Simulium (Inseliellum) littosodalis Craig & Evenhuis

Evenhuis, Neal L., 2017, Society Islands beach bum black flies (Diptera: Simuliidae), Zootaxa 4311 (3), pp. 373-388: 382-385

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Simulium (Inseliellum) littosodalis Craig & Evenhuis

n. sp.

Simulium (Inseliellum) littosodalis Craig & Evenhuis   , n. sp.

FIgs. 30–41 View FIGURES 27 – 30 View FIGURES 31 – 35 View FIGURES 36 – 41 .

Description. Adult female (based on 7 specImens). Body ( FIgs. 30 View FIGURES 27 – 30 ): overall dark blackIsh brown, abdomen slIghtly lIghter ventrally; total length 1.5–1.9 mm. Head ( FIg. 31 View FIGURES 31 – 35 ): wIdth 0.55–0.58 mm; depth 0.36–0.39 mm; postoccIput black wIth vestIture of sparse short black haIrs; frons broad dorsally, narrowed ventrally, frons/head wIdth ratIo 1.0:7.5; frontal angle 50°. Eye: mInImum Interocular dIstance ca. 0.08 mm; eyes dark red, ommatIdIa dIameter 0.012 mm; ca 36 down and up at mId-eye. Clypeus: wIdth 0.14 mm; mottled medIum brown, vestIture of scattered haIrs. Antenna ( FIgs. 32 View FIGURES 31 – 35 ): total length 0.40–0.42 mm; evenly medIum brown, pedIcel subequal In sIze to flagellomere I, that rectangular; flagellomere II 0.5× as long as wIde, III –VII IncreasIng slIghtly In length dIstally, occasIonally varIable, flagellomere IX cone-shaped. Mouthparts: feebly developed, ca. 0.27× length of head depth; maxIllary palp ( FIg. 33 View FIGURES 31 – 35 ) length 0.48 mm, palpomeres I and II small, palpomere III small, slIghtly elongated, darker than other palpomeres, proportIonal lengths of palpomere III –V 1.0:1.0:2.0, respectIvely; sensory organ spherIcal, 0.25x length of palpomere III, openIng 0.3× vesIcle wIdth; mandIbles ( FIg. 33 View FIGURES 31 – 35 ) small, not flared dIstally, straIght sIded, ca. 18 small Inner teeth, outer teeth absent; lacInIa small, wIth 6 and 7 teeth on Inner and outer edge respectIvely; cIbarIum not observed. Thorax: length 1.0– 1.2 mm; scutum blackIsh brown, vestIture of sparse fIne pale haIrs, postpronotal lobe concolourous wIth scutum, vestIture slIghtly longer; scutellum slIghtly paler than scutum, vestIture of sparse very fIne yellowIsh haIrs; postnotum brownIsh, pollInose anterIorly; antepronotal lobe, proepIsternum and fore coxa essentIally bare wIth few haIrs; anepIsternal membrane bare; katepIsternum dark brown, sulcus deep and dIstInct. Wing ( FIgs. 35 View FIGURES 31 – 35 ): membrane slIghtly smoky on anal lobe, length 1.6–1.8 mm; wIdth 0.8–0.9 mm; anterIor veIns well expressed, not markedly pIgmented; costa wIth mIxture of haIrs and spInes; Rs wIth spInes and haIrs; a/b ratIo 1:5; r-m cross veIn slIghtly pIgmentatIon and extended onto surroundIng membrane; basal medIal cell well expressed; CuA2 not markedly sInuous; A2 extended nearly to wIng margIn; crescent shaped pIgmentatIon In anal angle. Haltere: tan. Legs ( FIg. 34 View FIGURES 31 – 35 ): overall dark brown and hIrsute, forelegs wIth markedly darker tarsomeres, less so on mId and hInd legs; hInd tIbIa slIghtly curved, wIth row of ventral stout spInes poorly expressed and absent from dIstal portIon; calcIpala half wIdth of hInd basItarsus, as long as wIde; pedIsulcus well expressed; tarsomere II ca. 2.0× as long as dIstal wIdth; claw ( FIg. 36 View FIGURES 36 – 41 ) small, wIth maIn talon moderately curved and evenly tapered, basal tooth small, 0.25x length of claw, heel cone-shaped and InsubstantIal. Abdomen ( FIg. 37 View FIGURES 36 – 41 ): dorsally evenly black, tergItes paler and mottled; basal scale dark brown, markedly pale medIally, vestIture of short haIrs; tergIte II, 4x broader than long, tergItes III –V 3x broader than long, remaInder of tergItes markedly broad, vestIture essentIally absent, better expressed on posterIor segments. Genitalia: small; sternIte VIII evenly pIgmented, lackIng mIcrotrIchIa medIally, sparse larger haIrs posterolaterally; hypogynIal valves ( FIg. 38 View FIGURES 36 – 41 ), lIghtly pIgmented, vestIture of mIcrotrIchIa and sparse strong haIrs, medIan gap between valves deeply U-shaped, slIghtly narrowed anterIorly, edges slIghtly dIvergent posterIorly and concave, strengthened medIally, smoothly rounded apIcally; genItal fork ( FIg. 39 View FIGURES 36 – 41 ) stem markedly evenly narrowed, not expanded apIcally, lateral arms narrow, strengthened posteromedIally, lateral plates small, elongated posterolaterally, apodemes sharply developed; spermatheca ovoId ( FIg. 40 View FIGURES 36 – 41 ), small, dark brown, wIth slIghtly wrInkled surface, lackIng Internal spInes, membranous area at junctIon wIth spermathecal duct small wIth fluted edge; cercus lIghtly pIgmented, In lateral vIew bluntly rounded, wIth slIght apIcal depressIon, clump of apIcoventral haIrs not marked, anal lobes small, angulate ( FIg. 41 View FIGURES 36 – 41 ).

Etymology. In reference to occurrIng wIth other beach sImulIIds; derIvIng from litto [= “beach”] + sodalis [= “comrade”, “crony”]; hence a thIrd “beach bum” of sorts. The name Is treated as a noun In apposItIon.

Material. Holotype: Female, mIcropInned. Label data [Holo / type] [ Simulium   / ( Inseliellum   ) / littosodalis   ] [FP: TAHITI ITI: 3.5 km E. / TautIra, 0 m, North Road / beach rubble, 18 Jul 2006 / N. EvenhuIs, P. O’Grady] [BPBM 17,840], (ca. S17.7667° W149.2719°).

Paratypes: Four females, mIcropInned; one In glycerIne mIcrovIal on pIn; one slIde mount. Label data as for holotype, but wIth [PARATYPE].

Other material: One slIde mount, label data [ Simulium   / ( Inseliellum   )/ littosodalis   ] [FP: TAHITI NUI:/ North Road, PK 42.7 / 17 Jul 2006, 0 m, beach/ rocks. N. EvenhuIs]. (ca. S17.6474° W149.3103°). ( FIg. 42 View FIGURE 42 )

Distribution. Known only from TahItI.

Remarks. Simulium littosodalis Is   slIghtly smaller than Simulium littosocius   , overall darker In colour and lacks the paler antennal scape and pedIcel of the latter specIes. The frons Is markedly broader than that of S. littosocius   (cf. FIgs. 17 View FIGURES 16 – 21 , 31 View FIGURES 31 – 35 ). The mandIbles of both specIes are parallel sIded (cf. FIgs. 20 View FIGURES 16 – 21 , 33 View FIGURES 31 – 35 ), not slIghtly flared as In S. littopyga   . Simulium littosodalis   has low numbers of teeth on the lacInIa ( FIg. 33 View FIGURES 31 – 35 ) and Its legs are more evenly brown and hIrsute than those of S. littosocius   , and whIle the calcIpala and pedIsulcus of both specIes are sImIlar, the claws are markedly dIfferent (cf. FIgs. 24 View FIGURES 22 – 26 , 36 View FIGURES 36 – 41 ), wIth S. littosocius   possessIng a large basal tooth and heel; both In S. littosodalis   are smaller. AbdomInal tergItes dIffer, wIth those of S. littosodalis   larger (cf. FIgs. 25 View FIGURES 22 – 26 , 37 View FIGURES 36 – 41 ). The genItal forks of both specIes are sImIlar, except that that of S. littosodalis Is   slIghtly strengthened along the medIal edge of the lateral arms (cf. FIgs. 27 View FIGURES 27 – 30 , 39 View FIGURES 36 – 41 ); the hypogynIal valves (cf. FIgs. 26 View FIGURES 22 – 26 , 38 View FIGURES 36 – 41 ) are sImIlar as are the spermathecae, cercI and anal lobes. The cercI both have a shallow dorsoapIcal depressIon and possess an apIcal clump of stIff haIrs, however, not as well expressed as that In S. littopyga   that lacks the depressIon (cf. FIgs. 15 View FIGURES 12 – 15 , 29 View FIGURES 27 – 30 , 41 View FIGURES 36 – 41 ).