Dicrepidius ramicornis

Casari, Sônia A. & Biffi, Gabriel, 2012, Immatures of Dicrepidius Eschscholtz, 1829 and Dipropus Germar, 1839 (Elateridae, Elaterinae, Ampedini: Dicrepidiina), Zootaxa 3587, pp. 65-77 : 66-67

Dicrepidius ramicornis (Palisot de Beauvois)

( Figs. 1 –15, 38, 40)

Larva description. Length: 21–31mm, width: 2–3mm. Elongate, subcylindrical, heavily sclerotized ( Fig. 38 ). General coloration from reddish-brown to ferrugineous; head from dark-brown to black; thorax dark-brown dorsally, paler basad; meso- and metathoraces and abdominal segments I–IX with one dorsolateral anterior elongate striate darker area each side (muscular impressions), oblique in relation to lateral margins; abdominal striate impressions almost reaching middle of tergite; striae parallel, slightly curved; circular or semi-circular muscular impressions forming irregular band near anterior margin ( Fig. 38 ). Ventral surface slightly sclerotized; band of circular or semicircular muscular impressions of abdominal segments II–IX increasing in density to apex direction. Integument dense and coarsely punctate. Pubescence yellowish, long and sparse.

Head (Figs. 14, 15) flattened with punctation coarse, umbilicate and moderately dense, intermingled with simple and fine. Frontal arms lyriform, convergent at base; in one specimen with black head, frontal arms indistinct. Nasale prominent with one trilobed tooth; lobes rounded; paranasal lobes well developed each with one row with four setae dorsally (one represented by puncture) and a fringe of stout setae ventrally; one long seta near each frontal lobe. Frons ( Figs. 8 , 14, 15) 1.10 time longer than wide; anterior half gradually narrowed to middle direction, making lateral margins inclined; basal half narrow, widened near middle, with rounded apex; a raised area near middle forming a tubercle-like prominence; punctation of basal two thirds umbilicate, coarse and moderately dense, intermingled with simple, dense punctures; punctation of frontal lobes and area near paranasal lobes simple, moderately fine and irregularly dispersed. One lateral translucent stemma below each antenna. Each epicranial half with three pairs of long setae: one pair dorsal near middle, one pair lateroanterior and one lateroposterior; dorsally with a longitudinal row with three tiny setae near base; ventrally with one longitudinal row of moderately short setae parallel ventral epicranial ridge. Epipharynx ( Fig. 10 ) densely setous, with stout setae; one transverse row with small irregular rounded lobes at nasalar area; one transverse curved sclerotized plate at base. Mandibles ( Figs. 5–7 ) symmetrical, wider at base with apex sharpened and curved; one well developed retinaculum; lateral margin strongly grooved on basal third to accommodate antenna; with one seta laterally near middle; penicillus elongate, formed by short moderately stout setae. Antenna ( Figs. 1–4 ) inserted laterally in wide groove at mandibles base, with antennifer membranous and three antennomeres: basal antennomere very long bearing nine dorsal and two lateroventral setae near apex (some represented by punctures) and seven ventral campaniform sensilla; median antennomere elongate, shorter than basal, bearing two setae dorsal and one seta and one campaniform sensillum ventral and one well developed membranous cupuliform sensorium at apex; distal antennomere narrow and elongate, slightly shorter than cupuliform sensorium, approximately 1/5 width of median antennomere width, inserted laterally at apex of median antennomere, adjacent to sensorium, bearing at apex, five moderately short stout setae. Maxilla ( Fig. 9 ): stipes elongate narrowed laterally basad, more strongly narrowed near middle; lateral margin sinuous; five latero-external setae on distal third, one longer; mala palpiform, twosegmented; basal segment with three campaniform sensilla ventral and one dorsal; distal segment narrower and shorter than basal, almost straight, bearing five long and stout setae at apex (two stouter dorsally) and four campaniform sensilla ventrally near base; cardines elongate; each cardo with an internal wide and one lateral subtriangular elongate sclerite. Palpiger membranous, microsetous; triangular sclerotized internal area bearing one seta. Maxillary palpi with four palpomeres: first slightly wider than long, bearing ventrally two setae and ten campaniform sensilla; second elongate bearing ventrally one seta externally near apex and one campaniform sensillum and dorsally one campaniform sensillum near base; third slightly elongate, shorter than second, bearing ventrally one seta each side with one campaniform sensillum at middle and dorsally, three setae; distal elongate, narrower, bearing dorsally one wide and one thin seta and microsensilla at apex. Labium ( Fig. 9 ) narrow and elongate; postmentum connate with stipites, elongate, slightly narrowed near middle, bearing one pair of long setae near distal third and one pair near base; prementum wider than long, narrowed basad, not punctured, bearing two long setae and five campaniform sensilla medio-anteriorly. Labial palpi with two palpomeres: basal elongate, narrowed at base, bearing ventrally, four moderately long setae and one campaniform sensillum and dorsally, one campaniform sensillum; distal elongate, narrower, bearing one wide seta dorsally and several microsensilla at apex. Hypopharynx ( Fig. 11 ) densely setous with one triangular esclerite near base of each palpus and base of mala and one transverse basal sclerite each side; ramified setae near triangular sclerite forming a tuft.

Prothorax longer than meso- or metathorax; dorsally, punctation denser on anterior third; each side with three lateroanterior setae and two laterobasal; each side of prosternum with one long anterior seta. Meso- and metanota similar, densely punctured laterobasally; each side with one lateroanterior (at base of muscular impression) and two laterobasal setae. Legs (Figs. 13, 38) inserted at midline of thorax; increasing in size from anterior to posterior; with fine and long and short and wide setae; coxa elongate, wide and robust, trochanter triangular, femur and tibia elongate, femur wider than tibia; pretarsus elongate, claw-like with two setae.

Abdominal segments I–IX with one lateroanterior elongate striate area each side (muscular impressions) oblique in relation to lateral margin, almost reaching middle of tergite. Segments I–VIII transverse, with impunctate transverse basal narrow band; punctation denser on basal 2/3; anteriorly with a band of circular or semicircular muscular impressions; one biforous spiracle lateroexternally each striate muscular impression; each side with one longitudinal lateral carina, starting laterally at striate area and not reaching posterior margin; each side with one lateroanterior seta (between spiracle and striate muscular impression) and two near base. Ventrally, segments II–VIII with anterior irregular band of circular or semicircular impressions; each side of segments I–VIII with one lateroanterior and one lateroposterior setae. Segment IX (Fig. 12) elongate, rounded laterally, with constricted and sharply pointed apex; densely punctured; punctation coarse interspersed with rounded tubercles especially dorsally at distal half, giving a rugose appearance; tubercles larger than punctures; tubercles denser near apex; each side with two setae near apex and three near lateral margins. Segment X ventral, tubular; anal opening elliptical.

Pupa. Identical that of Dipropus brasilianus .

Material examined. BRAZIL. Mato Grosso: Pantanal (Taiamã), 08.VIII. 1980, L. R. Fontes & C. R. F. Brandão cols, 3 larvae reared to adult ( MZSP 3341, 3342, 3343), 1 larva dead ( MZSP 4322), 1 larva fixed with exuviae ( MZSP 4319), 5 exuviae ( MZSP 4320). São Paulo: Ribeirão Preto (EERP-MST), 22.V.2009, G. Biffi & E. A. Nascimento cols, 1 larva fixed and 1 larva reared to adult ( MZSP 10242).

Figures

FIGURES 1 – 11. Dicrepidius ramicornis, larva: 1, 2, antenna (dorsal, ventral); 3, apex of antenna (dorsal); 4, antennomere distal; 5 – 7, mandible (ventral, external, dorsal); 8, frons; 9, maxillolabial complex; 10, epipharynx; 11, hypopharynx. Bars = 0.5 mm except figs. 1 – 4 = 0.1 mm; fig. 10 = 0.2 mm.

FIGURES 38, 39. Larva, habitus (lateral): 38, Dicrepidius ramicornis; 39, Dipropus brasilianus. Bars: fig. 38 = 2 mm; fig. 39 = 1 mm.