, males pale yellowish-grey with paler intersegmental regions, difference not marked. Head (Fig. 14f): both sexes evenly dark brown including labral fan stalks; dorsal head spots negative, but not distinct; sockets of trichoid sensilla pair 5 and 6 markedly pale, darkly aureolate; width 0.74–0.82 mm; length 0.79–0.82 mm; distance between antennal bases 0.39–0.41 mm; ecdysial lines slightly convex, diverged markedly posteriorly, broadly rounded at maximum width; lateral margins of head convex, especially posteriorly; posterior edge of cephalic apotome slightly emarginate; postocciput with fine medial extension. Antenna: total length 0.36 mm; distal article 0.22 times as long as basal articles; markedly shorter than labral fan stalk; distal article dark brown, remainder pale. Labral fan: stalk heavily pigmented anteriorly, anterior palatal bar noticeable, but not markedly protrusive; 39–43 substantial rays, 0.84 mm in length, medial rays 0.02 mm in width, 8–10 posterolateral rays finer than others; microtrichia substantial, subequal in length to ray width, pattern distinct, with 4 or 5 shorter microtrichia between those longer. Postgenal cleft (Fig. 17f): markedly arrowhead shaped; posterior edges parallel, sharply tapered at mid-length to pointed apex, 1.5 times longer than width; postgenal bridge subequal in length to cleft depth; genae evenly pigmented dark brown, paler around stemmata; ventrolateral elongate muscle spots partially negative. Hypostoma (Fig. 19f): ratio 4.2; median tooth and lateral teeth prominent, latter slightly scalloped medially occasionally directed more laterally, sublateral teeth distinct; paralateral teeth and lateral serrations not obvious; 11–13 substantial hypostomal setae per side. Mandible (Fig. 21f): apical tooth markedly prominent, preapical and subapical teeth not so; spinous teeth small, gap distinct; serration and sensillum robust and fused basally; blade region smooth and slightly convex. Abdomen: thorax and anterior abdominal segments subequal in width, expanded gradually to maximum width, callipygous posteroventrally; colour pale laterally and ventrally, marked diagonal gray banding laterally on sixth segment; posterodorsal tubercles absent. Posterior circlet: directed ventrally; 170–175 rows of hooks, 29–35 hooks per row (total ca. 5,500). <i>Additional material examined</i> Last and earlier instar larvae in Carnoy's fixative. Label data – as for types (larvae; DAC). <i>Etymology</i> Dedicated to the memory of Mike "Spiro" Spironello. <i>Distribution</i> VANUATU: Malekula. <i>Comments</i> Known only from the type locality (Fig. 23c) on Malekula, larvae of <i>S. spiroi</i> appear to be habitat specialists. They were taken in moderately large numbers only from smooth travertine substrate in fast flow (1.3 m /s; Table 1). However, larvae exhibit little structural adaptation to that habitat beyond the scarcely steatopygous abdomen and a relatively large number of hooks in the posterior circlet. Superficially similar to <i>S. adsonense</i> in possessing a darkly pigmented larval head and lighter coloured body (<i>rf</i>. Figs. 11m, n), <i>S. spiroi</i> differs in the structure of the pupal gill filaments (cf. Figs. 10e, f), size and shape of the postgenal cleft, and markedly larger hypostomal teeth. Although grouped together with <i>S. adsonense</i> from Malekula, we are of the opinion that the body shape and the head colour in both species may be independent adaptations to full sunlight in shallow, fast water. Dark pigmentation of larval heads is a known adaptation to full insolation (Craig 1997) and most likely is protective against UV light (Donahue &amp; Schindler 1998). Preliminary CO1 mitochondrial DNA analysis indicates that <i>S. spiroi</i> and <i>S. adsonense</i> are not genetically close (A. Cywinska, unpublished data).
description: Published as part of <i>Craig, Douglas A., Currie, Douglas C., Hunter, Fiona F. &amp; Spironello, Mike, 2006, A taxonomic revision of the southwestern Pacific subgenus Hebridosimulium (Diptera: Simuliidae: Simulium), pp. 1-90 in Zootaxa 1380 (1)</i> on pages 79-80, DOI: 10.11646/zootaxa.1380.1.1, http://zenodo.org/record/5071393
description: {"references": ["Craig, D. A. (1997) A taxonomic revision of the Pacific black fly subgenus Inseliellum (Diptera: Simuliidae). Canadian Journal of Zoology, 75, 855 - 904.", "Donahue, W. F. &amp; Schindler, D. W. (1998) Diel emigration and colonization responses by black flies (Diptera: Simuliidae) to ultraviolet radiation. Freshwater Biology, 40, 357 - 365."]}