Stilobezzia fiebrigi Kieffer

Cazorla, Carla G., Diaz, Florentina, Spinelli, Marino Gustavo R. & Ronderos, María M., 2013, New contributions to the knowledge of the immatures of Stilobezzia punctulata Lane and Stilobezzia fiebrigi Kieffer (Diptera: Ceratopogonidae), Zootaxa 3745 (1), pp. 93-99 : 94-96

Stilobezzia fiebrigi Kieffer

( Figs. 1–6 , 13–15 )

Stilobezzia fiebrigi Kieffer, 1917: 309 (fema1e; Paraguay); Lane, 1947: 199 (male; Brazil).

Stilobezzia (Stilobezzia) fiebrigi: Forattini & Rabello, 1956: 45 (larva, pupa, Brasil); Wirth 1974: 45 (catalogue of Neotropical species); Lane & Forattini, 1961: 85 (in key); Spinelli, 1983: 410 ( Argentina record; Buenos Aires province); Spinelli & Wirth, 1993: 51 (in list; Argentina); Borkent & Wirth, 1997: 111 (catalogue of World species); Borkent & Spinelli, 2000: 54 (catalogue of Neotropical species); Cazorla et al., 2006: 111 (adult and pupa redescription, Argentina); Borkent & Spinelli, 2007: 87 (catalogue of Neotropical species); Borkent, 2012 (catalogue of World species).

Description of fourth instar larva ( Figs. 1–6 , 13–15 ). Head capsule ( Figs. 1–2 ) pale brown, conical, small, tapering to rounded apex; ventral and ventrolateral chaetotaxy as in Figs. 1–3 , dorsal chaetotaxy not in position to be photographed; HL 0.182 mm (SEM), 0.20–0.23 (0.22, n=3) mm (BCM); HW 0.137 mm (SEM), 0.18–0.23 (0.20, n=3) (BCM); HR 1.328 (SEM), 1.00–1.13 (1.08, n=3) (BCM); SGW 0.092 mm (SEM), 0.12–0.14 (0.136, n=3) mm (BCM); SGR 1.49 (SEM), 1.40–1.60 (1.50, n=3) (BCM). Labrum ( Figs. 1, 3–4 ) wider than long; palatum ( Figs. 2–4 ) with two pairs of sensilla trichoidea, anterior one thin, elongated, distal one absent ( Fig. 4 ); messors well developed, sclerotized, lateral to scopae ( Fig. 4 ); scopae thin, elongated; palatal bar not in position to be properly described ( Fig. 4 ). Mandible ( Figs. 1–5 , 15 ) bidentate, thin, curved distally, lightly sclerotized; apical tooth long, submedian tooth short; basal portion with long, thin seta and a pore; fossa mandibularis on ectal surface, MDL 0.05–0.06 (0.056, n=3) mm. Maxilla ( Figs. 3–5 ) sclerotized, galeolacinia ( Figs. 4–5 ) with lacineal sclerite with short thin seta, lacineal sclerite 2 with long, thin seta; maxillary palpus ( Figs. 3–5 ) cylindrical with 2– 3 papillae. Hypostoma ( Figs. 1–3 ) with smooth, triangular, mesal elevation flanked by serrate margins with 7 teeth. Epipharynx ( Fig. 13 ) massive with three combs; comb 4 massive, its anterior margin irregular with 10 stout, pointed teeth; other two combs superimposed, poorly developed; medial sclerite v-shaped; dorsal comb sclerite with posterior margin with numerous, thin teeth; lateral arms stout, sclerotized, handle-shaped, without curtain or fringe; LAW 0.076–0.088 (0.082, n=2) mm, DCW 0.030–0.040 (0.035, n=2) mm. Hypopharynx ( Fig. 14 ) elongated, thick; divergent arms connected posteriorly; U-shaped, sclerotized, internal sclerite; hypopharyngeal fringe hyaline. Thoracic pigmentation not visible. Caudal segment chaetotaxy as in Fig. 6 ; medium size, stout, setae “o”, seta “i”, thinner; CSL 0.200 mm (SEM); CSW 0, 0 98 mm (SEM).

Material examined: Argentina, Corrientes, arroyo Pay Ubre, 29º01´41.2´´S, 58º10´26.6´´W, 66 m, 18-III- 2010, G. Spinelli, 3 larval exuviae.

Material examined by SEM: same data, 2 larvae (instar IV).

Bionomics. The larvae of Stilobezzia fiebrigi were collected in a temporary muddy puddle located approximately 10 meters from the bottom of a shallow stream.

Live larvae exhibited the typical fast, undulating swimming motion of other members of the subfamily Ceratopogoninae . The adults emergence occurred after a week under laboratory rear conditions.

Taxonomic notes. The larvae of Stilobezzia fiebrigi is very similar to the one of its Neotropical congener S. coquilletti Kieffer. They were collected in similar environments and both species show features typical to carnivorous-predatory larvae, such as a mouthparts anteriorly directed, curved and sclerotized mandible with fossa mandibularis, epipharynx gently massive and the hypostomal mesal elevation flanked by serrate margins (Thomsen, 1937; Hribar, 1993; Ronderos et al. 2008a). However, S. coquilletti can be distinguished by the absence of scopae; the palatum with three pairs of sensilla styloconica (one large, two short) and one pair of sensilla trichoidea; the galeolacinia with a bundle of four setae and the dorsal comb sclerite with an irregular posterior margin bearing 9–10 lanceolate teeth. Both species also shared the presence of medium sized setae in the caudal segment, a characteristic typical of larvae breeding in shallow water and muddy bottoms.

Figures

FIGURES 1 – 6. Stilobezzia fiebrigi Lane, four instar larva. 1, head capsule ventrolateral view (chaetotaxy); 2, head capsule, ventral view (chaetotaxy); 3, head capsule, anteroventral view; 4, head capsule, frontal view; 5, head capsule, frontolateral view, detail of mouthparts; 6, caudal segment, posterior view. Scale: 0.05 mm.

FIGURES 13 – 18. 13 – 15, Stilobezzia fiebrigi. 13, epipharynx, dorsal view; 14, hypopharynx, ventral view; 15, mandible, lateral view; 16 – 18, Stilobezzia punctulata. 16, epipharynx, dorsal view; 17, hypopharynx, ventral view; 18, mandible, lateral view. Scale: 0.05 mm.