Simulium (Inseliellum) littosodalis Craig & Evenhuis, 2017

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

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

FIgs. 30–41 .

Description. Adult female (based on 7 specImens). Body ( FIgs. 30 ): overall dark blackIsh brown, abdomen slIghtly lIghter ventrally; total length 1.5–1.9 mm. Head ( FIg. 31 ): 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 ): 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 ) 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 ) 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 ): 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 ): 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 ) 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 ): 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 ), 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 ) stem markedly evenly narrowed, not expanded apIcally, lateral arms narrow, strengthened posteromedIally, lateral plates small, elongated posterolaterally, apodemes sharply developed; spermatheca ovoId ( FIg. 40 ), 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 ).

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 )

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 , 31 ). The mandIbles of both specIes are parallel sIded (cf. FIgs. 20 , 33 ), not slIghtly flared as In S. littopyga . Simulium littosodalis has low numbers of teeth on the lacInIa ( FIg. 33 ) 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 , 36 ), 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 , 37 ). 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 , 39 ); the hypogynIal valves (cf. FIgs. 26 , 38 ) 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 , 29 , 41 ).

Figures

FIGURE 42. Type locality of Simulium littosodalis. Tahiti Nui, North Road, PK 42.7. 17 July 2006. Image N. Evenhuis.

FIGURES 27 – 30. Simulium (I.) littosocius n. sp. FIGURE 30. Simulium (I) littosodalis n. sp. (27). Genital fork. Scale bar = 0.05 mm. (28). Spermatheca. Scale bar = 0.05 mm. (29). Cercus & anal lobe. Scale bar = 0.05 mm. (30). Holotype. In ETOH. Scale bar = 0.5 mm.

FIGURES 31 – 35. Simulium (I.) littosodalis n. sp. (31). Frontal view of head. Scale bar = 0.2 mm. (32). Antenna. Scale bar = 0.1 mm. (33). Maxillary palp, lacinia, mandible Scale bar = 0.1 mm. Insert: mandible & lacinia tips. Scale bar 0.02 mm. (34). Hind basitarsus, calcipala, pedisulcus. Scale bar = 0.05 mm. (35). wing. Scale bar = 0.5 mm.

FIGURES 36 – 41. Simulium (I.) littosodalis n. sp. (36). Claw & basal tooth. Scale bar = 0.02 mm. (37). Abdominal tergites. Scale bar = 0.5 mm. (38). Hypogynial valves. Scale bar = 0.05 mm. (39). Genital fork. Scale bar = 0.05 mm. (40). Spermatheca. (Damaged). Scale bar = 0.05 mm. (41). Cercus & anal lobe. (Damaged and partially reconstructed). Scale bar = 0.05 mm.

FIGURES 16 – 21. Simulium (I.) littosocius n. sp. (16). Holotype, female Simulium (I) littosocius. In ETOH. Scale bar = 1.0 mm. (17). Frontal view of head. Scale bar = 0.2 mm. (18). Antenna. Scale bar = 0.1 mm. (19). Maxillary palp, lacinia, mandible. Scale bar = 0.1 mm. (20). Mandible apex. Scale bar = 0.02 mm. (21). Cibarium. Scale bar = 0.1 mm.

FIGURES 22 – 26. Simulium (I.) littosocius n. sp. (22). wing. Scale bar = 0.5 mm. (23). Hind basitarsus, calcipala, pedisulcus. Scale bar = 0.05 mm. (24). Claw & basal tooth. Scale = 0.02 mm. (25). Abdominal tergites (holotype). Scale bar = 0.5 mm. (26). Hypogynial valves. Scale bar = 0.1 mm.

FIGURES 12 – 15. Simulium (I.) littopyga n. sp. (12). Hypogynial valves. Scale bar = 0.1 mm. (13). Spermatheca. Scale bar = 0.02 mm. (14). Genital fork. Scale bar = 0.05 mm. (15). Cercus & anal lobe. Scale bar = 0.05 mm.